Degradation starts at 260 °C and shifts towards full blown decomposition towards 350 °C. 250 °C is technically fine, but you should keep in mind that you've got little to no wiggle room for error at that temperature. Your thermistor and board may not be accurate enough to guarantee you'll never overshoot that temperature, and the way 3D printers often handle temperature adjustment exacerbates that risk. You can print at 250 °C, just be aware you've got basically no margin for error.


Depending on your G-code flavor you may be able to use M109 (heat and wait) instead. If supported M109 will wait until the target temperature is achieved.


The surface defects you describe is caused by Z-wobble. Basically this leads back in a defect in the Z axis gantry where X and/or Y movements are transferred into the print head. This can be cause by:

a damaged nut,
lead screw not straight,
stick-slip,
binding,
lead screw out of alignment with the coupler,
lead screw touching the stepper shaft in the coupler,
the Z guide (at the other side of the X-axis arm; the one without the extruder mounted on it) has too much friction of the wheels on the profile,
play on the carriage,
lead screw should be the same distance from the extrusion profile from top to bottom,
etc.


What is the best infill pattern for shearing strength?

Yes, some infill patterns are better than others for preventing separation of layers. Basically (modulo some assumptions about uniformity of distribution of force), the shearing strength of the part in the Z direction at a particular layer is going to be proportional to the surface area of bonding between successive layers. So infill patterns that stack identical infill extrusions on top of each other at each layer should be expected to be much stronger than patterns where successive layers make only partial contact. In other words, "2D infill patterns" - grid, lines, triangles, tri-hexagon - should be a lot stronger than "3D infill patterns" - cubic, octet, gyroid, ... This matches my experience printing bolts oriented along the Z-axis - ones printed with gyroid snap easily unless other measures are taken to strengthen them, while ones printed with triangles are fairly strong (though nowhere near as strong as ones printed oriented in the XY plane.

If you have other reason to prefer a "3D infill pattern", its weakness can be mitigated mostly by increasing the infill line width, so that the lines of successive layers which don't entirely overlap still touch on more surface area. (Just increasing the infill line width also works to make "2D infill patterns" even stronger.) However, be aware that with high print speed typically used for infill, increasing infill line width can easily exceed the capability of your hotend, resulting in underextrusion, extruder skipping, and stringing all over the place.


How to improve resolution using 0.3mm nozzle?

knowing that the min layer height can be 1/4 the size of the nozzle?

I'm not sure if that is a limitation of your printer specifically, but going "down" there is really no hard limitation to the layer thickness ratio that I know of or have experienced myself.  At least not on modern printers using standard stepper motors and 1.75mm filament (older 3mm printers were more limited on this).

Going "up" you will hit a hard limit at around 3/4 of your nozzle diameter, as layers will have a hard time bonding to each other past that, and the wall surface will be very corrugated (but I take your question about "best settings" is about making the print better, so with thinner layers...)

If you print at reasonable (as in: not too fast) speed and have calibrated your extrusion properly, you should be able to print at any layer height your printer supports, the limiting factor normally being the mechanical precision of your printer / the gearing of your stepper motor.

In particular, you should try to print at layer heights that are multiple of the distance your printer will travel upwards for each step of your stepper motor.

Simplifying a bit how stepper motors work: say that your screw raises 8mm for each revolution of the stepper motor, and your stepper does 200 steps per revolution... your printer will raise 8mm/200 = 0.04mm per step.  If you print at 0.05mm, most layers will be 0.04mm, with 1 in 4 being 0.08mm to compensate for the lost 0.01mm at each layer.  This will produce noticeable defects in the print.

The information on how your Z axis is geared is seldom available in the official specification sheet, but usually there is always somebody knowing it on the printer user forums.

As for "best settings", those depends typically from the type and brand of filament being used, as well as from the 3D model geometry.  Printing slowly is always a good idea though, as it limits the "noise" on the print due to vibration.

In your particular example, threads (which are substantially a very long overhang) will actually benefit from a high ratio between nozzle width and layer height (so a larger nozzle or a lower layer height).  This is because, the overhang angle being the same, higher ratios will give more material to extrude onto at each layer.  You can visualise this by thinking to how easier is to offset a stack of books compared to offsetting a stack of dice.


Not easily.  Some folks have been messing with both 2 and 3 LCDs and based on their posts, the pinout is different between the two.
Ender 2 display pinout from when one GuzLightyear figured it out for Marlin (MKS MINI 12864 LCD):

          -----
     5V  | · · |  GND
   MOSI  | · · |  LCD_RS
 LCD_A0  | · · || BTN_EN2
  RESET  | · · |  BTN_EN1
BTN_ENC  | · · |  SCK
          -----

From a user called arnd13, the Ender 3 equivalent would be:

         -----
5V      | · · |  GND
MOSI    | · · |  LCD_A0
SCK     | · · || BTN_EN2
CS      | · · |  BTN_EN1
BTN_ENC | · · |  Buzzer
         -----

Maybe you have some luck in debugging your screen (sometimes with these LCD screens, a contrast adjustment resolves the issue).


Prusa i3 hotend not getting to the temperature that I want (180 to 230 celsius)

Usually, this kind of problem is due to an issue with the control loop of the temperature. You can try to do PID Tuning by running the command M303 E0 S200 C8. This will heat up the hot end and cycle it around 200C a few times, and afterwards tell you Kp, Ki and Kd values which you need to enter into the PID settings of your firmware configuration, or store them in EEPROM using M301.

If this does not solve the problem, then disconnect the heater cartridge and check its resistance with a multimeter. For a 12V system, it should not be higher than 6Ω (24Ω for a 24V system).

If the heater cartridge is okay, then perhaps it is a problem with the power supply. While the hotend is heating up, measure the voltage across the heater cartridge. It should not be much less than the nominal 12V/24V your printer runs at. If it is, you may have a bad MOSFET or power supply.

Finally, if you have a very powerful fan blowing on the hotend this can cause issues with heating up as well. Adding a fan shroud (or pointing the fan away from the nozzle and only at the print) can help with this.


You have to secure your print to the build plate.

One thing that I always do is to use a brim in cura.  prints a single layer which extends in all direction away from your object, adding extra adhesion between your object and the print bed.

You can also use a slower extrusion speed for your initial layer but I would use this after trouble shooting everything else since you will be adding time to each print.

If you are using a heated bed make sure that the temperature is set for the correct material.  For PLA i think that is 40C-60C.

We put down a layer of craft/school elmers stick glue before most prints.  This helps a bit with adhering to the build plate, and also seems to allow the prints to pop off a bit easier.

Also be sure to double check you Z calibration and your bed level.  If there are inconsistencies and your nozzel moves to far away from you bed, you will be extruding in air and not getting and stickage at all.


Out of order operations on AnyCubic Prusa-I3 clone

This is just your slicer doing this. If you inspect the G-code file, you will see that the printer is faithfully doing what the slicer told it to. Most slicers use a fairly simple heuristic for determining the order in which lines are processed, which sometimes comes up with sub-optimal solutions like these.


It takes at least a few cm of extrusion to purge the old color before switching to a new one due to mixing in the melt zone, and possibly much more depending on the particular pigments. If the old color is something bright like red and the new one is white or something close, it can even take many tens of cm before you get a clean new color.
Multi-color extrusion setups either use separate hotends per color or fancy retraction setups where each color can be retracted separately, along with purge towers. You cannot get a clean color switch in the print just by having one in the input filament, and this is probably why all the mixed color filament that's sold is blended - so customers don't get disappointed when it doesn't work like you expect.


You're going to have to drill those holes. The plastic will melt if you drill too quickly. If at all possible, use a slow speed drill, a hand drill, or wrap a cloth around a drill bit and twist it with your hand. If you go too fast, the part will melt. If you press to hard the part will break.

Once the hole has been drilled you will need to reinforce it with a metal/plastic tube of the required diameter. Press the tube into the hole. I don't know what your wall thickness is, but try to ensure the tube is the same length.

If at all possible you should get flanged tubes like these from mc master car:

The parts with the 1/2 inch inner diameter and 5/8 outer diameter should fit your 10 mm requirement. The rest is up to you. Go to mcmaster.com/inserts scroll down to "Other Inserts" then "Tube and tube fittings".


Please look into this question, this is a very similar question and also involves PWM and a RAMPS 1.4 shield.

In your case you connect the top red wire on the right bottom connector to the D4 pin and adjust the firmware accordingly as described in this answer.

The bottom 2 wires of the lower right connector should be connected to ground and 12 V (resp. black and red).


Typically the black pigments in polymers are mineral based. If you are having true WiFi issues then it sounds like your filiment is using black iron oxide also called magnetite for the black pigment. This is the same material they use in radar absorbing paints which would make sense as to why you are having radio related issues.


Looking for CAD files of basic crystal structures

You may find that OpenSCAD regular polyhedron library may serve your requirements.

From the linked site:
All polyhedra are centered at the origin and have an edge length of 1.
From the linked site:
Included polyhedra:
tetrahedron
octahedron
hexahedron
icosahedron
dodecahedron
cubeoctahedron
truncated_tetrahedron
snub_cube
rhombicuboctahedron
truncated_hexahedron
truncated_octahedron
icosidodecahedron
snub_dodecahedron
rhombicosidodecahedron
truncated_cuboctahedron
truncated_icosahedron
truncated_dodecahedron
truncated_icosidodecahedron

OpenSCAD is a reasonably easy "description coding" program at the base level. I suspect that for something such as this, it might not qualify for the easy reference.
My search also linked up a few Thingiverse entries, but they weren't as sophisticated as the above and may be a subset of the library link.


Printing a non-self-aligning caged deep-groove ball bearing

Two aspects of your question can immediately be addressed, one with much less certainty than the other.

If you were to print the indicated parts using PLA on an FDM printer and assembled as much as possible up to say, the outer bearing ring, you might be able to use boiling water to soften the ring with boiling water enough to get it around the balls. It's also possible that the deformation will effectively destroy the usefulness of the part.

On the other item, SLS is virtually perfect for this type of part. The un-sintered nylon powder provides positional support for all of the other parts being sintered. When the print is completed, the powder is blown out with high pressure air, freeing up the individual components as per the original design.

