Is this very large flat panel printable in ABS?

ABS would be fine, as a material, for the application.

The problem, given the scale, would be the printing device used. I would suggest that you have the piece cut to spec for you using a polycarbonate.

If you have access to a workshop you could do so yourself if you set up proper fencing using a larger sized bandsaw(with a very fine toothed blade), had rollers to help support the size of your piece(as it would not fit on the tool's platform) and likely need a second set of hands to help control the outfeed. You would also need to drill access for the cut out then cut the perimetre.

You could also consider printing(ABS) in smaller sections then fusing each section together edge to edge(solvent welding of ABS is very strong and permanent), if you were really dead set on using a typical 3D printer for this. It would, in theory, be possible, but it would be very tedious. The adhesives, and cleaner, would be available from any plumbing supply and/or (home depot, lowes, walmart et al.). If you go this route be sure to have ample ventilation and plan your work space well in advance. I would not recommend this option but it is "possible".

Given the scale of the piece though, and for sake of accuracy, going to a shop with CNC equipment and using polycarbonate would be your best bet.


No
PETG is a material that can only be used in FDM machines. This precludes any internal medical use, as FDM prints can't be made sterile or even hygienic - the sterilization processes would destroy the print, and FDM layers create many spots for germs to grow. Atop that, you can't get the needed precision with FDM - which means any FDM prints are at best waste at worst endangering the patient!
In contrast, 3D printed metals and laser-printed nylon can be created and post-processed in ways that do not have layer lines. Resin prints do not have layer lines that offer these discrete hiding spots for germs. They all are made in a fashion that kills germs or disallows them from being embedded and they can be properly sterilized or made hygienic.
No!
PETG can't be printed completely clear in FDM. By the processing method, air and layer boundaries are included, making prints at least somewhat opaque.
Only Resin prints can be fully transparent as they contain neither boundaries nor air.
NO!!!
STL files contain only surface data and need to be processed into printer readable format. G-code is one of those formats, commonly used in FDM machines and CNC machines.
The processing from STL or other surface data into FDM-3D-printer G-code is done by a program called a slicer. Examples are Cura, PrusaSlicer, Slic3r, and many others.
Resin printers using DLP use different slicers that create images of the model's crossections together with some sort of machine code for the movement. For SLA machines, the code is entirely different again.
Further Reading
I highly suggest you read more about 3D printing dental applications before trying anything for dental use, and especially anything that is printed for any medical application!


Yes that happens! It finds its source in various possible reasons.

The print bed is not square! There are cutouts caused by the print head;
The Ultimaker 3 has 2 nozzles, when you have 2 active, the effective print bed is smaller than with 1 nozzle active;
Using a brim or a skirt also makes the effective print area smaller.

In re-creating your example, the settings in your projects are not correct (but even if done properly, you will not be able to print it flat on the bed). Take a look at the image below, as can be seen your example still has a brim/skirt reservation, be sure to disable the second extruder (as shown by a cross X before "Generic PLA" at the top).

The only solution to print this on this machine is to print it upright:


What type of plastic can be used to produce your own filament?

Filament manufacturers (for example, Colorfabb) also sell pellets, price per kilo would be about 10 times less than the same plastic in filament form.

Out of household garbage only ABS can be easily extruded into filament with Filabot-grade machine. PET AKA plastic bottles looks promising as well.

You can also use certain products "off-label". For example, string trimmer string (line) is simply a nylon filament and can be used as-is in modern diameter-agnostic hot end.


After many hours tinkering, pulling things apart, testing them and re-assembling them, it turned out that the problem was a broken wire for the X_Min endstop. This has now been replaced and the problem is resolved.


Tronxy X5S-400 Marlin stuck at splash-screen

It looked like the firmware wasn't flashed correctly in the factory. What I did was to flash a bootloader using an Arduino compatible board and to flash the Marlin software e.g. according to videos from this guy.

Next, the menu wasn't displayed correctly so I added, in the Configuration.h the following lines:

#define ST7920_DELAY_1 DELAY_NS(63)
#define ST7920_DELAY_2 DELAY_NS(100)
#define ST7920_DELAY_3 DELAY_NS(125)

Now the display is working fine, and the Marlin firmware can be directly flashed from the computer because the bootloader remains there.

I also had a problem with the heating bed which was heating very slow and I had to raise consistently the TEMP_BED_RESIDENCY_TIME and decrease TEMP_BED_HYSTERESIS to 1.


Klipper doesn't seem to adjust Z after BED_MESH_CALIBRATE

I have identified the problem as lead screw backlash!

Bed calibration and Z-axis offset compensation appear to be working as intended, but there is enough backlash in the Ender 3 stock lead screw that the corrections in Z-axis movement commanded by Klipper result in almost no actual nozzle movement.

I'm measuring about 0.35 mm of backlash in my lead screw.  With differences between the lowest and highest points of my bed being only 0.6 mm the best case scenario (which would only happen if I was using my entire bed) is that the actual nozzle movement would only be about 42 % of what Klipper commanded.  The fix for this is to change out the lead screw for a ball screw. The problem could also be mitigated in Klipper if Klipper implemented backlash compensation, but from what I've read on GitHub it doesn't seem like that is a feature the developer of Klipper wants to implement.

Update:

I installed this anti-backlash nut and it greatly reduced the backlash, but didn't eliminate it. I've uninstalled my solid bed mounts and reinstalled springs until I upgrade to a ball-screw for the Z axis. The auto bed leveling compensation still does something, but the adjustment allowed by having springs is what is really doing most of the leveling work.


How do I get circles on small interior holes to adhere to the bed?

are you using hairspray or tape to help with bed adhesion? If not that might help.

Also try printing the first layer slower or try adjusting the bed level offset so you are squishing the first layer down a bit more.


Maker Select Plus 3D Printer Head Size Settings for Cura

TL;DR

The settings that you seem to need can be found here: Print One At a time settings? CURA:

  You actually can!

  Providing that none of your object is too tall (taller than the Gantry
  clearance). Also the objects cannot be too close from each other (when
  you activate the option and move objects on the bed, you see a gray
  box around them showing this limit).

  The reason you cannot use it at the moment is probably because you
  didn't filled the printer head size parameters (Menu "Machine ->
  Machine Settings..."). You will have to measure them, but on mine
  (Australian clone of the i3) I use those values and it works fine:

  Head size toward X min: 30
  Head size toward Y min: 70
  Head size toward X max: 60
  Head size toward Y max: 50
  Printer gantry height: 35

  Those are "conservative" values (a little bigger than the actual
  values). It means I'm losing a little bed space, but I prefer that to
  the risk of having the print head knocking out previous prints if one
  of the measurements is too low :o).

  PS: The option will automatically disable itself if some object
  dimension are too big to avoid collisions

To be fair, the rest of the thread is people debating whether you can successfully achieve sequential printing, or not, with the Wanhao Duplicator I3.

However, the setting above seem to be the settings that you are looking for. Apart from Head size toward X max, they also correlate, pretty much, to the settings that you have already determined. As the poster notes, their settings are, somewhat, on the conservative side, which would explain the difference.

Extra detail

If this is so that you can achieve sequential printing1, then this may not be suitable for your printer, unfortunately. Sequential printing works best for printers with a long nozzle with nothing (fans, X-axis gantry, etc.) around it, for example a delta printer with a low hanging nozzle would be ideal. Your printer type has a wide head with attachments, as well as an X-axis gantry, and so the clearance is less than that of an (ideal) delta.

See WanHao Duplicator i3 Printer Head Size Settings for Cura for more details.

If you wish to go ahead and still try it, then from the same link:

  The way to measure is lower the nozzle to the bed.

  Then measure the space taken up around the nozzle by the heater block, fans, mounting, the motor, and finally, the distance between the X axis rods and the bed "WHEN the nozzle is touching the bed".

  That gives you some idea of the clearance you have where an ALREADY printed object can exist on the bed and NOT get slammed into the gantry or moving head when printing a second sequential part.

  Just a visual with a moving bed printer and it's not promising.
  Not impossible, but in a 200mm square build area, you might really only get 4 objects at a time in the 4 quadrants.

  Even that is height limited because the gantry will slam into it at a certain height.

  Maybe some weird staggering pattern.

Also, of use, for obtaining your own measurements, from Ultimaker - Cura 14.07 Printer Head Size:

  If I'm not mistaken all measurements are taken from the nozzle tip. So, for the first one, measure the size of your head from the nozzle tip towards the direction in X to where your machine homes.

and

  There's a tooltip when you mouse over these settings which describes what they mean.

  Gantry height is the vertical clearance between the build plate and your x-y gantry (on the Ultimaker, these are the 6mm shafts which hold the head).

  If you print two objects - one after another - then the first object must be shorter in height than the gantry height. Otherwise, the gantry would crash into the first part while printing the second part.

In more detail, paying attention to the placing of the objects can aid with any issues that you have with a low gantry:

  If you place multiple parts in a diagonal line across the build-plate so the gantry and head never intersects earlier parts after printing them, you can set the gantry height to an artificially high value, to ignore it, without problems.

  I place pieces along a diagonal from right-front to left-rear, to avoid conflict when the head homes after finishing the print. I can fit 3 to 4 small but tall pieces on the build plate that way for sequential printing.

The purpose of these Printer head size settings is to enable Cura to determine the order in which the objects are printed:

  ... none of those settings are important as long as you only print one STL file at a time. It's when you want to print multiple objects "one at a time" that these numbers have a purpose - it allows Cura to figure out which order to print them in and if it can do them one at a time or if it has to print them all at once.

Footnote

1 Sequential Printing is where one object is completely printed, before moving on to the next object, instead of the usual method of printing all objects simultaneously one layer at a time. This method can give superior quality prints, but not always. The main advantage appears to be reduced "stringing" of filament between objects, and a cleaner surface finish, due to reduced print head movement between objects. The process is detailed in Multi-part printing.


