What are the limiting factors when trying to print flexible filaments with a Bowden extruder setup?

As a user of an UM3E, which uses Bowden tubes and has TPU as an available material, I can tell you that the kinking issues can be alleviated or downright avoided.

I've printed quite a few things with the Ultimaker-brand TPU 95, and never had problems with kinking in the tube.

Ultimaker uses 2.85 mm filament, with Bowden tubes adapted for those and a rear motor, i.e. the motor is on the back on the printer and not right on top of the print head.

I personally wouldn't consider Nylon as one of the really flexible material, but that's my opinion. Never had kinking in the Bowden tube with Nylon either in my UM3E.


Which is the difference between MK6 and MK8 and even MK10?

All credits for the following go to user "vermon" who posted in this thread.

The following is a heavily amended version from his longer answer there.

Makerbot did start its hotend series using MK as iteration designator (for Mark). The first commercially available version was the [Makerbot] MK4 on the Cupcake circa 2009. MK4 was hand built with nichrome wire heaters and prone to all kinds of failures. They only worked with ABS and 3 mm filament.

Following here, Makerbot was skipped as a manufacturer and that it is the hotend we talk about. The correct nomenclature would be Makerbot Hotend MK#

MK5 was a complete redesign and had huge nozzles and a thick PTFE liner. It used 2 large power resistors in parallel for heating and was also prone to failure.

MK6 was the first hotend sold as a kit that I know of (however Repraps had also started using them probably before).

Mk6+ was the first cartridge heater hotend sold in kit form. The MK5/MK6 heater block was stainless steel, where MK6+ upgrade kit was an aluminum block that was slightly smaller, a lot lighter, and had the now standard 1/4 inch heater cartridge.

MK7 was the first hotend you folks would think looks familiar. It was the first move to 1.75 mm filament dedicated extruders. While a MK6+kit had parts to adapt to 1.75 mm filament, it never worked well at all and was really a failure.

Again, this is all Thing-O-Matic and Cupcake era. Other than a few clones, there really was no third party market in the US at this time. You either had a MakerBot or some other Reprap based kit. Wanhao, FlashForge- they didn't even exist and if they did, weren't talked about like now.

MK8 was the all new dual extruder hotend setup on the MakerBot Replicator. The cooling bar was thicker than the MK7 but the same all metal thermal barrier and supposedly, the MK8 has slightly different nozzle geometry internally and externally.

MK9 was a MK8 hotend, cooling bar, thermal barrier, and nozzle, but the new feeder with spring lever we know on all current models. This is why it's confusing, MK9 was a feeder upgrade, not a hotend change.

MK10 was a complete change of the hotend. MK10 uses smooth OD thermal barriers with a larger 4 mm OD 2 mm ID PTFE liner. MK10 also uses M7 threads, vs the M6 of all previous models. This is because a 4 mm PTFE liner is barely enough metal to make the outer tube with M6 threads. MK10 is completely incompatible with all previous hotend parts. Every part is different. MK10 still uses MK9 feeder parts.

MK11 on the D6 is just an MK10 nozzle and thermal barrier, but a different heater block and the cooling bar is part of the D6 central cross. Again, the only real difference is MK11 is a different heater block, and that's to adapt a different and longer heater cartridge and slide in the thermocouple. MK11 still uses MK9 plastic feeder parts.

  I wanted to know to which group belongs my printer, as base is a Prusa clone with direct extrusion.

This question seem difficult to answer concretely, as the number in the series seem to be assigned based on a combination of heating block technology and format, the feeder geometry and the nozzle shape and thread that was adopted on the MakerBot printers.  Your actual combination of those three may not exist in the MakerBot universe.

I suggest you read the full, unabridged version of the post linked above though, as more details relevant to your inquiry may be disclosed there.


You cannot print edible models using a "standard" consumer 3D printer without first installing an "hot end" capable of depositing edible - normally thicker - substances as well as a suitable extruder mechanism.

However, there are not necessarily any technical limitations in the electronics, software, slicers etc. in a typical printer that wouldn't allow you to install such an upgrade. For instance, you could calibrate your extrusion rate and nozzle width to suit batter and similar.

Some commercial printers, such as the DeltaWASP allow for upgrades that print clay, which wouldn't be very different from printing liquid food.


Prusa i3 MK3S keeps clogging during print. Ugly streaks sometimes, and complete clog when printing with lower layer lines

My problem was 2 things. The heatbreak, which was switched out for the MK2 version(Explantation below). And the Teflon Tube that runs down the heatsink.

Heatbreak

Change the heat-break to a generic E3D one. You can order the heatbreak for the MK2 from prusa, or any generic heat break for the E3D hot-end assembly.

On the Prusa i3 MK3(s), this component has been given a 45° taper in the middle, between 2.2 and 2 mm. This is done to ease filament retraction for the MMU, and will be nothing but problematic if you are not using the multi-material upgrade. Especially with higher nozzle pressures(eq. with lower layer lines), the filament may be squeezed into this taper, clogging the hot-end.

You may not experience full clogs, but partial ones that will show themselves as streaks in certain layers on the print.

Heatsink Teflon Tube

There is a teflon tube that runs down the heatsink. It's crucial that this is mounted correctly and it is not entirely intuative how.

First, press the teflon tube into the heatsink all the way to the bottom. Then, try to pull it out slightly. You'll notice that the small plastic ring at the top of the heatsink will pull out slightly along with it. Now, hold this black plastic part at it's current position with your fingernail, and push the teflon tube in the extra amount. When done, there should be no play in the tube.


Do not consolidate ground wires, use as many as the positive ones. In fact, use one wire of each twist for ground and one for the related positive, so that they balance each other.

Mixing voltages is fine, the CAT 6 cable will hold 24 V fine.

Concerning the number of wires, you should check the allowed current per wire and calculate the required number of wires.

Each pair can carry 0.36 A. 50 W is 2 A, you need 6 pairs for the heater.

You get two spare pairs, which can carry in total 0.7 A at the voltage you prefer. You could use two for the thermocouple and two for the fan, or two different fans.


How would you clean/prepare a flexible/magnetic mat (e.g. Ender 5) as compared to a glass bed?

I have the WhamBam system which uses a PEX layer over flex steel (which sticks to a magnetic sheet on the printer bed). To clean old material off, I use a "brass sponge" intended for cleaning soldering iron tips to remove the old plastic, then give it a wipe with a paper towel with some isopropyl alchohol (I have 99.99 anhydrous on hand as I use that for cleaning printed circuit boards as well).

The brass sponge is fairly soft, does a good job of grabbing the old plastic without tearing up the PEX layer.


Gap between infill and walls for one filament only

I have observed similar issues between walls, not necessarily between the infill and the walls.

It is most likely that the viscosity of this filament is way different (less fluid) than the other filaments you print. Not only mechanical issues (to be precise: inaccurate positioning e.g. caused by loose belts) could play a part in this, but also printing speed. A more viscous filament needs more pressure and time to get the filament through the nozzle. This is exactly what happened in my case, because of different wall speed line settings (inner and outer), the filament did not flow fast enough leading to under extrusion. In your case you probably also have a higher infill than wall speed, so lowering your infill speed may mitigate your problem. Also, most slicers have an option to define the overlap between the infill and the perimeters/walls, you could also increase that for this filament.


You need to level the bed properly by setting the correct distance between the nozzle and the bed. Ideally, you need to be able to drag a piece of plain A4 paper between the nozzle and the bed when the nozzle is at Z = 0 giving you a little drag (you feel that by a stuttering movement). From your pictures you can clearly see that the nozzle is way too far from the bed when depositing the first layer (as seen from the video you posted in the comments) as the hot filament drops/falls down to the hot plate. Once it is too far from the plate, each consecutive layer is too far from the previous layer.

From the images you posted, it is clearly visible that you have a mechanical/calibration issue. Your belts are probably not tight enough too, but it is difficult to say at the moment as the products are way off from what they should look like.

Note that the printer configuration could be incorrect (although very unlikely as it is out of the box). E.g. the stepper motor needs to make a certain amount of steps to advance the carriage in Z direction. If the mechanical layout requires 400 steps per mm (which is typical for TR8x8 (p2) lead screws on 1.8°(200 steps per revolution) stepper motors and 1/16 microstepping) but is configured as 800, your layer height advances twice as much although the Z=0 level would be okay! I now read (from the updated question) that the value for the steps/mm for the Z axis is 2560, this implies that you are using M8 lead screws with a pitch of 1.25 mm on a 1/16 microstepping board and 200 steps per revolution steppers.

From the specifications of your printer follows that the Geeetech Prusa i3 Pro B uses:

Stepper Motors: 1.8° step angle with 1/16 micro-stepping

This image show the configuration of the axes:

So 2560 is correct!

Conclusion:

Your initial leveling and height setting is incorrect, when you printer is at Z=0, it actually is positioned higher. Hence your first layer has very bad adhesion and is not properly flattened and each consecutive layer shows the same problems of falling hot filament. When the speed increases on the next layers the hot filament deposition cannot follow the nozzle, hence the "spaghetti" looks.


Prusa i3 Mk3 - Top layer wrinkles (not on buildplate)

Waves in printed surfaces with FFF are observed at either the bottom layer (common) or the top layer (less common).
Waves in bottom layer
Rippling/wave generation/wrinkling is a common problem for first layer to occur and has a direct relation to the print nozzle to bed distance; a too short of a distance or over-extrusion can lead to this effect. However, this effect is less commonly observed in top layer finishes.  Bottom layer waves are described in more detail in this answer.
Waves in top layer
I have seen this defect before. It is caused by a combination of incorrect hotend temperature and print cooling fan settings. Please reduce the hotend temperature and reduce the fan cooling. The image below clearly shows the differences of such measures.


Looks like an over/under extrusion. This can be fixed by:

decreasing/increasing your extrusion multiplier (flow)

lowering your print temperature

checking the diameter of your filament. Do you use the correct diameter?


The free slicers are catching up with Simplify3D, and are even overtaking it in some areas, so purchasing it may not make much sense to hobbyists. However, for professional print shops, where printers may cost twenty times as much (or even more), 150 dollars is nothing (especially since it is 150 dollars per PC, not 150 dollars per printer).