Be advised that there is to be expected some shrinkage of the parts which will affect any segment of the component that has tight or close clearances.

From Shapeways site regarding SLS printed parts (Shapeways)

Executive summary:

maintain a wall thickness of at least 1mm,
accuracy is 0.1mm,
always keep a clearance of 0.6mm
and parts may have a deviation of 0.2mm.

When designing something mechanical that has to be 3D printed or when adding a mechanical feature to your model there are several main considerations.

Also listed in the above link are the considerations of enclosed parts. Each of the balls in the bearing design may or will be printed as a hollow sphere filled with nylon powder. The bearing rings will also be printed as shells, unless appropriate steps are taken to make them solid.

By the same token, if a part need not be solid and can be designed with holes to "drain out" the un-sintered powder, the cost will be reduced accordingly.


Layer height issues creating partial top layer

Your model isn't perfect. I took it into Windows 10 3D Builder for simplicity. I kept clicking the "Mirror" function and noticed as it basically flipped there is some slight movement. I measured some points from bottom to top and noticed some differences.

Try to take your model into some software to fix/flatten it. Or recreate it making sure its perfectly flat on both sides. It is definitely not your Cura software.


How to make moving parts not stick together?

If parts stick together after printing, the positioning or extrusion is not working optimally.

This can be related to various issues:

Positioning of the head is not correct; this could be related to incorrect belt tension, incorrect steps per mm, streched belts.
The extrusion process is not working optimal; this could be related to over-extruding (incorrect steps per mm for the extruder, incorrect multiplier in the slicer, filament too hot) or the first layer height is incorrect (too low, so the lines spread out and tough each other). Extruder calibration is explained in more detail in this answer.

A very good start to verify what exactly your tolerance problem is is to print this tolerance test. Basically, these are diabolic shaped objects in a slightly larger outer shape object. Please slice this STL file with your favorite slicer to obtain the G-code for your printer. When the print is ready, you use a screwdriver to turn the diabolic shaped objects from large to small tolerance, the last one that does not turn is the maximum tolerance of your printer. So when printing in place hinges, you should use tolerance values higher than the one that did not turn.


Creating a two part label for storage boxes

In OpenSCAD, apply the offset transformation to inset the letter outlines before extruding them. However you may find it works better to fill the sunken letter shapes with nail polish then remove the overflow with acetone; see my question & answer https://3dprinting.stackexchange.com/a/10872/11157.


Ender 3 with direct drive has severe stringing printing TPU

Due to the flexible characteristics of TPU, stringing is a known "complication" with this material.

             is a video from Matterhackers:

no retraction - stringing is expected
dry filament - ensure the filament hasn't been exposed to the air for extended periods - use an oven or dehydrator if needed

There are many other tutorials and videos covering the process.
Tom Sanladerer has also a video covering the use of flexible filament.

ensure correct alignment of hobbed bolt and feed hole
consider to use a piece of PTFE tubing downstream of drive mechanism
use 3 mm (usually 2.85 mm nowadays) filament for better results (if possible)
bed temp - 40 °C with glue stick on bed
print slower
adjust extrusion multiplier by testing various settings

Obviously some of the above references don't apply or are being observed.


How to remove adhered nylon from build platform?

One important and missing aspect of your question is what is your build platform? Glass is likely to give you the best results, while aluminum has some risks, depending on your choice of solvents.

My hasty research at first showed Glacial Acetic Acid to be a candidate, but as a very strong acid, it will require some care in use.

I found a pdf document with a comprehensive chart of possible solvents for nylon. The above noted solvent (100% acetic acid) lists with an Unsatisfactory result. I read this at first as being unsatisfactory for dissolving, but the correct interpretation is that nylon is unsatisfactory for being resistant to this solvent. Additional notes show nylon will dissolve in this solvent.  I have a bottle of white vinegar (acetic acid) but the panel reads as five percent concentration, almost certainly ineffective for your purposes.

There are other solvents listed as unsatisfactory, which points them in the right direction for your purposes. A couple of them are in the chlorine family and no reference is made regarding concentration. Chlorine of even weak concentration will attack aluminum very quickly.

Despite the weak concentration of the white vinegar, I've dropped a segment of 3 mm nylon to see what happens overnight and may report via an edit here later.


After having looked into them, these boards certainly seem to be rather interesting.

There appear to be two varieties of this board, as I have seen photos with either RobotDyn:

rear (from Instructables)

or WeMos logos on them.

They may, or may not, be the same. There is also this one, with just a generic "WiFi" logo (from the eBay page below):

Memory Discrepancies

However, there is certainly some discrepancy relating to the specification and amount of memory (unless there are a number of variants - which would certainly be possible):

4 MB of Flash is in the ESP8266-12, as Dan states, see ESP8266 SMT Module - ESP-12. But is it the ESP8266-12 in the board, or is it another ESP variant?
This WeMos product, on eBay, WeMOS Mega + WiFi R3 ATmega2560 + ESP8266 USB-TTL For Arduino Mega NodeMCU appears to agree with the 32 Mb1
This RobotDyn board, Контроллер RobotDyn Mega 2560 R3 + WiFi ESP8266b, flash память 8Mbit, USB-TTL CH340G, MicroUSB, has 8 Mb apparently.
However the same product page, but in English, upgrades the memory to 32 MB! See MEGA+WiFi R3 ATmega2560+ESP8266, flash 32MB, USB-TTL CH340G, Micro-USB

Looking at this article, Instructables - Arduino MEGA 2560 With WiFi Built-in - ESP8266, it isn't exactly the ESP8266-12:

  In today's text, we discuss an Arduino that I consider extremely special, as it has an ESP8266 embedded in its board. It doesn’t have the ESP12 soldered onto the board. Instead, it has the Espressif chip. So, on the board you have the built-in Tensilica chip with 4MB of memory, along with the ATmega2560, which is the traditional Arduino Mega.

So the ESP has 4 MB, but where does the 32 Mb come in to play?

Well, looking at this RobotDyn memory table (taken from the Instructables page):

The 4 MB of the ESP appears to have been immediately contradicted and upgraded to 8 MB! The ATmega2560 somehow has 32 Mb (which seems a bit of a lie - as there isn't an ATmega2560 known to man that has that much memory2), and is confused further by the corresponding text:

  As we see in the table above, the ATmega has 32MB of memory, not counting the ESP memory. This is wonderful, since the traditional Mega Arduino has only 256kb of memory.

So MB or Mb? Is there an additional flash IC external to the ATmega2560? Looking at the schematic, taken from the Russian RobotDyn page, there doesn't appear to be:

So this could be nonsense. Logic would dictate that the ATmega has 256 kB and the ESP has 4 MB... But I could be wrong..?

Links from Контроллер RobotDyn Mega 2560 R3 + WiFi ESP8266b, flash память 8Mbit, USB-TTL CH340G, MicroUSB:

Schematic (PDF)
Pin out (PDF) (JPG)
Mechanics (PDF) (JPG)

Reliability of communication

Regardless of the actual spec, to address your question of ESP/Arduino communication reliability:

As the ESP8266 and the ATmega2560 are on the same board one would assume that the (serial) communication between the two would be faultless. However, some issues have been reported3.

Nevertheless, from your question, it seems that you were having issues with the ESP to the OctoPi communication, rather than ESP to Arduino, so maybe this doesn't actually answer your question.

Also, as to their compatibility with RAMPS, there is very little information available currently, and it would seem to be a case of try-it-and-see. The closest I got was this post on the thread, OnStep and RAMPS1.4, but it seems to be spam.

However, it certainly sounds worth a gamble as it would be a nice combination of technologies. However, I would imagine that some modification of the firmware would be necessary.

Useful Notes

From post #8 of Mega + WiFi R3 ATmega2560 + ESP8266 (8 Mb mémoire)

  To upload the sketch to the board:

5, 6, 7 ON
RXD3 - TXD3

  To run the sketch:

5 and 6 ON
RXD3 - TXD3

Here is an excellent manual in Russian

Footnotes

1  From WeMOS Mega + WiFi R3 ATmega2560 + ESP8266 USB-TTL For Arduino Mega NodeMCU

  WeMOS Mega + WiFi R3 ATmega2560 + ESP8266 USB-TTL For Arduino Mega NodeMCU

  Features:

  Full integration on one board: Mega R3 ATmega2560 and WiFi ESP8266 with memory 32Mb (megabyte)
  All of the modules can work together or each separately. And everyone has their own pinout headers
  The convenient solution for the development of new projects requiring Uno and WiFi
  Via USB you can update sketches and firmware for ATmega2560 and for ESP8266. For this on board have the USB-serial converter CH340G
  Use this board is very simple
  The board has DIP-switch, to connect the modules. For example to:

  USB and ATmeg2560,
  USB and ESP8266,
  ATmega2560 and ESP8266

  Table DIP- Switch:

Connection                                                          DIP
                                           1        2        3         4       5         6        7
ATmega2560<->ESP8266                      ON       ON       OFF       OFF     OFF       OFF      OFF
USB <->ATmega2560                         OFF      OFF      ON        ON      OFF       OFF      OFF
USB<->ESP8266 (Update firmware or sketch) OFF      OFF      OFF       OFF     ON        ON       ON
USB<->ESP8266 (communication)             OFF      OFF      OFF       OFF     ON        ON       OFF
All independent                           OFF      OFF      OFF       OFF     OFF       OFF      OFF

Special solution:
USB <->ATmega328<-> ESP8266
Connection                                                          DIP                                     SWITCH 2
                                           1        2        3         4       5         6        7

USB <-> ATmega2560<-> ESP8266             ON       ON       ON        ON      OFF       OFF      OFF         To RXD3/TXD3

  USB converter CH340G connect to RX0/TX0 of ATmega2560
  ESP8266 connect to RX3/TX3 of ATmega2560

  Size: 10.5x5.3cm/4.13x2.09inch

2 From the Atmel ATmega640/V-1280/V
-1281/V-2560/V-2561/V datasheet

3 From Mega + WiFi R3 ATmega2560 + ESP8266 (8 Mb mémoire), there do appear to be some issues communicating between the ATmega and the ESP ICs, with a number of users reporting problems.

