Layer Shift with a new CoreXY printer I've started assembling a Sapphire Plus CoreXY printer and produced a nice calibration cube (no layer shift, although a bit of over extrusion in the corner). Then, I started printing a 3D benchy, and got this:

I've checked belt tension and it seems correct (I've printed this belt gauge with another printer and checked that both belts are tensionned the same), with a bass sound when pluked.
I've checked both Z-axis lead screw and it's not 100% perfect (one lead screw has a 1mm deviation on one side when rolled over my desk). When the bed goes down, the effect of the lead screw is only visible when the bed is half the height or more, so it shouldn't matter here.
Also, I had multiple filament breaking before entering the extruder in other prints, so I'm not 100% confident with the extruder.
The machine is a Core XY printer with a Bowden extruder, with linear rails for all axis, and 2 lead screws for Z axis (and 2 stepper motors attached by the same belt). It's level, on a concrete base.

Shifts in a diagonal direction in CoreXY indicate loss of synch between the two belts.
If it's the belt very loose skipping, you may not hear much but such a loose belt is easy to notice.
If it's the belt a bit loose skipping, you would hear relatively loud noises which make very clear what's happening.
If there are no particular noises, it's the motor skipping steps. One motor move along the X+Y diagonal, one along the X-Y diagonal, so you know which one it is.
If you have missed steps it could be because of excessive friction (maybe one motor is mounted tilted, or it is damaged), or because of excessive acceleration setting, which the motor cannot handle, or because of too low current.
If you decide to increase the current be aware that it may work on simple tests, but during longer prints the stepper driver may overheat and lose steps for self protection.
To check what acceleration and/or current you actually need per each motor and to compare whether motors are significantly different from each other, try this.
Without printing, you set the maximum acceleration relatively high (5000 mm/s^2).
Place a paper square (relatively big) on the printing area, parallel to the axes and tape it.
Align the printing head to one corner of the paper square.
Give a G0 command to move the printing head to the opposite corner of the square (G0 F600 X... Y...) and check that the alignment is correct. Also, only one motor should be moving.
Bring back the head to the opposite corner.
Set the feed rate to high values, like F9000 (150 mm/s) and move the head again. If it reaches the correct spot, the current of the motor is sufficient for that acceleration.
Try for the other diagonal of the square you taped to test the other motor.
You can now reduce the current of the motors which successfully passed the test. If you have Klipper it's super easy and requires only the command "SET_TMC_CURRENT STEPPER=name CURRENT=amps", with Marlin I don't know.
See at what current each stepper fails the test, then decide whether to reduce the acceleration (5000 mm/s^2 is anyway probably too high for your printer frame, you would get artifacts like ringing) or to dial back up the current. I would say that 20% above the current required to pass the test is enough. More than that and you are just overheating the TMC2008.


How does this Martian habitat 3D printer built for NASA work? The ArchDaily article AI SpaceFactory Wins NASA's 3D-Printed Mars Habitat Challenge shows a working 3D printing apparatus using an unusual material containing

  basalt fiber extracted from Marian rock (simulant) and renewable plant-based bioplastic.

The photo below shows part of the printer. Is this printer just leaving a slurry to dry, or does the mixture somehow catalyze or harden spontaneously? I'm also wondering what the (looks like) twelve black hoses are around the central nozzle.

Let's start with the general design look and feel: This printer contains a robotic arm with a toolhead, pretty similar to a welding robot, and probably is controlled with a similar CAM software.
 Picture by Robotics.org
Tool head
The really interesting part here is the tool head. So let's look at it and try to reverse engineer the use of some parts by how they are placed and what one can see about them, together with the information given by OP.
Black pipes
There's a bundle of 12 black pipes that go from the main body to the print head, ending at the side of some distance disk. To me, these look suspiciously like a system to deliver an airstream, so most likely some sort of cooling system. This is further supported by the huge fans at the base of the machine, pumping air into the flexible pipe.
Silver Tank
The first picture shows a silver tank with the label V7 (version 7?) or VT (as in Virginia Tech) or something similar on it. This is connected via a grey hose to the base of the printer. The mounting of it over the extruder hints, that this is a hopper, most likely holding the print material in pelletized or powder form, and that it is fed via the grey hose. From the information given in the question, it might be some sort of PLA (synthesized from cornstarch) or other bioplastic using the Martian dust as a filler material. From here, the print material falls into the central column...
Central Column
...which goes down through the distance disk into the thick nozzle, so it must be the extruder and heater combo. At its top, there is a large stepper motor in Z orientation, which hints that inside of the matte grey tube is an arbor, pressing down the melting pellets past a heating element into the nozzle below.
Print material and further information
The last picture shows proudly "Autodesk" on the side of the printer. Autodesk has an own article about printing in space from August 2018, where Nathan Golino of the NASA owned GMRO states this:

Abrasion has been an issue with the 3D printer we use. It’s very rough on the feed screw and the barrel and nozzle as the material is extruded through the system.

This confirms the general makeup akin to a pellet-style extruder.

Combining a small amount of waste plastic with crushed rock known as regolith can form an additive construction material that’s stronger than concrete. (on a picture caption)
The material we’ve been using in our additive-construction experiments is regolith mixed with waste polymers. You can get polymers in the form of astronaut trash and shipping containers, or you can synthesize polymers. You can use that as a binder for regolith, with a relatively low ratio of polymer to regolith, to make a construction material pretty similar to Portland cement in compression and 20 times stronger in tensile strength.

"Waste polymer" could be anything from ABS to PETG, from ASA over PC to PLA, but it seems that the plastic-to-regolith mix is on the high regolith side. It seems that it behaves more like a plastic than concrete, hardening/solidifying from a molten paste to its hard concrete as it cools.
As an interesting extra tidbit: Golino also states, that the mars-printers are at the moment on level 2 to 3, where 0 is "general concept" and 9 "ready to fly", so in early development.
Further reading into the background of the project - a design competition in 2015 - hinted, that the software for the arm might even be Autodesk PowerMill.
Looking back at the question if that is V7 or VT on the printer's hopper, an article with the same dome printed in OP's question popped up: Virginia Tech had been part of the crews that were taken to the finals of the aforementioned design competition and was part of the finals. They worked with the AI Space Factory team, which came out winning. In a related article, the printer OP showed us can be seen from a different angle and stripped of the cooling pipes and with a different, longer extruder. It tells us a little more about the work distribution of the teams and participants:

Large format vessel printed by AI SpaceFactory in the Autodesk BUILD Space for the construction phase of the competition. The tooling was developed in collaboration with Virginia Tech and Autodesk.

The main company behind it, AI SpaceFactory, showed a different version - the one without cooling pipes - in motion on a YouTube video on April 10th 2019 and the performance of the air-cooled version during the competition finals on May 3rd 2019 (warning, 10 hours of 3D printing galore!) At 9:52:12 we also start to learn what that disk is in picture 1: It is the endcap of the structure which sadly fell through the hole due to navigation issues.
In the following shorter and commented video, we see that the printer also contains some sort of gripper to place the window frames and skylight just as well as the load bearing test performed after the print. Apparently, the material they use is engineered to a point where it can be reused after regrinding it to dust again.


After some time stepper motor is hot I have three stepper motors.
One Nema 17 - 2.4 ohm, the second smaller noname from color printer - 9.5 ohm and third the smallest noname from cdrom - 10.5 ohm.

I have connected them to arduino mega 2560 with ramps 1.4(set to 1/32 micro stepping) and drivers drv8825. See my previous question.

After some time (less than one minute) the first is cold. The second motor is hot. And the third is very hot. I can not even touch it.

What can I do to fix it.

The second motor is hot. And the third is very hot. I can not even touch it.

This is to some degree, completely normal and expected. From the datasheet for a typical NEMA 17 stepper, the rated temperature rise is 80 °C above ambient and the maximum operating temperature is 130 °C (implying an ambient temperature of 50 °C). It is normal that stepper motors (in general) get a bit hot.

"Too hot to touch" is still relatively cold. 60 °C is already too hot to touch, and that's only a 40 °C rise above a 20 °C ambient temperature.

You can reduce the temperature rise of the motors by reducing the current they receive. The stepper driver has a small potentiometer that can be turned to adjust the current, but keep in mind that doing so will also reduce the torque of the motors and thus they might skip steps if you reduce the current too much.

Technical details: Note that stepper motor drivers used in 3D printers are constant current drivers, and the little potentiometer controls the current. If you had not paid much attention to this potentiometer, the drivers might all have been set for the same constant current of $1.0\ \text A$. The stepper driver would (to achieve the same constant current) send a higher voltage to the higher resistance motors. This would imply a power dissipation of $2.4\ \text W$ in the Nema 17, and a power dissipation of $10.5\ \text W$ in the small stepper. $2.4\ \text W$ in the Nema 17 would only heat it up by about $20\ °\text C$ above ambient. A dissipation of $10\ \text W$ in the small stepper, which also has much less surface area to dissipate the power, would heat it up by a lot (and probably, given that you didn't fry it, the current was set lower -- or a technical peculiarity limited the current given that the motor likely also has very low inductance).


PVA support with small tolerances I am at the moment designing some in place mechanical parts. Something like two cylinders that rotate with respect to each other. I need in my design some overhangs that cannot be printed and I was thinking of using soluble supports to be able to print these overhangs. I am afraid that by using something like PVA the PVA will end up between the two parts and glue the together.