Using stepper motors with integrated controllers

Many of the motors that look like stepper motors in laser printers are actually three-phase brush-less DC motors.  These look like stepper motors, but are intended to be used differently, controlled differently, and serve a different function.  Like stepper motors, they have a permanent magnet rotor surrounded by coils of wire.

They typically are used in applications that require a definite rotation speed, rather than a definite position -- velocity rather than location. They create feedback to their controlling board via an encoder.

Differences include having a smaller number of poles, and possibly having three coils rather than two.  I suspect that the magnetic field profiles of the poles may also be different, since the primary design purpose is not to sharply define the restoring torque curve for a small deviation of the rotor from a rotational position.

If these are the type of motors you have in hand, you won't find them very useful for a 3D printer motion control system.  They are great for any form of continuous movement where position isn't critical -- maybe wheel motors for robots or for peristaltic pumps on your automated drink mixer.

You may ask on what experience I speak.  I have done tear-down analysis of several laser printers by different manufacturers.


How do I add an emergency stop button over Micro USB?

The most effective way to effectuate an emergency stop is to pull the plug or turn the printer off. An alternative is a software stop using a print server program like e.g. OctoPrint.
Indeed M112 is capable of stopping the printer:

M112 is the fastest way to shut down the machine using a host, but it may need to wait for a space to open up in the command queue. Enable EMERGENCY_PARSER for an instantaneous M112 command.

In order to use emergency stop functionality, you need a firmware capable of doing an emergency stop by having this enabled in the Configuration_adv.h printer configuration file, otherwise it will have to await the queue to be emptied first. I doubt if this is standard enabled in your default firmware (the Marlin default is disabled).
From Marlin's Configuration_adv.h:
/**
 * Emergency Command Parser
 *
 * Add a low-level parser to intercept certain commands as they
 * enter the serial receive buffer, so they cannot be blocked.
 * Currently handles M108, M112, M410, M876
 * NOTE: Not yet implemented for all platforms.
 */
//#define EMERGENCY_PARSER

Please note that this might not be implemented; it has not been implemented for all platforms.
An earlier question "Can G-code scripts be run automatically on inserting an SD card when using Marlin Firmware?" has an answer that hints to changing the sources on SD card insertion. In your case the USB needs to be monitored, and it a signal is detected the printer stopped.
So, since:

I use default firmware and don’t plan to change it

without modification of your firmware it is not possible to do what you want. But, there are perfectly viable options mentioned and available to do what you want (executing an emergency stop). Alternatively you could even use a (n Arduino powered) relay to cut the power based on the signal you want to send.


Cura printer settings for Alladinbox SkyCube 3D

Okay, after some research and experimentation, I've come up with some settings that seem to work.

Firstly, some specs about the Alladinbox SkyCube 3D:

Firmware: Marlin
Nozzle diameter: 0.4 mm
Nozzle speed: 20 to 70 mm/s
Layer thickness: 0.1 to 0.4 mm
Printing area: 110 x 110 x 125 mm (WLH)

Note: There is NO cooling fan present and the base is NOT heated.

Now for the actual printing settings...

I'm using the PLA supplied with the printer so far, and it works well at a nozzle temperature of 210C.

I'm printing at 0.2 mm per layer, which seems to afford to a good level of detail. I've printed a scanned Greco-Roman basin, and the details are very nice indeed.

So far I'm using a 20% line filling, and this seems to give the structure a good solidity and strength. I'm also operating the nozzle at its maximum speed of 70 mm/s and it seems to work just fine.

Obviously, I'm still experiments, and different materials may require different settings, but overall I'm very happy. I hope this post helps someone.


This MKS-GEN-L board is in essence a plain RAMPS board, and as such it uses the same pinout apart from some specific pins. Do note the include of the RAMPS pinout in the MKS-GEN-L at the end of the file.

From your comment you have changed the pins 14 and 15, in doing so, you need to plug the Y-min endstop in the Y-max socket after uploading the modified firmware. With the unmodified firmware (no pin switch), if the Y-endstop works in the Y-max socket, this means that you have a hardware issue. The pin labeled 14 is connected to the Y-max instead of the Y-min. If you did the pinout switch and left the endstop in the Y-min socket, then you can conclude that the 15 pin is not connected to the Y-min socket. Basically you don't have a 15 pin that is exposed. Could be that there is an issue on the board with the traces or the soldering.


Hooking up an optocoupler in a 24V Machine, is a 2 kOhm resistor sufficient?

TL;DR
Yes, a 2 kΩ resistor is sufficient to limit the current to about 12 mA through the optocoupler. With a maximum current specification of 60 mA you require at least 400 Ω; any resistor in between the values should be suitable for this optocoupler component when used at 24 V. More information is found below.

Having a glass bed and using an inductive probe may not work optimally. In such cases a 3D touch sensor is a very good alternative. For inductive sensors, remember that these sensors optimally detect steel, aluminium is harder to detect (about 60 % less than iron; a glass sheet in between the bed and the sensor requires you to acquire a sensor with a large detection range, e.g. 8 mm or more. To optimize the detection distance such sensors need to be powered to the maximum voltage they can handle (usually 36 V) or the highest voltage you have available (e.g. power supply 12 or 24 V). To protect the board, that is only allowed to receive up to 5 V, an optocoupler is an excellent way to guarantee the separation of voltage levels.
Considering your questions, it is fair to assume you are not an experienced electronics tinkerer, purchasing an optocoupler module is the best alternative, you just screw the wires into the respective input screw terminals as shown in this answer.
As the optocoupler separates two circuits, you can safely use 24 V on the one side and the 5 V on the other side, you do not need an additional resistor when you use a module board. If you plan to buy separate components to build your own circuit, you need to look at the maximum current that the optocoupler can handle on the input side (that will be 24 V). From the documentation from the optocoupler one reads that it is limited to 60 mA. A maximum current would therefore require a resistor of:
$$ R=\frac{U}{I}=\frac{24}{60\times10^{-3}}=400\ \Omega $$
My 12 V optocoupler module uses a 1 kΩ resistor implying a 12 mA current. In your case allowing 12 mA of current yields a 2 kΩ resistor.


My 3D printing part starts to bending after about 1 cm height and blue tape separates from bed

Multiple problems here. Let's try to isolate them.

Blue tape. Good for PLA, not suitable for ABS. ABS works fine with kapton tape, glue stick, hair spray, ABS juice over glass, aluminum or PCB epoxy composite board.
Always use at least brim feature to ensure good adhesion along the edges (your last photos have none). For parts with small hotbed contact area use raft.
Hotbed temperature should be 100°C+, because at 80°C adhesion is weaker. If you can't raise hotbed temperature to 100°C, think about thermal insulation.
Layers of plastic don't stick to each other. Either plastic comes from extruder being already cold (check that there are no draughts of cold air nearby), or you're printing too fast (50 mm/s should generally work, if not try 30 mm/s).
No infill between walls. Either it is set to 0 or optimized out by some option.
Round walls aren't round. Either printing speed problem, or your belts are loose.
Underextrusion. Bottom of your first print looks like mesh rather than solid surface. Check that plastic flow is around 100%.

Also check that your thermoresistor measures the actual temperature of the extruder (i.e. is in direct contact with it). Otherwise you will get overheated plastic extrusion, which looks like your first photos.

Also, print a 1 cm cube first. Don't do anything complex, just cube.


Clicking noise from the extruder and no filament coming out

There are a number of points missing, but I can offer a few suggestions. The re-leveling of the bed could have resulted in the bed now being in a position to block the nozzle. I have done exactly that in the past. A clean glass bed makes for a perfect clog.
The marks on the filament fit the description of a hobbed gear (extruder drive bolt) chewing into the filament, which would move only slightly from being blocked at the nozzle.
Additionally, filament temperature may be a factor, although it's difficult to determine with the information provided.
For a test, consider to use the controls available to you to raise the nozzle/lower the bed. Bring the nozzle up to your normal filament temperature. Execute an extrusion of sufficient length to ensure that the filament will reach and exit the nozzle.
If this does not provide extrusion, raise the temperature five degrees C and make another attempt. It may be necessary to raise the temperature in steps more than one time.
Use undamaged filament in these tests to ensure that the damage does not factor into the problem.


The price dependss roughly on material, machine hours, operator labour, profit and administrative overhead.
Some companies deduce the operator labour, machine hours and overhead to roughly 10 times the material cost. I think that is kind of fair. In your case I assume that you use PLA, the perabola is hollow (just a flat surface) and the company needs to construct the 3D model the parabola to a specific tolerance.
this model in PLA should not cost more than \$5 in filament, so about $ 50 should be an okay price for your parabola. The total price of \$147 leaves about \$97 for modeling the parabola. I think that's fair, given that a non-mathician has to find a way to construct a model and test the results.
If, for example, you want a metal print and you provide the 3D model I find the price of \$147 to be very normal. These metal printers are very expensive, labour intensive and eat up energy.
You can get instant quotes at the following sites: https://xometry.eu/, https://formalize-am.com/
All above is just my best guess, given the data you provided. Expect a better answer when you provide more data.


I think the command you're looking for is "Thicken". Recent versions of Fusion360 have moved this around, but now it should appear under the Create Panel when you're in the the Model mode (see the image below for details). A detailed description and short screencast on the Autodesk website here.


How to prevent stringing with 0.25 mm nozzle?

First, you should change the nozzle diameter setting, not just the line width setting, in Cura. Both are involved in determining extrusion. Line width can be less than or greater than nozzle size, but setting it much larger or smaller is not going to work well.

I suspect your main problem, though, is print speed. The area of the 0.25 mm nozzle orifice is only 39% of the area of an 0.4 mm nozzle orifice, bounding the material extrusion rate at best at 39% of what you could get with the larger nozzle (in practice it will be even lower due to complex fluid dynamics, probably much lower), but at the same linear print speed with narrower lines, you'll be extruding (or trying to extrude) 62.5% as much material per unit time. Now, if that much material can't actually make it out of the nozzle, pressure builds up between the extruder gear and the nozzle, and stringing is the result.

So, try lowering the print speed. A lot at first. If that solves the problem, gradually increase it until you find the limit. Increasing retraction and temperature may help you push it a little further. See my question and self-answer on stringing with flexible filaments, which might give you some ideas on other things to try:

Avoiding stringing with flexible filament


Can mold release agent be used in 3D printing?