Printer is over extruding for the first few layers

Depending on your slicer, there might be settings that modify the flow ratio, First layer height or extrusion width for the first few layers. If those are different from the modifiers for the rest of the print you might be able to play around with these variables.


Cura messes up my print. How can I make it print what I see in Blender?

It's common for modeling software to flip normals, causing what you describe. You said,

I only care about the externally facing faces.

But are you sure they are truly externally facing? Turn on normals in Blender and ensure that all the arrows/pointers are external.
Another problem that can generate the results you're seeing are self-intersecting surfaces, non-manifold edges, and a couple others that are explained in a 3dhubs article. Correcting those problems involve a bit more examination and trouble shooting.
The slicing software prefers to have clean, well defined triangular surfaces in order to create a print file. When something is amiss, you get results you've presented.
With the STL in hand, I opened it in Meshmixer (free) and immediately was given a clue.

The zebra-stripes are reversed normals.
Here's another error point, difficult to see clearly in flat 2D image, but panning and zooming and orbiting and all those 3D manipulating things shows there's nothing there:

The other end of this not-joined area shows a bit better:

After selecting all I could find/locate, I did the reverse normals and here's a slightly improved result:

Unfortunately, the other borked up portions prevented meshmixer from performing a suitable auto-repair, completely destroying the model in the process.
Those joint corners and any other colored lines have to be addressed individually.


Cannot configure default E step for extruder on TH3D

Initializing

After changing your firmware, you always need to overwrite the old values in the SRAM and EEPROM with those from the Firmware. Which you do with M502 & M500:

  Installing firmware does not by itself alter the EEPROM, so these settings needed to be seeded into SRAM via M502 and then saved into EEPROM via M500.

You could also run a G-code that has only these two lines:

M502
M500

Altering the EEPROM

Via command

Alternatively, you could access the printer via a terminal and send the command M92 E415 to overwrite the SRAM directly, then M500 to save the new setting to EEPROM. The associated G-code that only alters the E-steps/mm would read

M92 E415
M500

Via Software

Or you use a terminal that supports direct alteration of the EEPROM, like Repetier Host.


Can a sandstone 3D print be printed as a solid object?

Yes, you can just print it solid. However, it might be significantly more expensive to print your object entirely solid. For instance, Shapeways charges \$0.75 per cm³ of material for their full-color sandstone. A solid cube of 5x5x5 cm would cost \$96 to print, whereas it would only cost around \$6 if you printed it hollow with 2mm walls.


That's a retraction issue, not layer shift.
Your nozzle starts printing a new line in those areas but doesn't extrude enough plastic at the first moments, resulting in a weak line.


Dead thermister or dead board on Ender 5?

"Heater core" wires are not the same as thermistor wires, are they?
Check if thermistor is properly connected?
Reading -14 C in my case always pointed a disconnection of thermistor. (I didn't had a case of broken one so far.) In case of short it would probably show som max temperature (my guess, I dont want to try), but it is always good to check if wires are do not touch each other and are properly insulated?
Measure thermistor's resistance
If you are able to use multimeter, then:

disconnect thermistor from the printer board
set multimeter to resistance measurement (200k Ohms)
connect thermistor and multimeter using wires - the ones having aligator clips would be the best
read resistance measurent

My spare shows 97k Ohms in room conditions. So value should be high (you may refer to specs sheet of given type when in doubt).
Check that hotend is actually powered
If thermistor is OK, then indeed the hotend powering may be broken. Ths definitely require skills and may introduce many risks to electronics and maybe even to your health - but if you are skilled enough, you may measure with voltmeter if there is correct voltage provided to the hotend. For example the MOSFET on the board may be broken (I already replaced one in the past for my heated bed).


Marlin keeps restarting when I push the LCD controller button

If the trouble was just a short between 5 V and ground, the board probably would restart whenever you pushed the button, with all kind of power sources.
The fact that the Arduino restarts only when powered from RAMPS makes me wonder another cause for this problem.
It's well known that most of Arduino clones don't have a good voltage regulator onboard. This causes trouble when you power Arduino from RAMPS, because RAMPS sends 12 V to Arduino through Arduino's Vin pin, and this 12 V goes to Arduino's voltage regulator, which should reduce it to the 5 V used by ATMega MCU.
The question is, probably the Arduino's onboard voltage is running almost at its capacity and, when you press the button, the extra processing load or the redrawing of the display makes Arduino reset.
The solution would be disconnect diode D1 in RAMPS, and power Arduino from USB, or feeding 5V directly to Arduino's 5 V pin (not Vin).
A third option (more complex) would be feed about 7 V to Arduino barrel power-connector. This lower voltage would reduce the task of Arduino's onboard regulator. My 3D-printer uses an Arduino clone, but, as I discovered about this problem before building it, I've never powered it from RAMPS. I dessoldered D1 on RAMPS and, since the first day, Arduino was powered from USB, or from a DC-DC buck converter that reduces 12 V to 7.2 V.


Are there white filaments, that are not so translucent?

Most of the plastics used for filament are inherently transparent and largely colorless. Color is achieved by adding pigment. Translucent and transparent colors are easy, but opaque colors require large amounts of opaque pigments, and even then, their opacity has its limits - even with black filament!

You can probably find very opaque white filament, but beware - too much pigment will affect the raw properties of the filament itself, either in terms of print temperature or things like layer adhesion or stringing/clogging etc.


As far as I know, this is currently not possible.


Considerations for placing STL on build plate

Orienting items
Orienting items on the build plate should consider:

overhangs - many hangning fragments will need additional support to be printed (cost of time and material, risk of failure); gravity and colling process will affect loose/hanging plastic in this or that way
layered structure - parts will be stronger in X-Y directions, and weaker in Z direction
adhesion - it is good to have wide foot to touch and stick to the bed, then only thin base growing big upwards, which may easily fail by any accident
space - if the thing is big, it may have to be rotated diagonally to fit the printing surface

So most of it comes from particular shape. Try to look at thing from different sides, spatial awareness helps a lot.
Placing items
Also, placing items on the build plate should consider:

heating system - heated bed surface may be warmer at center; even if the bed is heated evenly, than surface will cool down faster at sides, which may affect adhesion (e.g. ABS will wrap more often)
cooling system - sometimes printer has better cooling from one side (depending on location of fans or construction of cooling ducts), so any overhangs (fragments which have to cool down very quickly) should be properly exposed, otherwise they will wrap
environment (external influences) - they may affect heating / cooling as well; also mutual position of few objects may affect cooling or act as wall for wind
printer construction - e.g. backside of Prusa Air 2 frame is shrinking going up, and anything mounted behing extruder will hit the frame - so high prints should be X-centered/narrow, and rather wide along Y axis
multiple extrusion - if you use dual extruder, then mixed fragments may not be located on edges, because one of nozzles just cannot reach it
surface quality - e.g. I print ABS on Kapton tape; sometimes the tape gets small holes or tearing from hotend accidents or forceful part detachment - then I just avoid damaged areas
other issues - e.g. my Y axis is louder than X, therefore I rather try to use X axis more often (especially when printing late evenings)
view point - easthetics of printing: which objects, which sides you want to observe during printing?
acessability - if you may want to influence area during print, put something inside the part during printing?

So most of it comes from the experiences with particular printer - its technical parameters and observations. Many times it is only a choice - like simple PLA prints sticking well.


There are some software tools that let you manually design support structures so you can target the areas that need them, and avoid others.

For example, Meshmixer can be used to add supports into your STL. I believe you still use a separate slicer.

Some slicers also have the ability to manually add support. I have found that CraftWare and Simplify3D have this kind of feature.


Spindle DC motor and drill bit specifications for Circuit etching CNC machine

There are several sources of PCB "etching" bits.  They tend to be single straight flutes and high angle, very pointy bits.

For the motor, high speed is good.  Look for 30k+ RPM.  The main thing to be concerned about is the amount of runout, or wobble in the tip.  With a tiny tip, you can't afford much runout at all.  It will broaden the gap you are cutting and put stress on the bit, probably snapping it.

The key to low runout is very careful alignment of the chuck that holds the tip with the shaft of the motor, and a collet chuck to hold the tool.

The power needs aren't high since the speed is high and the cuts are light.  I would think that a 250 watt motor should be way more than sufficient.

The question now asks for drilling and routing, which should work better with the high-speed spindle.  30k is better for the tiny drills than a much slower spindle.  These are hurt by run out.

Usually the drill bits are made of carbide.  For cutting, carbide router or file bits are used.  All drill-bits and router bits and copper cutting bits I have seen for sale have 1/8" or 3mm shank.


Auto bed levelling with Rumba board - Servo not deploying

For future reference.

My issue about the servo not moving was caused by a wiring mistake.
The Exp. 3 has 14 pins has per this diagram.

However when phisically looking at the board, what you see is this:

I took the first 2 pins on the right of such connector and the 3rd one of the first row thinking that I was connecting pins 2-4-5 of Exp. 3.
I was wrong, because the first 2 (1-2) pins are not part of Exp. 3.

The right way to connect the servo is as following:

Then use PWM1 (pin 5 Ext.3)
I decided to leave trace of this issue and the relevant solution for someone that may experience the same issue.


How to correctly clean the Lacquer from bed?

The Ender 3 does not come with a lacquered surface at all.The bed should have a rough build surface that is a clone of the BuildTak build surface. It is intended to be rough and satin-gloss in its native state. I do not remember if there was a thin protective plastic foil on my Ender-3 bed on delivery, but if there was, it should have been removed during assembly.

A BuildTak surface can be easily cleaned with isopropyl or ethyl alcohol of grease and fingerprints. The odd discoloration at the edges seems to be a layer of grease and dust, which can be easily cleaned away by soaking it in Isopropyl alcohol and then wiped with a microfiber cloth.