Does anyone have any experience with this? Can something be done about this apart from 'not using PVA'?

Edit:

Here is an (minimal) example of an object I would be worried about. The blue and red cylinders are supposed to turn around each other and there is a cutout in the blue cylinder that will need support (the bridge is to long to print without support).

You've not stated this, but one must presume that you have a dual or multi-material extruder equipped printer.

Because PVA dissolves in water, the supports will be eroded on contact when the part is immersed. As the PVA dissolves, it increases the concentration of PVA in the water, but only slightly. You would have to agitate the water, change it if you feel it is becoming too concentrated. At some point, you should be able to rotate the cylinders, creating more turbulence, causing more PVA to dissolve into the water.

If you are determined enough, you can cause all of the PVA to dissolve, followed by a rinse with clean water. This would remove any residual PVA.

The water containing the dissolved PVA is somewhat sticky, but would not glue parts together if the parts were thoroughly rinsed. It's not out of the question to use an ultrasonic cleaner with plain water to provide sufficient turbulence, again changing the water periodically to keep the concentration low.

If you use an ultrasonic cleaner, test a sample of your print filament to determine if the heat generated will soften the plastic. I've had success with PVA to the extent that I have not had to use an ultrasonic cleaner to remove it.


Raft hard to remove? I've been having a hard time lately getting the raft off of my ABS prints.

Is that a symptom of either a nozzle or bed that are too hot? Or is there some other factor I should be looking in to?

I have an UP mini that I've modified both the nozzle and bed to customize the temperatures on.

Bed gets heated to 100˚C and nozzle is either 266˚C for UP ABS filament or 236˚C for off-brand ABS filament.

A couple things to consider:

Ensure that your build plate is flat and level. An un-parallel HBP could result in the object "welding" to the raft.
Turn down your nozzle temperature. It is likely that the material is hotter than it needs as it is extruding. This results in a slower "cool-down rate". So, if it takes longer for the filament to cool between the raft and the first layers of the object. Therefore, cooling together in a manner that somewhat binds them.
Personally, 266C seems VERY high to me. I've primarily only used ABS on my MakerBot and have successfully printed with 225C +-5C nozzle temperature and 110C +-2C HBP temperature.
Typically you want to extrude slightly above the melting point. You don't want to liquefy the material, but make it pliable enough to bond it to other layers of material (or a BP).


Warped bed - bulge vs dip? Theoretically what is better- a warped bed with a dip in the middle, or a bulge in the middle?

(I would instinctively think that a dip would be better, since in a perfect world the glass build surface would still span the dip, and then the flatness of the surface relies on the structural integrity of the glass, whereas a bulge would not do the same, instead causing the glass to teeter atop the bulge)

Thoughts?

That depends on the use. If you have a slate of glass a dip might be better (but the heat transfer at the dip would not be ideal), a bulge would stress and tilt the glass.

If you print directly onto the metal build surface it would not matter if you use a(n automatic) bed levelling system because you can compensate for the bulge or the dip using a mesh of the bed. Without a scan of the build platform you would have issues in getting the filament to stick.

Basically, there is not a better solution, best solution is to get a flat bed if the bulge or dip are making printing difficult.


Using two feeders at the same time I am using Prusa i3 MK2s with the first version of the multi-material add-on.

As far as I understand, the slicer defined the used feeding motor using the T0-T3 code which defined one feeder at the time.

Is there a way to have two feeder motors working at the same time?

The first multi material add-on version off J. Prusa includes several separate steppers that load filament into the hot end. Note that selecting an other color will retract the existing filament so that the next filament can be loaded. There is no mixing hotend nozzle. It is therefore working serial, not parallel. Working 2 steppers at the same time will  lead to clogging the filament joining position.


Where is the auto-reset jumper on the Wanhao i3 PLUS? I'm having some issues when connecting to the printer via USB, see Wanhao i3 PLUS restarts when connecting USB.

After some research I thought I would try to remove the auto-reboot jumper. Now that the i3 Plus uses a custom board instead of the standard Melzi, I'm not sure where to find it.

See pictures attached:

The pictures don't help much, and I don't know the board. But if it is as described here, Elec Freaks Wiki - RAMPS Melzi, then you need to look for the FTDI Chip FT232. The reset is caused by the DTR Signal. There needs to be a copper trace from pin 2 to the capacitor and then to the jumper. From the jumper a trace leads to pin 4 of the Atmel ATmega.

If it is a clone, the jumper might have been "optimized away". If so, desoldering the capacitor gives the same result.  Be certain to desolder the right one. If unsure keep the capacitor and solder it back in if it was the wrong one.


How to create an air-free design? I am creating a bottlecap-like design. The design is sealed by rotating the lid. I am adding a chemical to it for an experiment. I would like the inside of the design to have no air circulating to it through the lid tiny spaces.
My design:

Are there any simple solutions I can implement out there? Design-wise, material-wise, or maybe an extra piece?

Are there any simple solutions I can implement out there?

A gasket made of rubber or other elastic or deformable material is probably the best option. Printing one or both of the parts using a deformable material like TPU might also work. Finally, if you don't need to open the unit during the experiment, you could use a sealant like silicone caulk might make sense.


Nozzle goes down after bed leveling BLTouch I am new and I really hope you could help me out.

I have two printers, one is an Anet A8 and the other one is a CreatBot DX plus. On both of them I installed a BLTouch, firstly on the DX and today on the A8. I have never had a problem with the probe, but today I am experiencing some problems. I just set the offset, by doing the procedure, and I found to that the Z0 is -0.8 mm.

Problem is, when I start to print (I use Cura as a Slicer and OctoPrint), I run G28 and G29, everything is fine and the bed gets mapped. When the print starts, something weird occurs: the nozzle goes down for the regions where the bed is higher! So, the layer that is put down, is very thin and the nozzle actually dives into the bed! It is like a Z0 too low, so the nozzle crashes into the bed, but it is not because in X100 Y100 it is perfectly fine! Could you have any idea why this occurs?

What have I tried?

Changing bed springs
Because I was curious, and impatient I changed the springs with the Ender ones I bought online. The problem is still here! I can see the bed closer to the nozzle during bed leveling, compared to the left side. So I screwed the right side, to see any difference. However, the nozzle seems to be always closer on the right side! I checked the X rods, they are leveled.

Searched online
I checked almost everywhere online and I found out that it could be a problem related to the bilinear bed leveling. So I changed to linear, and apparently now I can print! I believe it is something related to the mesh the firmware creates after the leveling, which is avoided for the linear.

Check and potentially replace your bed springs as this is a common cause with cheap bed springs.
An immediate workaround is redoing your Z-offset but most likely after a while you have to repeat it until you replace the bed springs with stronger ones.

After replacing springs you have to redo Z-offset again.


Z offset in Marlin is not working recently My printer is ignoring the "Z offset" setting in Cura and the "Bed Z" stored in the printer LCD settings? It has been working before but after a firmware update of my printer, it doesn't work. Even after flashing the previous firmware back "Bed Z" changes no longer affect anything. No matter if I change "Bed Z" during prints or if I use the "Z offset" option in Cura, the nozzle still prints at the same height.

I have the same problem. You need to check your G-code to detect where's the problem.
Try comparing the G-code file with different values of the Z offset.
In my case it looks like this:
No offset
;LAYER_COUNT:107
;LAYER:0
M106 S255
G1 F300 Z0.84
G0 F6000 X124.645 Y78.208 Z0.84
;TYPE:SKIRT
G1 F300 Z0.44
G1 F1500 E0

With offset (comments made by Cura)
;LAYER_COUNT:107
;LAYER:0
M106 S255
G1 F300 Z2.06 ;adjusted by z offset
G92 Z0.84 ;consider this the original z before offset
G0 F6000 X119.093 Y42.498 Z0.84
;TYPE:SKIRT
G1 F300 Z0.44

I hope this helps.


Hatch Distance and Scan Distance I am going through some of the basics about one of the 3D printing techniques - Selective Laser Sintering, and I am confused between the above mentioned parameters - scan distance and hatch distance. Are they the same ?

How do we calculate the value - the overlapped area of two parallel scan lines in linear scanning technique. There must be some area of overlapping for the selective laser sintering to work.

Any idea ?

Scan spacing

  Within each of the ‘islands’, simple alternating scan vectors are used with the spacing between these vectors defined as the ‘scan spacing’ and the speed with which the laser spot moves across the surface defined as the ‘scan speed’.

Source

The influence of the laser scan strategy on grain structure and cracking behaviour in SLM powder-bed fabricated nickel superalloy
chapter: 2.2. SLM processing and laser scan strategy

Hatch distance

  The stripe pattern is a band defined by the scan vector width (ie stripe width), the hatching space between adjacent tracks and the scan direction as well as the overlap with the neighbouring stripes

Source

Scanning patterns in SLM

Notes

The computer controlled laser scans the surface of the bed to selectively melt the current two-dimensional slice of the CAD file.
The laser scanning remelts some of the previously built layer to ensure good bonding between layers and a fully dense component overall.
Cool printing image


What can cause a 3D printer to catch on fire? From what I've seen, you can take a typical extruder heater, apply the designated supply voltage without temperature control, and as long as the heater isn't contacting something with a flashpoint below the temperature the heater reaches, the heater will not catch on fire.  Thus, unless one catches the filament on fire, it seems that thermal runaway of the extruder heater wouldn't normally start a fire.
I'm not sure what would happen if someone installed wrong components, such as a 12V heater to a 24V supply. What are situations that could cause a 3D print to catch fire?