It seems I misread your question.

3D Printed Mold

You were asking about (or the question now states) use of a mold release compound to prevent a molded part from sticking to a 3d print mold.

Yes.  It is always beneficial for the molded part to not stick to the mold.  Easy separation and part removal is important for the life of the mold and for the surface finish of the part.

There are two molding situations that seem important.

Flexible Mold or Object

In the first, either the part of the mold is elastic, so the actual sliding of one surface on the other isn't important.  Here, a mold release agent would help by preventing the cast object from binding to the mold material.

Stiff Mold and Object

The second case is where both the mold and the object are stiff, and the object must slide out of the mold.  Here the layer lines should be considered, since there may, locally, be reverse draft angles where the larger part can not slip past an obstructing filament line.  Using a process that doesn't leave filament lines, or using the thinnest possible filament layers, or smoothing the mold internal surfaces, or possibly filling the spaces between the ridges with another material may eliminate the problem.  A "mold release agent" would still be used to reduce the attachment of the object to the mold, although one may be able to use ample release agent both to fill the groves in the mold and prevent adhesion.


How can I create PNG image files from STL files?

If you have OpenSCAD installed, this shell script will generate 100x100 pixel PNG images for each STL file in your current directory.

for i in *.stl; do
  T=__tmp__$i
  b=`basename $i`
  echo import\(\"$i\"\)\; >$T
  /Applications/OpenSCAD.app/Contents/MacOS/OpenSCAD -o $b.png --imgsize=100,100 $T
  rm $T
done

Credit to 0scar for pointing out STL files can be imported into OpenSCAD.

Update: This code does the same, and generates an html file with annotated images of the files rendered.  When I printed a batch of spare parts for my 3D printer I made a hardcopy and stuck it in the box so I could identify the parts later.

n=-1
H=00-catalog.html
echo >$H '
'
echo >>$H '
'
for i in $*; do
  n=`expr $n + 1`
  if test $n = 4; then
      n=0
      echo >>$H '
'
      echo >>$H '
'
  fi
  echo $i
  T=__tmp__$i
  B=`basename $i .stl`
  echo import\(\"$i\"\)\; >$T
  /Applications/OpenSCAD.app//Contents/MacOS/OpenSCAD -o $B.png --imgsize=200,200 $T
  echo >>$H
  echo >>$H '    '$i'
	'

  rm $T
done
echo >>$H '
'
echo >>$H '
'


Marlin (on RUMBA board) switch extruder fan automatically

The RUMBA board has two fan outputs. The primary fan output is switched by pin 7, the secondary one by pin 8. The reason your fan is not working when you set #define EXTRUDER_0_AUTO_FAN_PIN 8 is because it's switching the secondary fan. If you switch the wires over to the secondary fan output it will work correctly.

If you do want to use the primary fan output then you can achieve this by setting #define EXTRUDER_0_AUTO_FAN_PIN 7 but you will need to search for the #define FAN 8 in the appropriate pins.h file and change 8 to something else (-1 or 7, for example).

I would recommend the first solution, because you should have a controllable print cooling fan, and an automatic extruder cooling fan.


Quality depends on 3 things:

Quality of pellets (purity, fillers, color)
Where/how they are stored before and during the extrusion (humidity, contaminants)
Have a filter in your extruder to get rid of random junk and air bubbles ending up in your filament (250 micron wire mesh filter)

There's no secret formula the filament producing companies have, they just have very efficient and very fast filament producing machines (of course very expensive, too). But when it comes to vanilla ABS or PLA, it's almost the same content.

Personal experience: no. If you get the same pellets, store it in the same place and run your extruder in the same place, it should behave the same.
I don't think there is some filament mixture you won't be able to find anywhere, but you might be able to make it yourself cheaper. Example: mixing strontium aluminate powder for glow in the dark filament (come in many colors, not just green).

I'd recommend this design: http://www.instructables.com/id/Build-your-own-3d-printing-filament-factory-Filame/
It produces filament pretty fast (one full 1kg spoon in 3-4 hours). Just make sure you have enough experience to not electrocute yourself while assembling this as the heaters use mains power.

I personally think the commercial "hobby" extruders are not worth the money. I also own the Filastruder and it's just no different and slower than the above, unless you care about a pretty plywood case for your extruder I see no advantage and since it uses off-the-shelf parts itself why bother buying a kit like that than sourcing the parts yourself?


Problems with ColorFabb XT: over extrusion

Level the bed and check your filament diameter.
Usually this occurs because the space between the nozzle and bed is greater than it should be for the material put out of the nozzle.
Such conditions can happen for a variety of reasons but usually it's an improper bed leveling.
Filament diameter vs what your slicer program thinks is the filament diameter is one of the easier ways to control material output after bed is level.  (Sometimes I tell my slicer that the material is smaller than it really is to get it to output more)
Sometimes your z axis moves too much or you are using a layer height that your z axis could not handle.  You may have to increase layer thickness.
Getting the temperatures into a point where it is not too hot and not too cold is also important.  If the material is too cold, it won't stick.  If too hot, it cools and shrinks by the time your new layer gets to it ( making it lower or warped out of place from where the new layer tries to stick )  Increasing bed temperatures is a good way to help counteract the shrinkage.


What are my options if I want to install a bed levelling sensor capable of operating at 100 °C?

Have you considered using or adapting Prusa’s P.I.N.D.A. V2 or SuperPINDA? Seems that within some bounds they’ve solved the temperature compensation issue.
The older P.I.N.D.A. V1 sensor seems to be temperature-sensitive. See more information in P.I.N.D.A./SuperPINDA Sensor testing article of Pruse Knowledge Base.


Creality CR-10 slightly jerks when moves from right to left

It looks like the nozzle is not perfectly perpendicular to the bed. It is also dragging which might indicate overextrusion or bad z stop calibration..


This looks as if there is a side-to-side force being generated as Z is changed.  Ideally, the X or Y position is determined by the smooth rods, which should bear any force, not the threaded rod.  The threaded rod should cause no motion except upward and downward.

If the rod is bent, but the rod is lightly constrained, then the top, being the free end, will draw a circle.  The bottom is constrained by the motor.  The middle is constrained by the nut, so the top would wander.  If the threaded rod is perfectly straight, and the stepper motor axis and the nut are perfectly aligned, the top would spin without movement.

If the rod is bent and the nut is very tight, there may be a twisting force exerted by the nut, which could cause movement.

Everything is a tradeoff between tightness and looseness, between precision components and the reality of alignment errors.

You asked if the shaft coupling is too tight.  Maybe.  Try removing everything except the motor, coupling, and the threaded rod.  Does the rod fall exactly where the nut would be?  If not, it isn't aligned correctly.  Incorrect alignment can be mitigated by a flexible coupling.  It looks like you are using a Lovejoy coupling with a plaster spider.  Depending on how tightly the spider fits, a Lovejoy coupling can be tight or loose.  I see a lot of machines with the one-piece coupling and a spiral-cut joining region.  THis might be a good alternative, but they tend to take up more space than a lovejoy coupling.

Because Z-axis motion is pretty slow, it is unlikely to be a z-axis vibration issue.  You may have changed the resonant frequencies enough to cause some other problem, but I don't think it is related to the problem in the photograph.


Can I increase retraction length on an E3D v6 beyond 2 mm if I have a really long Bowden tube?

Yes, you can increase retraction past E3D's max 2 mm recommendation to compensate for Bowden tube stretch and slop. The reason for the recommendation is that jams will occur with most all-metal hot ends if you pull molten filament up into the cold zone. Any molten filament that enters the cold zone rapidly cools and hardens and sticks to the walls, very often forming a jam.

So, the requirement is to keep your retraction distance at the extruder less than 2 mm. Additional retraction travel that is absorbed by the Bowden tube and not seen at the extruder is fine. I personally run 2.5 mm retraction on an E3Dv6 Bowden system without any issues.


How to smooth PLA Prints without using sandpaper, solvents or paint

Unfortunately, there is no way to smooth PLA without sandpaper, solvent or paint - but you can fix the finish after sanding.

If you heat the plastic after sanding to just the point the outer shell starts melting the horrible matte finish goes away and the original color of the plastic returns.

You have to heat the plastic and then remove the heat source just as it's start melting (right before the original color returns, so when you see it working it's too late) because otherwise the object will deform.

I use a heat gun set to 180C and work quickly in short bursts, an hair dryer is probably nowhere as hot, so it will take longer to heat the surface.

You have to do this after sanding, applying enough heat to smooth the layer lines will just cause the object to melt and deform.

Try on a few failed prints first, you will need to get the feel for when to stop heating and you will still probably ruin prints every once in a while.

Another option is to coat the object in an epoxy that will hide the layer lines the best known brand for this is XTC-3D.

If you do decide to paint, you get extra thick primer that's supposed to fill the gaps between the layer lines so you don't need to sand as much (sorry, can't remember the brand name)


Why is my print displacing along the y-axis by 2-3 cm?

This has happened to me in the past and here are a few things that I determined could have been the cause:

Limit Switch triggered. My coworker was able to repeat the issue by manually triggering a limit switch during the print. Somehow, this seemed to cause the relative axis to shift on his MakerBot Replicator 2.
Skipped steps. It's possible that, if stalled due to excessive load, the stepper motor could skip steps. I have a dual extruder, so if a part curls really bad then the second nozzle gets caught in the print. I'm not sure exactly how this works, but my coworker suggested this as an issue.
USB connection. I had sliced a model and tried printing over USB connection, however each time I attempted the print I encountered the "shift" at the same exact location. However, using the slice, I exported a G-Code file and printed from the machines SD card with no errors.
Slicing Engine bug. This is in correlation to the USB connection issue. I noticed that the issue occurred after updating my slicing engine. My solution in the long term was to re-install the previous version that was stable for me. I was using MakerWare 2.4.2 and reverted back to MakerWare 2.4.1.

If you're printing via USB connection, I'd suggest exporting to G-Code if you're able to print via SD Card until you can find a stable version of software for your machine. This has been the most repeatable solution for me in the past.


What is a good book to read about 3D printers?