If the bed surface is destroyed by chipping holes into it, sanding it or otherwise ruining it (like melting plastic rap into it), you will need to replace it. Replacement surfaces come about 5 bucks on Amazon. Doing this, you might find How to clean up my buildpate for a new build surface? helpful.


What material best to use for press fit parts?

A flexible material, such as PETG or ABS, is probably the best.  PLA is brittle, especially after absorbing moisture, and probably would crack under continued use.
Nylon is good, but not easy to use.  With PETG in an enclosure, I end up running fans to avoid heat creep; so PETG may actually do better without an enclosure.
If you're printing to flex your print, keep in mind the the x and y axes are stronger than the z-axis, which depends on how well the layers stick together.   PETG tends to stick to the print surface too well; so I use an Elmer's glue stick for it to pull up the glue layer instead of damaging my print surface.


PROBING_MARGIN and MESH_INSET make the effective probing area smaller, so if you want to have more area, you should reduce the value of these constants.
As of Marlin 2.x, the probing area isn't defined directly by the firmware configuration settings, but calculated, based on the probe offset settings. The constants you mention are reducing the probing area to keep the carriage/nozzle on the build surface.
If you have enough space on your printer to accommodate probing the whole bed, you could minimize the marging and define edges:
#if PROBE_SELECTED && !IS_KINEMATIC
  #define PROBING_MARGIN_LEFT PROBING_MARGIN
  #define PROBING_MARGIN_RIGHT PROBING_MARGIN
  #define PROBING_MARGIN_FRONT PROBING_MARGIN
  #define PROBING_MARGIN_BACK PROBING_MARGIN
#endif


Can OctoPrint web interface be turned off during a print?

Assuming the OctoPrint server is running on your Raspberry Pi, which is the usual "OctoPi" setup, then yes, once you have uploaded the G-code to OctoPrint, you no longer need to leave the web interface open.
For example, one could upload code from their desktop running the slicing software to OctoPrint, walk to the printer to turn it on, then use a different device (a phone, for example) to connect OctoPrint to the printer and begin the print. At no point does the device accessing the web interface matter. The Raspberry Pi is in control of the printer, not the device that started the print.


What is the MakerBot Grip Surface lifespan?

There's no quantitative formula for the lifespan of any grip material, be it tape, glue, or PEI sheet.  If you find a lack of stiction and it's not due to small changes in the Z-origin (50 microns can make a big difference in the way the first layer grabs the bed!), then replace the tape.  It's cheap.

Just to be pedantic, torn and scarred tape should be replaced :-)


Can anyone suggest what technology and 3D printing material is most suitable for printing of dental models?

If resolution is your upmost concern then resin 3d printers are the way to go. They use a liquid resin that does not harden until a UV laser is shined through them. Apparently they get ultra high resolution and smooth finishes right out of the box. The downside is they are generally more expensive machines and the resin material itself is also a higher cost. but if you are in the dental field then money is not a problem. Look into resin 3d printers.

otherwise if you want to try FDM printers then try looking into .1mm brass nozzles which will increase resolution but vastly increase print time. Not sure what material would be best. ABS has toxic smelling fumes, but is the same as LEGOS and is able to be easily smoothed (if necessary) with Acetone fumes. PLA might work well at .1mm nozzle resolution though and is a starch/dextrin based non-toxic biodegradable filament.


This is going to become a 3-step answer, as 3D Printing uses 3 different steps:
Design, Slicing & Material choice before I elaborate alternate ways to some fair dice. Yet, we start with the material, as we need to know about it first. In this case it does impact everything from design to slicing and the print.

Variant A: Printed perfect(?)

Step 1: Know your material

Let's face it: most materials used in Fused Deposition Modeling (FDM) face an non-homogenous shrinking between XY plane and Z axis. But if you know these specific properties for your printer/filament/temperature combo, you can compensate for that. Know your material - you will need that for slicing. Run a test print of a 10x10x10 mm cube and measure - the offset of the 10mm on each axis is what you need to compensate for via your slicer.

Step 2: Design fairly

Platonic bodies

When designing your STL, try to design as fair as you can. Either indent the numbers as little as you can while maintaining readability, or, if you have a 2 color printer, fill the numbers with same density material but from the other color.

Another thing to consider: indent the same surface area on each face of the body. That way you remove the same volume and thus same weight from each face, making it somewhat fair in the design, as the Center of Mass should be mostly in the center of the body now.

Prism-"dice"

A cylindrical (or rather: prism) design that is rolled over its "cylinder" surfaces might be the most easy to be designed fairly and be reasonably easy to slice, without having to resort to specialist slicing methods and tons of different compensations to keep in mind or having to assemble the object after print. It might be made with or without a "fall over" cone/elipsoid shape at both ends. Or it might be made like a dreidl, having only one conical/elipsoid tip for easy printing, possibly even havign the 'stem' printed as a different object and then assembled after print.

Step 3: Slicing

Now, there is a pretty fair design... but what settings to use when printing it?!

Infill will make it wonky, so there are 2 options: solid (100% infill) and fully hollow (0% infill). Solid is easier to print and heavier. Hollow saves (depending on surface sides) 95% or more of the material in contrast to solid but can fall victim to sagging flat surfaces or wall thickness being not the same as flat area thickness.

Now, after we chose the infill settings, we need to choose some other things. We want to print fairly delicate stuff, so we should use a smaller layer height than normally (0.05 mm, for example), and better a smaller nozzle - 0.2 mm or even less, if available. This again means, calibrating the printer/material combo for these two settings (XY / Z shrinking).

After calibration, finally print! The dice should be pretty ok in fairness with that, but they are still not totally fair...

Extra-step: Postprocessing

You might make a test for bias by floating it on a salt water layer under tap water... if you managed to get it solid enough to reduce the air inside it to make it sink between these layers. That way you can slightly sand the heavier side until it is unbiased.

If you manage to print somewhat fair and hollow, you might consider filling the cavity with some kind of resin (for example epoxy) to give the objects a bit of weight. This has some caveats on its own though: you'll have to leave a filling hole and you'll have to coat the inside equally or refill it several times to ensure a complete fill as most resins shrink when curing. Also, most resins heat up in curing, though usually not to the degree it melts FDM. As you work with resin, Wear gloves as it is aggressive to skin!

BUT! 3D printink can do more!

Variant B: Printed Perfection

FDM is home printer stuff, but maybe you have access to something more... industrial. They are tricky in their own way, and you better know what you do with them.

SLS (solid laser sintering) You just need to know your material shrinking coefficients in that case... and no, you don't need to think about infill, you only can do solid, 100% filled objects this way. But you will also have virtually no air in your print. Having SLS at home is rare though. This is however likely what you get when you order printed... but remember: the SLS powder is highly hygroscopic and will need to be sealed. Also, it does turn yellowish over time if it starts white. Using reused powder to a large degree degrades print quality also. And never look into the working machine.

DLMS (Direct Laser Metal Smelting) is quite new and pretty much the metal variant of SLS. If you make your dice in that way and get them almost indistinguishable from cast metal. Polish the surfaces a little, don't sniff the breath the powder and don't look into the laser.

DLP/SLA (Direct Light Processing/Stereo Lithography) Printing the thing from curing resin actually is pretty much close to SLS, but it has some resemblence to FDM in parts... biggest benefit: you can make very delicate details, and your layer heights get really thin - and you have a huge array of colors to choose from. But you have to take in mind, that you might want to either make the dice solid or design them with a hole in each of the sides or corners to allow surplus resin to flow out. You get perfect surfaces and can reuse the resin for quite a bitdepending on printer and storeage, but remember: SLA is a stinky thing, never look into the printing machine & the resins are very agressive to skin, so use gloves when working with the printing and the print until properly cleaned.

Variant C: Lost Print

But wait, what if you don't actually print the dice but just print a positive of the dice and then make a negative mold from that?

Yes, that can be done. You know lost wax casting? There you go. Here's your step by step:

Print your dice.

maybe even puzzle the positive together from several faces printed all in the same orientation for maximum equality in the print.

Add a casting inlet and air outlet to the print.
cast the positive in either a clay material or gypsum. Allow it to dry/set.
Burn/melt out the positive, you get a hot and empty negative form.
cast in liquid metal or a resin
break mold, remove the inlets, polish some and... voila!

If you are good at green sand casting, you might use that instead of lost wax casting - and reuse the positive for a second casting. Or, if you are good, you can make two-part molds that are reuseable.

Variant 3b: mold it!

If we can print a positive and make a mold from that, we might as well print a mold directly. We can just cast in "cold" materials then, but if you have something that can be cast that way (some resins or wax) you can make either the dice or casting sprues for lost wax casting that way. Designing here will be different on the last steps though: after doing your wanted object, use this as a "tool" to cut out from a more or less square block that surrounds it. cut out the inlet/outlet for material and air from the block. Then cut up to your liking, if you want a reusable multi-part mold. You might want to add a roove to add wire or a rubber band around the print to keep the mold together while casting.

Or we go industrial with that model, grab a CNC and make the mold halves that way and give up on printing the dice...

tl;dr:

Know your printer, know your material, design for your printer's requirements, design fairly, maybe avoid printing the actual dice but print a positive to be molded and cast or print a mold.


After watching the video, it looks this is a Bowden style extruder.  The extruder assembly is encased in the black box the OP mentions.  The assembly is user removable.  It appears they also include two cleaning tools

Small (0.4mm?) wire to clean the nozzle tip
Large (1.7mm?) rod for pushing filament down that is stuck in the cold end

It appears the OP tried accessing the filament in the cold end by removing the fitting at the top of the assembly without opening the assembly.  Unfortunately that caused the nut holding the fitting on from the inside fell off.  At that point he was in a bit of a mess.

I believe the manufacture's intent is to "ram" any broken pieces in the cold end through the hot extruder by using the provided rod and pushing while the extruder is on.  It seems that it should work but would not be easy to do if the filament broke off outside the extruder (which seems to be the case).