However, a couple of solutions are provided:

Solution 1

From post #2

  Set the DIP switch to "special" mode: (1=on, 2=on, 3=on, 4=on, 5=off, 6=off, 7=off, 8=off) see the the description of the
  product.
  Set the switch in RXD3
  Run the below sketch, change the SSID and PASSWORD values. this is just to test that Arduino and ESP8266 are working together. The code
  originated from BISSA ORBOEA in Element14.

  Code:

#include "ESP8266.h"

#define SSID        "YOURSID"
#define PASSWORD    "YOURPASSWORD"

ESP8266 wifi(Serial3,115200);

void setup() {

  Serial.begin(9600);

  Serial.println("Restart");
  wifi.restart();
  delay(1000);

  Serial.println("FW Version:");
  Serial.println(wifi.getVersion().c_str());

    if (wifi.setOprToStation()) {
        Serial.println("OprToStation ok");    }
        else {
        Serial.println("OprToStation  err");
    }

    if (wifi.joinAP(SSID, PASSWORD)) {
        Serial.println("Join AP success");

        Serial.print("IP:");
        Serial.println( wifi.getLocalIP().c_str());
    } else {
        Serial.println("Join AP failure");
    }
}

void loop()
{
}

Solution 2

From post #6

  First you need to write the code for each board according your
  application, but in your code you need to establish a commmincation
  between serial port of Atmega and ESP in both code, again in according
  you application. Finally, put the switches which make the intenal
  interconnection between both.

  For example, I made a code for ESP to connect in an Access Point and
  put on a TCP server. When a wireless client is connected in ESP and
  consequently in the TCP Server, all data send by client I redirect to
  the serial port. As serial port of ESP is connected with serial 3 of
  the Atmega, the code in Atmega pass to theat the data from serial 3.

Solution 3

From post #11

  Follow this if you have the same to my cases:

  programm to the ESP(upload sketch) for wifi connection by configure the DIP to 5:on,6:on,7:on and other off.
  program to mega(upload sketch) in case you want to send communication to each other by configure Dip to 3:on,4:on, and other
  off.
  switch two  RX0/TX0(in my case I use Serial.print() and Serial.readString() for communicate between Esp and Mega)
  after you already upload sketch to both Modules you can test communication between them by configure DIP to: 1:on,2:on,3:on,4:on.
  and then press Reset Button to restart the boards.
  In ESP you can get the string from Mega by  if(Serial.available()) Serial.readString();  and In mega you can get data from ESP by :
  if(Serial.available())Serial.readString().
  After you got a string so you can split or do anything whatever you want.
  If you want send data to Firebase you must use the Firebase Library at the Esp side, in Mega it not support.


SVG to STL conversion to make symbols recognisable for visually impaired users

If you install inkscape, pstoedit and ghostscript version 9.21 (not the latest as pstoedit is incompatible)   you can get the file into a format that openscad can
import using two commands in a cmd file

"C:\Program Files\Inkscape\inkscape" -E "traffic lights.eps" "traffic lights.svg"
"C:\Program Files\pstoedit\pstoedit" -dt -f dxf:-polyaslines "traffic lights.eps" "traffic lights.dxf"

then in openscad

linear_extrude(3) import ("traffic lights.dxf");

will import gives me

With a thickness of 3mm - you can see the model needs some scaling but its seems possible although - I can't see an option to scale based on color -


This seems to be a recurring problem with Slic3r.

Slic3r appears to have problems with perimeters that are not attached to infill.  I suspect that it is getting confused on what is the inside and what is the outside.  I know that seems a bit silly; but as you slice an object with indentations (like the bunny's face) then the perimeter can cease to be a simple closed shape and it gets confused.  If you use a viewer to step through the gcode layers around the place it starts having problems you may be able to see what is going wrong.

Here are a couple of examples of why I say this is a recurring problem with slic3r.  I also recall seeing a video that showed the problem but I can't remember where.  That was one of the reasons I don't use slic3r.

Reported on Sic3r Git in 2012 - Can't tell for sure if this was ever fixed
Infill Perimeter issue in 2015

Here are three options that may work

Use a different slicer for this specific condition.  Every product is going to have vulnerabilities - this may be one of slic3r's.
Increase the perimeter and top and bottom layer thicknesses.  Making them thick enough it will bridge the problem areas.  Use a gcode viewer to inspect that area to see if it fixed the problem.  That way you don't waste material on another fail. It sounds like you may have already tried this but you didn't like that it made the model stiffer.
Repair the STL file using an application like Meshmixer.  Maybe you will have to get the file close then tweak it where it doesn't.  Here is good article from PinShape repairing and STL file.

Good luck, hope this helps.


High-viscosity gel/polymer to suspend conductive material while it is being printed

The material you are describing sounds very similar to the material used for Metal Injection Molding except that you want to print the material rather than molding it.

A company called MarkForged is making a printer called the Metal X that uses this technique of printing & sintering to produce solid metal parts.  Here is a article describing more details about the printer.

It sounds really cool.

If you investigate papers around those processes you may find what you are looking for since they are so related to what you are trying to do.


Why did my printer's nozzle dig itself into my print?

You are using incorrect commands in your end-code for the incorrect tool with respect to the print head raise.

Slic3r has no knowledge of the maximum printer height (as in variable max_print_height) because there is no input field to specify this, as can be seen in this partial screenshot:

However, in Slic3r PE (Prusa Edition), there is a possibility to enter such a value, as seen in the following partial screenshot:

Note that in both editions, the Bed shape interface is equivalent when Set... is pressed:

To use the raising of the head, respecting the maximum print height, in Slic3r PE, you need to add the following line:

{if layer_z < max_print_height}G1 Z{z_offset+min(layer_z+60, max_print_height)}{endif}

This will parse fine in Slic3r PE, but not in Slic3r (as max_print_height is not known).

If you want such a command in Slic3r, you need to enter (for a printer with a maximum print height of 240 mm):

G1 Z{[z_offset]+min([layer_z]+3, 240)}

results in Slic3r for a 20x20x20 mm calibration cube with a zero z_offset to:

G1 Z23


Inconsistent printing results using same settings but different calibration models

First of all, I would try printing a little bit hotter, let's say arround 210 °C. Secondly, due to how the X and Y letters are being printed in the sides of the cube I would suggest to tigthen both the X and Y belts.

Regarding the gaps, I would first try a flow rate test. You could use a cube like this one.

Using:

extrusion multiplier = 1
layer height: 0.2 mm;
layer width= 0.4 mm ;
wall count= 2.

Then measure the walls with a caliper and you should have 0.8 mm walls. Do a couple of measurements, get the average and divide  0.8 by it  and multiply by a 100 (100*0.8/average). That's your new flow rate.

I would also try to add 1 or 2 top layers to the print.

For the first layer, I would definitely get a glass bed and use hairspray. The bottom of the pyramid doesn't seem to be sticking well. Apart from this, I'm not really fan of using Z-offset. Just try leveling a couple of times manually with a paper to get it right.


Marlin has G2 (clockwise arc) and G3 (counterclockwise arc) commands that could be used to do this. You can find detailed documentation for the command here.

Basically, you can use

  G2 R1 X5 Y5

to draw a (clockwise) arc from the current position to $(X,Y)=(5,5)$ with a radius of $1$.

So, your rounded triangle could be drawn with 3 straight line moves and 3 arc moves. Figuring out the exact coordinates for each move would be a quite challenging geometry exercise, as you'd need to know where the straight line portion of each side ends and the rounded portion starts.


Ender 3 Pro not interpreting G-code correctly?

It ended up being something with the printer, I powered it down, let it set a few minutes and then powered it up and it printed correctly. Is there a way to "reset" it without the power cycle, and is this something common? Thanks for the response!


Would adding fiberglass packaging tape to a bowden tube be beneficial?

The question seems to be built on a false premise, namely that the major extrude/retract errors in a Bowden design come from tube stretch. The PTFE tube is not significantly elastic, actually it is reasonably stiff so there is minimal scope for improvement here.

A longer tube will contribute to degraded precision, but slack in the filament/tube gap is roughly as significant as stretch (and filament compression). Constraining the tube path may help marginally (but there is no need to 'bond' the tube). There is not much you can to to reduce the gap between filament and tube, but this will dominate the error for a long tube.

The most obvious weak point is the clip used to secure the tube at each end. I saw a review of a recent Prusa design where high quality clips were called out as making a big improvement to securing each end of the tube.


Problems with under extrusion and clogs on CR-10

Turns out the filament was the problem, I tried printing a model with a high quality sample PLA filament I had and it printed perfectly; one of the cleanest prints I've had. Never skimp on filament.


Vary line with Z-axis for imported SVG file

In OpenSCAD you could create a bevel using the minkowski transformation by transforming the curve using tapered shape such as a pyramid or as I do below a tapered cylinder:
minkowski() {

  linear_extrude(1)
    import("drawing.svg");

  cylinder(h = 20, r1 = 10, r2 = 1);
}


How to create attachable/detachable printed parts

This question may yet fall into the too-broad category, but I'll give it a shot.

You don't want to use glue or adhesives, but does that exclude bolted or screwed fasteners? Threaded inserts are metal "nuts" with knurled grip extrusions that enable one to use a matching bolt. The insert is heated with a soldering iron or similar source and embedded into the part. It's especially useful when the part thickness provides sufficient strength and the threaded insert is on the surface of the part opposite the bolt head.

Another option you have is to design into the part a "conventional" joint such as a dovetail or slot with the matching dovetail or T shape on the adjoining part. This requires access to the end of the part to enable the sliding action of joining them together, of course. Some testing of prints should be performed to ensure proper mating.

Directly related to that method is pins and holes. With suitable testing, one would create a hole on both parts and print a pin to match. If one is well versed in the software of choice, one hole with a built-in pin on the adjoining part would work too.

Yet another extension is provided free from 3DKitbash:
http://www.3dkitbash.com/free3dmodels/
in the form of friction fit pins. I've constructed one of their models using this design and find the straight-line pins eventually work free. The pin model with "mouse ears" allows for a bit stronger gripping due to the compression of the shape on insertion.