You can learn a lot just by reading the forums.  I'll just list a few that are quite popular...

Reprap Forums - Has a ton of information on DIY printers including build logs and posts dealing with many issues.

Soliforum - Large user base with lots of information. Not sure what it's standing is now that Solidoodle is gone but I'm sure the forum will stick around.

SeeMeCNC - Support forum for SeeMeCNC, has a lot of information for Delta printers and also other printers.

There aren't many books that I know of...Make magazine has done a few issues on 3D printing that you could try to obtain.  I'm not sure what your idea of building a printer is, do you want to design your own or follow someone's instructions and put one together?  Designing one would require some basic hardware and engineering knowledge.

All that said, the best learning experience would be buying a kit and learning as you go.  You'll never read in a book what you will learn from having your own printer.


I think this depends on what you are trying to accomplish with the 3D printer.

I have seen people online build metal 3D printers from a robot arm and a welder this would probably be the simplest design and build but robot arms that can weld are expensive.

I have also seen that someone at MIT build a glass 3D printer by building a small kiln with a hole at the bottom and moving it around like a normal extrusion printer. This method might work for a metal printer as well if you could get the temperatures right. This might be cheap enough a hobbyist could do it as well because you just need the same parts as a normal FDM 3d printer just able to more more weight.
But with the same parts you could also do lost pla casting and that would be a simpler approach with a better end product.

But probably what you would be really interested in building would be a laser sintering 3D printer. Where a layer of powder is put down and then a laser melts part of the powered to join it to the model. For this the main thing you need would be the laser. I don't know a lot about how these printer work but the laser would need to be able to melt metal so I would think it would need to be very powerful and that would make it very expensive.


Makerbot Replicator (5th generation) poor print quality

Your printer is improperly leveled with respect to the distance of the nozzle to the bed. This, and a high raft to print part distance, causes consecutive layers to not adhere well.

PLA should not need that high temperatures to print nor does it need a raft. Rafts are interesting when printing filaments that have high shrinkage. Furthermore, a 90 mm/s infill speed is pretty high, and do not use the part cooling fan for the first few layers (if you cool too much it can curl up).

You need to re-level the bed and make sure that the nozzle to build plate distance is the thickness of a sheet of A4 paper when Z = 0.


Ender 3 V2 blank screen and LCD continuous beeping with clicks

Thanks to @Rykara, they led me to the answer. The whole problem was kinda a firmware issue but on the SD card side. The reason why it wasn't flashing was because I didn't flash the SD card to use the FAT32 format. Unfortunately I tried every other format option except that one before hand, mostly because I am mainly on a Mac. Now there is no more problems and I am back on track to printing. :)


Very old 3D Printer, which brand or type is this?

Here are some further details on:

The control board, and;
The stepper motors

Control board

The electronics board has this marking:

EJE Electronics Gubbels Engineering

The serial number is 0070-003

According to this site Xinchejian First Mendel V2 Reprap the board is:

  Gen6 Electronics, with AT Mega 644p processor (PCB EJE Electronics, Gubbels Engineering - mendel-parts.com)

It seems to be this board (the serial numbers match):

Information on this board can be found here: Generation 6 Electronics:

  Generation 6, or Gen6, can be described as a dedicated, Plug-&-Play, single board solution for FFF/FDM 3D Printers. It is designed to be professionally manufactured, with many small surface mount components, as opposed to Generation 7 which is designed to be printed on a Mendel(among other design goals).

  Another major difference with Gen6 electronics is that they use Texas Instruments DRV8811 chips to drive the stepper motors. This means they require firmware modifications from the normal Polulu-based electronics which use Allegro A4983 chips.

It goes on to say:

  Benefits of this Design

  These electronics are a single board solution, so you don't need all those cables and one thick sheet and 4 reprap parts less.
  However, the thick sheet does add a fair amount of rigidity. @$@#?? the bottom thick sheet (big one) doesnt add
  much rigidity, the front one is used for stiffness of the frame, not
  the bottom one.
  It has a standard USB connection (USB A>B cable needed)
  It uses micro-stepping (1/8) for quieter operation.
  It is cheaper than for example Makerbot's version of the RepRap Generation 3 electronics.
  It uses small standard Molex connectors for motors, heater, and optos.
  The pcb of the optos are integrated, so you only need the optos on cables with 5way Molex connectors

  Hardware Features

  on-board USB-RS232 convertor
  Integrated hardware for driving one extruder (stepper, heater and thermistor)
  RS485 bus connector with the possibility to link through the extruder step and dir signals
  Integrated hardware for driving H21LOB or TCST2103 slotted optosensors
  High input voltage range: 12-24Vdc
  Use of standard connectors with easy and clean installation
  Debug LEDs for power, communication and heater output
  Reset button

  Specifications

  Dimensions 110x60mm
  Mounting grid: 100x50mm (4x M3)
  Input voltage 12-24Vdc
  On-board controller: ATmega 644p (Atmel Corp.)
  RS485 connector: RJ45
  Heat output: MOSFET output, 4A
  Thermistors input: 100K thermistor

There is a lot more information on that page, including information about the power supply, USB, End stops, Heaters, Motors, Firmware, etc. I suggest that you read it fully, in order to understand the board's functionality.

Stepper Motors

The stepper's model number can be seen here:

The stepper's model number is SY42STH47-1683B,

which is a NEMA-17 High Torque Hybrid Stepper Motor, with these specifications:

Step angle: 1.8°
Number of phase: 2
Rated voltage: 2.8 V
Rated current: 1.68 A
Holding torque: 4.4 kg/cm

This would be, at least, part of the datasheet:

Here are a couple of links, should you need replacements (~€17):

NEMA-17 (SY42STH47-1684B Stepper Motor) - Polabs)
SY42STH47-1684B High Torque Hybrid Stepper Motors

This stepper motor is also listed on the RepRapWiki - NEMA 17 page:

Model           Holding Torque  Rated voltage       Shaft   Step angle  Motor length    Rated current   Inductance
SY42STH47-1684B   43.1 N·cm        2.8 V       Ø 5 mm double    1.8°        48 mm            n/a            n/a


I am not sure what the hardware config is for the Tevo Tarantula

Make sure your configuration.h file is setup for your hardware.
The extruder defines are describe in Conditional_LCD.h

It looks like the configuration.h file on GitHub is configured for a single extruder.

For example, if you have 2 hotends; but, "HOTENDS=2" is not set then the I/O will not be configured for the 2nd hotend.  I just looked at the code and if HOTENDS == 1 then the MOSFET_D_PIN will be used to control FAN1 (which sounds very similar to what you are describing that you are seeing).

  #if HOTENDS == 1
    #define FAN1_PIN     MOSFET_D_PIN
  #else
    #define HEATER_1_PIN MOSFET_D_PIN
  #endif


Do you need to manually level the bed with a BLTouch? Adhesion issues with Ender 5 and BLTouch 1.3

yes
Even with auto mesh bed leveling, you ought and should level the bed to a good degree to make the leveling not only more efficient: the mesh bed level is to work out small dimples and hills in the bed, bot to work with a crooked or heavily misaligned bed.


While most components (cooling body, heatblock, heater cartridges, thermistors) of knockoff e3d-v6 hotends can be similar enough to not notice in a large part, or at least functionally the same. Note that I don't say the parts are necessarily interchangeable - a lot what is sold under the name is not what it claims to be. The main distinguishing difference is the heatbreak: a proper e3d v6 hotend is hard to manufacture, so let's compare the designs of the real and the knockoffs.
Original
e3D v6 heatbreaks are necked considerably and have a socket with an airgap to the cooling body in top to take the lining and prevent heat flow to the PTFE pipe. This makes it an "all-metal" hotend, because the liner stops in the cold zone, where the cooling block is screwed on, and thus gets the least heat to the bowden, allowing to print hotter than with a lined hotend. The cooling block and the heather block threads are also not the same: M6 and M7. They are flat at the front to securely butt the nozzle thread against.
Their internal and external geometry looks like this:

Knockoffs
Knockoffs vary a lot how their heatbreak is constructed. Some are lined all the way through. Others are pass-through - and neither is an all-metal hotend. Some knockoffs are necked but use the same thread on both sides.
gallery of knockoffs

Conclusion
If you print a lot of high-temperature materials, the need for a proper all-metal hotend is there. Many knockoffs don't do this necking properly or invalidate its effect by lining the hotend all the way through.
Note that the machining quality can be quite different.
Due to sizing, not all knockoffs allow to mount a genuine heatbreak with knockoff cooler and heater block.


Can't connect Cura to my Anet A8 on OSX 10.11.6

There are a lot of problems with the CH340 chipset drivers to be found on 3D SE and various forums on the internet. To use this cheap CH340 chip that is used by a number of Arduino compatible (clone) boards to provide USB connectivity (a USB bus converter chip that converts USB bus signals to serial interface) you need to install a correct working driver.

For Mac OS X you can try to download a working version for the OS system you are using. You can try to use this driver installer or this driver installer. Both reported to work with Mac OS.

Edit: If you are using OSX El Capitan, please read this. To  get the CH340 drivers to work you need to use the tool csrutil.

  Reboot and press CMD+R immediately after hearing the startup sound to boot to Recovery Mode
  Open Terminal
  Execute the following command: csrutil enable --without kext
  Reboot

More information is found here!


How to sort G-code on SD card based on material (ABS|PLA|SBS)?

Good question as I also ran into some files not remembering for which purpose or which material I printed these. The online G-code visualizers do not display the temperature or the correct filament width, so basically that won't help you (unless you modify the open source programs...). Reading from firmware would not be possible without adding a new feature, as far as I know, this is not implemented in Marlin Firmware or in Prusa firmware (which is based on Marlin).

When using a printer server like OctoPrint, you can store your G-code files in a folder structure that you can define yourself; so basically create a directory structure based on the material type, brand, etc.

However, it is relatively easy to write a small program in Python to read a file and interpret the lines (even if you're not a programmer). There are lots of tutorials and examples to find to open files read the file e.g. line by line and detect strings to identify the settings for G-codes M104/M109 (hot end temperature) and M140/M190 (bed temperature). Usually you slice your models with a specific set of bed and hot end temperature (which you know), so basically you can find out which material was meant to be printed with the G-code file. You could even let the program sort the files for you by moving them into separate folders.