At the point he left it, it would seem that he would either have to do surgery or replace the extruder assembly.


Three phase stepper motors are superior in several ways: see this advertising literature.  Unfortunately for using this with simple stepper drivers, they have an extra coil of wire that simple drivers have no way to control.  Two phase motors have two isolated coils, while three phase motors have three coils connected in a star configuration.

Texas Instruments offers this design suggestion for using three-phase motors: TI White Paper.  Ultimately, it is driven by three synchronized PWM signals connected to three H-bridges, each driving one of the three motor wires.  One could build a board with a micro-controller that accepted step and direction pulses and output the three-phase drive.  At that level, you could substitute the micro-control-plus-H-bridge board for the Pololu-style driver in an existing 3D printer framework.  You would need to configure the steps-per-mm correctly for the new drive system.

If you did this, and the sales literature is correct, you should get quieter operation with higher torque.  How that would affect operation would depend on the torque of the motor, the rotating mass of the motor, and the gearing or belt drive you use.

Like two-phase motors, high torque at high speed requires driving the motor with a voltage much higher than the "specified" steady-state motor voltage.


If I were to print one on my own, what is the cheapest price point I could obtain a printer that could do enough detail to make it hard to tell the difference from the real thing.

Around 15.000 US$.

FDM printers (the most common consumer-grade ones, the ones with the roll of filament beside them) all print with distinctive layer marks.  Next are resin printers, but resins tend to have a very peculiar feeling to it, that is difficult to mistake for ABS or other injection-molding plastics, when you hold them, plus they typically struggle with largish objects.  So you would probably be looking at a sintering printer, melting nylon powder with a laser.  That is expensive to buy and very expensive to operate.

Now, while the above is all technically true, it is only half the story...

In fact prints done on a cheap FDM printer can be post-processed to look almost indistinguishable from an injection molded model.  That takes probably more work to accomplish than modelling the object in cad and printing it though, so it's a matter of setting your expectations correctly (don't think to your print as "the product" but as the "base material" for your finished product).

I would say that you essentially have two options:

if you are looking at picking up a new hobby, and do a lot of sanding and polishing in the process, then: "welcome to the club!".  There are plenty of relatively cheap printers that can print acceptably well (more on this below).
if your interest is not towards 3d printing in general but is really limited to getting project done, than you could consider having a printing service doing that for you instead (basically you send them the file with your design and choose what kind of printer and material you want them to use, and they send you back the end result). It will be cheaper and probably of a higher quality than what you could achieve yourself.  Certainly it will require less time investment from your side.

If you go with option one, an affordable printer that got very good reviews from trustworthy reviewers is the cetus.  It is 299 US$, have quality components and is very very silent.  The build volume is not huge but should be more than enough for your project.

However don't take my suggestion as "this is the best you can buy for your money": there are plenty of models out there that will get the job done in the price range 300-500 US$, and if you are wishing to spend a bit more, you could get an Original Prusa MKIIs (the printer that topped the charts last year) for 600US$ as a kit or slightly more fully assembled.

Should you go for using a printing service instead, there are a lot of them.  Two among the most well known are 3dhubs and shapeways.


Horizontal lines on feature/geometry/density change

This is varying underextrusion due to loss of material to oozing in the interior of the model.
When printing the infill pattern, the nozzle doesn't follow a single continuous extrusion path, but moves from the end of one path to the beginning of the next, and under Cura defaults, does this without retracting the filament. This causes unpredictable amounts to ooze out during travel from one to the next, thereby desynchronizing the planned/intended amount of material extruded so far and the actual amount. This means, when the next outer-wall extrusion starts, there's an unpredictable deficiency between the amount of material at the nozzle to extrude, and the amount the slicer intended to extrude. The result is what you're seeing.
To fix it, you need to eliminate oozing, not just outside the model where it appears as visible stringing, but inside too. Either disable "Combing" entirely in Cura, or set "Max Comb Distance With No Retract" to something very low (0.8 mm or less). Also set "Minimum Extrusion Distance Window" to 0 to ensure Cura doesn't skip retractions for other reasons.
You may also want to play with extrusion length and speed. Too short or too long can be bad; 5-7 mm is the reasonable range for PLA with a bowden. Higher speed generally helps too; the printer should be able to handle 50 mm/s or faster.


Warping is caused by the plastic shrinking as it cools and inadequate bed adhesion is usually the what lets it warp. Either cleaning your print surface very thoroughly with rubbing alcohol or using something like a glue stick on your print bed will mitigate that warping enough that you won't suffer problems with your print. Printing too hot can also be a problem because the plastic will need to even cool more after it is extruded and could possibly lead to more stresses buildup in the plastic.

The dimensional stability of PLA really depends on the quality of the plastic. Storage conditions come into play as well, but it is mostly the quality of the material you need to worry about; I have some cheaper PLA that has gotten brittle due to having absorbed moisture despite being in a (albeit somewhat loosely closed) package with desiccants, and I also have a different brand of PLA that is of much higher quality that I just leave out in the open; this PLA doesn't exibit signs of moisture damage. Higher quality filaments are designed to resist moisture better and be more stable in terms of dimensions. With the cheaper brand of PLA, I have also experienced warping, but that is not due to moisture in the filament; that was actually from a new roll.

When a filament absorbs too much moisture, it can become brittle but still print. Excessive moisture will cause any water in the filament to vaporize when passing through the hotend and form bubbles that will ruin the finish quality of a print. You'll know if filament is excessively wet because you will hear quiet and sharp snapping sounds as the result of the bubbles that are formed in the plastic popping. You will also be able to see steam if you examine your hotend with a bright light as it is extruding.

I'd suggest trying a different brand of filament if possible, cleaning the print surface / adding glue, or at the very least, a new roll of filament.

(When using a glue stick to increase first layer adhesion, it could be worth noting something unusual I found; adding glue to the build plate of a Prusa i3 MK3S actually reduces bed adhesion in my experience. It might be worth playing around to see if super clean works for you, or if super sticky does. The build plate is coated in a very finely textured PEI if that is some information that could help your case.)


There are a few main safety precautions you should consider.

Make sure the area is well-ventilated. Acetone is flammable. A buildup of acetone gas could quickly get concentrated, meaning that a single spark could lead to disaster. Using a fan is good; angle it towards an open window. This is also to prevent exposure to acetone because of its toxicity.
Be prepared to fight a fire. Should vapor ignite, you may need to fight the fire. If it is large enough, then you should clearly evacuate the area. If it appears to be small, use dry chemical powder to snuff out the fire. Alcohol foam, water spray, and/or fog may be used on slightly larger fires. Acetone is not likely to cause a large inferno to rip through the building. But there's always the chance of a small fire. Be careful.
Create a vapor chamber. This is another way to stop a potential fire from spreading. It can also reduce contamination.
Wear gloves. This can minimize any potential transfer toxic effects. However, skin exposure is unlikely to cause major issues.

Acetone is toxic, as I mentioned before, but it is not highly toxic. Exposure via the eyes and nose/mouth is the main risk. Skin effects may occur (e.g. mild irritation), but they are minor and generally arise only after long-term exposure (hence the recommendation of gloves in some cases).

Acetone exposure is only a serious problem when a person is repeatedly exposed to levels greater than 1,000 ppm (severe effects only arise at much higher levels). It seems unlikely, given a proper ventilation system, that this will be an issue

In addition to all this, basic safety precautions such as wearing a ventilator mask and goggles should definitely be taken. When working with any such chemicals with the potential for bodily harm, these should absolutely be used.


I am an official Wanhao Distributor

By experience I can recommend you to print with this settings:

Extruder 230 °C
Heated Bed 65 °C
Have a glass surface
Use hairspray over the glass
Continue to enclose the printer or at least put it where there is almost no wind
Print at 45 mm/s

Note that this settings vary a lot depending on humidity and other factors related to where you are printing, so it would be very useful to know where in the globe are you experimenting.

Also note that humidity is very very bad for 3D Printing Filaments so keep them sealed while not using them.

Please do  comment if you have any more doubts.


How can I print a 1 cm overhang with minimal supports?

Three ideas

If either side of the red ring can have a chamfer to meet the cylinder, add the chamfer and print with the chamfer side down.
If both sides of the red ring must be perpendicular to the axis of
the cylinder, can you print the cylinder lying on its side?  You
might get good enough print quality, especially if printing with
thinner layers toward the top.
If that is unsatisfactory, try explicitly adding an inner support
ring as part of the model. Don't depend on the slicer to do what
you want, do it yourself.  You would then be bridging to make the
red disk, but that can work surprisingly well with a good cooling
fan and printer.

In all three cases, consider the slot holes you have in the red ring.  For case 3 you may need to add a support around those holes as well.  In case 2, they would want to be pointed vertically.  In case 1, the chamfer would be modified to have holes of cavities matching the slot holes.


What tweaks do slicers use to get rafts to stick?

You could experiment with the 'cleaning' part of the startup gcode shown here

G1 X100 Y0 F4000 ; move half way along the front edge
G1 Z1 ; move nozzle close to bed
M109 S200 ; heat nozzle to 200 degC and wait until reached
G4 P10000 ; wait 10 seconds for nozzle length to stabilize
G1 E10 ; extrude 10 mm of filament
G1 z15 F12000 E5 ; move 15 mm up, fast, while extruding 5mm
G92 E0 ; reset extruder

I'm not completely persuaded that it helps a lot, but the idea is to fill the extruder (with some pressure from the bed at a 1mm gap) right before starting the skirt. Typically, I still find the first line of skirt may be quite blobby, but a 2nd line of skirt seems much better. Obviously you need the bed alignment right too. A raft seems to have enough 'extra' extrusion to mask these issues a little bit.

Later reflection suggests that these introductory G-code snippets (I've now started using the PRUSA one of a line along the edge of the bed) risk problems  with flexible filament, so it might be best to err on the side of conservative for the extrude volume rather than assume that more is better here.