In short:

The control board does not have thermal runaway installed
The heated bed connectors are loose and begin to heat up until the wires catch fire
The power supply or it's connectors begin to heat up until they catch fire
The modifications that you made to your printer were not well thought out resulting in a capacitor to explode (raises hand; that's happened to me.)


Are there differences in filament consumption between ABS and PLA I have been printing the same model once with Verbatim PLA and once with an ABS material from Switzerland. For both I was using two brand new 1 kg spools of filament. I was printing both at the same speed, same additions, same infill percentage, solid layers, solid wall count, etc. Literally everything the same except temperature.
Simplify3D indicated 300 g for each print, however I already realized that all of Simplify3Ds estimates for time and material are - unlike Cura - very poor. However I was still kinda surprised when I checked the two spools after printing. Originally they had the same diameter of material and same depth. After the print the ABS spool looked almost the same as before the print, in terms of diameter it shrank less than 5 mm, however the PLA roll was definitely at least 1/3 empty. The difference was also confirmed by a scale. ABS only consumed like 220 g, while PLA was using a bit over 300 g. ABS surely did not look like more than 20 %, but maybe its inner diameter is larger than the PLA spool.
Since I can order ABS considerably cheaper than PLA I was wondering if this is a common phenomenon. Googling for that leads to a million of pages outlining the differences between ABS and PLA where 999'999 of times it says that ABS is more prone to warping than PLA and the other one is about dimensional accuracy, but I could not find anything about material usage.

I’ve never actually printed anything other than PLA, but...
Searching the web for filament density, I found this article , among others, that indicate that PLA is nearly 20 % denser than ABS, on average (1.24 vs 1.04 g/cm3). This indicates that a 1 kg reel of ABS will have 20 % more volume (therefore length) than a 1 kg reel of PLA.
This does not quite explain the difference you see as 300 g vs 220 g is 36 % but maybe your measurement is off or the particular PLA mix you’re using is slightly denser.


GRBL with low feed rate not working I have a cheap 3000 mW laser cutter that I'm trying to cut 3 mm black acrylic. I'm lowering the feed rate to try to get it to cut in one pass.
I have the G-code for a small circle (16 mm) but it seems any feed rate below about 25 mm/min is being ignored and it uses 25 mm/min anyway. The laser cutter has been set up with GRBL 1.1h and I have checked that feed rate is being read in by GRBL correctly. If I set a feed rate of 35 mm/min, that is processed correctly - but it needs two passes to cut the acrylic.
Please see G-code below:
G90 (use absolute coordinates)
M4 S0
S0
G0 X9.6 Y18.16
S1000
G1 X10.98 Y18.21 F20
G1 X12.27 Y17.99
G1 X13.48 Y17.55
G1 X14.58 Y16.9
G1 X15.56 Y16.07
G1 X16.41 Y15.1
G1 X17.12 Y14
G1 X17.68 Y12.82
G1 X18.06 Y11.56
G1 X18.26 Y10.28
G1 X18.27 Y8.98
G1 X18.08 Y7.7
G1 X17.82 Y6.88
G1 X17.48 Y6.11
G1 X17.06 Y5.39
G1 X16.56 Y4.72
G1 X16 Y4.11
G1 X15.37 Y3.55
G1 X14.7 Y3.06
G1 X13.98 Y2.63
G1 X13.22 Y2.27
G1 X12.43 Y1.98
G1 X11.62 Y1.77
G1 X10.8 Y1.63
G1 X9.15 Y1.6
G1 X7.62 Y1.89
G1 X6.23 Y2.47
G1 X4.99 Y3.3
G1 X3.93 Y4.34
G1 X3.06 Y5.55
G1 X2.41 Y6.89
G1 X1.98 Y8.33
G1 X1.81 Y9.83
G1 X1.91 Y11.35
G1 X2.3 Y12.85
G1 X2.99 Y14.3
G1 X3.38 Y14.87
G1 X3.8 Y15.4
G1 X4.27 Y15.87
G1 X4.76 Y16.29
G1 X5.29 Y16.67
G1 X5.84 Y17
G1 X6.42 Y17.29
G1 X7.02 Y17.53
G1 X7.64 Y17.74
G1 X8.28 Y17.92
G1 X8.94 Y18.05
G1 X9.6 Y18.16
S0
M5 S0
G0 X0  Y0 Z0 (move back to origin)

This G-code was produced with LaserGRBL (and modified by me, to no effect). I have tried F1, F2, F3, F4, F5, F10, and F20 and they all take the same amount of time to complete.
What can I do to perform a cut in one pass since these low feed rates appear to be ignored?

This was likely due to reaching the limitations (maybe minimum step rate) of the stepper drivers which were 4988 drivers. I updated them to 8825 drivers which were able to support a speed of F20 correctly. I have not yet tried them at lower speeds.


Bed temperature command going to 0 °C with no obvious reason when print is started Configuration

Printrun/Pronterface
Slic3r 1.3.0
Windows 10
Arduino Mega + RAMPS 1.4
Marlin 1.1.9
Prusa i3 -- Hephestos BQ with following modifications:

450W PSU (230V to 12V)
heatbed
3D touch
led stripe
ps_on with relay on the PSU

Issue conditions

I was printing fine until something happened, do not know what.
What I can tell is I can reach any bed temperature with Pronterface, and for any duration. (my little 450 W PSU provides enough power for my needs, like 60, 70 or 80 °C, a bit hard for 85 °C though)

But as soon as start the print (when the temperature is already ready extruder and bed -- and as I always did), the motors move the extruder in the bed center and then I get the following error :

Error:Heating failed, system stopped! Heater_ID: 0
[ERROR] Error:Heating failed, system stopped! Heater_ID: 0

Error:Printer halted. kill() called!
[ERROR] Error:Printer halted. kill() called!

If I check the temperature with M105 ; temp report, the printer gives me:

before I press the "start print" button >> T:245/245 , B:80/80
after I press the "start print" button >> T:245/245, B:80/0

so bed temp command is fine.....until I start the print

Temp command set to 0

What causes the printer to be halted is a huge temp difference between command and sensor.
In the provided G-code, the bed temp was lowered to 30 °C, which helps :

running the test faster
this shows that the problem is still going on (bed temp command to 0 °C)
I can "print" (move the nozzle without error but the PETG won't stick to the bed) and I don't get temp error.

See the full log here.

So, what does cause the bed temp command to get to 0?

Not from G-CODE

I checked in the G-code, and there is no M140 *0 nor M190 *0 until the end of the G-code, and I'm sure the problem is not comming from the slice/G-code because I ran some previously successfully run G-code/config and they fail the same.

Not COM related

I ran the same gcode on sd card (to see if the USB was involved), but the behavior is the same: as soon as the bed temp is reached and print started, the bed temp command is set to 0 (I can see command on LCD screen).

Hardware related?

I did not change the firmware, and print were going fine, before the printer was doing this, so I guess the root cause is Hardware.

Firmware involved

Because of the "0 °C command", the firmware react to something but I could not understand what is happening here.

when checking the firmware code, the only reasons why bed temp is set to 0 when print is running without asking for it would be

gcode_M140()/gcode_M190(): it could be bad interpretation of ascii command.
_lcd_preheat() ?
PID_autotune() : PID algo error?
ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED : maybe but it would also put the extruder temp command to 0

nothing that would really explain this...

Any hints?

I tried, by instrumenting code, to know where/when the temp bed is modified.

I found that it is called in the gcode M81 when starting the print.

Wait M81? isn't it M80 to switch on the PSU?

What I did in fact was both wiring this up side down and mixing M80 with M81.

But what I didn't know is that M80 and M81 are not strictly opposite functions.

Indeed, M81 puts the PS_ON signal to PS_ASLEEP != PS_AWAKE but also disable all heaters.
I couldn't see it without serial trace because the extruder temp is set back after the M81, but not the bed temp.

Problem solved.

Hope this can help people in the future to spend less time than me on that simple mistake.

Note: What remains a mystery, though, is: why was it working before on previous prints and then, suddenly, broke?!!


What to do with failed/unwanted 3D prints? I am planning on getting a 3D printer soon and I was just wondering, what do you do with 3D prints that either failed or were prototypes that you no longer want?
I tried looking online but the closest I got was effects on environment, turning prints back into filament, or restarting a failed print half-way, none of which were the information I was looking for.

The solution should be somewhat eco and just keeping unwanted prints in a box somewhere isn't a very good solution either.
Finishing off failed prints isn't totally applicable because it wouldn't apply to prototype prints that you don't want to keep.

Is there anywhere to send failed 3D prints for professional recycling, or are there any recommendations for properly disposing 3D prints?

In case this is of any use, the printer I am planning to get uses filament that can be made of PLA, ABS, Nylon, and possibly other materials. The printer is this one specifically (https://www.kickstarter.com/projects/101hero/101hero-the-world-first-us49-3d-printer) from KickStarter.

The "obvious" answer is re-grinding the prints and making more filament. Unfortunately, this isn't yet a very economical or simple operation. A decent filament extruder capable of holding acceptable diameter tolerances is around $1000, and even then they can be pretty fidgety to operate. You have to have a LOT of volume throughput in your filament extruder for regrinding to be an economical proposition.