The friction fit pins would be considered to be the snap-fit parts you want to avoid, but the level of expertise should not be beyond that of a model designer.

Trial and error works wonders when it comes to putting these things together. I printed an Overwatch logo for a fellow makerspace member. The part used a pin on the insert and a hole on the logo. I was astonished when the two different colored parts slid together quite snugly. I have not calibrated my printer and it was indeed a snap together build. On the flip side, when I pried the two pieces apart (low infill) the pin remained in the hole, snapping cleanly off the insert. Should I be asked to do this again, I would have much more infill on the pins.

For clarification, consider also to note what software you are using for your design. Some programs lend well to creating connections, others not so much.


"Analog pin" is misleading nomenclature. Every pin is a digtal pin, but some digital pins happen to also be connected to the analog-to-digital converter and can thus also handle measuring analog signals.

Every analog pin can also serve as a perfectly good digital pin. The reverse is not true; if something requires an analog pin you cannot use a digital pin. The only things that require analog pins are the thermistors, for the rest (motors, MOSFETS, endstops,...) you can use either a digital pin or an analog pin.


What slicer settings would produce the strongest part?

If your real question is what would be the strongest then I say - the solid would be the strongest - no doubt.

But if the question is:

what be the strongest in comparison to weight or
what is the strongest in comparison to the cost (amount of material)

then these are good questions!

You can of course find many tutorials and comparisons on the net and there will be many answers - which all of them could be good/bad ;)

If these are your questions then instead of simple answer you can ask more questions like:

in which orientation or
for what purpose or
for continues stress or maybe for variable stress or
for bending forces / shearing forces or maybe tearing forces

all these forces and circumstances could require other answer... which could also lead to other questions :)

But according to my experience, the strongest settings (for general purpose) is 3 outlines (and the same number of first/last layers) and triangle infill 20-25 %

Why I think this is the strongest, 3 layers gives good chance to have well stickiness even if there are geometric/design issues and triangle infill gives good (and common) way to carry and spread forces.

But as I said it depends on many input data.

Let's look at these figures:

in figure A we have the strongest composition for compression; this is because all working forces try to damage material particles which is of course hard to do (depending on material density and length of polymers and the way they are tangled and so on - in general - material strength only).

If we consider figure B where forces try to tear apart layers then we know that we base on stickiness between layers which can vary on printing parameters (as is temperature and speed).

Finally, figure C shows shearing forces - in terms of layered structure it doesn't really differ from tearing apart but the results (the resistance of and object) is even weaker - it's because we base on stickiness and we additionally have less effective field of working stickiness) which reduces endurance of an object.


I wonder if there is a glitch in the firmware producing this unexpected result (which I think I also observed).

If you navigate to quick settings you should find preheat pla. Selecting this has little obvious effect (except for fan speed droop as the heater kicks in), but the target temps will now be 190C / 60C.

Print File seems to wait for the pre-heat to have reached a threshold before starting to run.


How to convert .obj file to .stl so I can slice to G-code?

One can import an OBJ file into free program Meshmixer, then export it to STL format. There are other programs that are free and paid (such as Fusion 360) that will perform similar tasks.
As noted by user agarza, Prusa Slicer will import an OBJ and will also export to STL format. PrusaSlicer is also free.


Getting precise measurement of a complex rod

You need to disasemble the part and measure it with special equipment, a caliper can help but only as reference since the part has an angled shape.

I recommend to use an optical comparator (base shadows) with this you can have X and Y data to calculate the angle and curves. If you want more precise measurements you can try an Optical Measurement Device (based camera), this also can give you Z but X and Y will help you a lot. Both equipments use a system called Quadra Chek many industries has at least one of this to assure his quality due meets all requirements for Ford GDT guides (geometric dimensional tolerances). no matter the manufacturer brand.

I´ve tried to measure with the phone or table application but is hardly to calibrate on each required dimension. I had to buy an optical comparator.


Anet A6 Z-axis min endstop not triggering

There is no such thing as a software endstop for the 3D printer. When you power a printer the print head can be located at every X, Y, Z position (usually, Z is  at the print height of your last print, X is at the minimum X, and Y is at an arbitrary location determined by the last print).

This is exactly why we need endstops, either mechanical, optical or electronic (inductive or capacitive) end stop switches or sensors. You instruct the printer to home by using a known fixed location of the printer; this is the hitting of all endstops. The origin of the printer may have offsets, as the origin of the printer may not coincide with the endstop location. For the Anet A6 this is a few millimeters, e.g. for Marlin firmware this is defined in the configuration by:

#define X_MIN_POS -3
#define Y_MIN_POS -5

The answer to your question: "Is it possible to do this with software?" is therefore, no, you cannot do this solely with software.


This looks a lot like layer shifting, both gradual and sudden.  This is frequently caused by excessive friction on one axis, the one along which the print is leaning.  You mentioned tightening the X-axis; if these are leaning along the X axis, chances are good the belt is too tight and causing something (either the belt or the toothed gear it is attached to) to rub against something else (the frame, the v-slot extrusion, the motor itself in the case of the belt gear).

Both the X and Y axes should be fairly easy to move by hand with the power off.  Feel for any points where that isn't true.


How to create a very accurate STL file as well as the slices for a 3D printer?

Your objective has a serious constraint regarding the pixel resolution. Within that limitation, the software (slicer) you are using will generate "best guess" images, particularly dependent on floating point math. There may be a single combination of circular shapes (radius) and spacing for these shapes that provides your objective, but that's likely not a practical exercise.

You have not indicated if you've tried other slicers, which would be the primary direction. A list of choices can be found here:

Free Slicing Program List

Another option that you can consider, not included in this list, is to use OpenSCAD, import the STL file, then use the projection() command to manually slice and export the image file. I use the term "manually" but the program can be coded to perform this task automatically, and there is a command line feature to OpenSCAD that may be useful.

Note also that the output of these slicers and/or OpenSCAD may exceed the resolution you desire. Manipulation of the image with a graphics editor could result in the same floating point disarray as you perform the changes.


Water does not flow through 4 mm hole when there is a small amount, how to let water flow through small hole even when there is low pressure?

What you encounter there is a combination of Adhesion, Cohesion, and Capillary Force.
Cohesion is what holds the water together. Adhesion is the force to retain water against a wall or hanging from a pen's end, it is proportional to the surface wetted. Capillary Force is the resulting effect where water moves up through a thin tube, it is anti-proportional to the diameter and in the opposite direction of the weight (force). Their relation can be shown in this picture, where a droplet hangs on the end of a glass rod, which has a capillary in it:

How to reduce the water sticking in the cup then?

Make the straight part of the bore as short as possible. This can be done by having a thin cup. The shorter the hole, the less surface there is the water can adhere to vertically, and you might overcome capillary force.
Smooth the hole. Maybe print it 3.5 mm and drill it up to your 4 mm diameter. This reduces adhesion.
Smooth the inside surface. Reducing the adhesion to the inside by having less steps.
Chamfer the inside of the holes. This alters the whole geometry and flow setup in the very low water level case, especially when the surface separates into several areas, above each hole. Then the larger volume belonging to each hole on the inner side means there is a little more pressure and you can get out some more water - and it also shortens the distance the hole has to bridge.
make sure there is some slope everywhere inside so that the water will collect in one of the holes.

An example for a (non measured) design which relies heavily on chamfering to guide the water to the already chamfered holes and then keeps the straight section as short as possible could look like this: the central hole has a very wide chamfer, the whole plate directs water to the center and each of the other holes has a chamfer to guide out water.

However, there is a lower limit to where just tweaking the design will workd, which is based on cohesion. Cohesion is what results in surface tension and viscosity. You can only shift those limiting factors by altering the properties of the liquid, for example by adding an agent that lowers the surface tension and viscosity (soap).


I can set the voltage and current of the TMC2130 driver manually. But, in which cases some of the components could burn up?

The driver has a potentiometer to change the voltage that is giving to the motors.
[...]
As one person answered me in another question, I would need 3.2 V to make the motor work well (2. Ω * 1.3 A = 3.2 V).

You are misunderstanding that answer and what the potentiometer does. The potentiometer does not control the voltage going to the motors. It makes no sense to compare this voltage to the rated voltage of the motor. The potentiometer controls the current going to the motor, with a potentiometer voltage of 0V corresponding to 0% of the driver's current, and a potentiometer voltage of 2.5V corresponding to 100%. The documentation of your driver is a bit unclear but it looks like the maximum peak current is 1A per phase or 0.7A RMS (per phase).

There is a file in the Marlin firmware (Configuration_adv.h) where I can set the current that the driver is going to give to the motors.

This only works if the driver is set to SPI mode, otherwise the setting is ignored. To enable SPI mode you need to remove the jumper resistor labeled "SPI" mode and make connections to the long pins sticking out the top of the driver. This configuration option overrides the current setting set by the potentiometer.

What I am going to do is to set the drivers potentiometer to the maximum and check what happens. And I will also set the current in the Marlin to 1838.5mA

That's not such a good idea. It would be wiser to set the potentiometer relatively low, and increase it just enough so that the motors do not skip steps.

As the drivers have less voltage to give to the motors, are my drivers going to burn because they will have to give more current for a long period of time?

No, because the drivers do not have "less voltage to give to the motors". They don't work that way. They are constant current drivers.

Or will the stepper motors burn because they won't get enough current or voltage?

No. The only thing that could cause the motors to burn is (far) too much current or voltage. This will never happen because your drivers will burn up before the motors ever would.
Keep in mind that in the question you linked to, one answer is more detailed than you can reasonably understand with your level of electronics knowledge, and the other answer is completely wrong.
Summary

The current setting in configuration_adv.h is irrelevant unless you have enabled SPI (but I doubt that you have)

Do not start out with the potentiometer set to maximum

Everything will be fine. The motor can handle more current than the driver can ever deliver. The driver you have is configured so that it can never exceed its rated current.