You can find other similar solutions in this question: Writing G-code : swiping at start of print


Monoprice Select Mini V2 retraction/stringing problem

The Monoprice Select Mini V2 uses a Bowden style extrusion system. Bowden extruders compress the filament in the tube where the gap between the filament and inner tube diameter allow for the filament to buckle slightly and compress causing a pressure build-up in the hotend. Without retraction this implies that the filament will start to ooze out of the hotend once you stop extruding.

From your settings can be seen that you are using retraction. The question now arises whether you retract enough? Furthermore, this stringing can be reduced by setting the correct settings for e.g. print temperature, retraction, coasting, travel speed. It is up to you to find the correct settings; test print objects like calibration prints (like in the image you showed) help you with finding the correct settings.

Apparently, the retraction you use still allows for some filament to ooze out of the hotend as shown in your image. This means that prior to the travel move there is still some pressure left in the hotend. A parameter that reduced the pressure prior to the travel movement is called "coasting"; basically you define to stop extruding while the head is still completing the printing moves prior to the travel move. It is advised to explore this setting. Other options to investigate further include lowering filament print temperature or increase travel movement.


From the video it is very clear there is a major problem with bed adhesion.

It also looks like you are printing on bare metal (aluminium?) which I never saw anybody doing. I must admit I don't know it is impossible or simply very rare, but the first thing I would try in your case is covering the bed in painter's tape and wipe it with some alcohol.  This is a surefire method to get good adhesion with PLA, which - from the temperatures shown in the video I assume is what you are using.

If you haven't tried this before, you should know that:

some brands of tape work well even without being wiped with alcohol
you may need to readjust your nozzle height after having applied the tape

Unless you have already done this, I would also suggest to print some test cubes and possibly some stress tests as your first prints, in order to check that the basics (extrusion rate, dimensional accuracy...) are working correctly, as well as getting familiar with the limitats of your printer.


From  forum

  Bison plastic - works great for me, only it's not "quick dry" but it's very strong, not brittle, holds PETG and PLA very strongly.
  Buy paint stripper that is/contains methylene chloride (dichloromethane). It will solvent weld both PLA and PETG.

Or see  other forum  which recommends Eastman-910 (original brand of cyanoacrylate) or any equivalent, polyurethane glue, or even epoxy.


Understand and developing firmware - IDE help

As far as I know, Marlin - assuming that is the firmware you are using - is a standard C++ (the big brother of C) project that can be opened and compiled in the Arduino IDE, but also - at least - edited lots of other IDEs.

Depending on your OS, there are several alternatives. Visual Studio, Atmel Studio, Qt Creator, XCode, Eclipse, Visual Studio Code, Atom, Sublime Text and the Arduino IDE are just some of them.

I also believe that this question should be moved to StackOverflow. However, if you have questions as to how you can make specific modification to Marlin, this forum is the right place to ask. If that is the case, consider reformulating your question!


Which material "creeps" (plastic deformation) the least (or nothing at all) under pressure after being printed?

Your question can not be answered theoretically -- only empirically.

You need to print some trial brackets with materials of interest and measure them.  The question is: under what conditions should you test them?

The problem is that creep involves both compression and tension, and the behavior may be different.  It is also impossible to fully translate material specifications into component behavior without a really good model that includes the details of the infill, adhesion to peripheries, and all the microscopic detail of a real 3D-printed part.

The problem with typical PLA may be the low temperature.  Raising the temperature of a normal PLA printed object to 160°F (70°C) softens it to the point of nearly being limp.  I have used this for force-fitting PLA parts by warming a pot of water and placing parts in it for a few moments.  That temperature is hotter than your room, but a hot summer day in the sunshine could soften the part to the point of failure.

For anything load bearing, I would want a material with a higher plastic temperature.

There are PLA formulations which are annealed after printing.  This is claimed to allow the PLA to slowly recrystalize and become both stronger and usable at higher temperatures.  I don't have experience with this.

Depending on your printer, you can also consider using a higher temperature filament, such as ABS or PC (polycarbonate).  PET-G is a little better than PLA, but it softens at a lower temperature than ABS.

As important as the material itself is the anisotrophy of the printer parts.  Be sure to print the parts so that the major stresses are along the strongest axes, typically X and Y, and not along the weaker Z asis.  Choose your infill to contribute to the strength, and use plenty of it, or design the part so that the infill is not intended to contribute to the strength.


I use a product called 3DLAC but I suppose it's regular hairspray. Makes my PLA stick to the heated bed like a charm. After cooling down the print can be removed from the bed with ease.

Only today, after a few thousand prints the glass bed of my printer broke. But I suppose this is because we didn't have enough patience to let the bed cool down to room temperature before removing the printed piece.


Extending extruder heater and thermistor wires

Soldering is fine, both for the thermistor wires as for the heater.

The wires don't need to be particularly special, though there are some things you should keep in mind:

Current. The heater can draw up to 3-4A, the wires need to be able to handle this. The wires for the thermistor can be thinner.
Flexibility. The hotend (presumably) moves, so the wires should be able to withstand frequent movement. Use stranded (rather than solid) wire.


How to prepare bed for printing ABS filament?

ABS can be a problem to print, but there are generally a couple well established methods to prepare your glass bed, which might be combined for best results:

Heated bed. A heated bed is almost a must for ABS and would be set to about 75 to 90 °C for most printers. Often this can suffice on its own, but keep the bed running for the whole print!
ABS-Slurry. One of the best functioning adhesive helpers is ABS-Slurry, which is made by mixing a little acetone with as much ABS filament as it will solve, then applying a thin layer of this compound to the glass bed right before the print. It will stink a lot, but it most certainly will offer one of the best adhesions you can get and might even prevent Warping due to the stronger bond to the bed.
Rafts. You might want to add a raft of at least 2 layers under the print. The Raft can be removed in the end, but it increases the surface area and can often help to reduce the chance of warping.

Now comes the good part: you just need to remove all the ABS residue and the bed is ready for the next preparation for any other material. This can be done with a scraper blade quite easily, maybe some Acetone and then alcohol if there are some really nasty bits.


a) about

  Is B-REP a mesh that only represents a boundary [..] ?

B-Rep contains more information, see here:

  There are two types of information in a B-rep: topological and
  geometric. Topological information provide the relationships among
  vertices, edges and faces similar to that used in a wireframe model.
  In addition to connectivity, topological information also include
  orientation of edges and faces. Geometric information are usually
  equations of the edges and faces.

b) about

  and therefore ready to be printed

it is need not only check that the model is correct (no lack of a face, no wrong face normals, ...) but also that is valid for a 3d printer (no "floating" parts, addition of supports, ...).

Finally, recall the model is not what drives the printer, the printer is controlled by the machine instructions, usually gcode. Thus, the usual evolution is: parts description (.scad, ...), model format (.stl, ...) and machine instructions (.gcode).


Sizing belts and rods for a Cartesian printer

8 mm rods and 6 mm GT2 belts are generally accepted as a good tradeoff between price and performance, an exact calculation is possible but might not be very relevant if another part is flexing. Also, generally speaking, the smaller the part the sooner it will wear out of specification. Thus your service interval might be higher compared to an over-engineered printer.
In short, it depends on what your goal is, if you desire low maintenance and accurate machine, you might be better off with heavier gauge parts. Obviously, this will also affect the speed of printing.
A 6 mm GT2 belt might have a higher stretch factor compared to a 10 mm belt, but can be mitigated by adjusting the acceleration. In addition, a 10 mm belt has a larger pulley reducing the number of steps per mm, lowering precision. As such you might be better of using two 6 mm belts.
Increased rod size for the print bed will not affect printing speed much but might help with accuracy since the bending modulus is lower. Play around with the calculators below to get an idea of the force your beam will have to withstand. That said, there are a lot of other factors that will flex under load, for example, the bed leveling springs. You can replace them with solid spacers, but that might warp the bed when it heats up.
https://www.engineering.com/calculators/beams.htm
https://www.omnicalculator.com/physics/acceleration
To conclude, I would use the calculators to figure out if the 8 mm rods are within tolerance for the intended speeds and load, but don't forget to look at the overall picture. The quality of parts you choose is one such thing.


Okay so one problem at a time.. You have several issues.

1 You will likely note while it prints, the pillar will almost catch and sometimes twang as the layers get higher and higher. Issue here is you are over extruding a bit and the head is dragging on the print. Add some leverage and then you get this strange pattern. Letting it cool more between layers or by adding a fan will also help. A small pillar like this will not have much time to cool.

Or it could be that your Z is not straight. Whats the name of this test? Right the Z resonance test. Check out your smooth rods and screws and see if they are perfect or not.

2 Hmm maybe some oozing / over extrusion. I mean it will never be perfect.

3 Looks good to me. You are printing PLA not ABS?. Looking at your temps and I hope you are doing ABS.. Which probably should bridge a bit better. That said even my highly calibrated machines would have a hard time with a bridge like that. I've been at this for years. Fan will help. Different material will help. I mean you are printing over air. That said 1-2 degrees will make a difference. Try slowing it down. Try lowering temp. Add that fan. Remember every spool will need a new perfect temp. Even a different color will need calibration as the pigments change the temperature profile.

Last over all, simplify 3d seems to really help. I rarely spend time calibrating these days. Albeit they cost a lot. no affiliation.

I also like this visual guide
http://reprap.org/wiki/Print_Troubleshooting_Pictorial_Guide

EDIT. I see you have added more photos!
For the Z axis, I stick with my first assessment. Over-extrusion. Or it could just be getting too hot the higher you go. Maybe add a min time between layers option if your slicer supports it. Fan is good too.

XY resonance.. Tricky tricky. My research shows this can be solved by using a different slicer program. You will have to research how to solve this with your preferred program. Maybe try to tighten belts, and tweek your oozebane settings. I would also play with acceleration and Jerk at the Firmware level..