Some of the reasons why recycling prints into filament can be difficult:

Most plastics will degrade to some extent each time they are extruded. (Both by the 3d printer and by the filament extruder.) PLA will thermally degrade with extended exposure to heat. PET will hydrolyze and break down if not meticulously dried to remove moisture prior to heating to the melting temp. (PETG seems to be less prone to hydrolysis damage than plastic bottle PET, but it still happens to a limited degree.) ABS holds up to extrusion conditions better than most, which is part of why it's favored for injection molding, but there's still the potential to affect properties by depleting additives or cooking out plasticizers. In practice, this means regrinds generally need to be mixed with fresh pellets at some ratio. That dilutes the degraded or additive-depleted polymer with good material so you can maintain the material properties and performance.
If you print a variety of different colors, and don't want all your recycled filament to mix and end up a muddy brownish color, it can be difficult to manage the color sorting and matching. Most people don't want different colors along the length of a spool, either. So the regrind has to be mixed evenly in with virgin pellets and a suitable amount of masterbatch colorant to get a reasonable color output. You're not going to run off a new spool with 95% virgin pellets just to recycle a 50 gram failed print, are you? Likewise for material matching. Mixing materials is a bad idea. If you only print white PLA, this is all pretty easy to manage. But if you print a variety of colors and materials, you've got to set up a material tracking, sorting, and storage operation. You can do it... it's just a hassle.
Diameter control is difficult. 3D printers need a fairly tight diameter control for reliable performance and good quality. This is really the key challenge in any filament extrusion process. Extruded polymers like to change shape as they extrude and cool due to molecular alignment effects. You can't just push molten plastic out a 1.75mm nozzle -- "die swell" will make the extrudate bulge to a larger diameter immediately upon exiting the nozzle. Then you have to actually pull on the soft filament as it cools to carefully draw it down to the right diameter. The way the filament extruder measures diameter and controls tension is the key to getting acceptable results. Most hobbyist/desktop filament extruders have not succeeded at this.

Those are just the major issues. Filament extrusion is a complex subject with a lot of depth. For a home user of 3d printers, making filament basically becomes a whole second hobby. In my opinion, it only really makes sense in a commercial production printing environment where paid technicians can run the extruder(s) and a very large print throughput makes the pellets+regrind economics much more favorable than just buying new filament.

Reducing and reusing are preferable to recycling. Making your printer more reliable and gaining experience with calibration/configuration will reduce the volume of waste produced.

There are also some productive uses that let you reuse unwanted prints as-is or "downcycle" them for productive uses.

I personally keep a box of failed prints (and calibration prints and
no-longer-needed prototypes) as showpieces for people who want to
learn about 3D printing, and as toys for my nieces and nephews. I strongly recommend doing your calibration prints with a "toy" calibration model like Benchy or CaliBlocks. 3D printing is still new enough that people will happily take dozens of Benchies off your hands for the novelty value.
Failed and unwanted prints can also be used around the workshop for shims, sacrificial
cushions when clamping or hammering or drilling, or as scrap for experimenting
with adhesives or post-processing techniques.
ABS scraps are good for making ABS-slurry as a print bed adhesion treatment
layer, or for solvent-painting and filling gaps in other prints. Unfortunately, most other filaments do not have such convenient and safe solvents.
Some people have experimented with putting piles of scrap prints on a cookie sheet in an oven and melting them into multicolor cutting boards. There's a lot you can do with this sort of heavy remelt plate if you get creative. (I personally wouldn't use cheap Asian filaments for food contact though, they often have unpleasant contaminants.)


3D printed mold techniques for long and short term usage 3D printing can be used to make injection molds of unimaginable complexity but which kind of 3D printing process is suitable when?

Suppose that a part is to be made using injection molding in large quantity for an extended period of time, what Additive Manufacturing (AM) process will be the best, such that the mold does not give way too soon?

Also, suppose that the part to be made is custom and only has to be made in small quantities - that is to say that the injection mold will be used limited number of items and then thrown away - which is the best AM technique then? Best in the sense of economic feasibility, lower cost, lower capital investment etc.?

Yes, this is very broad. That said...

For high detail you want SLA. i.e. jewelry. If you just want a prototype of a mold, you can do a standard FDM style printer (95% of printers are FDM, and that number is a guess)

Really, you should be asking what material you need for your mold, but you can open a second question for that.

Do more research on injection molding. There is a great deal of information on how molds are made, i.e. How It's Made Plastic injection molds.

You will see there is a vast difference between a plastic, or silicon, mold and an injection molding machine. You are thinking that injection molding as a single mold, when it is really it is a system composing of several pieces of heavy duty machinery that can pump out hundreds of items a day automatically. However, it usually starts at 20k USD for the tooling for injection molding. Your costs could be a fraction of that or could be several times that. This is just a generality. So, if you are making 100 units you won't want to go down that route. For 10,000 units, on the other hand, it would be acceptable.


Selective laser melting and building near the road (vibrations) Our company want to implement selective laser melting(metallic powders). But our building close to the road plus we have industrial machines near us, what vibration levels are dangerous in SLM printing? What numbers is admissible? Vibration are dangerous because of lasers? Or because layer of powder can be distracted during the build?

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

Powder grain diameter
Powder composition
Powder shape
Aimed for resolution

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


Homing X and Y after stopping print through display How can I include homing X and Y  of a Marlin firmware operating printer after I press the stop printing in the display?

In which folder I need include the command?

It's EVENT_GCODE_SD_STOP in the configuration_adv.h file.

It appears to have been added to Marlin 2.0.x on 2019-04-03.


Where is the line between "inspiration" and copy and derivative? Scenario:  I'm cruising Thingiverse, and I find the awesomest thing.  I NEED THIS IN MY LIFE.  I download it, print it, and for whatever reason, it doesn't work quite right.  OK, no big deal, I'll just download the source because the maker was so kind, modify it ever so slightly, and I will have the most awesomest thing evar!

Several hours later, I realized that I could have designed it from scratch in a software that is way more user friendly, deterministic, simpler, etc.

And then I do redesign it.  From scratch.  Maybe taking a measurement or two from the thing, or something related to the thing.  And I refine it, and it turns out better than the original was.

Did I make a new thing?  Did I only draw inspiration from the previous thing?  Did I make a derivative work?  Using Thingiverse's terminology, did I remix it?

I'm looking for some canonical guidelines to refer to for the US.  Thingiverse can be an example, but god answers should not be limited to Thingiverse, nor my specific example.

I ran into this issue while trying to print out a case for a Raspberry Pi Zero.  I'm not done redesigning it, but I've been wondering how I could share it on Thingiverse, and if any restrictions from the original model's licensing might affect me when I post my thing.

I should start by saying that I am not a lawyer.  I have been both the complainant and defendant in patent cases, and have had the role of observing copyright compliance for a performing arts organization.  With that in mind, the following is my own opinion and information.

Ultimately, there is no simple answer to your question.  It would depend on the case law that applies to 3D printed objects, which is not very clear.  You are venturing into Copyright law, which is very different than Patent law.

For example, if someone had a patent on "A Raspberry PI case with a <describe a novel, special, functional feature>", and you made a case with that feature, you would be in infringement.  It wouldn't matter if the case looked like the original, or was completely different.  If it included that patented invention, you would be more likely to lose if challenged in court.  The one thing about patent court prosecutions is that it is really rare that anyone actually "wins".  The cost to put forward a case is very high, and usually someone runs out of money (sometimes even the "good guy") before a decision is reached.

Copyright is much harder and softer at the same time.  Copyright can relate to the design feel of an object -- such as rounded vs. square, or using a trash can vs recycle bin icon.  Prosecuting a copyright violation of this kind would require that the aggrieved rights holder demonstrate that the design was copied, or at least derived in an unpermitted way, from the original work.  This is often more a matter of opinion than law, which is why the lawyers matter, as well as the judge and potential jury.

Technically, you are not free to do whatever you wish in the privacy of your own home.  You are much less like to be detected and then prosecuted, and the penalties would be lower, but you are just as much in violation if you make one for your own use or sell them by the millions.

The best way to handle it, if you are prepared for possible adverse reaction from the original designer, is to ask them for permission.  You can say ask for clearance to use, such as by saying:

    I loved your object <thing> on Thingiverse.  I plan to <put in your plans here -- make a few for me and my friends -- sell further varieties online -- whatever>.  Although I didn't copy your design, I would like to acknowledge that I saw your design before doing my own.  How shall I do that?

Your next steps will depend on how they respond.  Most likely, they will either give you free leave to do as you wish, or they will ask for something.

This happens a great deal in music, and expensive and acromonious problems have developed over who actually composed a particular guitar riff.  You can pick up the "Stairway to Heaven" case here.  If you are doing this commercially, it is better to negotiate ahead of time.  If you are putting your object back on Thingiverse for sharing, I'd just identify it as derivative an get on with life.