Regarding your update
Yes, if you are using SPI current control then the potentiometer is ignored.
The TMC2130 can handle 1.2A RMS per coil, though the datasheet notes that more than 1A RMS per coil requires special attention to heat dissipation (the small breakout PCB probably does not have great thermal properties).
Your calculation is overly conservative because it treats the 1.2A figure as peak current when RMS current is meant. You do not need to divide by $\sqrt{2}$ to convert to RMS because the figure already is RMS.


Strange problem with quality, what might be the reason for these bubbles?

Looking at the second photograph and the way that the filament switches abruptly from smooth to irregular deposition, I would say that you have a partially clogged nozzle.

Pre-heat the nozzle and extrude some filament. It should drop straight down from the nozzle. If the filament curls as it comes out of the nozzle, the nozzle is partially clogged. You may be able to clear the clog by doing what is called a "cold pull":

Pre-heat the nozzle so that it is possible to extrude filament. Then switch off the heater and allow the temperature to fall below the pre-heat temperature of the filament (140°C for PLA, say). Now disengage the extruder gears and gently withdraw the filament completely from the hot end. On removing the filament completely from the printer, you should find a "bullet" on the end of the filament in the shape of the melt chamber. Hopefully, the dirt that caused the clog will be embedded in the bullet.

In order to prevent dirt from entering the nozzle, it is a good idea to install a filament cleaner. This can be as simple as a piece of sponge containing a couple of drops of light machine oil, or you can make something a little more sophisticated. There are plenty of designs that you can download on Thingiverse.


I tried the same setting old kinect (but for PC - actually with power supply and usb-cable) plug to my surface windows10.

After some troubles, it works now ;-)

The mentioned MS 3D scan and kinect readiness wont work. It is supposed for the new kinect2 model, because of the new driver. Best you deinstall both. Even the drivers and SDKs.

You need Kinect for Windows v1.8 for the old kinect. https://www.microsoft.com/en-us/download/details.aspx?id=40278

RecFusion is a software for using a single or multiple depth cams for getting 3d models. It works quite good with my kinect. It costs 99euros.  http://recfusion.net/index.php/en/download


Can I have a glass bed with only the center heated?

If you're using borosilicate glass (aka pyrex) then it won't crack. You can get squares of ~20x20 cheaply off aliexpress.

If you're using window glass, picture frame class etc then you might have issues with cracking, it will depend on lots of factors like the wattage of your heater and the temperature of the room.

Your biggest problem will be that the bed heats very non-uniformly, which is unlike to give good print adhesion. I'd suggest a sheet of aluminium underneath the glass if possible, it will allow much more even heating.


Heated bed for the XYZprinting da Vinci mini w

Instead of replacing the bed, you could invest in a silicone heating element and top it off with a piece of (Borosilicate) glass.

If the printer board has exposed headers to attach a heated bed, which is possible, but not certain, you could use an SSR (solid state relay) to power the bed using the signal from the board to set the temperature. Alternatively use a thermostat for an incubator to create the signal for the SSR. Note that all these parts can be sourced from those typical online websites.

In case the wires of the silicone heater stick out, use a layer of cork where you cut out space for the cables and thermistor.


I'm not sure exactly what you mean by your comment to Davo's answer, but with respect to your use of a sheet of paper reference, it seems like you can still use 80 gsm paper as a reference for 0.1 mm layers.

From Paper Sizes Explained (emphasis is mine):

  There is no universal calculation for the thickness of paper based on the gsm as varitaions in paper composition can affect the weight, so two different brands of 120gsm paper could have slightly different thicknesses. However, an average sheet of 80gsm paper, the most commonly used weight, measures approximately 0.1mm in thickness, which means that 10 sheets would measure 1mm. By comparison, 10 sheets of 120gsm paper would be 1.5mm thick, assuming the paper composition was the same.

So, given that:

80 gsm => 0.1 mm
120 gsm => 0.15 mm

Then

40 gsm => 0.05 mm
60 gsm => 0.075 mm

From A Guide to Paper Types and Sizes

Paper Weight Descriptions

Weight        Feels Similar to:

35-55 gsm     Most newspapers
90 gsm        Mid-market magazine inner pages
130-250 gsm   A good quality promotional poster
180-250 gsm   Mid-market magazine cover
350 gsm       Most reasonable quality business cards

So, it would appear that you could use a newspaper sheet (or two) to test for layers of less than 0.1 mm.  Obviously this would depend upon where in the world you are, and the (physical) quality of your newspapers. Here in the UK, or rather Europe, the exported version of the Guardian used to be printed on some extremely lightweight paper (almost transparent tissue thin), in order to keep the costs of transport down to a minimum. So a folded sheet of that would certainly be in the range of 0.75 - 0.99 mm (which seems to be the range that you are looking for). However, given that the printed media (as opposed to the online version) is currently in decline, I am not entirely sure if it is still available.

Or, how about grease proof paper? From the Wikipedia entry:

  Basis weights are usually 30–50 g/m²

Although, this paper has been processed (supercalandered) and treated with starch, which will increase the density, so the thickness will not correlate to the table above (i.e. it will be thinner).

Giftwrap paper (not the really thick stuff) could be another option.

After having doing some long winded googling, I guess that the best bet would be to get hold of a micrometer and measure whatever paper yourself, as the specifications of paper are generally given in gsm and not mm (which is a bit annoying), and so it is somewhat difficult to provide you with a definitive answer (without physically measuring it).


How to create a 3D model as mold for a 4-legged animal with parallel legs

In traditional mold making, this would require a "sectional" mold -- one that breaks into mutiple pieces to free the legs, rather than just two halves.  Sometimes you can use a non-planar mold break line to avoid this issue; look at the molds made for casting miniatures that aren't neatly arranged to see examples, but as you note, with one rear leg alongside the other, the narrow space between isn't accessible with a rigid mold and a molded figure that can't be flexed.
One way around this would be to print the figure and make a flexible mold from it -- the mold wouldn't be printed, but would be molded from a positive figure.  That would let you use a flexible mold material to run a join between the rear legs and still separate the mold, with a little care.  You may also want to make the mold in layers, as would be done for denture making -- using a soft, highly flexible material such as the alginate used in denture making for direct contact with the original figure, and then reinforcing the very soft contact layer with a sturdier backup layer to provide support.


I am experiencing some severe under extrusion

Assuming your filament dimension settings are correct and your extruder is correctly calibrated...

Your extruder temperature may be too low.  While 184C can be hot enough, it is very near the bottom of the range for PLA and it appears your filament isn't melting quickly enough to keep up with your other settings.  Your extruder may even be running slightly cooler than you think so your 184C setting may actually be printing at 180C or less.

To solve this:

Raise your extruder temperature. I suggest raising your print temperature to 220 degrees and then gradually lower it until other aspects of your print quality are acceptable (bridging, oozing, etc).
Slow down your print. Slowing down reduces the volume of melted plastic your extruder has to deliver in a given amount of time.  This allows more time for the plastic to melt and allows you to use a lower print temperature

Your filament feed mechanism may be slipping.  Even if you have adequate temperature and perfectly calibrated firmware and print settings, if your filament feed mechanism (the thing that pushes filament into your extruder) is slipping, you will have under-extruded parts.

To solve this:

Make sure you have adequate tension on your filament feed mechanism.  If your feed mechanism is too loose, filament may slip and cause under extrusion.  The part to check is the part the pushes the filament into the rotating hobbed bolt or friction wheel...make sure it applies adequate pressure.  "Adequate pressure" or "adequate tension" will vary depending you your printer's design, but it should be enough to provide a firm grip on the filament.
Verify your feed mechanism is clean.  A hobbed bolt or similar filament drive mechanism that has become clogged or otherwise contaminated may cause filament to slip and under-extrude.
Ensure the end of your filament is not damaged from slipping.  Once your filament has slipped, it may be damaged with a worn spot, a bulge, or some other defect that can prevent proper feeding even after you fix the root cause of your problem.  So, as tbm0115 pointed out, be sure to clip off the damaged end to make sure you have good filament feeding into your extruder.

I hope this helps!


M3D Micro printer stops extruding but is not clogged

I'm not sure how similar the two systems are, but I use a Stratasys uPrint SE Plus and I've run into a similar problem.

There are two rollers in the head that pull the filament through to the extruder nozzle, and in one instance they appeared to have heated up, melted the filament enough to create two "indentions" on either side of the filament, making it such that the rollers had no purchase on the filament itself. There was never any clog, no material feed error, but it was still failing to print. Wound up having to replace the head altogether.

Again, not sure how similar the extrusion mechanics are in the M3D, but suggest checking the components that actually advance the filament, and the filament itself.


It looks like you some of your layers are printing with 100% infill.

If you are noticing plastic still coming out at the end of lines then I think your pressure in the nozzle is high when it is getting to the end of those lines and that pressure is pushing out the extra plastic.

That could be because your over extruding, but if it is only happening on layers where you are printing with 100% infill it could also be because lines are too close together and so when your trying to push out plastic to fill all the gaps in the model the pressure is building up in the nozzle because the gaps in the infill are to small for the amount of plastic the printer is trying to push into them.

I would see if it is happening on all your lines or is it worse on layers where the printer is printing 100% infill. Then maybe try adjusting the amount the printer is extruding and see how it changes the print.

Adjusting the speed could also make a difference. And some slicers have a setting to tell the printer to coast at the end of a line so the printer will stop extruding just before finishing a line as well. If you think the other setting are all tuned as good as you can get them then trying the coast setting might help for the model you are trying to print.


What parameters affect cylinder regularity?

This is probably a result of bad quality filament. If you haven't changed much in your setups, haven't changed slicers, but may have changed spools, then this might be the result. I would try using another spool and perhaps switch suppliers. I know it's expensive and there seems to be a stigma around it, but MakerBot Industries provides quality PLA (some ABS also).

Other than that, you've done some of what I would suggest in this case which are the following:

Speeds
Layer height

My only other suggestions would be:

Check how level your build plate is
Check material requirements. ie ABS is ideal between 230-240C according to MSDS with about 110C build plate temp, PLA between 210-230C. Sometimes too hot of a hotend can result in overextrusion or ooze.
If the cylinder is smaller, try changing your slicing settings to have a time minimum for each layer. In my experience, a material like ABS will begin to flare out with variations in the print environment. When the material flares out, as the nozzle comes across the area again, the flared areas will be pushed aside. If you adjust your slicing settings to about 15 seconds (refer to this calculator), then the material will have time to cool slightly from its plastic state. You can cheat this slightly by adding another object somewhere further on the plate with the same height, since the time it takes to rapid to the area and print the layer might be enough time for cooling.