Last one, Bridging. You have bigger issues than bridging. All that shows is you don't have temp dialed in 100% yet. 230 might be high.. 85 for PLA would be high as well.


Try Fusion 360. It's free for educators, students, enthusiasts and start-ups. It's not 100% intuitive, but once you learn the basics, it probably has all the facilities that you will ever need for mechanical design.


Thermoelectric cooler for part cooling fan?

On the printhead?
TECs or Peltier Elements are incredibly inefficient compared to airstream coolers. Their only benefit is perfect temperature control, from which you will have nothing because there is no firmware that cares for the temperature of cooling air or the cooling body of a Hotend. Also, a TEC creates a lot of heat on its output side - which means you heat the air just millimeters away from where you want to cool the air!
To get the heat produced by the TEC away, you either need a rather large cooling body - which is a lot of weight and space you need. As a result, you reduce the maximum print speed a lot. A water cooler isn't necessarily that much lighter, but it also gets us the trouble of having a highly conductive liquid right on the printhead.
lighter alternative: compressed air
You'd have much better efficiency by having compressed air decompress (as in: get out of a slim nozzle) slowly just a few millimeters in front of the air intake of your part cooling fan - expanding air cools down a lot, and running a compressor for a few moments takes less energy than running a Peltier element with the same temperature drop. In a pinch, a CO2 canister could provide the needed high pressure air, and a nozzle like you have it on an airbrush would work.
Move it off the printhead?
As the weight of the necessary secondary equipment is an issue, it might be better to move the Peltier element off the printhead. For example, by using a flexible hose that supplies the air to the cooling fan, and feeding that with precooled air - and now a Peltier element can shine: by having the weight be no longer a matter, we can use a rather large cooling body on the outside and cooling fins on the inside.


Are there many assembly type 3D printers?

Yes and no:

Yes, there are machines, that assemble things from parts. For example, SMT placement equipment & pick-and-place-machines. Almost all electronics are made this way. In fact, a lot of items are made by using Pick-and-Place machines in the final assembly.

On the other hand: No, there is no 3D-printer, that works by just being a P&P machine: it simply is not inside the specifications of additive manufacturing to be just an assembly machine. That is an assembly or pick and place machine, no matter if they call it printing. It is not.

However, I have seen a recent makerfaire video and a talk that was showing a prototype of an E3D toolhead swapper, which - in its idea - would allow to combine a 3D printer with a P&P machine. Their idea is to fully automate the manufacturing process, including adding non-printed parts with grabbers or the like.


Selective laser melting and building near the road (vibrations)

That depends...
Among the fact that can influence if vibrations could be the problem in this case, I see the following s is the most prominent:

Powder grain diameter
Powder composition
Powder shape
Aimed for resolution

The grain diameter and composition are the more influencing factors: fine powders of low-density metals will be much more affected by vibrations and almost behave like dust or fluid under resonating vibrations. On the other hand varicose powders of high-density metals will more easily settle down and have much higher thresholds for how much vibration affects them.
The shape mainly influences how particles coagulate: very coarse particles, think snowflakes, will interlock and bond to one another creating flakes of several powder particles. Vibration can influence the formation and compactness of such flakes and such influence the resolution.
If you want to print very coarse with rough, large powders, vibrational mitigation might be not needed. But should you want to print pretty much in aluminium dust... you need to take it into account.
Vibration mitigation
If the Vibrations influence your prospect machine placement, you'll have to inquire about at your machine manufacturer, best with a seismometer measurement of the places where you want to build. By placing special fasteners and vibration dampeners (springs or rubber feet) in between the machine and the floor, anchoring it to a separate foundation that is not connected to the surrounding building, or even by having the machine float, vibrations can be mitigated.
It's often much easier to install larger vibration mitigation equipment on lower floors and mounting it directly to the foundation of a building (ground floor and basement) is often preferred.
In case of special projects, the local municipality might allow banning (heavy) road traffic or even pedestrians from areas that affect the manufacturing in such a way - the Cologne Opera is partially under a public space right next to the cathedral, and during events, pedestrians may not use a chunk of it. In my city, the use of one road with trucks is banned due to vibrations they can cause in a nearby old building.


Sort of related, see the answers to:

Commercially available 3D printer fume and UFP extractor, and;
What are the best air filtration options for enclosures?

Addressing your points in turn:

Ventilation - Probably not, as you want to keep the print warm. However, when printing with filaments where well ventilated conditions are recommended1, to prevent the build up of noxious fumes, from ABS for example, you would need (active) filtration, see this answer.
Filament Placement - I have seen printers fully enclosed, including the filament. However, there is the potential issue, especially if using PLA, that if the temperature inside the enclosure reaches temperatures approaching those of a closed car, on a hot day, then the PLA filament could become damaged/melt, and not roll of the spool correctly. In that case, you could place the reel on to of the enclosure and feed it through a (small) hole in the top. Feeding it through the side, could add additional resistance to it being pulled from the reel, depending upon placement.
Noise cancellation - Line the enclosure with non-flammable foam, or some other non-flammable noise cancelling lining
Material - As Mark states in his answer, be extra careful of thermal runaway, as 3D printers run hot, and an enclosed printer, even hotter. Wood is the sort of material you probably want to avoid. Whilst it is cheap, and would probably work fine in most situations, in the case of an emergency (read, fire), then you are merely providing additional combustable material. It would be advisable to stick with an aluminium frame (non-combustable) and glass (non-combustable and insulating).

Additonal Points:

Electronics - You may want to consider placing the electronics (i.e. controller board) outside the enclosure, as the RAMPS board generally likes to be kept as cool as possible (especially the stepper drivers).
Display/Control - Along with the electronics, it could be a good idea to also place the LCD display, and conjoint control panel, outside the enclosure, so as to provide ease of access. You don't really want to have to keep removing/opening the enclosure to change a minor setting.
Access - Do you want a lift-off type enclosure, or have an access door? The latter is certainly more user friendly, or convenient.
Sturdiness - Do you want a light weight (flimsy?) enclosure, or a heavier, more robust, enclosure?
Safety - An air-tight fire box could be worth considering.

Note: After having stated that wood is not the best idea, it seems that IKEA tables are sometimes used, by stacking two on top of each other: New IKEA hack lets you create a 3D printer enclosure for cheap

A safer bet is this delta printer enclosure, which is, essentially, a larger delta frame, made from aluminium extrusion and acrylic, enclosing a smaller delta printer:
4 Simple Steps to Build Your Own 3D Printer Enclosure

For an example of a cheap, yet extremely flammable enclosure, made from plastic sheeting and piping, see How to build an enclosure for your 3D printer

1 See Davo's comment.


Gaps in Cura's Slicing for Monoprice Select Mini V2

If you enable the option "Coasting", the extruder will follow the extrusion path at the end of switching to the next layer or the next section, but will not deposit any material as it uses the build up pressure in the nozzle to deposit the final bits. This shows up in your G-code representation by empty (non-depositing) gaps (in reality, when fine-tuned correctly, will be filled).

E.g. sliced without "Coasting" enabled:

E.g. sliced with "Coasting" enabled:


Kapton tape would be the logical material. It's unfortunate that your vendor did not supply that as a separate item, rather than sticking it to the "cotton" (I'm guessing not actually cotton, as things might get a bit scorching for cotton, so I'm assuming some type of ceramic fiber or the like.)


Gobs of filament during initial movement of extruder

The G-code you posted indeed extrudes a blob of filament at the origin (6 mm). During this extrusion pressure is build up in the nozzle/heatbreak, if you command a move after this prime blob, the nozzle will leak filament releasing the leftover back pressure, it is normal to include a retraction before moving to the start of the print, e.g.:

; problematic!
G1 F200 E6 ; extrude 6 mm of filament
G92 E0
G1 F1500 E-1
... ; End of start G-code, move to skirt/brim etc.

An example Cura start G-code could look like:

G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode

G28 ; Auto Home All AXIS

M117 Heating bed 1st...
M190 S{material_bed_temperature_layer_0}
M117 Heating core 1st...
M109 S{material_print_temperature_layer_0}

M117 Priming...
G1 X0 Y0 F2500
G1 Z2
G92 E0
G1 E15 F250
G1 Z4.0 F500
G92 E0
M117 Wiping...
G1 Y5 Z4.0 F500
G1 Y10 Z0.2
G1 Y15 Z0.2 F500
G92 E0
G1 F200
G1 E-3

M117 Printing...


If you can, set your slicer to do honeycomb fill.  Depending on the weight requirement choose maybe 10% - 20% fill.   That ought to do the trick.  It won't be solid, but it should be strong enough.

What are you going to put on the platform?


I'll try to give it a shot as the other answer (perfectly sound answer b.t.w.) does explain "how" we use heated beds, but not "why" they are actually needed for good prints.

Plastics or polymers are mostly amorphous (no macro crystalline structure) and usually relatively hard and brittle at low temperatures (this is referred to as "glassy"). By increasing the temperature of the plastics the state of the material changes as it becomes soft and more ductile (called the viscous or rubbery state). The temperature at which this transition takes place is called the "glass transition temperature". It is this temperature where you would heat your bed too (or close to this temperature). Below the glass temperature, the expansion is reduced/low because the polymer chains cannot move easily due to the closer packing and stronger inter-molecular forces; increasing the temperature increases the expansion lowering inter-molecular forces. The difference in stress between the bed and your print is therefore reduced (as of the expansion  of the heated polymer).

This explains why we use heated bed to get the prints to stick to the bed. To answer your question why it helps in removing prints is that when the temperature is lowered, the polymer gets back into its "glassy" state, shrinks a bit and automatically loosens the print from the bed.

Indeed for printing PLA you can print without a heated bed, but for materials with a higher glass transition temperature and higher printing temperature it's almost a must to have. Downsides of heated beds are that they require a lot of power and when improperly installed lead to burned wires and connectors. It's usually wise to strain relief the wires from the bed and use proper gauge silicone leads and connectors.