Ender 3 severe under-extrusion I've been using my Ender 3 for about four months now and it's been working wonderfully. The print quality is amazing and all the prints are very strong. Then about three weeks ago, my entire system crashed while Ultimaker Cura was open and it lost the profile for my 3D printer. I recreated the profile to the best of my ability with other people's working profiles online, but none of them worked right. I've been getting severe under extrusion in all my prints, and they're incredibly fragile. For now, I've just been printing a 1"x1"x1" test cube. I've tried many steps from other people's posts online to fix the problem, including:

Raising the print temperature for PLA to 200 °C.
Checking the extruder for signs of too little tension or too much tension. I checked, and the PLA has light tooth imprints on it, and no grinding or damage to the filament.
Clearing out the extruder. I disassembled the whole extruder assemble, and flushed all the plastic from each part with a heat gun, and metal pick, and then tried reprinting, but it didn't work.
Trying a newer Ultimaker Cura version. At the time, I was using Ultimaker Cura 3.1 and hadn't updated because it was working well. I then tried the newest stable release of Ultimaker Cura 3.6, with a few different profiles, and then I also tried the beta version of Ultimaker Cura 4.0, but none of these worked.
Increasing the extrusion rate. I incrementally increased the extrusion rate from 100 % all the way up to 130 %. The prints looked a little better and were a lot stronger, but this still didn't fix it.
Trying a different slicer. I then downloaded Slic3r and created a new profile in that. The prints turned out a lot better, but there was still significant under extruding.
Checking the filament tube for any burns or damage, and ensuring it's inside the extruder assembly all the way.

If anyone can help me figure out what's going on with my printer, I'd really appreciate it!

Here are some pictures of the prints I've been getting:
These were made in Ultimaker Cura with different small changes to the profile made

These were made in slic3r with a flow rate adjusted up to 130%

These were prints I made before I lost all my settings in Ultimaker Cura.

Here's some of the material I read/watched and checked before posting myself:

I am experiencing some severe under extrusion
Sudden underextrusion on Ender3
r/3DPrinting: Under extrusion on Ender 3
Fixing a Filament Flow Problem on CR-10 mini, CR-10 or Ender 3 by CHEP

Edit: Here's my printer profile:
Ender 3 Profile Google Drive

It is not too rare to create a new machine in Ultimaker Cura to be set to 2.85 mm as this is the default. Also some bugs in the past did reset or assume this diameter unless you manually set it, and unless we know your exact version we can't confirm it is really this.
Underextrusion why?
The 0.55 mm more radius result in an underextrusion due to the pressed through volume, and since $V=A\times l$, we need to see the area to see how severe the underextrusion is for one given extruded length. $A_{1.75}=2.405\text{ mm²}$ and $A_{2.85}=6.379\text{ mm²}$ are rather obvious, so $\frac {\text{real extrusion diameter}} {\text{calculated extrusion diameter}}=\frac{A_{1.75}}{A_{2.85}}=37.7\ \%$, so only about 40 % of the needed filament is pressed through the nozzle as the slicer thinks it is almost twice the diameter. This matches well with the 130% still being very spotty, as that'd need a much higher factor to compensate for the underextrusion. A compensating extrusion multiplier would be $\frac 1 {0.377}=265.25\ \%$.
Fixing
To fix this, check under filament and set it to 1.75 mm so you force the correct diameter. Remember that filament diameter is not saved in the printer profile but in the material database.
You might need to restart Ultimaker Cura to activate these new settings.


E3D V6 Original vs Clone What is the difference between an original E3D V6 rather than a clone?
I know an original would have its own advantages, since there is a huge price difference between the two. Will there be a huge difference in the output? By considering the following:

Print quality
Printing Speed
Maintenance
Life Span

If anyone has used both, please share your experience.

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

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

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


Is the Vref trimmer relevant on TMC2208 in UART mode? I'm going to use TMC2208 stepstick in a printer and the firmware can control via UART the current during printing and during holding (static, no movement): the firmware has an explicit setting for running current and for holding current.
In this case, should I care about the physical trimmer which controls the Vref?
I tried to understand the TMC2208 datasheet (page 50) when it's talking about current control but I don't understand whether the Vref becomes superfluous or it still acts as a maximum value which the UART must obey.

The potmeter does not work in UART operation, see e.g. this quote:

You don't have to fiddle with jumpers to set your micro-steps, just
change it in the firmware, and you can dynamically change the amount
of current going to each stepper motor (no more adjusting that small
potentiometer on the driver board) just by sending a GCode command
(M906).


Overhanging section of part turns into spaghetti A part I've printed (on a Monoprice Maker Select V2, sliced with Cura) has a small peg on it, which is an unsupported overhanging section of the model.

The first few layers of the peg end up a mess of PLA spaghetti. Here I've rotated the part to get a better shot, normally it would be printed on its side.

I've done test prints that contain L-shaped overhangs and they worked ok, so I'm not sure what's broken about this one.

One guess I have is that because the peg is relatively low to the heated build plate, the material isn't cooling as quickly, and it needs to be more rigid in order for subsequent layers to print.

I also tried with supports but I found it too hard to remove.

Unsupported parts need to be printed with support. If your supports are too hard to remove, try the Tree Support setting and make sure that your support structure is set up with a gap to the actual print. As we don't know which slier you use, I can't go into more details here.


Safe way of disposing resin I have some leftover resin (100 ml) that I`m not planing to use anymore. What is a safe way of disposing it that doesn't involve curing?

Resin is notoriously hard to handle, especially as exposure to air and light can and will cure it over time. The uncured resin is a hazardous material.
Handling hazardous waste
The rules for safe disposal can - generally speaking - be broken down to this:

make sure the hazardous material can't contaminate water or food sources
make sure the hazardous material won't be touched or ingested accidentally

This means (for example for acids) that they are neutralized (to pH 7) and then handled as chemical waste.
WHY?
Why go all these lengths? Let me explain with an example from Germany: The city of Leverkusen is the main site of Bayer. They produce pharmaceutical and chemical products there, which includes a lot of chemical and hazardous waste. Bayer knows how to handle waste, they handled 541000 metric tons globally in 2015. Most of the following information comes from Germany, and is in German, but I do provide my sources.
For the remains of pharmaceutical product production at Bayer in Leverkusen around 2007, the process, as I was told on a tour to the fabrication plant, was generally speaking this: The nasty stuff got neutralized and reacted in ways to make it inert, the resulting sludge got dried and incinerated to destroy most toxic compounds. The remains were bagged in thick plastic bags that were carefully stored with a catalogue of what was stored where in a dedicated chemical waste landfill with (iirc) 3 independent groundwater protection systems, covered with a thick plastic sheet, then with a several meters thick cover of carefully constructed layers of dirt, clay, cement, more plastic, gravel, and rock to protect the rhine and the ground-water. Today, this process is done by the Currenta in a similar way.
In the past, the landfills were less secure: the old landfill that was started by Bayer in 1923 in Leverkusen. It was used by Bayer, the local population and (for some time) the IG Farben. It was finally closed in 1965, contains 65000000 tons of waste, of which approximately 15% is residues of chemical processing (~1 million tons). Nobody ever cataloged what had been stored where in these times, one just knew that it was filled south to north. It had to be pretty much re-engineered in the 1990s and brought it to match the (then) current landfill standard, for example with a 38m deep cement wall: Checks had found that nobody knew anymore where what materials were stored and that residues - among them possibly LOST - had found their way to the surface. These chemicals threatened to get into the Rhine and the water supply at some point. It also lead to a case of public domain and following demolition (for public health concerns) of a group of houses that had been erected on one part of the closed landfill.
You see the length people go to keep you safe from chemical waste: LONG.
Now, how do we fix the problem at hand both safely and effectively?
Getting rid of small batches of resin
The basic rules of handling hazardous waste (the two bulletin points) tell us we should take a two-step process:

find a temporary storage solution (e.g. storing in a safe container)
decide on a process that can get rid of the stuff in a safe way.

How could one fulfill the target number 2? I came up with three options:

re-cycle the unused resin from the print-tub back into the resin for later prints of the same color/resin.
find a specialist to take care of the uncured waste ( => give it to the waste disposal center in a clearly marked container)
make the material non-hazardous and allow disposal through the home-waste ( => curing)

Your local waste disposal service might charge a fee for taking care of your resin, but your problems end when you hand it over with old paints or other chemical waste. Check out who provides these services and what laws, rules and regulations apply for small batches of resin and paints.
A different kind of specialist that would take the resin could be a maker or artist that plans to use it in their own SLA/DLP printer.
Making it inert could be done by curing with only sunlight, without the need of much special equipment or chemicals in a very well ventilated area and make sure nobody touches it: pour the resin into a (disposable) mold like a cardboard box or yogurt cup. If you can't have a well-ventilated place, storing the resin in sealed transparent plastic or glass container (plastic bottle or marmalade glasses) in sunlight can cure the resin very slowly over time. Note that it will take quite some extra time, as such containers do filter out some of the 400 nm light that commonly cures the resin.
The resulting resin chunk can be handled like any plastic block once thoroughly hardened through: Use it for other projects, as a paperweight or dispose of it through the normal waste.
tl:dr;

Until you have chosen a method to get rid of your resin, keep hold of it in a sealed container.
You might find a local maker or artist that would like your resin.
The best way to get rid of resin wastes without curing it yourself is handing it to a professional waste disposal service. Check your local laws, code and regulations about it.
Curing it allows disposal through the normal garbage cycle.


What type of plug is this? I'm not really sure what the type of plug on the heater cable is. Is it a Molex KK or maybe a JST PH?
The printer is a Prusa I3 Hephestos (aka BQ Hephestos). It came with this "BQ HOT-END HEATCORE CLASSIC" hotend from the "BQ Witbox 1" extruder.