I would also recommend doing some in depth maintenance to eliminate in obvious problems (such as cleaning your nozzle, rods, belts, etc.)


Determining the temps and speeds for DIY printers?

The short answer is, you use the temps and speeds that give you good results. It's trial and error.

The temperature number your printer reports really doesn't matter. That's just a process control variable: it needs to be consistent and repeatable, but it doesn't need to be accurate against an independent reference. What you should care about is your print results.

Some signs your printing temp is too cold:

PLA printed parts have a dull, matte surface
Poor layer adhesion
Extruder stalls or strips the filament at fairly low printing speeds for your extruder and nozzle size

Some signs your printing temp is too hot:

PLA printed parts have a very shiny surface
PLA has a very strong sugary/waffle smell, or any material smells burnt
Stringiness during travel moves that you can't eliminate by tuning retraction
Excessive oozing while the nozzle is stationary off the print
Bubbles or cloudiness in extruded strands in extruded strands even with dry filament

You will also calibrate speeds via trial and error. There are two main speed limits for a printer: how fast the motion mechanism can move the nozzle without running into issues or unacceptable print quality degradation (which is also a function of acceleration settings), and how fast the hot end can heat up and melt filament.

The mechanism speed limits you have to find via trial and error. Pick a test print you like (such as Benchy) and repeat it with different tuning until you find your preferred limits.

Melt flow restrictions are slightly more complex, because they are a function of VOLUME flow rate, not commanded speeds. Make a large boxy test print (with long straight lines) and multiply extrusion width times layer height times feedrate. That will give you your approximate flow rate in mm3/sec. Generally speaking, every extruder + hot end + material combo will have a maximum feasible flow rate. For example, most "average" hobbyist printers with 0.4 mm nozzles and good extruders can extrude about 4-8 mm3/sec with PLA. PTFE-lined hot ends are at the lower end, all-metal hot ends are at the higher end. The value will depend on your hardware. But you can do a few quick benchmarking tests to find the limit, and then use that to determine peak feedrates to avoid exceeding the melt capacity of your system.


How can I print gears using very high resolution material like nylon

Proceeding with the expectation that you mean nylon rather than vinyl, there are a few options open for you. What resolution are you seeking? Layer thickness of 0.100 mm is quite good, allowing for ten layers per mm of part thickness, with infill adjusted as required.

If you've already determined that your printer will not print at the resolution required for your gear design, you would perhaps purchase a higher resolution printer. Of course, that may be an expense you would like to avoid.

If your parts count is small, you could consider to print samples of the parts to confirm fit, but not worry about strength and then use an online service to have them printed via SLS method.

Selective Laser Sintering places nylon powder on the work surface, then selectively melts the powder into a solid. Each layer when completed is covered with another layer of powder and fused to the previous portion (or not) until the part is complete.

Because the un-fused powder provides support, there is no requirement for the model to have supplemental support structures. There is a requirement/objective that the part have "drain holes" in areas which might otherwise be solid. Any surface that entraps powder is charged to the purchaser as if the space within is included in the part.

An example would be a cube that can be printed as six square faces only. The cube wall thickness can be specified and if a drain hole is incorporated, the cost would be the volume of the walls only. No drain hole would mean the cube would be charged for the entire volume.

For gears, which are typically low profile/flat items, that's a minor consideration.

The same concept applies to SLA printing, which uses a laser in a vat of resin. If the model is a solid with no drain holes, the interior will retain the resin. It is possible that the interior can be cured with strong UV light and/or sunlight, but opaque resins would not accept this work-around, nor would it reduce the cost involved. Also note that SLA printed items would lack the necessary strength.

If farming out your parts is the direction you intend to travel, ensure the dimension stability reference in the vendor you use. Nylon sintered parts will shrink a known amount during the fusing process. The vendor should provide the appropriate reference, or the vendor should confirm that he adjusts the model appropriately for shrinkage.

I have one very tiny part constructed from SLS nylon and it's amazingly strong for such a thin wall. Nylon wears well too.


Assuming line 585 of Configuration.h looks like this

// Almost all printers will be using one per axis. Probes will use one or more of the
// extra connectors. Leave undefined any used for non-endstop and non-probe purposes.
#define USE_XMIN_PLUG
#define USE_YMIN_PLUG
#define USE_ZMIN_PLUG
//#define USE_XMAX_PLUG
//#define USE_YMAX_PLUG
//#define USE_ZMAX_PLUG

That is to say, if the Maximum endstop ports/plugs aren't currently being used, then you could just redefine the pin used by ZMIN (Z-) to be that currently being used by the ZMAX (Z+), in the appropriate pins_XXXX.h file (contained within MarlinTarantula/Marlin/src/pins/), where XXXX depends upon which board you have (I don't know what board your printer has).

For example, if you have a RAMPS board then in pins_RAMPS.h at line 79 you would change

//
// Limit Switches
//
#define X_MIN_PIN           3
#ifndef X_MAX_PIN
  #define X_MAX_PIN         2
#endif
#define Y_MIN_PIN          14
#define Y_MAX_PIN          15
#define Z_MIN_PIN          18
#define Z_MAX_PIN          19

to become (note the change in the last two lines)

//
// Limit Switches
//
#define X_MIN_PIN           3
#ifndef X_MAX_PIN
  #define X_MAX_PIN         2
#endif
#define Y_MIN_PIN          14
#define Y_MAX_PIN          15
#define Z_MIN_PIN          19
#define Z_MAX_PIN          18

Then compile and reflash the firmware.

Obviously you would then plug the Z_MIN (Z-) wire from the endstop into the Z_MAX (Z+) port.


Without the images of how you connected the endstops, the best guess for your problem is that the endstops cause a short circuit, once pressed, the microprocessor trips and shuts down. If you provide more information, other people may even add better answers based on your added information.

E.g. how is everything connected at both sides of the cable (board and endstop), does the message occur when you press an endstop, maybe it is even wise to add a link to your configuration files.


Accidentally printed a chocolate mold instead of the object itself

Cura contains a few different so-called "special modes" which changes what the software does with your STL. One such special mode is Mold mode which, instead of recreating the object, creates a mold for the STL. It appears you may have that setting turned on, so disabling it will cause Cura to work as intended.
To answer your other questions:

Most settings affect "rough shape", properly slicing your STLs to fit your printer and printing material is an essential skill to master in 3D printing. So there is no magic setting to get it all working, you need to tune all your settings according to what you want to print.

Your speed sounds fine, I can't speak for this printer in particular but print jobs taking hours or even days is not out of the ordinary. 3D prints in general take quite some time to complete.

Yes, usually it's called Retraction Length.

Yes it is definitely necessary to set up Cura to your printer settings because Cura needs to know the build volume of your printer and what flavor of firmware is installed on it.


Heater cartridge with 7.2 ohms - 12 or 24 V?

e3D Heater Cartridges are documented to be around 4.8 Ω for 12 V & 30 W, 3.6 Ω for 12 V & 40 W, 19.2 Ω for 24 V 30 W and 14.4 Ω for 24 V 40 W.

7.2 Ω is a value quite far away from these values - about double of what the 12 V versions are listed and about a third/half of a 24 V heater cartridge. So it is not a cartridge that is similar to those. I have contacted e3D about updating the specs of their High Precision Heater Cartridges to include the nominal resistances to get more references, but that information is pending.

However, we don't need that. A variant of Ohm's law can help us estimate what this cartridge could be: Power is the square of Voltage (U) divided by Resistance.

$P=\frac {U^2} R = \frac {144\ \text V^2}{7.2\ \Omega} = 20\ \text W$

$P=\frac {U^2} R = \frac {576\ \text V^2}{7.2\ \Omega} = 80\ \text W$

Mounted in a 12 V Machine this should act work at 20 W, in a 24 V it would work at 80 W. It does not say, however, if it is designed to get powered with 12 V or 24 V. It doesn't help, that both types exist: I was able to find 12 V 20 W heater cartridges just as well as 24 V 80 W heater cartridges. If it is an underpowered 20 W one and mounted in a 24 V machine, you risk burning it though, but not the other way round.

To differentiate what exactly you have, a photo of the heater cartridge would be needed - it should bear at least a marking of what it's nominal wattage or voltage is.


Print quality problem with M3D FDM printer

It appears that there are several issues with the prints.

First layer too far from bed
The picture showing the bottom of the print clearly shows the deposited lines and gaps in between the lines. Please re-level the bed to get the print nozzle closer to the bed (usually a sheet of paper should fit between nozzle and bed without too much friction when pulled). Edit after new information: Your initial layer is definitely incorrect, a 0.4 (assuming you have a 0.4 nozzle) is too high, a rule of thumb is to not exceed about 75% of the nozzle diameter, so this should be max 0.3; this is a strong indication that your bed level is indeed to far from the nozzle. Also 1.5 mm line width for the first layer is way too high for correctly leveled bed to nozzle distance; this should be close to 0.4.
Too much flow
Various pictures show zits and blobs that stick out of the print. The best solution is to calibrate your extruder.
Too high temperature possibly/too few cooling flow
The deposited filament is not sharp, it looks like the filament it pretty fluid during the deposition. Please lower the temperature to 195 and or increase the part cooling flow.
Z banding or wobble
The wavy walls show that the printer suffers from X-Y movement (eccentric movement) when the Z lead screws advance. This cannot be fixed easily as this involves the mechanics and the design of the printer.

To determine to improve the print quality you first should look at the bed leveling issue, second calibrate the extruder (see if you ask it to spit out 100 mm of filament it actually is 100 mm rather than randomly lowering the extrusion flow parameter) before you print some calibration cubes at reduced temperature and or increased part cooling flow.


How do you call the Z-axis mechanism in a Cartesian 3D Printer?