TL;DR
Yes, glass warps when hot. Use a physical touch sensor and calibrate it out, or swap glass if it's "bad".

The further you go into mechanical studies like 3d printing, mills, and lathes, you will find out that nothing is perfectly flat. Everything has a tolerance to it, whether the manufacturer provided it or not. Better manufacturers provide the tolerance data.
As you have or will find out, yes, glass does warp when heated. That is because you are not warming the glass evenly. When hot and cold spots form in glass, the glass tends to warp up or down, depending how the heat travels.
It's common for 0.01 mm warp when a glass bed is brought to printing temps (60-100 °C). If one has a larger format bed, like my Vulcanus at 500x500, 0.03 mm changes are possible.
One can remediate this warping, as it usually appears in the same place during the heat cycle. So if you calibrate after the bed is heated, you should reduce said errors. Another more comprehensive way to fix this, is with a physical touch sensor and create a grid map of the bed geometry.


The patents that cover Lego bricks have expired, so you are free to print bricks using the same interlocking system. You are even allowed to offer such prints commercially.

What is not allowed (and a violation of trademark law) is to call them "Lego bricks" or use Lego's logo. "Compatible with Lego" on the other hand, would be fine.


Can a 3D model of a copyrighted work be rendered legally without infringement?

First, copyright laws are complex and depend heavily on the specific details.  IMO, your question is really too broad to answer.

An interesting example of how details and interpretation affect whether something is a violation or not is Kienitz v Sconnie Nation.  In this case a copyrighted photo was clearly copied, modified, and used to make a t-shirt that was sold; but, it was not deemed a copyright violation.  On the surface it seems like a violation; but, the court ruled it was not a copyright violation because of the specific details of the case.  Using something as a starting point for a unique creative work that is clearly your own creation is not copying.  I am sure you can tell the difference.

Second, in your description you mention "Free Use".  If the owner has granted "Free Use" of their product; but, they are still wanting to declare the item copyrighted, I would hope that they have granted that "Free Use" under a defined agreement.  In that case, it would seem likely that the creator may just be trying to protect his design from being plagiarized and/or sold/used in a way that is against his intent.

If you have a way to contact the owner, why not just contact them and ask their permission for what you want to do.  If they have put it out for public use, they would probably be excited to have other people see their creation.  Just make sure they gets the credit for the design.  If it is a creation they are intending to protect (like Disney does with Mickey Mouse); then, the answer will be an unequivocal no.  Note that one weird exception is that Disney has granted use rights for Donald Duck to the University of Oregon "Ducks".

Finally, you state that that your intent is "for no purpose of using, distributing, creating, mixing, ..." and you list almost every way of making it public.  If your intent is for what you make/copy to never make it into the public domain; then, how will your question ever be anything other than hypothetical?  I know that there is presently no "private use" exclusion for copyrighted material.  It isn't legal to copy someone's DVD for you to watch privately; but, in reality, no one gets prosecuted for a single private instance.  It is abuse that gets prosecuted.

In what you intend, it would seem that you be best suited to seek out first what would be the "right" thing to do rather than just focusing on what would be "legal".  If you are concerned what you want to do may be wrong and/or illegal, it is probably best to not do it.


Are there any methods of limiting exposure of hazardous fumes and odors emitted by heating the plastics?

Using negative pressure ventilation and a suitable organic filter will limit your exposure to toxic compounds, but won't completely remove them from your environment.

Enclose your printer in as air-tight a box as you can manage, then use a fan to suck air out of the box.  This negative pressure will ensure that any leaks in the box will not allow gasses to escape.

The air should be blown through an organic filter.  This might be done with face mask filters for painting, for instance.

Additional filtering may be done depending on the compounds you expect the printer to produce, but the ideal situation is to set up a ventilation system to the outdoors where the products cannot concentrate and harm anyone.

Another poorer option is to simply wear a proper organic filter mask yourself.  It's not as good, since the compounds can spread through your residence or remain in the air and be inhaled when you aren't printing.


In general, PLA is known as a "food safe" filament, especially Natural PLA. However, filament suppliers have different processes that may detriment the food safe quality.

Doing a little digging, I found an article on the M3D site which mentions the following about their filament

  All of our products, including our filaments are made from 100% non-toxic components and considered generally safe under normal use. They are not considered a chemical, or a hazardous material by OSHA standards. Therefore, OSHA defines it as an "article" and does not require MSDS sheets. You can see more information about that here: http://www.ilpi.com/msds/faq/partb.html#article

So, without contacting M3D directly to acquire an MSDS (or asking if its food safe), you will not find one online.

Here is an article on a few tips for printing food safe objects as well. In a nut shell, don't 3D print food handling objects with crevasses, using uranium, or intend to put in the oven (a.k.a common sense).


Nozzle always "randomly" moves to 0 during print, then resumes

I see two problems in your video:

It looks like the first layer is built too much upwards. (The level calibration should be so that a Z-height of 0 can barely fit a sheet of paper under the nozzle. )
Your printer is not extruding at all. As you said, the extrusion has some problems. Extrusion problems will cause adhesion problems too.


Paper as build surface - how will that work?

Blue masking tape is a common bed surface, especially for unheated beds. It is effectively an adhesive applied to a paper, although I suspect the paper is treated in some manner to serve as a barrier to paint, as the blue tape is sold as paint masking tape.

A sheet of ordinary paper isn't likely to catch fire, as the bed temperature will not reach combustion temperature for paper (more than 230 °C), but you still have to have the means of providing adhesion of the paper to the bed.

A thick enough weight of paper may provide sufficient rigidity to provide for a stable print surface, if the perimeter is well secured and uniformly (smoothly) attached.

You'll have to experiment with various types of paper surfaces as well, as some may be treated (calendared) during manufacturing, which could affect the results.

Blue tape is your best bet if you want disposable. Also if you use care in removal, it is not a single use bed covering.


Subdividing an existing mesh further won't do anything because you're not adding additional detail, just representing the same thing with more triangles. Subdividing as "preparation" doesn't make much sense. You should make sure the mesh is created with sufficient detail while modelling.

A mesh created for 3d printing should generally have a lot more triangles than one created for use in rendering, but within reason. It doesn't make sense to make the mesh (much) more detailed than the printer can print, and similarly having lots of triangles can make the slicer slow or unreliable. As a very rough guideline, I would say that 10.000-100.000 triangles per model is reasonable (but this obviously depends on the size and level of detail).

Some slicers may output G-code that will have segments corresponding to each and every triangle in the model, even if these segments are very tiny. This may cause the printer to slow down a lot while printing, but most slicers take care of this by merging small segments into larger ones. Depending on your slicer, you might have to watch out for not having the triangles be so tiny that the number of segments created becomes a problem.


Is 3D printing really just 2D printing? Because only 2 motors move per layer

I was wondering the other day why don't all three motors move at the same time?

That is perfectly possible for most printers (with limitations, "3D Printing" with all steppers being used is called "non-planar" printing), but there are some major cons you need to deal with. First, there are not that many software suites that slice objects perfectly well like the "normal" per "fixed/variable layer height" slicing as the slicers are under developed. Second, it requires a specific tall and slender nozzle/print head, else the height of printing is very limited. Last, besides generally not being useful for rectangular prints (except for 90° overhanging structures1)), this method is only/best suitable for curved objects as the top layer will follow the contours of the object.

It makes sense if a 3D printer really does print with all three motors moving.

No, it does not make sense, the essentials of 3D printing it that it produces a 3D object, not that all stepper motors should be running simultaneously.

Won't it also be more efficient if they do 3D print in all axes?

Not necessarily, there are limitations to non-planar printing like geometry and print quality, but, you could (in some cases) print with less support material.

1) : From Rene K. Mueller, published March 3, 2021, https://xyzdims.com:

Note that these are demonstration pieces, normally you would rotate the print for 90° and print it sliced normal (planar).


You should see MAX endstops similarly as MIN endstops, or as an additional option to protect the printer:

Similarly seen as MIN endstops, you would define in the firmware that you are using them to set a reference point at maximum values, your offsets and bed dimensions would be calculated from the MAX positions;
You can configure the MIN endstops and have additional MAX endstops set beyond the bed size dimensions. If the printer would encounter a layer shift causing the nozzle to go beyond the printer (MAX) boundaries, the printer shuts down when the MAX endstop is triggered.


Heatbed PID vs Bang-Bang - which one is more stressing on components?

The frequency of the cycle shouldn't affect the efficiency as such, however more might be lost due to physical properties.  Fast should cause less stress on the printed part, unless it hits a resonance frequency, which it unlikely.


Problems with noise, heat bed temperature and no X / Y endstop sensor on Makerbot Replicator 2X

First, your Y-belt is way too loose! (seen at the beginning of the first video). It is so loose the idlers barely grip onto it!

Second, the X-endstop metal pin is loose, seen at 1:22 of the first video. Could be that the endstop is not working. Maybe you can hook up your printer to USB, you can then send direct commands to the printer, e.g. M119 will report the status of the endstops. Sending this code multiple times will alternatively pressing the endstops manually you can find out if they work.

From the second video can be seen that the nozzle to bed distance it too large, and if fixed and still not adhering you need to apply an adhesive (hairspray/glue stick/or 3D print adhesion spray).

This printer is in need of some serious maintenance! Depending on your technical skills this may be a challenge!


3D printer manufacturers - sales statistics

Getting this data is not easy.  Many companies that make 3D printers are either private companies that do not report results or are larger companies where 3D printers are one of many products they manufacture.  Some companies study this information through mining public sources and surveying users for their opinions and experience.  The result of some of these studies are available for a fee.

Occasionally, a trade publication will survey data sources and produce an article.  In other cases, a trade pub will publish an article generously offered by a commercial contributor.

It is always difficult to know what is true when abstracting information from obscured, noisy, and biased information sources.