As 0scar noted, this looks suspiciously like a JST connector, but the left one is not a JST RCY connector and it is neither one of the common JST PH nor JST XH, JST manufacturer pages show. In fact, it's not a wire-to-wire JST connector. The BQ-store claims it is a 2.5 mm JST connector, but JST has some 10 dozen different types of connectors, some three dozen of them with a 2.5 mm pitch.
"JST Quick" / JST RCY

This one is rated 3A, and looks like the connector on the right, the thermistor one. So if you need to fix that, you know what to get for that.
So what it is?
The connector however looks at first glance suspiciously like this one:

I found this product on several warehouses, listed as 2-PIN CONNECTOR W/HEADER, .10", and even found a specsheet. Those products appear, in design, to be based on the Molex KK 254 from the 2659 series. A genuine Molex 2659-series connector is rated for up to 2.5 Ampere, and looks somewhat similar.
However, the shop did claim it is a JST 2.5 mm pin, and they give a side view:

That is not a Molex KK. It appears more similar to a JST NV, which however has a 5 mm distance between the peg centers (= pitch) and it's rated for 10 A (or 120 W at 12V!). While matching in style it does not match in measurements - as OP confirmed, there's a very close to a 4 mm pitch (+- measurement tollerance) on the connector. So it's not an NV, but something os similar style.

But then it has to be the VH! The VH series has a 3.98 mm pitch, it has that latch and it is rated 10 A, for 120 W at 12 V. In fact, the pins on the Hotend seem to be B2P-VH, matching VHR-2N or VHR-2M "female" adapters.

Safety?
I would not trust a Molex KK 2659-series connector with a heater cartridge on a 12 V Machine! With a 12 V, 30 W Heater cartridge draws exactly 2.5 Ampere, so you'd have a safety margin of 0! That's bad design. A 40 W heater cartridge would draw 3.3 A - that's 132 % of the rating! That'd be a fire waiting to happen!
Only a 24 V machine could be built with a Molek KK 2659 connector and stay within the 2.5 A rating (40 W & 24 V -> 1.67 A, 30 W & 24 W -> 1.25 A) with a safety factor of about 1.5 to 2 to the rating (depending on heater cartridge).
However, this is a JST VH with a rating of 10 A. That means, at 12 V, it's safe for 120 W load, so plenty safe: That's a safety facor of 3, and on a 24 V machine it'd be 6. That's Perfectly safe and sane! After all we look for at least a 5 A rated connector in conjunction with a 12 V/40 W heater.
The more tedious variant to connect safely is to use either an even higher rated connector (requiring replacement) or a continuous wire to the board.


Change 1.75 mm 3D printer to 3.0 mm printer I am planning on buying a cheap 3D printer to get into 3D printing, but the printer I'm planning to buy only takes 1.75 mm filament, I was wondering if it might be possible to change the hotend of that printer or something to take in 3.0 mm filament, the reason I want to use 3.0 mm filament is because it is cheaper than 1.75 mm filament.

First it really depends on your printer / extruder. That said generally 1.75 mm is cheaper and much more common.
If one were to change the hotend, likely you will need to replace most or all of the hot end. In the case of my personal hot ends, when I did this conversion I had to replace both the tube and the PETF lined mouth. I did not have to replace the tip, core, or the thermsister.
My advice is to pick a different printer. You see 3 mm on older extruders like J Head direct gear from around 2012-2013 and Bowden style (like the Ultimaker) use 3 mm (actually 2.85 mm).
Possible yes, advised, no.


What type of fire alarm/smoke alarm should my printer have? I know you should, like an infant, never leave your printer without surveillance.

But sometimes we all do, trusting our double thermistors and heat runaway configurations. But electronics fry and who says there is no danger even after the print job has finished and it's cooling down, still hooked up?

I have searched but smoke/fire detectors come in a wide range of varieties:

They can be battery powered or hardwired, they detect different things: carbon monoxide, heat, smoke..., they thus also have different detectors like photoelectric sensors, ionization sensors or both. We also print with different materials...

So what's the best safeguard for my 2 year old (CoreXY ^^)?

Since some prints can take literally days, I would use a combination of techniques if you're worried about a fire.  According to The Internets, firefighters are willing to inspect your stuff to see if they pose fire hazards.  You could ask your local firefighters what they think of your risk with yoru 3D printer.

Keep your workplace free of dangers

Don't keep flammables, explosives, or similar stuff near your printer.  If it does catch fire, these kinds of things will make it worse.  There are plenty of valid 3D printer supplies that fall in this category: alcohol, alcohol pads, acetone, acetone pads, various glues, various cleaners, hairspray, etc.

Periodically inspect the high amperage parts of the system

Inspect crimps, but splices, solder joints, relays, etc for burn marks, loose connections, or other problems.  Solve the problems before they catch fire.

Alarm

One or more smoke alarms should detect a fire.  However, they may give false positives for ABS, because ABS gives off that burning plastic smell.  I would experiment with the super-cheap ones and one or two more expensive models to see what kinds of false positives you get.  You'll probably want to put at least one of them directly above the printer.  If your printer is enclosed, put a sensor in the enclosed area.

I think smoke alarms should be sufficient, but I'm not an expert (or even hobbyist) on fire alarms.  I have not come across any information that states Carbon Monoxide or Radon are a worries with 3D printers.  Area-affect heat sensors may give many false alarms because of how hot printer stuff gets.  However, you could use contact heat sensors for parts that should not get too hot and monitor them with a microcontroller or Raspberry Pi.  Reading this article, it seems you may want some ionization sensors for the printer, and not photoelectric.  My WAG (link) is that the plastic (or electronics) would smolder long before catching fire, so you want sensors that would detect the smoldering.

Camera

OctoPrint/OctoPi make it easy to use a webcam to monitor your printer.  However, if your printer is on fire and you're remote, it may or may not be able to shut the printer down.  Even if successful, you still have a fire to deal with.

Fire extinguisher

You should have a fire extinguisher available to someone to put out your printer should it catch fire.  Printers will need at least an extuingsher of Class C rating, and since we're working with plastics, you probably want Class B as well.  Most of the fire extinguishers you can find in consumer stores are going to be ABC rated, and powder based.  The powder will make a mess and wreak havoc on electronics.  CO2 or Halon will not themselves damage the electronics, but are substantially more expensive than their powder based brethren.  For example, I get 5lb Fire Extinguishers for ~$30 at Costco, but an equivalent in CO2 would be several hundred.

Automatic suppression system

As a maker, you could build a reactionary fire suppression system.  I imagine it would be cost prohibitive to hire someone to do it for you.  Basically, you would use the alarms or special sensors to activate one or more fire extinguishers.  You should over-engineer this so that your fire suppression system completely overwhelms any fire that occurs.  According to The Internets, firefighters are willing to inspect your stuff to see if they pose fire hazards.  You could ask your local firefighters what they think of your risk and suppression system.

Firefighting Robot

You could build a robot to detect fires about put them out, as sort of an advanced automatic suppression system.  Something like Tony Stark's robot, or something emulating what is actually in service (US Navy (CNN), Australia tracked firefighter).


Using an Arduino Mega with burnt voltage regulator Due to a not-given compatibility with Makerbot mechanical endstop wiring (and carelessness on my side) I ended up burning the voltage regulator on my Arduino Mega 2560. Now, powering the Arduino separately from a USB power supply, I can operate the electronics, however, I am still unable to receive any signal from the endstops and I don't want to hook up my replacement Arduino until I see that my wiring is correct.

Could I have burnt anything else on either the Arduino (pullup resistors were firmware disabled) or the RAMPS 1.4 which makes it impossible to receive a singal from the endstops?

Take a look at Ryan's answer to my question. I believe the MightBoard is based on the Mega 2560, so it is possible that some of the other components could have been damaged. If you look at the comments below Ryan's answer, we discussed the possibility of the processor itself being damaged. I had attempted this fix on two different MightBoards and they both ended up turning on, but the firmware wouldn't boot. So, it's safe to say that in my case, the processor on the Arduino was shot.

All and all, I'd recommend not using MakerBot's endstops as they seem to be the main culprit for this issue and has been for years (it happened to me twice since I got my machine in 2012).


How thick is 0.1 mm? I have a printer with a 0.1 mm typical layer thickness. Of course I can choose some different sizes in Cura or other slicing software, but most prints on this machine will be .1mm. In my (admittedly limited) experience thus far, the 0.1 mm seems typical for other printers, too.

I want to get a sense of just how thick this is. I know about the paper trick for leveling the print bed, but my understanding is the first layer pushes into the bed a little, meaning it's less than 0.1 mm and so paper isn't a good example for the typical layer.

Is there a similar item with close to 0.1 mm thickness I can use to visualize this?

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).


Z height incorrect on calibration cube I tried to print 30mm calibration cube with my TEVO Tarantula. I found that a few bottom layers was missing as shown in picture. I noticed that a few bottom layers looks thin during printing. Anyone know how can I solve this ?

Anyone know how can I solve this ?

In order to know how to fix it, you must first diagnose what the problem is.

Two things you should verify in Slic3r:

Check that under "printer settings" the Z offset is really what you want it to be (if you don't know what that is, you want it at zero).
Check that in the preview (Plater plane, the "preview" tab is on the bottom), you can actually see the bottom layers being generated by the slicer (you can verify this by moving up and down the slider on the right of the main window).

If both of these checks are positive, then the problem is probably not with the slicer but with the printer or printer setup.  The ultimate proof of this would be to try another slicer like for example cura.