Linear actuator would be the proper name for the mechanism driving the movement along a single axis. There are 2 linear actuators driving the X-axis platform (for a Prusa i3 Cartesian printer, or the build platform for a raising bed Cartesian printer like a CoreXY, H-bot, etc.), the collection of parts could be named the Z-axis assembly.


If the fan you are using is not defective and if you test another fan that behaves in a similar manner, it's possible your firmware or hardware are the root cause of the problem.

The controller directs the driver to vary the power provided to the fan. It's a method called pulse wave modulation, aka PWM. Full voltage is applied to the fan one hundred percent of the time, for full speed operation.

For fifty percent performance, half of the time full voltage is sent, while half of the time no voltage is sent. The time period is rather short, but I didn't determine that aspect of this answer.

One can find a clear explanation of PWM online but one word is worth one one-thousandth of a picture:

If your fans are not performing properly, either the program embedded into the controller is buggy, or the driver module for that unit is bugging out.


Why does my model stop printing at the same spot?

The answer is that you have not used support structures. The printing fails as a result of missing support structures.

If you look closely to the Ace of Clubs card at the top, you will see that the lower point is being printed from out of nothing, this corner needs to be supported. When unsupported, the extruded filament flows freely and where it deposits is unknown. Usually this extruded filament sticks to the nozzle or ends up stuck at the next piece of the printed layer building up. This build-up can cause the head to hit the print and ruin the print.

To enable support in Ultimaker Cura configure your setting accordingly:

These settings are accessible when you select custom settings:

If the options aren't visible, use:

and type in the option.

Please do note that using supports does not guarantee that the print will not fail! Especially when using long slender support structures, the chance that a support structure fails increases with the amount of support structures and the length of the structure. Sometimes long slender support structures are knocked over.

Sidenote:
Your printer has more issues, if you look at the brim, it is not a continuous bed adhesion layer, it looks like it does not adhere too well, see also the bottom of your trophy.


You could put the z endstop at the top, and flip the motor connector to make it move the other direction. This should make it home to the top near the nozzle, and then move downward during the print.

Otherwise, you'll have to tweak the firmware configuration and reflash.


Weight Reducing Design Change for Extruder Driver

Very cool idea,

One motor would definitely be more than capable of producing the required torques even through a flexshaft connector. For any normal sized 3D-printer the torques required, and the speeds you'll need for rapid response are well within the capabilities of any off-the-shelf stepper motor.

Just a note on the idea though, with a normal, 'rigid', connection there is essentially no winding or unwinding, and only the backlash between the gears and the filament to consider, and that is effectively zero. With a flex-shaft though, the stack-up of twists and flexing will be much greater. The system will require more rotations at the source to effect the same amount of torque at the end effector as the flex shaft flexes and bends under the load. For tiny torques with short flex shafts, this wont be an issue as filament pressure is pretty minimal. But if you scale up this project or start working at much higher speeds, you may run into some issues with this design.

I have no idea how big or fast you'd need to be working at for this to begin to become a problem. I'm imagining pretty big though. Just something you might want to keep in mind if you try turning this into a huge, super fast 3D-printer.


Is there a way to invert motor direction with GCode instead of Firmware in Marlin

You can use M92 to change the axis steps per unit to a negative value, which causes it to move in the opposite direction. I.e. if normally your X axis has 160 steps per mm, using M92 X-160 will invert all of its movements.

However, this is more of a hack than a real, intended solution. It would be better to (if you are concerned with the homing direction) change the configuration to have the printer home in the other direction. Unfortunately, this can only be done by changing the firmware and not through G-code.


Acetone smoothing not working on ABSPlus-P430

Make sure that your acetone is actually acetone. According to the MSDS, ABSPlus-P430 is indeed "ABS resin" so acetone smoothing should work. Some companies sell confusingly-labeled products that might be mistaken for acetone, but are actually "eco-friendly" alternatives such as 2-butoxyethanol. While these alternatives work for some of the uses for which acetone is normally used (such as cleaning or degreasing), they don't work for smoothing ABS.


An extrusion width of 0.5 mm is too wide for making a sharp outline, I do use this sometimes for extrusion width for the infill.

Note that you can sand plastic (e.g. PLA or ABS) to sharpen the edge.


Filament moving around and not sticking to bed

If the printed material moves with the nozzle, you might have several problems at hand, e.g.:

adhesion,
nozzle to bed distance and
overall level.

Nozzle to bed distance needs to be the thickness of a plain A4 or Letter paper. This needs to be at the same distance (when pulling the sheet of paper you need to feel a little drag) at the complete area of the bed. This is sometimes difficult as not all beds are perfectly flat from itself. Finally, you need to pull some tricks out of your sleeve to get the filament to adhere to the bed. Many example can be found, popular ones are using blue tape, glass bed, glue stick, PVA based spray (e.g. strong hairspray or dedicated spray cans like 3DLAC or Dimafix, etc.), or a combination of these. You just need to experiment some more what works best for you, but it is good to start with a correctly levelled bed with the proper nozzle gap. Sometimes, increasing the bed and filament temperature with 5 °C for the first layer also helps.


Printing copyrighted objects as a print shop for a customer

There are two aspects to this question that probably should be addressed separately.  This is not legal advice and I'm not a lawyer, so consult with an experienced IP attorney.

Copyright law may apply, and other IP laws, such as patents and trademarks, may apply.  They each have different requirements and restrictions.

Notably, IP law varies from country to country.  WIPO has made significant inroads into regularizing IP law across many countries, but this answer will still focus on a US-centric reading of US IP law.

Copyright law

It's already established that printed works, such as photographs, texts, and similar works will result in prosecution against the person and the company that the person outsourced the copying of the copyrighted work to.  Attempt to copy a book or copyrighted photo at a paper copy shop and they will typically refuse to reduce their liability.

Even if you show that you have rights to the work, through educational use laws, for instance, they may still refuse because they may be putting themselves in danger of a lawsuit by a particularly aggressive copyright holder.

This applies to 3D printing shops in a similar manner.  If you don't know the source of the 3D model, and that the person has a right to the model, you may find yourself liable for copyright infringement.  Even if you are sure, a lawsuit can financially ruin your business if it comes from a large corporation.

Patents

Patents apply even if you were unaware of them.  So any model you print that contains patented techniques, technology, or concepts may also pull you, as the print shop, into a lawsuit for patent infringement.

Reducing liability

A suitable contract with the person requesting the 3D print, as written by an IP lawyer, may reduce, but not eliminate, your liability. It won't completely absolve you of all responsibility, but may reduce your exposure to such lawsuits, and give you some leverage in court should someone prosecute you.


It sounds like your bed is unstable. This is what I had to do with my Tronxy X1, and I fixed it by installing a decent bed stabiliser. Now that I have a stable bed, I only have to re-level it occasionally. However, the Tronxy X1 is a cantilever printer with a single rail for the bed, not an Ender 3.
I would suggest that you tighten the bed-levelling springs as far as they will go whilst still leaving sufficient movement for bed levelling, and re-position the end-stop switch. Then re-level the bed. If that doesn't work, try fitting stiffer springs. Upgrades are available for the Ender 3. If that still doesn't work, look for bed stabilisation solutions for your printer.
Note also that the bed-levelling knobs have a reputation for coming loose on the Ender 3. Tightening the springs (or fitting stiffer springs) may cure this, but some users fit locking nuts to stop the knobs moving.


Will I still be able to export my Fusion 360 models to other CAD packages after Autodesk's recent license changes come into effect?

Most of my answer is based off of what Autodesk has said and this video from Maker's Muse, which explains this topic in much more detail.
In summary, Autodesk is planning on restricting your ability to export any parametric file formats like .STEP or .IGES, leaving no useful CAD-specific files available for users with personal licenses.
I would recommend exporting everything you want to keep as .STEP right now just in case you do decide to switch programs later on, because you won't be able to switch after the changes go into effect.
I hope that helps.
EDIT: As Oscar has pointed out, .STEP exporting is now also part of the general consumer's license, and you can export to other CAD packages at any time. As far as I can tell, other parametric formats, notably .IGES, is still not available for consumers. This shouldn't pose too much of a problem.
I'm going to leave my original post intact for now.


Which is a more accurate linear motion system?

I used a few different linear rail systems in my build:

plain smooth rods for Z motion
smooth rods bonded to a T-haped steel base for a 1200mm Y axis (similar to those at https://cdn.automationdirect.com/static/specs/suremotionlinear.pdf)
igus "low profile linear slide" for X (https://www.igus.com/drylin/profile-rail-guide)

They all seem to work pretty well. The one problem I had was with the igus slides, which I found had a little too much play -- so each change of direction on X had a slight backlash, from the "cars" twisting a tiny bit within the rails. I improved that with careful tuning: shifting the rails a tiny bit farther apart, so they kept the cars under a little tension against the inner sides of the rail -- some call this "preloading".

I think systems that use actual bearings should generally be more accurate than spring-loaded slides. But the igus rails are still pretty good, and they're quite light, compact, and reasonably priced. I still use them, though once in a while I think about swapping them out to do a serious comparison.

The rails aren't the only factor in accuracy, though. I can't detect any play or warp in my Y rails, but that says nothing about accuracy and repeatability of motion along them. That's controlled by the motor and the belt, leadscrew, or other things actually moving them. Leadscrews, in particular, vary quite a bit in accuracy, depending on the shape of their threads, the kind of "nut" riding on them, and other factors.

You can even make your own leadscrew system from just a threaded rod and a nut -- but those threads are not the same, and they allow far more play than a real leadscrew does. Nice article on the "backlash" problem at https://www.liutaiomottola.com/Tools/Backlash.htm.


Failing slow extrusion after upgrade to E3D hotend

I bet your old and new extruders have different hobbed pulley/bolt effective diameter.
It looks like your new extruder has smaller hobbed diameter that's why it pushes too less material.

In MatterControl application there is a slider which allows user to tuneup extrude ratio on the fly (while printing). You coud check it so it would confirm the issue.

In Slic3r you could go to

Printer Settings > Advanced > Extrusion width

and experiment with it (especially with Default extrusion width)

Both (Slic3r and MC) could answer your question if it's extrusion ratio issue. If you confirm that - you can proceed with calibration. Here is method to calibrate extruder flow and general calibration article here.