I'll add it to my list of things I'd like to do some rainy day! :)

Note that some printers use different, or even custom G-codes to control bed temperature; e.g. when reading Ultimaker 3 G-code files you cannot see the bed temperature!


How long are the carbon fibre rods for a Travelling Kossel?

Most information I was able to find was the arms are 80% the length of the horizontal structure.  I did find a copy of the original Google Sheets that everyone used a few years ago here.  The source of that link did mention that there may have been some issues with it but all of those links were dead ends.

Some things to note:

The height doesn't matter, it has no relationship with the arms other than you are losing approximately the arm length from the height when figuring print area as some arms will approach vertical when reaching the outsides of your print area.

The arm length isn't terribly important from what I could find.  Longer arms = less travel of the carriages and possibly lower resolution.  Shorter arms = more travel of the carriages and possibly lower print speed due to required movement.


What is acceptable voltage drop from PSU to controller?

Regardless of how the voltage is lowered, you aren't delivering the power to the heating elements that they are designed to deliver.  For a resistive heater, the power scales with the square of the voltage.

Delivering 11.4 V to the heaters will result in the power being $11.4^2/12.0^2 = 0.9025$ or 90 % of the intended power.

There are two things you could do to increase the power at the heaters.

Your voltage is starting out low, which you may be able to increase
at the power supply to 12.0 V.
The voltage drop in the 1-meter cables can be reduced by using
shorter cables or larger cross-sectional area conductors.  13 gauge
is not a very heavy wire for low-voltage high-current DC.  I would
suggest 10 gauge, and would prefer 8 gauge.

The logic in the controller board should be fine as you are now.  Controller boards include regulators that being the nominal 12 V down to the 5 V or 3.3 V required by the digital logic.  These will automatically adjust for changes in the 12 V supply.

To actually answer your question, the permitted voltage drop is application dependent.  As a rule, though, I would suggest that the voltage on the pins of the controller should be 12 ± 5 %, or from 12.6 V to 11.4 V.  The voltage you measured should be acceptable if it is the true minimum voltage.


How does the Filament production process work?

Some general comments about the process used (plastic extrusion):

The plastic extrusion process is not simple- many textbooks dense with equations have been written about it. The lowest cost industrial extrusion processes do not use pellets at all- because pellets have already gone through an extrusion process so they are more expensive than powder resin. There is typically a 'compounding' stage where colors etc. are added before extrusion.

Significant heat is generated by the screw (which often has a complex geometry) via shear action that is itself temperature and pressure sensitive, and the heat is added to by external heaters in various zones (or subtracted by water cooling and chillers in larger extruders). In some cases we were able to operate an extruder adiabatically- the heat created by the screw motor matched the heat loss as the product left the die and no heating or cooling was needed once the process was stabilized.

The end result is that you want to plasticize (melt) the plastic and achieve a certain pressure at the die. The plastic is deteriorating the higher the temperature and the longer the time so you want to limit the residence time at high temperature. There is some trial-and-error and a lot of previous experience in the setup person's task. Once the parameters are determined they are recorded and are used the next time that material is run.

The size of an extrusion is typically determined exactly by downstream equipment rather than controlling the conditions at the die. It is essentially stretched as it comes out of the die and the heat is removed in a cooling trough.

Here you can see a factory environment with a very typical extrusion setup, used in this case for 3D printing filament (but the setup would look almost the same if they were making slats for Venetian blinds). Notice that there are cooling fans as well as band heaters on the extruder barrel. They control the diameter by adjusting the take-off capstan RPM once the extruder is running well. This extruder looks like it has 4 heat/cool barrel zones and two (heat-only) nozzle zones (6 temperatures total).

https://www.youtube.com/watch?v=40HOAsUnSQ8

Extruders are categorized by the barrel bore diameter in inches or mm. A very small extruder might be 25mm. An extruder used for pipe production might be 6" (150mm) or more. Some machines use multiple screws.


Welcome to SE.3DP!

First off, F360 isn't the best with STL files. If you're having trouble with constraints and dimensions, I would suggest watching this Maker's Muse video first: How to use Constraints! CAD for Newbies with Fusion 360.

Second, Fusion360 is very tricky with importing STL's. My steps below should help.

In the lower right-hand corner, at the rightmost end of the timeline, you'll see a little gear. When you click on the gear, click the very top option: "Do not capture design history". This puts you into Direct Modelling mode.
In the top left-hand corner, where it says "Model", and select "Mesh" from the menu.
Along the toolbar, in the "Create" section, click "Insert mesh". When that's done, go back to the top left where it now says "Mesh" and use the menu to go back to "Model".
Now that you're back in "Model", go to the "Modify" menu. In there, find the "Mesh" section, and in that box, click "Mesh to BRep". That will convert your STL into a Fusion360 file that you can edit.

Now, if you want to use constraints, I would suggest sketching out your object entirely in Fusion, making constraints and dimensions along the way. I know it's annoying, but it'll be easier to modify it in Fusion.
Hope that helps!


Wanhao Duplicator i3 Mini - Not reaching temperature -> screen freezes

The solution was posted in a comment, as the asker hasn't posted an answer yet, it is answered in this community wiki answer:

  Ended up replacing the thermistor which solved the problem.


What is the maximum length of the TMC drivers signal wires?

10 cm would be fine. That's the short answer, the real answer is that it depends on the UART speed and the exact conditions that you will be extending them. If you expect noise feedback from the motor coils inducing voltages into the UART lines, then perhaps they should be shorter. Keep the high current wires and the signal (UART) in separate places if possible. Also if you can use a shielded cable (e.g. and old shielded USB cable) then you could get away with a meter thereabout.


Layer shifting on product printing after raft support structure

Layer shifting is a result of the use of open-loop control systems. This means that the printer just instructs the head to go to certain positions without checking that it actually did arrive at that position. If something happens along the path, like hitting some part of the print or the printer, the motors could loose steps or the belts may skip teeth without the printer knowing it, so it continues further without correcting this.

There are a couple of causes for the skipping to occur. Usually it is a mechanical issue, but it can also be related to an electrical problem or a print settings problem (if e.g. your print speed it too high, the steppers could miss steps).

Looking closely at the image, you will see that the infill of the first layer does not touch the outer lines. This could be a hint that your belts are not tight enough (mechanical issue). Too loose belts cause the stepper driving pulley to skip. Also check the pulley whether it is securely fastened so that the pulley is not slipping when subjected to an increased torque. The nozzle most probably hits the raft (ABS? as it curls up and detaches, you see some irregularities on the left of the bottom right product in your image). Do note that too tight belts are also not wanted as they stress the stepper by an increased torque load. If the issue is electronically related, you could thick of increasing the torque by increasing the current through the stepper (and driver). Too much current will overheat the stepper driver though, so make sure that these do not exceed their rated maximum and properly cool the stepper drivers.

To solve your issues it is recommended to first try printing at lower speeds (this can be skipped if you already have low print speeds), then check the mechanical system of the printer, and finally, if this does not fix the problem, you could look into the electronics.


Why laser is not used to melt/soften material in polyjet?

The question in the title references a specific printer technology, while the question in the body of the post is more generic and is the one being answered here.

There are 3D printers which use lasers to cure liquid resin in a manner similar to MSLA 3D printers. The vat of resin sits atop a transparent panel, under which a laser assembly resides. The computer directs the laser over the surface of the panel in a manner associated with each layer of the print. Once the layer is completed, the bed is lifted, peeling the print from the base of the vat and then lowered again.

There are some printers which apply the laser to the surface of the liquid but the results are the same. The resin is photosensitive and cures when the laser is applied.

Additionally, there are SLS 3D printers. Selective Laser Sintering uses a laser applied to the surface of a nylon powder (one example) which sinters the nylon causing it to bond to adjacent particles. When a layer is completed, the bed of powder is lowered and another layer of powder is applied. The laser again "draws" the layer in the powder and the process continues.

This method requires compensation for shrinking, as the nylon powder changes dimensions as it is melted. The bed is also pre-heated prior to printing in order to reduce the amount of energy required by the laser to sinter the design.


First 3D print made up of diagonal strands

Based on your comment to the comment of 0scar:

  When I go to Fillament, I get: E in mm3: On; Fil. Dia. 1.750

That's almost surely the problem. Unless the model was sliced for "E in mm3", this setting needs to be off. What it does is change how the printer interprets extruder moves in the G-code: rather than in linear mm of filament to move, as volumetric mm³ to extrude.

At 1.75 mm diameter, that's a factor of 2.4 mm³/mm, so you'll only be extruding 1/2.4 = ~41.5 % of the material needed. That extreme underextrusion will give exactly the effect you're seeing.


Is it advisable to use additional external fan(s) for printing PLA?

The printer already has a built in fan with a fan shroud that directs air to the hotend

Unless your printer is defective, it may look like so, but the airflow should really be directed towards the print, not the hot-end.  Cooling the hot-end will at best just waste energy, requiring extra heat to keep it hot, at worst affect your print quality negatively.

  is it beneficial to add an extra fan in order to get better results on overhangs?

The issue with external fans, not connected to the printer, is that you can't properly direct their ariflow, so:

you will direct some of it on the hot-end itself (see above on why that's not good)
you will potentially cool your print unevenly, which - depending from how much, how fast, and what type of filament you are using - may warp your prints

That said, depending from a number of factors, including your ability to position the fans appropriately, you may gain some benefit from them (I saw people doing this to help with PETG stringing), but I would recommend instead to upgrade the part fan of your printer (e.g.: larger diameter, higher RPM) and your duct (better focus on the extruded filament), as these upgrades will have no drawbacks and will perform consistently on each part of the print.

For most common printer, there are printable mods that allow to do both, often available off thingiverse or on dedicated user community forums.


E3D V6 nozzle vs MK8 nozzle, first layer adhesion

When filament curls up this generally means that there is some sort of obstruction or burned material in the nozzle causing uneven flow. You can use the Atomic Method from this answer.

Being a new nozzle, I would expect that this is not the case, so that it should just drop out of the nozzle and not curl up. It could be that the nozzle is not perfectly machined and a defect in the geometry is causing this. You could try to replace the nozzle with another nozzle. They are pretty cheap, you should buy a few extra.