If the problem is with the printer, the only obvious one I can think of, is that the bed is too high, the nozzle touches is, and the plastic cannot be extruded for the first few layers.

You can confirm or refuse this hypothesis by simply observing the printer while in operation. If it is the case:

you should observe the nozzle moving "as if" it was extruding the first layers
the nozzle should be touching the bed
very little plastic should remain onto the bed
you should hear some grinding or clicking noise from the stepper motor of the extruder (as the printer will try to push the filament, but the filament will have nowhere to go)

If you realise this is the problem, stop the print immediately: this is the typical situation in which you could generate a clog in the cold end of your extruder, which is not a permanent damage, but fixing it is a somewhat complex and tedious procedure.

The good news is that if this is the problem, the solution is trivial: you should simply set the nozzle height correctly.  How to do this changes from printer to printer and you should refer to the user manual of your printer.  Here is a video showing a few of the most common method to achieve that.


How to utilize/calibrate print fans for PLA? At the moment, I am thinking about print fans that cool the plastic when printing. I am not asking about the design of the fanducts, which might be a whole book on its own. I would like to know how to find out the best application of print cooling for a given PLA filament, - that is fan speeds and setup in a slicer of your choice (to learn what the different options are).

Everybody's combination of fan hardware and print settings is different. Unless someone else has the exact same printer and slicer profiles as you, there's no way to really say anything like "use X% for PLA" or whatever. For practical purposes, you just empirically figure it out with test prints based on a few simple rules of thumb:

Use lots of cooling for PLA, moderate cooling for PETG, and minimal cooling for ABS. (Note that sometimes ABS does benefit from gentle airflow, and PLA shouldn't necessarily always just be blasted at max power.)
Use less cooling on big prints where each layer takes a long time, more cooling on small prints where each layer is very quick.
Axial / box fan? You'll probably want to run it at full power. Radial / squirrel cage blower? You may want to run lower power.
Overhangs curling up or sagging? More airflow may be needed. (Lower layer heights also help enormously.)
Hot end temp sagging when the fan kicks on? Try less airflow. (Or insulate your hot block better.)
Weak layer bonding? Try less airflow. (Or raise your hot end temp.)
Small, fast prints getting mushy or corners "pulling in"? You need more airflow. (Or lower heatbed temps.)
Print warping / corners lifting off the bed? Try less airflow, particularly on the lowest few layers. (Or higher heatbed temps, or a better adhesion layer, or less nozzle/bed gap for the first layer, or any other approach.)
Fan too noisy? Try less airflow. (Or get a better fan.)
Filament stringing during travel moves? Try less airflow pointed directly at the nozzle. (Or tune your retraction settings better, or get the moisture out of your filament, or lower hot end temp.)


How is FDM Better than CBAM? So there is a company called impossible objects that use CBAM technology witch the description can be found here http://impossible-objects.com/technology/ I am pretty sure that they are the only ones using this process, I want to know why.  CBAM makes stronger material out of carbon fiber in a very sophisticated process stronger than FDM(Fused Deposition Modeling). This is interesting and I want to know why. I understand the process but not the pros and cons.

Well the CBAM stuff is SUPER new, requires a lot more work done by hand (currently), and is going to be WAY expensive compared to widely used FDM machines.

Seems to me like a carbon fiber mixed filament is a cheaper way to go, with a possible annealing process to get the tensile strength up post-print.

Try locating a CBAM printer for $200! Maybe if the process becomes quicker, and the machines/materials cheaper to purchase, we could be using this method more in the future. I feel that we will likely advance the materials we have with FDM much faster than this other process would catch on and become affordable.


CR-10 Layers not printing after certain amount of filament printed I am printing on a CR-10 for the first time with white filament1. The problem is it seems that after a certain amount of filament printed one or two layers don't stick to the print which causes a huge gap in the end.

I think the pictures speak for themselves:

Here is what I already tried:

Different print speeds (60 mm/s and 45 mm/s)
Different nozzles (both 0.4 mm)
Print-temperatures of 200 °C and 205 °C
Resliced models in case of faulty .gcode files
Support densities of 10 % to 20 %
Different models

I tried this with two different models, two print attempts each. The gap occurs earlier in the larger model and at almost the exact same layer on both attempts, same for the smaller model.

The most frustrating thing about this is that it happens a few hours into the print so I can't just sit next to it.

It seems that at a certain layer the filament doesn't stick to the print anymore which causes those straight parts.

I ruled out a faulty z-Rod since the gap occurs at different heights.

I am printing White PLA from Janbex with 60 °C bed temperature. I slice with Cura 4.0 (the linux version).

1 I've been printing for over a year now, it's the first time I use white filament. I don't think that it is entangled filament since the spools from Janbex are always perfectly wound. It did occasionally happen with other filament too though but not this often. I have a theory that it might have something to do with the geometry of the model since there were a few very close hard edges at that height. Maybe the filament didn't have enough time to cool down on those spots. I'm trying to print with lower layer height (0.15 now, 0.2 earlier), maybe that will make a difference...

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...


OctoPi command v412-ctl not found I try to set up the focus of my Logitech C920 in OctoPi. I follow several guides, which all propose to set the command sudo v412-ctl --set-ctrl=focus_auto=0 by SSH'ing OctoPrint.
I always receive the answer in SSH, that v412-ctl command not found.
What's wrong?

It's an l (ell) not a 1 (one). v4l2-ctl.


Order of solving printing issues 3D Printers (those who print, not the machine, dummy)!

I haven't been printing in a while, so when I returned to my Monoprice Select Mini VII, of course it had been sprung out of whack. Some of my first prints would not even come out of the extruder until I realized I had some pretty bad (and worse, unnoticed!) heat creep going on. After fixing that issue, it became apparent that many more persisted.

My question for you all is this: In general, what problems should be addressed first when looking at a complete disaster of a print?

I'm not going to specify any singular problem, but I am interested in seeing the "order of operations" for general problem solving when multiple issues exist. For example, "Fix bed height before anything else; this is a common problem that produces multiple others." Hopefully, this can help others with multiple printing issues, too.

for sure the answer could be dissertation or even a book because there is no simple way to address "all" issues - it's just to wide area

but as the simple troubleshooting i would list it this way

is your printer alive so is it

working at all (check power, cables)
communicate with the world (check app, drivers, cables)
moving HE and heating HB (check jams, end-points, belts, screws)
is it extruding (check heating, temperature, HE jams, filament path)

if all above is "yes" then

is your printer making printouts and are those printouts

starts and continues (check heating HB, HB adhesion, leveling, cooling)
finished at all (check all above again, stepsticks temerature)
keeping the shape (check screws and nuts, couplings, stiffness, stability, temperatures)

if all above is "yes" then in general you are half way ;)

common issues - printout is

bent or skewed (check geometry, stiffnes, leveling, belts, vibrations, stepsticks temerature)
wrapped or overextruded (check temperature, extruding, printout angles)
underextruded (check filament flow, filament path, stepsticks temerature)
stringy (check temperatures, app settings)

that is the main path i think. all above is more or less applicable to all DIY printers and all prusa clones and all clones of clones ;)

it can go wrong and fork in all possible moments as there is so many aspects to screw...


Slicer/Printer Origin I am very close to buying a 3D printer and have started to do some preliminary design work from the things I'd like to make, but I have a question: Which corner of the print bed corresponds to the origin (0,0,0) in slicer software? Is this the same across slicers and printers?

The reason I ask this is because of the difficulty some have in removing items from the bed. It seems to me like I'd want to print small items closer to the front of the printer to make access easier, but it looks like most slicer hosts only show a box representing the build volume with no real indication of what's "front".

Depending on what kind of printer you have, the build table origin and slicer origin (0,0) are usually either the front left corner, or the center of the build plate. This can be changed by the end-user in most open-source printers. There is no standard or requirement for a particular origin location. The important thing is merely that the slicer and printer coordinate systems match, so parts actually come out where your slicer thinks they should.

In practice, it's usually quite easy to tell what's "front" in your slicer's build volume. When you open the program, the bed usually appears as it does when you stand in front of your printer. It is rarely an issue.

In terms of difficulty removing prints from the bed, a removable build plate is an excellent solution. Plastic has a higher coefficient of thermal expansion than most build plate materials (like glass), so throwing the print+plate in your freezer will generate large separation forces and help remove the part for you. Non-removable build surfaces are a deal-breaker for most serious 3D printer users I know. Either don't buy such a printer, or add a removable plate yourself.