You likely need to re-calibrate the Z-height of your nozzle. The reason that a lot less plastic is coming out of the nozzle at 0.1mm is that the actual gap is likely smaller than 0.1mm. This makes the print bed act essentially like a partial "lid" on the nozzle which occludes the outflow of molten plastic.

Simplify3D has information on their website regarding the issue which can be found here: https://www.simplify3d.com/support/print-quality-troubleshooting/#not-extruding-at-start-of-print. Hope this helps!


Help installing my Anet A8 printer to my computer

Your question addresses (USB) computer connection, so that will be addressed in this answer. For connection to the printer, you need 2 things (apart from the apparent things as computer, printer and cable):

A working CH340 driver installed on the computer for USB communication with the board,
a piece of software to talk to the computer at a bit transfer rate the printer understands.

The cheap Arduino based boards rely on the CH340 chip for USB communication. You should check whether you have correctly installed this driver. These drivers are erroneous and prone to cause problems. Sometime re-installation works, once did work for me.

The SD card supplied by Anet contains a folder (on my SD card: .\A8\A8资料\Software\CH340G Drive) with the installer file of the driver. Once installed properly, you should be able to connect various applications to the A8, provided you use the correct baud rate of 115200.

All this said, are you asking the correct question? Why do you need to connect to a computer, as you can print just fine by putting sliced .stl files (.gcode files) onto the SD card (when inserted in the computer using the adapter) and reinsert the card again in the printer to select the file using the menu buttons of the printer. Printing from SD card is considered safer then printing via the computer over USB as the print will stop when the PC is shut down or crashes.


Are 3D printers efficient for printing a detailed iris to bypass iris identification system?

I take lectures in university and was asked to read a review paper on 3D printed organs by Anthony Atala (the most famous paper in printed organs research). The paper discussed about using several techniques to print the tissue we need at functional resolution. The review also cites detailed procedures to 3D print lung and skin tissues.

Coming back to your question, we have reached a point in time where we can scan a real Iris and print them! Yes. And people use this technique called self assembly to achieve this (Other design approaches like Biomimicry and MiniTissue assembly is also being used right now). To do this we first extract cells from the donor. Or We do a functional high res scan of the extracted cell/part that we want to replicate. This is done via FMT-CT-Fluorescence Imaging, etc. And we cultivate the cells in bio incubators (we can also print cells btw - If the exact environment and operational conditions are maintained, we can print cell-replicas that will later self assemble to form the Iris with the same resolution and functional properties as that of the real one). The cultivated/printed cell is used as the tissue forming material. Forming is done by the cells themselves and is thus christened Self assembly.

Although this may sound futuristic, Autonomous Self Assembly is something that's already being done in Labs! The method works by studying embryonic organ development. For instance, Early stage cellular components of a developing tissue makes their own ECM. Like mentioned before, if we use proper signalling, and environmental manipulation,  we can create autonomous organization and patterning to make something we want. Advantage of this method is that we can work without scaffolds. This method relies on cell as primary driver of histogenesis. Knowledge of how an embryo grows into tissue (embroyo tissue genesis and organogenesis) is applied to achieve "real" cell dimensions/properties.

I would recommend you to read the paper for detailed information. The method I mentioned in this post is only one among three other methods that are being used currently in this domain.

So yeah. My answer is yes. You can print an Iris and fool the system.

--
Updates

S. V. Murphy and A. Atala, “3D bioprinting of tissues and organs,” Nature Biotechnology, vol. 32, no. 8, pp. 773–785, Aug. 2014. DOI: 10.1038/nbt.2958
Withdrew my claim "any given resolution"
Details of the process


Make sure that your heating device (resistor) is for 12v, not 24v (resistance is < 10Ohm)
Check if the temperature readings that you get in your system are (at least roughly) the same as actual temperature (thermocouple with multimeter or any other device that can measure ~200C will help)
Check if connections are good enough. Low voltage at hotend is an indication of possible problem. ATX power wires are often too thin to transfer enough current. Consider replacing them with at least 2.5mm2 (AWG 14)


Printing PLA on PEX surface - is heated bed needed?

I print PLA on a PEI bed at 60°C.  I have also printed PLA on an aluminum bed at 60°C with Elmer's Glue Stick for bonding, which worked better for me than PLA.  I recently switched to Aqua Net Hairspray on the aluminum bed at 60°C, which also worked well.

I have found no reason to avoid bed heating with PLA.

If the object is stuck too tightly on the PEI bed, you could try adding hairspray.  It acts as a glue, but also as a release agent, and, being soluble in water, you can help release the object with a few water drops.


Flexible filament how to print a hollow "sleeve"

Print orientation is usually the key to print with a minimum of supports. If you print this part with the sharp point down, you will get some support structures on the outside for overhang support to prevent it from tipping over, but no support on the inside.


CR-10 Layers not printing after certain amount of filament printed

If the problem occurs at same height I would focus on the Z axis, in particular the gantry and its rollers.
Try to remove the Z axis screw and feel if the you can slide the gantry up and down with ease, in particular if it gets harder to slide at roughly the height where the problem occurs. You can use the eccentric nuts to adjust the rollers preload and make it slide smooth.
Next on my checklist would be the screw: verify there is no issue on the screw at that height, the Ender 3 is renown for having a Z rod issue due to misalignment between the motor and the nut on the gantry.
While writing another idea came to my mind, but I'm sure already checked that: the filament is not clashing or being clamped somewhere when it reaches that height, right? A filament guide would generally exclude that...


E3D has a Cyclops product which mixes two filaments inside a melt chamber.  Clones of the E3D Cyclops can be found through the usual outlets.  E3D also has software recommendations for using their Cyclops product, which are found here.  They suggest cura as the slicer.

The RepRap firmware (and possibly others as well) allow two extruders steppers to be used in an extrusion move, proportionally mixing two filaments.

In case you want to go further, to get a broad color gamut, you will need five filaments mixed into one extrusion bead.  Cyan (sky-blue), magenta (or bright purple), yellow, white, and black filament can be mixed to make most colors.  "2D" printing is done with four colors (cyan, magenta, yellow, and black), but for 3D printing, you also need white.  2D printing uses white, but it is the white of the paper.  Black is needed to get dark colors, as well as to form neutral gray colors.

Based on the OPs comments, I understand that the software sought is a shader that creates a marble effect on the surface of a print.  I don't know of such software, but, as a software engineer, I imagine it would take roughly this form:

Slice the object conventionally, producing G-code for the object.  Identify all exterior extrusions with a special extruder number.  Multi-material slicers should provide this option (Slic3r-PE does).
Project a 2d image or synthetic pattern onto the 3D external surface of the object.
For each voxel (volume pixel) of the exterior extrusion, determine what it's color should be based on the shading.
With previously determined propagation delay from when the mix is set to when the color is extruded, back up along the extrusion path the correct distance.
Split the extrusion command at the point where the mix must be changed.  Insert new extrusion values.
Output the modified g-code.

I've left out many implementation details.

The scheme depends on how predictable is the delay (in extrusion distance) from when the extrusion mix is changed to when the change comes out of the nozzle.  The variation (if any) in that distance will make the output look jagged and fuzzy.  In some ways, that variations limits the 2D bandwidth of the color information.

Schemes that require sharp, line-to-line coherence may require a purging process.  I assume that for a marble pattern, which I characterize as having soft color changes on a scale that is larger than the extrusion width, purging on every change is not desired or possible.


Which 3D printer should I use to make custom miniatures for a tabletop game?

The Form 2 will definitely give the best results for your application.

Both the Fortus and the Dimension use FDM, which builds the model up using a bead of molten plastic. Because this bead is typically 0.5mm in diameter, this strongly limits the details you can print.

The Form 2 uses liquid resin, that is cured by scanning it with a laser. This process is called SLA. The laser produces a 0.14mm dot, and so you can produce much finer details. The Form 2 can also use much thinner layers (down to 0.025mm v.s. the 0.178mm of the Fortus) so the models will be much smoother.

To make small miniatures SLA is much more suitable than FDM.


Creality Ender 3 - printing in front of the build plate

When a print is not printing on the build platform, you either:

Have the incorrect settings in the slicer (e.g. Ultimaker Cura, a common mistake is that the "origin at center" option is active), or
Have the center of the bed incorrectly stored in your firmware. (See: How to center my prints on the build platform? (Re-calibrate homing offset) or Recalibrating Home-position).

Note that the most simple change (after you verified the slicer settings and confirmed that it still does not print in the center) is adjusting the settings in the slicer (bed settings, of start G-code script), this way you do not need to compile and upload new firmware (e.g. if you are uncomfortable or inexperienced in doing so), but, fixing it in the firmware is the best solution. Why? If you change the offset in the slicer you force the bed dimensions to a new position that you know where it is, while if changed in the firmware, the printer "knows" the actual size and the limits.

To fully answer your question, we need a little more information what slicer you use and what the current settings are. From your question it sounds as if the offset is more than a few millimeters. Usually this hints to an incorrect slicer setting (frequently Ultimaker Cura).


Can I use different sized steppers for different axes?

Each axis is fine using a different stepper size and/or quality. You will still need to tune their operating current and steps/mm for each of course. Make sure your motor mounts fit too.
Where it might become challenging is if you wanted two different steppers on the SAME axis. As in, a NEMA17 + NEMA23 for a dual Z axis. I don't think this is what you intend though.


The overall torque, and thus the incremental torque is less with your new stepper, this may result in less smooth operation because of moving the weight of the carriage (e.g. when you have a direct extruder mounted on the X carriage).

You could be facing skipping steps, resulting in less accurate prints. Maybe the Vref has not been adjusted correctly, or the stepper is just not working for your application.


Your images look as if your initial nozzle to heat bed offset is too large. This causes the filament not to be squished. Try re-levelling and have a piece of plain printing paper have a little drag when pulled.


I've seen mods for the Hypercube (and Hypercube Evolution) using linear rails (e.g. this mod), so yes that is possible. You need to redesign a few parts and make sure you have the correct length, but that shouldn't be too difficult.