As far as why the filament sticks easier to the E3D nozzle when it curls up, is that this nozzle has a (hexagonal) flange that sticks out, while the other nozzle does not have such a flange. If it curls up, it has a larger probability to hit the flange and stick to the outside of the nozzle than a nozzle that has no such flange.


I'm gonna go out on a limb here and say this is probably not a good idea in any capacity.

First off, if you take a look at this list of cooking oils, you'll notice that pretty much all of them have smoke points below the printing temperature of ABS, with a handful of exceptions that have smoke points just barely above that temperature. All that means is that the hydrocarbon chains are going to break down inside your extruder, which really accomplishes nothing helpful for you. As the compounds break down further and oxidize with the small amounts of air coming into the extruder, you're going to get carbon fouling on all surfaces, including the filament itself as it extrudes.

Second, and this depends entirely on the amount of oil present, but I'd expect to see oil actually coating the filament somewhat as it comes out of the nozzle, and acting as a separating agent between the lines of filament on the print itself. I'm not sure how much you'd actually experience this, but again, best case scenario is it doesn't happen, and the oil doesn't give you any real advantage here.

Third, the process of seasoning cast iron works because the surface of the cast iron should be smooth for minimal food sticking, and any kind of rusting causes pits and porosity in the metal. Seasoning just ensures that oil stays in the metal to prevent moisture from interacting with it, and to provide a very thin oil layer that somewhat separates food from the metal until the food is hot enough that its own fats have started to lubricate it against the pan. Extruders on the other hand really shouldn't have porous surfaces nor be made of easily oxidized materials. Stainless heatbreaks, aluminum blocks, brass nozzles, all of these really aren't going to rust readily and probably won't benefit much from an oil coating.

Fourth, if you're looking for a nonstick coating for the interior of the extruder, a PTFE liner has been known to give excellent results for a very long time now. If you're printing above the temperatures PTFE can survive at, then unfortunately you're also printing above the temperatures that pretty much any cooking oil (or petroleum jelly) will survive without rapidly breaking down.

So to summarize, you're not going to find many oils that can even survive inside an extruder, and they wouldn't really give you many benefits for the duration of time that they weren't just a charcoal slurry.


Ender 3 pro extruder skipping steps, tried multiple things

Since you've said you can feel a problem at the nozzle pushing it through manually, and since you say it goes away for a while after cleaning, you probably have somewhere that molten filament is getting into that it's not supposed to, then solidifying and jamming. Check that the cooling fan for the heatsink on the coldend is working, and that the PTFE tube is properly installed all the way through the heat break and butted up against the nozzle with no gaps or irregularities, and that the pressure fitting is holding it firmly and not allowing it to back out. If you can't find anything wrong, it's possible that something is just defective/damaged inside the hotend assembly.


Why does my PLA filament form a spiral shape and clog my extruder?

The shape you get is quite easy to explain. It's the shape of the lowest energy possible in your situation. Simple but it doesn't explain the issue... or does it?

It does. The filament cannot be put into the extruder as it becomes plugged. This leads us to some obvious explanations. You can read this post.

So how is that possible that there is enough room to form such corkscrew? My bet is you don't have teflon pipe inside the extruder heatsink. So filament goes into the heatsink and everything is ok until the heatsink itself warms up to the temperature when filament becomes soft, then there is no enough force to push the filament out of the nozzle so above the nozzle filament bends and forms the shape of the lowest energy as said.

Options to check:

Take your extruder apart. See if there is a teflon pipe. If its length is proper.
Check if cooling fan is working well, if it's pushing air to the heatsing but not sucks from the heatsink.

[edit]

Looking closer to your photos I'm pretty sure you don't have such teflon pipe. Your spiral has flat external (virtual) surface... it looks exactly as it would be pushed into hot pipe with diameter of 4mm.

[edit2]
please take a look on the picture


Can I mix ABS and PLA when recycling filament?

This is not a good idea. Both filaments have different melting points, that of ABS being much higher than that of PLA. To melt the ABS you have to heat the plastic to the point where the PLA starts to degrade.


true color printing with CMYK+White (not 3-in-1 diamond head RGB)

You may be a bit misled here. First of all, you do not want "RGB" , as those are additive colors such as used when combining light sources.  You do want "RYB" (red-yellow-blue) or the more accurate CMY(plus K just to get a 'truer' black)  for subtractive colors.

Next, there's really no reason to attempt pixel-mixing. What should happen, ideally, is that pigments get fully mixed upon extrusion so that the desired color is actually in place. Pretty much any pixel-based setup will not "blend" into the desired visual perception.  And as you propose, you really need a White and a Black to adjust the saturation (take a look at the Wikipedia pages on Hue and Saturation color maps).
So I'm not convinced that separate extrusion heads will ever get you a decent color continuum.  I don't know if anyone has, or is planning, a multi-input, single-output head but I'd sure like one.


This really sounds like there is a short somewhere on the RAMPS add-on board. It is advised to not use the RAMPS add-on shield to prevent damage to the Arduino or the shield.

Personally, I would ditch this one and buy a new one. By the looks of the picture you are using a clone RAMPS, these are mass produced and the quality is not always the best (many components are skew). If you are very into electronics you could try to find the short, but it can well be that the traces on the board are somehow connected. Alternatively, you could buy a new board where RAMPS and Arduino are already combined, e.g. an MKS board.


What is the largest microSD card that a Monoprice Select Mini can read?

Unfortunately, the answer isn't as simple as that a specific size of SD card works and another size doesn't. The Marlin firmware wiki mentions:

  The SD- or MMC- Card must be formatted as FAT and must have a MMC interface. This is more likely with cards <= 2 GB.

MMC is the predecessor of SD. SD cards are not necessarily fully backwards compatible with MMC. Apparently, Marlin uses some features specific to MMC, so your card should support it.

The SD card support in Marlin is based on the Arduino SD Card Library, which further mentions:

  The library supports FAT16 and FAT32 file systems on standard SD cards and SDHC cards.

Based on this:

Cards should be formatted FAT16 or FAT32.
Cards bigger than 32 GB definitely won't work (not SD or SDHC).
Cards at most 2 GB will probably work.
Cards between 2 GB and 32 GB might work, depending on the specifics of the card.


These symptoms are generally caused by friction in the extrusion path.

First, you should make sure the spool of filament can unspool freely.

Second, in order to prevent slipping of the filament, you should consider increasing the force of the roller bearing onto the filament and extruder wheel, or increase hotend temperature. A (partial) clog can also be causing this. You could try a "cold pull" or "atomic pull" where you heat up the filament to print level, push a little through by hand and let the nozzle cool to about 60 % of the printing temp and then steadily pull the filament out of the hotend, this should remove all gunk inside, repeat if necessary. A too low of a layer height can also put the filament extrusion under pressure.

As an aside, slipping of filament is often accompanied by an audible clicking noise. There are a few questions on this topic.

It also looks as though your bed is not centered in the middle as you are printing outside the bed limits in the front and have a little room left at the back!


What are the dimensions of the FlashForge Creator Pro heating block?

The FlashForge Creator Pro uses a MK10 hotend:

The Micro Swiss MK10 All Metal Hotend Kit for instance is reported to be a drop-in replacement for the FlashForge Creator Pro, it uses M7 threads.
The heater block for an MK10 has a threaded hole for the thermistor (M4), but some use a machined hole for PT100/3 mm thermistor cartridges. The block measures around 20 x 20 13 mm. The images below should give you enough information to create your custom blocks. However, there appear to be 3rd supplier after-market blocks available on on-line webshops and market places

The Flashforge original spare part heater blocks show that they are slightly different (the top image shows symmetrical heater blocks while the spare parts are not symmetrical), so above drawings and caliper measurements should give you enough information to reproduce the heater block.

It would be a great addition if you added your own answer once you measured your blocks and created some drawings!


Heaters won't match.
The ender3 is a 24 V machine. The Prusa 3 is a 12 V machine. Heater cartridges and Heatbeds are therefore not interchangeable.
Build surfaces can be adapted.
The Ender3 has a build surface that is a little bigger than the Prusa3, and thus you can, in a pinch, use an ender3 sized build surface and install it, possibly cut down, to fit onto the Prusa.


I printed some pots for sprouting seedlings this year from PLA.  A square array of pots with tiny drainage holes in the bottom.

The array filled the bed of a Prusa3d i3m3.

The seeds sprouted, except for the ground cherries, which I think failed because the seeds were bad.

I had good germination rates for tomatoes and basil.

According to the FDA, ABS is generally safe for food, although like any filament the pigment and any added chemicals may be contraindicated for continued health.


Holes in vertical walls will make it take significantly more time to print, not less. Rather than being able to make a continuous path around the box on each layer, keeping the print head at the desired speed the whole time, the printer will have to run around each connected component of the layer separately, slowing down, retracting, speeding up to travel, slowing down at the destination, unretracting, and speeding back up each time.


Maybe it would it help if you fix #default to #define in the current line:
set #default DEFAULT_ACCELERATION ...


Is this articulated Turtle print failing because of over extrusion on a Taz Workhorse?

It looks to me like you have corner curling on overhangs, which can be contributed to by a mix of:

overextrusion (poor dimensional accuracy of filament or wrong filament diameter setting)
uneven extrusion (due to changes in the print head motion faster than the flow response to changes in the extruder)
uneven cooling (especially due to proximity of one side to heated bed)
too little cooling

and possibly other factors. I would first try lowering the bed temperature. Technically you can print PLA on an unheated bed, but adhesion may be too poor. Dropping to 45°C (my preference now) should not hurt adhesion much and might help; it partly solved my corner-curling problems.

Both uneven extrusion and insufficient cooling can be solved solved by printing slower, but that's no fun. It works for uneven extrusion because, even under constraints on acceleration/jerk, print head can change direction almost instantaneously at low speeds, yielding near-uniform absolute velocity.

Uneven extrusion can also be solved by cranking up the limits on acceleration and jerk. This is a tradeoff because it might get you more vibration/ringing, and beyond the physical limits of your printer it may even start skipping steps and shifting layers (failed prints), but up to that point I think it's a worthwhile tradeoff. Effects from uneven extrusion are some of the worst, in my opinion, print quality/print failure issues, and worth other minor blemishes to fix them if needed.