Your question itself includes a bias.  You use a words that include a value judgement: "but that likely doesn't translate to sales, at least for the more overpriced ones."

The article you reference is not a deeply researched investigative piece.  It is simply some product details for the five printers in 2016 which sold the most on Amazon.com.  It doesn't include printers which were not sold on Amazon, so it leaves out any printers which use a different distribution channel.  Also, the article include an link, probably which generate revenue back to the magazine, to each of the five printers sold through Amazon.

To summarize, it is very difficult to aggregate this kind of information.  Those who try to do so like to be compensated.  A list of the top five devices on Amazon is a biased list.


Acetone is quite an aggressive solvent, so white residue could be part of your heatbed print surface that is dissolved, and then when the acetone evaporates the dissolved part crystalise on the heatbed again.
Acetone should only be used on PEI sparingly, not at all on powder coated surfaces. Use IPA (Isopropyl Alcohol) to clean of residue between prints. If you have problems with adhesion, you can also start by washing the build plate or surface with water and dish soap (with no other additives). The surfactant in the soap traps oils and other impurities and flush them away, instead of dissolving them temporarily and then depositing it on the build surface again when the solvent evaporates.
Like mentioned in other comments, use IPA or water/dish soap to clean off any residue.


FlashPrint visual glitch on Linux (Debian testing)

In addition to open source niceties of OpenGL, you need to will often need to install and update the drivers for your GPU.  If you do not wish to or cannot utilize your GPU (it'll cost u in performance), look for options to turn off hardware acceleration or use a purely "software renderer" type setting.  I don't know if FlashPrint has such settings, but i do know that OpenGL can do some screwy stuff if you lack correct Nvidia drivers (and have an nvidia gpu).


Extruder clicking issue with MKS Board v1.5

There is one reason why extruders "click": the material can't be melted and advanced fast enough.

There are two likely reasons why your extruder works when used manually, but not during a print:

1. The temperature is not hot enough for the speed (volume per second) demanded by the print.

Have you verified that you're using the proper temperature, and that the head is reaching the proper temperature?

2. There is too much resistance on the delivery.

Have you verified that the Z positioning is not too close, causing back pressure and interfering with the deposition?


Proper hotend heater for Reprap x400 Pro V3

The part causing the hot point failure was the connector for the heater and sensor. The connector showed no sign of burns on the heater pins, but the square tubes (see attached image) accommodating pins from the other connector had started to straighten out toward its original sheet metal state due to heating from current. Bending the tubes back in place allowed the connector to work temporarily and confirmed the failure cause.

Details: After getting a 12 V 30 W heater, it also didn’t work. The hot point had stopped working because a wire brush had shorted across the heater terminals. Because a spare hot point worked, the failure wasn’t in the circuitry. The spare was a 12 V 30 W heater (from resistance measurements), while the heater on the failing hot point was a 12 V 40 W heater (from resistance measurements). This made me suspect that the heater resistance had shifted, and the circuitry shut off the heater. However, apparently both 12 V 30 W and 12 V 40 W heaters work on RepRap x400 V3. The brief short caused the bent sheet metal of the connector to start straightening back out of the bend.


The failure you are faicing is underextrusion. Underextrusion can have several reasons. Among the three most common I encountered in my printers:

The nozzle could be clogged, hindering flow (Very crushy, squishy prints after it worked fine before)

Dissemble the filament path till you can push an acupuncture needle through the hotend, heat it, press out all filament, reassemble.

The extruder might be skipping steps or shredding filament

check if it is just not gripping the filament, not turning at all or clicking.
real Troubleshooting might be needed

The g-code might have a bad setup for the filament you are using - try upping the higher extrusion multiplier/flow rate and print at least 2 walls!

In Ultimaker Cura: Custom > Material > Flow

If not there yet: Gear > Material > hook Flow


Proper wire gauges for extending all CR-10S wires

If my calculations are correct, a typical ceramic heating element for the extruder heating block runs 40 W. At 12 V dc, that equates to 3.33 A. A 24 awg wire is rated for 3.5 A, which means it barely covers the draw from the heater. A high torque Nema 17 motor will draw 2 A (which is probably heavier than most standard stepper motors in most 3D printing applications). Seeing as how the 18 awg wire is rated to 9.5 A, you should have no issue extending your wires using this gauge of wire for all of the extensions.


Wash-away filament used for support in PLA printing is typically PVA, which is completely water soluble and may serve your purpose. It is easily 3D printed as the primary filament and attaches well to the build plate.

Many 3D printer filament suppliers will carry this type of support material. It is important to keep it in a sealed bag with desiccant as it will absorb moisture from the air, rendering it useless for printing.

One such resource is MatterHackers which prices a half-kilogram at US$45. The link provides suitably appropriate information:

  PVA (Polyvinyl Alcohol) is a water-soluble material that is often used
  as a support material, but can also be used to print independently.
  PVA supports are useful for complex designs where removing support
  material manually is difficult or impossible, but leaving the part in
  a water bath overnight will completely dissolve this material.


The first thing to understand is what causes warping.  Warping is caused by the thermal contraction of the plastic when it cools down.

Simplifying things a fair bit, you can visualise the process like this:

hot, expanded plastic gets deposited on cooler, shrunk layers,
when the hot plastic cools down, it shrinks and pulls the upper part of the layer below inwards
at this point, the layer below has a differential in the compression between its upper and lower parts, and curls up
the problem is exacerbated at the very first layer (the one touching the bed) as this is "locked" to a rigid body (the bed) and cannot shrink, while subsequent layers are only attached to the somewhat flexible plastic beneath, and thus can contract.

Also notice that the larger the part being printed, the stronger is the force trying to curl-up your print.

Once one understands all of this, then it is possible to appreciate the many ways the problem can be mitigated.

Here are the common ones:

USING A MATERIAL WITH LOW SHRINKAGE COEFFICIENT

This translates in smaller tensions and thus less force "pulling up" the corners of your print.  Historically, 3D printing started with ABS because this material was one of the very few, relatively safe ones to source.  Nowadays there are materials like PETG which have similar mechanical properties to ABS but are much easier and forgiving to print with, so - unless you need ABS for some very specific reason (e.g.: acetone smoothing) consider never printing with it.

DECREASING THE THERMAL DIFFERENCE BETWEEN MOLTEN AND SOLID STATE

Concretely, this means lowering the "gap" between the ~200°C of the nozzle and the ~20°C of room temperature by using a heated bed and - possibly - an enclosure.

The heated bed not only drastically diminish the shrinkage of the first layer, but because heat radiates, and hot air goes upwards, the entire bottom of the print has shrinkage mitigated.

An enclosure just increase the benefit of the heating bed, by reflecting IR radiation back towards the print and preventing hot air to escape.  A heated enclosure just improve things even further.

Some slicers offer a "shroud" option, that encloses the entire print in an enclosed, sacrificial structure, that tries to emulate the benefits of a proper printer enclosure.

INCREASING ADHESION WITH THE PRINTING BED

That is the "brutal force" approach: if you face a strong "curl up" force, oppose it with a strong "anchor down" one.

The increase in adhesion can be achieved in a number of ways:

Lower print speed (more time for the molten plastic to "bond")
Overextrusion (more pressure, more material)
Disabling cooling fan (more progressive cooling, more time to "bond")
Using a brim (more contact surface between print and bed)
Using "ad hoc" material on the bed (PVA glue for PLA, ABS sludge for ABS, kapton tape, hair spray, blue tape, etc...)

REDUCING THE CURL-UP FORCE

This is typically achieved during design.  Designing is a vast field and it would be impossible to cover all the possible mitigating strategies one could use, but here are some of the most common ones:

Prefer assembling smaller parts over printing huge ones.  This is self explanatory really, as the curling force increases with the amount of material "pulling", the least material one has, the less force one gets.
Make relief holes above the first layers in long structures.  This will essentially "break" the build-up of tension in the layer, creating many points with a little "curling up force" rather than two with a huge one.  Something along the lines of this, for example:

Avoid extensive overhangs close to the bottom of the print (this is because otherwise you will have considerably more material "pulling up" than you will have "anchoring down".  Here is an example of what not to do (to be fair: this was specifically taken from a bed adhesion/warping test).

Of course all of the above strategies can/should be combined, when possible.  Even if not warped, a part with a lot of internal tension will perform less predictably and possibly worse than a part where such tensions are lower.


Why do 3D Printers Suck? Please share your user experience

First, regarding "Why do 3D Printers Suck?" - The answer is They Don't!

Every tool has its limitations and you need to work withing the limitations of the tool.

Second, there are A LOT of different types/technologies, manufacturers, and price points and all of these have specific limitations.

I live in Tigard, OR and both my boys are in High School.  Our High School has a pretty advanced Technologies Department.  We have had a 3D printer for a several years and use it for printing parts for our after school programs (we have three FTC teams, one FRC team, and one (underwater) MATE team).  This last year the school introduced a CAD class and added about 15-20 new Afina printers so that the students can print what they design.

I talked to my sons (they have both used the printers) and they said the only problems they ran into were mistakes they made.  Two examples of that are:

Printing with ABS and having it warp (probably bed temp)
Trying to print a design with too thin a wall

I think there is a BIG opportunity for improvement here.  Having a "Slicing" program that doesn't require tweaking and would warn of likely print problems would help A LOT.  I like the idea of the new PrusaControl.  If this idea could be extended further as Thomas Sanladerer suggested in his video review

I know the Head of Technologies Department (I help mentor several of the after school programs).  He has been responsible for getting printers and I recall he was concerned about more high-level things:

Service, Maintenance and Repair
Fumes (this is a lot of printers in one place with students in the same room)
Network interface and driver compatibility with school computer/network standards.

I believe there is another opportunity here.  If you could provide some sort of a "printer farm" where the students could send their print to the "farm" and then have a highly visible indicator on the selected printer would their name/ID when their print starts.  That way you can get more efficient use of the printers and the space they consume.