Can't control printer via USB I've recently purchased a Makerbot Replicator Dual clone made by CTC. I'm in the process of upgrading/adding a few parts to it, but noticed that I can't control or print via USB.
The machine prints perfectly from an SD card and I can see information in the terminal from the printer via USB in RepG and through OctoPrint - Such as M105 -  but can't send any .x3g files to print or upgrade firmware (I wanted to flash Sailfish 7.7 eventually).
To clarify;
In Octoprint

Temperature auto-reporting is working
Can send M105, M27, etc.. & get response
Can select .x3g files from the SD card to print & the printer starts
Can upload files (.stl, .x3G, .gco etc..) to Octopi, but even the .x3g files wont actually start on the printer.
Tried sending M140 T0 S200 & M106 T0 S100 which received OK response, but there was no change reported, or indeed actually happening with the tool

Terminal Output from OctoPrint at connection:
Changing monitoring state from "Offline" to "Opening serial port"
Connected to: <octoprint_GPX.gpxprinter.GpxPrinter instance at 0x6c9a02d8>, starting monitor
Starting baud rate detection...
Changing monitoring state from "Opening serial port" to "Detecting baudrate"
Trying baudrate: 115200
Recv: start
Send: N0 M110 N0*125
Changing monitoring state from "Detecting baudrate" to "Operational"
Recv:  Makerbot v7.4
Send: N0 M110 N0*125
Recv: echo: gcode to x3g translation by GPX
Recv: SD card ok
Recv:  T:27 /0 B:21 /0 T0:27 /0 T1:26 /0 @:0 B@:0
Recv:  T:27 /0 B:20 /0 T0:27 /0 T1:26 /0 @:0 B@:0
Recv:  T:27 /0 B:21 /0 T0:27 /0 T1:26 /0 @:0 B@:0
Recv: ok
Send: N1 M115*39
Recv: ok PROTOCOL_VERSION:0.1 FIRMWARE_NAME:Makerbot FIRMWARE_VERSION:7.4 FIRMWARE_URL:https://support.makerbot.com/learn/earlier-products/replicator-original/updating-firmware-for-the-makerbot-replicator-via-replicatorg_13302 MACHINE_TYPE:r1d EXTRUDER_COUNT:2
Send: M21
Recv: ok
Recv: SD card ok
Send: M20
Recv: ok
Recv: Begin file list
Recv: 2GB
Recv: System Volume Information
Recv: mesh_bed.stl
Recv: xyzCalibration_cube.x3g
Recv: CTCB_3DBenchy.x3g
Recv: 3DBenchy.x3g
Recv: ActiveCoolingDuct.x3g
Recv: CTCB_ActiveDuctD4_UN.x3g
Recv: UK_TROLLEY_TOKEN.x3g
Recv: mesh_bed.x3g
Recv: z-axis-support.x3g
Recv: bed-screws.x3g
Recv: spool_nut.x3g
Recv: 2016_spool.x3g
Recv: 2016_spool_no_raft.x3g
Recv: ActiveDuctD4_UN.x3g
Recv: Z_Axis_Support_Ends.x3g
Recv: End file list
Send: M105
Recv: ok T:27 /0 B:20 /0 T0:27 /0 T1:26 /0 @:0 B@:0
Send: M105

In ReplicatorG

The software connects to the board via USB and recognises that it is a Mightyboard running f/w 7.4
Reports that it is an unvarified board
Cannot use the GUI control tab to send commands to the printer
Cannot send sliced .x3g files over USB, console shows a time out error instantly
Saving .x3g to SD card does work

Is my Mightyboard just a dud, or is there something I can do to try and fix it?
The reason I want to try and solve this now, is that I'm planning on adding active cooling and LED lighting control so don't really want to do all that just to find out that I need to replace the board soon.

Additional info
Some information meaning that the current firmware and board is reported, as well as current temperatures of the extruders and heat bed. I can print .x3g files from the SD card, but I can't send G-code commands or .x3g files through USB.
I have just tried a few G-code commands through OctoPrint terminal with mixed results. M105 works, M140 & M106 don't.

Good morning, and welcome to 3D Printing SE.

You said: "I can see information from the printer via USB in RepG and through OctoPrint, but can't send any prints, commands or upgrade firmware (I wanted to flash Sailfish 7.7 eventually)."  This means that the USB communication is working fine.  It isn't a question of drivers or the FTDI interface chip.  That must be working fine or you wouldn't have any USB communication.

I would look toward a problem with slight dialect differences in the firmware that is flashed compared with the expectations of the host software.

I am not an expert regarding the differences in firmware G-code dialects, but there are at least: Marlin, Repetier, Mach3, LinuxCNC, Machinekit, Smoothie, Makerware, Sailfish.  I got this list from the "about" page for Slic3r.

I would start by trying to slice files with different dialects and seeing if one of the resulting G-code files prints.  You may also find a description of the firmware you have flashed with references one of these names, which would save a lot of time.

For flashing, you could try dropping back to the Arduino level and use those flashing tools.

More answer in response to the information you have added to the question.

X3G files are not G-code files.  If you are using a control program that expects G-code, it will not be able to handle X3G code.  Similarly, if the printer expects X3G, it may not understand G-code.

Octoprint has an adapter layer that seems to interconvert between g-code and GPX.  You are running this layer.  At about line 11 of the log file you added to the question:

  Recv: echo: gcode to x3g translation by GPX

The GPX add-in may be perfect, and it may cover all version of firmware and all functions.  I don't use it and am unfamiliar with it.

To flash your board, I would be reluctant to assume that Octoprint/GPX new how to run that protocol.  I would use the host software supplied by the vendor.  Flashing is an infrequent operation, and add-on software is less likely to have it 100% correct.  If I were writing GPX, I would intentionally make flashing be out-of-scope, since the consequences of doing it wrong could easily be to brick the printer.

Since Octoprint/GPX claims to be able to print to the printer, I would being all software up the respective current versions.  Flash current Sailfish firmware using the supplied host tools.  Update to the current/best version of Octoprint/GPX.  Read the release notes of Octoprint/GPX for known issues.

It seems that X3D files are fairly limited in their use, which will constrain your options to be within the scope of the community that uses X3D files.  I tried to add the X3D tag to your question, but so far no one has created the X3D tag.

Makerbot is part of Stratasys, and should be well supported.  It may be well supported mostly within its ecosystem.  You have a clone of a Makerbot machine, so, even though most or all of the printer parts are open source, you may not be able to use the genuine Makerbot host control software.

Your question asked if your controller board was working.  It almost certainly is.  I think you have a software/firmware compatibility problem.


Which connectors should I use to connect my Power Supply Unit to the Ramps? I have read that the cable colours depend on multiple factors:

Used voltage
Kind of cable
Type of voltage (DC or AC)

My cable looks like this:

I live in Spain, in Europe. The colour codes of the International Electrotechnical Commission for AC circuits are these ones:

My PSU has these possible connections

So I guess these are the connections:

L (AC). Brown colour. Single Phase line or Three Phase Line (L1)
N (AC). Blue colour. Neutral
GND. Green and yellow colours. Protective earth or ground (PE)
COM, COM ¿?
V, V ¿?
V(ADJ). This is a potentiometer, in order to modify the current voltage. Should I touch this?

But I am not sure about what are the COM and the V ports. I assume they are for the DC connections, which is the positive and which the negative? The PSU does not have any manual and I am little lost

Should I turn the potentiometer to change the voltage to adapt it to the Ramps 1.6 Plus board?

Please correct me if I made some mistake in my question as well

You're quite right :)

L (AC): Brown colour. Single Phase line or Three Phase Line (L1)
N (AC): Blue colour. Neutral
GND: Green and yellow colours. Protective earth or ground (PE)
COM: DC Negative (-) - Also referred to as "Common"
V+: DC Positive (+)
V(ADJ). This is for a potentiometer, in order to modify the output voltage. You won't need this unless your power supply is far off.

The way to go about these things is to connect the AC side and to connect a multimeter to the output terminals (V+ and COM, there are two of them in case you need to wire up more than one connection). I like to lightly tighten down the probes under the terminals, that way you don't have to mess with the connections with the mains terminals exposed.

Now you can plug in the power supply (PSU) and make sure it doesn't start smoking or sparking.

Verify that the PSU is outputting DC 12V (that seems to be the voltage required by your Ramps board according to the picture). After that, you can connect it to the Ramps board (remember to disconnect the PSU before rewiring). If the voltage is anything but around 12 V (+/- 0.5VDC should be safe), you need to verify that the PSU is the correct type for your application.


How to setup PrusaSlicer to support long bridges Don't support bridge is a good idea to reduce support with acceptable print quality. But in this case, if I have a very long bridge and a short bridge, how do I tell the slicer to generate support only for the long bridge. How can I set some parameter like bridge length threshold?

Regardless of the choice of long bridge support or short bridge support, Prusa Slicer 2.3.0 has a feature which allows forced support or allows forced no support.

In Advanced or Expert mode, there is an icon in the left tool bar for "paint-on" supports. The left mouse button paints on supports, while the right mouse button creates support blockers. Shift-left mouse button erases errant paint splatters.
There are more details in the linked video. It's not a parameter, but it is a means to determine where you want (or don't want) the supports.
According to a thread in the Prusa support forum, in order to have the enforcer and blockers operate as expected, configuration settings should be for supports off. This may have changed as the thread is older and may have been modified in newer releases.


3d scan matting spray I want to scan a few ceramic items that are shiny and have multiple colors and found that using an artec 3d Spider that doesn't really work due to the shininess and thus want to use a matting spray or sth to be able to get proper results. Ideally sth without color that can be used on the ceramic items and allows to obtain proper texture results for the 3d model too. Any ideas?

There are many variations of a product generically known as chalk spray. Some of them should be considered permanent or semi-permanent, while the Montana brand product explicitly states "temporary" in the description. There is a caveat in that it has to be a non-porous surface to be considered temporary.

The product is primarily directed at outside/sidewalk art which can be washed away or will wear away under normal traffic. As such, it is suited for matting shiny surfaces for scanning purposes. White is the best color for scanning as it will accept light and shadows better than the other choices.

I have a can of white and can attest that it will wash off. Some of the product will wipe off dry but the small crevices require washing, which should be considered when spraying your item.

The product is available at many online outlets and may be found at local art supply retailers.