Why is 2 / -2 / 2 equal to -2 in OpenSCAD? (Mathematical Order of Operations)

I suspect the behavior you are seeing is an undocumented feature (aka, bug) of OpenSCAD. I've found in the latest stable release that if the - is placed on either end, the result is -0.5, but in the middle, my results are the same as yours. Surrounding the -2 with parentheses results in a correct answer, however.

It appears that the parentheses turns a mathematical operation into a signed integer. It follows that the operations without the parentheses is right to left:

2/2 = 1, negative 1 with the minus, 2/-1 = -2


I have used Styrol based Polyester resins on prints and they created the usual stench as well as a surefire bond and it is easily useable with unstructured fiberglass, as that fiberglass has usually a binder that will react with the styrol and bond the mat.

Epoxy resins also bond nicely to PLA and don't have the styrol smell, but they are not bonding that nicely to normal fiberglass, you want to use them with fiberglass weave.

Either resin is a quite viscous fluid. When you cast a flat surface, it will try to smooth out to a good degree under gravity. When coating a curved surface, you should make sure to align it in way that the lowest point is either the top of the dome or the lower edge, so it settles equally. You can aid in this process by providing heat as this will lower viscosity. An airstream will also aid as it presses onto the surface helping to smooth out unevenness.


Is it possible to 3D print shapes of atomic orbitals for a regular customer?

As Darth pixel mentioned, your best bet would likely be to explore subsurface laser engraving which makes little bubbles inside acrylic to make it translucent (frosted) on the inside in certain places.  However, it is expensive, it has no colors, and the resolution isn't usually great (it may look speckled on the edges instead of having a smooth gradient from clear to whitish).

A better option might be to 3d print a probability map of a 2D image an orbital cloud where height corresponds to probability rather than color. (So it will look like a hill or group of hills)  This would only run you a few dollars.


PLA chemical resistances? Especially HCl, other acids

As @T. M. notes in his comment, there are many good charts of chemical compatibility with various agents.  Very few (I found none) include information about PLA.  By all means, use search engines to find some information.

But, no data source is as true to your specific needs as is testing your candidate materials with your agents.

As a first test put the agent in a tall thin jar or test tube.  Use a few test filaments so that the ends are dipping into the agent.  Check for signs of dissolution, swelling, softening, or any relevant change in the material's characteristics.  Examine the candidate filaments right away, then after minutes, then hours, and if any material survives, perhaps in days.

Print test objects.  Test them with your agent.  Try until you find something that works.

The online material compatibility tables will help you eliminate materials before testing them.  If it says a material is incompatible, it probably is incompatible.  If rated as highly compatible, it should be tested because the formulation of a filament may not match the material tested for the compatibility tables.  If you are running out of options, try the intermediate compatibility plastics.

Bottom line, use the online information to help direct your search, but you should do your own tests.


Unable to upload firmware to a new motherboard

Your motherboard is not an MKS GEN L v1.0, it's a MKS SGEN L - unfortunately, a very very naming scheme.
Your board is actually a 32-bit board, and must therefore be flashed with Marlin 2.0, built for the 32-bit board.
The firmware is then updated by placing it on the SD card and restarting the board, as explained in the documentation for Marlin here


The inductive sensors work better when you apply a higher voltage than 5 V. Usually they are rated for 6-36 V, but please do check.

To prevent frying your board when connecting the sensor to (12 or) 24 Volts you could optically isolate the 5 V and the (12 or) 24 V circuit with an OptoCoupler module:

Image of an optocoupler module

This module uses an optical switch based on the output of the sensor and should be correctly connected:

Image of connecting an optocoupler module to the sensor and to the board
Please note that the image uses a capacitive sensor rather than a inductive sensor, both are connected similarly

Note that there are many sorts of sensors, a few are listed here. Generally speaking, the larger the diameter of the sensor, the larger the detection distance to the bed. Note that these work well with metal beds (Iron/steel better than Aluminium), but will not work for glass (capacitive sensors work on glass but are prone to drift by moisture in the air, a touch sensor may then be a better alternative).


How to add menu options to the (Marlin firmware) LCD menu?

The answer to your question is the file ultralcd.cpp. Nowadays, you can also enable extra option through the Configuration_adv.h file, just enable:

#define CUSTOM_USER_MENUS

and edit the options beneath it to your needs (otherwise it will use the preset values from the Configuration.h file).

Add custom items using ultralcd.cpp

This is how I used to do it if you want to add items to the menu in Marlin Firmware through the ultralcd.cpp. It is best to first look at the current implementation of the menu items. As you already mention Preheat PLA, that would be the first to search for. Searching in files is easy when you go to the github website with the Marlin firmware sources, functionality is available for searching in the files. Alternatively, download a copy of the firmware and use a free "grep" utility to search in files.

Searching for Preheat PLA will show you a bunch of language translation files. These point to the use of a constant MSG_PREHEAT_1 which finds its presence in ultralcd.cpp. This hints to function lcd_preheat_m1_menu that is called by MENU_ITEM which adds menu items to LCD. You could start there to add your own option.

Demonstration

As a quick demonstration, I've added a CUSTOM PREHEAT item by copying the lcd_preheat_m2_menu function in ultralcd.cpp and renamed this lcd_preheat_m3_menu (a full functional item needs changes within the lcd_preheat_m3_menu as it now uses the constants from the ABS preheat option).

You then add the item to the menu by changing this part of the code:

      //
      // Preheat for Material 1 and 2
      //
      #if TEMP_SENSOR_1 != 0 || TEMP_SENSOR_2 != 0 || TEMP_SENSOR_3 != 0 || TEMP_SENSOR_4 != 0 || HAS_HEATED_BED
        MENU_ITEM(submenu, MSG_PREHEAT_1, lcd_preheat_m1_menu);
        MENU_ITEM(submenu, MSG_PREHEAT_2, lcd_preheat_m2_menu);
        // ADD THIS LINE:
        MENU_ITEM(submenu, "CUSTOM PREHEAT", lcd_preheat_m3_menu);
      #else
        MENU_ITEM(function, MSG_PREHEAT_1, lcd_preheat_m1_e0_only);
        MENU_ITEM(function, MSG_PREHEAT_2, lcd_preheat_m2_e0_only);
      #endif

After compiling and uploading to the printer board, enter the Prepare menu and scroll down to see:


Are there any ways to make a 3D print transparent?

It depends on a lot of factors, type of plastic, whether the parts need to be strong, can you use a vase print, etc.  Here's a few thoughts.

PLA - The brand of PLA makes a big difference, some can be printed very clear, some can't.  Most of the transparent PLAs I've used print much more clear at around 240°C.

ABS - I've seen some pretty impressive clear parts printed as a single layer shell in ABS and then vapor smoothed. I tend to find ABS more translucent and less transparent though.

PETG - Again the specific PETG you use matters, but I haven't seen nearly as much variation as with PLA.  I'm not sure how much temperature matters, but if it's too hot you get bubbles which will decrease clarity.

Thin Wall Prints - I don't have much experience here, but the Smooth On XTC-3D or vapor smoothing seem to be effective.

Solid Prints
If I want transparency, I usually print it at 100% infill (should be a real 100%, too much overextrusion or underextrusion will decrease transparency).  Printing slower and with less cooling sometimes helps.  It's easier to get the infill solid with a direct drive extruder, I couldn't get decent results with a long bowden tube (a short bowden tube works fine).

Here's a page where I tested 10 transparent filaments, the printed samples are 2mm thick, 100% infill - http://thrinter.com/10-transparent-filaments.  Those samples are all overextruded a bit, you can get better results if you dial in the extrusion precisely, but that's hard to get right, and the optimal settings may change slightly depending on the part geometry.  Larger nozzles and thicker layers may help to, but I haven't experimented much with that as there are significant downsides to that approach.


3D printing overhangs that are over .200 in

The world of 3D Printers usually uses the metric system, especially in nozzle sizes. 0.2 inches are therefore better referred to as 5 mm, which is a considerable amount: that's 11 to 13 perimeters from a 0.4 mm nozzle, depending on extrusion width (0.46 and 0.4 mm respectively). Furthermore, the bore of the item isn't supported either, it is bridging.

To print overhangs and bridging without sagging, one should activate the generation of support material in the slicer.

Generally speaking, PLA (judging from the print temperature) doesn't need to be printed with a raft and would be better served with a brim for bed adhesion, unless you have a perforated bed. If you have to print in the shown orientation, then you should activate support generation in your slicer.

For this part, however, there is a better solution: it is of very simple geometry and it doesn't have to be printed as shown but equally could be printed "upside-down" by being rotated around the X-Axis by 180° in the slicer. This has two benefits: it removes all unsupported overhangs an avoids support structure, making the wasted material pretty much nonexistent.

I strongly recommend taking a look at my 3D Design Primer and the excellent question on How to decide print orientation? and then delve into further reading:

How to print an overhanging arc
How can I improve the overhang angles my printer can successfully print?
Is there any setting that could allow me to print this overhang without support?


Hotend heating failure too short before limit

There are many unknowns at this point, you need to work methodically through each stage. You probably also need some test equipment, at least a basic multimeter. Ideally a temperature probe too.

First, check that your power supply can drive the hot-end directly. You already know how long it takes to reach 120°C, so be sure to not let it heat too far beyond this time. This will bypass all of the control logic, and risks overheating your hotend/burning out the heater - but it should be OK if you limit to a few minutes.

Check the temperature reading, and cross check with some PLA or other low melting point filament to see if you actually reach ~180°C. Check the voltage as close to the heating cartridge as you have a connection point. It should be at least 11V (with a 12V PSU). My guess is that you have a bad connection somewhere...

If you observe the hotend getting hot enough to melt plastic, check the thermistor readings. You should see a fairly constant rate of heating well past 200°C. However, I expect this will work fine.

Finally, check the hotend mosfet drive and output as the hotend reaches the target temperature. It should be on, then switching on/off, then off as you pass the target.

If this all looks OK, repeat but with the board in-circuit and controlling the heater. It may be that the mosfet is damaged, or it is not being driven very well - but to progress past that point we need to see voltage readings at various points.


What does it mean when they say up to 256 interpolation and 16 micro stepping for the TMC step sticks?

Higher microstepping numbers result in smoother movement.
However, printer control boards are limited in how many steps the can generate per second - as low as 10'000 steps/s on an 8-bit AVR board running Marlin.

To get the benefits of smoother microstepping, without adding load to your control board, TMC stepper drivers support interpolation between each step impulse coming from your control board, up to 256 different positions with which the stepper motor is driven.

You will still have to set up your firmware for the 16 "real" microsteps, the interpolation is only done on the stepper driver itself.


Does the resin vary from a printer to another?

According to Formlabs (at least their FormLabs Form 2 and 3 models), their resin is 405 nm which is a fairly standard resin.
There's a wide variety of resins our there that are compatible with 405 nm, and many resin makers/resellers advertise what brand, make, and model of printer they are compatible with. I have an AnyCubic Photon v1 and it uses the same 405 nm resins. You might have to do some testing to see what specific brand or style works for you, including changing your settings (if possible in the software you use). FYI, I use a version of CHITUBOX which does allow settings for exposure time, raise height, pause time, and a few others.
Knowing that it uses 405 nm UV also allows you to know what kind of UV lights to get for easy indoor curing, too.
I'd like to say that it's not likely for these resins to damage the printer, but FormLabs seems to use a plastic tray, instead of the aluminum tray I'm used to so I don't know if there would be a chemical reaction, though I'm skeptical if there would be. I'm assuming it's using a similar FEP clear film for the bottom to the AnyCubic, but I can't confirm this, since the FormLabs film seems to be integral to the tray, rather than replaceable.
I can see why you are looking for other resin options. One place I saw online has a 1 L FormLabs cartridge for \$150, when 500 mL on Amazon is usually between \$20-30. I've seen special resin, such as flexible, as high as \$60 for 500 mL and ABS-like resin for $40, though. Water washable resins seem to be in the \$40-50 range. There's also "natural" or plant based resin for about the same price as regular resin, but might have a different reaction to your tank.
I'd assume that every brand of resin (except for the rebranded stuff) has their own chemical makeup besides the various types of resin, so you might have to some testing, although I realize that messing up a tank that's \$150 to replace is not exactly something you want to do every day.
I can tell you that I've used at least 6 different brands of resin and they all react differently to the UV. I mostly have tested clear, and just that produces a variety of results, from how easy/hard it is to cure to what color it turns when it over cures. (I'm still trying to find a clear that fully cures actually clear.) Where I was going with this is that with all these resins I've used, I haven't had any that caused damage to the FEP film. Some have stuck really hard and I had to be really careful pulling it off. However, I've only had 1 film need to be replaced due to clouding, and I have 4 Photons and used all resins I've tested with all my machines.


Anet A8 bad/inconsistent extrusion after changing nozzle

To be sure it's from your nozzle / extrusion mecanism, you could check calibration by extruding (in the air) 100mm of filament, and check how much it really uses. If it uses 100mm (or so), then the problem comes from any other parts (bed, filament feeding...).

If this is really an extrusion problem, first you can check again your extrusion step motor gear. If it's ok, then you could put back your old nozzle to ensure the new one is the problem... If all is ok with the old one, then yous should have something in your new one, or it's not a .4mm ?


Why does a raft adhere to the bed while skirt does not?

The raft base (initial layer) is usually printed with very wide lines. Cura's default is double the nozzle diameter, so 0.8 mm with standard 0.4 mm nozzle. This is ridiculously high flow, especially with the default 0.3 mm thickness, which is why the raft base lines are (and must be, unless you have a seriously overpowered hotend) printed so slowly. So, each line has significantly increased (double) surface contact, more pressure against the bed, more forgiveness if the bed clearance is too high (since it will still smash against the bed, just spreading out less than the whole 0.8 mm width), comes out slower (giving it better opportunity to adhere), and does not involve any curves (where the nozzle may "pull" just-extruded material that's not yet adhering).
You may be able to get a lot of the same benefit with skirts (or brims) by increasing the "Skirt/Brim Line Width" setting and slowing down its speed.


How do you know when your SLA resin tray needs to be replaced?

Once the non stick coating wears off you'll notice degraded print quality over time and a more agressive sound from the print breaking free when switching layers as the print uses more and more force to break free from the tray with each layer when the non stick coating degrades. The good thing is this will not happen at once so you will start to notice telltale signs previously and you can lessen the wear at specific points of the non stick coating by using different parts of the build platform instead of printing exactly in the center each time.


Limit Switch problems on RAMPS 1.4 and custom built 3D Printer running Marlin 1.1.0-rc6

Considering you're having issues with the board, and the limit switches appear to be registering, but the board isn't doing anything about it, a first good step would be to update the firmware to 1.1.9 as @0scar states. If the update in the firmware doesn't do the trick, then move on to doing as he suggests with changing the Xmax/min stuff around. This just seems like a good first logical step to getting it fixed.


Why could my opaque PETG be printing "transparent" in certain places?

Are you using Z-hop? Is there any play in the Z-axis direction? It appears that parts of the first layer are printed much thinner than other parts.

What can happen if there is a little play in the Z-axis direction that the nozzle doesn't return to the same level after a Z-hop movement (e.g. backlash in the leadscrew nuts).

The "transparent" printed part appears thinner, this must indicate that the Z positioning is not up to par.


How to force Cura to walk through a layer in one run?

I am not aware of a general solution.
For your specific issue, try rotating the object 90 degrees around the z-axis.


3D scanner for both replicate and quality control 3D prints

Thus question is very close to being out of the scope of the questions encouraged on the 3D Printing SE site,  but you have worked closely with Trish and Oscar to make it into less of a "recommend" question and more of a "how might I choose" question

What to look for in a 3D scanner?

You mentioned using the scanner for quality control.  Lets start with that.

The best way I know to do optical quality control is to image each layer after deposition rather than viewing the completed object.   Especially for printing engineered objects,  like rocket fuel pumps and jet turbine blades,  it is important to be able to see inside the object and detect voids, bad adhesion, and points of unexpected stress.  That is hard to do with the full object,  and easier to do layer by layer.

But this may not be the QA requirement  you are trying to meet.  Maybe the gross object appearance is what you are controlling for.

If so,  you need to define what is good enough and what is a failure.  With those criteria,  you can see which scanners give you that discernment.

I suspect that won't be far off the requirements for the "reverse engineering" you also intend.

Another criteria is the software.

It's the workflow simple,  or can it be made simple?  20 clicks through detailed menus which must be done correctly and in sequence is not easy to get right twice a week when you need out.

Consider the color of the illumination

Be sure it will not interact badly with your objects.   A red laser does not scan well a red object.

More is more, not necessarily better

Higher resolution is great if you have three I/O channels to support it,  the disk space to store it, the RAM to hold it,  and the processing power to absorbable it.


Monoprice MP Mini Delta - How to get started?

Updated Manual

Turns out an out of date manual was on the sd card that was included with the printer. But it was definitely out of date, as it referenced UI items that don't exist, and files that weren't on the SD card.

An updated manual can be found here
or possibly out of date here

Resources and sample files

A very helpful Facebook group has a bunch of files that are good sample prints. If your manual says you can print a cat.gcode you've got an old manual.
Note: Don't try and just google cat.gcode as I did. The model I found rammed the print head right into the bottom of the printer. The correct model works great (actually called auto00.g on the SD card)
Another great reference site appears to be https://www.mpminidelta.com/, and this reddit

Common Problems and Solutions
The following are some problems I had and their solution
Can't print custom models
If you find you can print prebuilt gcodes fine (cat,viking,toothless), but can't seem to print any other models without the print head ramming into the bottom of the printer and going off to the side, you probably haven't setup the autoleveling gcode that's required. You can add something like the following line to your software, in a "startup" gcode section. This is detailed in the manual (just search for G29), and more info can be found here
; auto-levels the build plate with a overall vertical
; offset of 0.3mm with a center offset of -0.8mm
G29 C-0.8 Z0.3

First layer doesnt stick
If you find your first layer isn't sticking, or it seems like the plastic is balling up, you need to adjust your startup gcode line mentioned above , so it has a lower Z offset, like Z0.25 for example
G29 Z[offset] ; raises
G29 Z-[offset] ; lowers

Notes

Please try a positive offset value first.
Each printer will require fine tuning in regards to the offset value.
Start with a higher value and decrease as necessary to get good first layer adhesion.
Using a negative offset value may send the nozzle digging into the build plate.


Filament clogging just above feeding tube - Duplicator 6

Sometimes the filament quality itself could be the culprit. Have you tried printing with a different spool of PLA?


Removing that line will not affect your printer, except that it will get rid of the warning displayed on the screen.

  I wanted to know [...] if there's something else to consider.

You should probably upgrade your firmware to the latest version to benefit from a couple of bugfixes and performance increases.


Z-offset persitently stored in memory?
Maybe the value of -2.97 for the Z_PROBE_OFFSET_FROM_EXTRUDER  is retained in the EEPROM memory when you upload new firmware.
You could try to send the G-code M502 to the machine to re-load the values from the firmware overwriting currently stored values.
Alternative Z-offset using G-code commands
Note that there is a different (and more common) solution to set the Z-offset using G-code M851, you can do this after you uploaded the firmware to the printer. Sending G-code commands can be done using printer software and a USB connection to the printer through a so-called terminal interface. This can be done in OctoPrint, Repetier-Host, Pronterface (Printrun software suite), and probably many more. Alternatively, you could make seperate G-code (basically text files with extension .g) files with each step in a single file and "print" the files through the SD interface of the printer menu.
The following strategy must be followed to specify the Z offset:

Heat your printer up to your printing temperature and allow a few minutes for it to expand and settle
Reset the existing Z-offset to zero M851 Z0
Home all axes G28
Move the nozzle to the middle of the bed G1 X110 Y110 (if your bed is 220 x 220)
Turn off the software endstops with M211 S0
Move the nozzle down so it is just gripping a piece of standard printer paper
Set the Z-offset to the displayed value. E.g. if the printer displays a Z-Value of -1.23 enter M851 Z-1.23
Store it to the EEPROM M500
Important notice! Enable the endstops again with M211 S1 or the printer head will collide with the bed on the next G28 command