Is it a good idea to include thermal fuses in a DIY 3D printer design? 3D printing should be relatively safe, however, the inherent nature of 3D printers, with all of the heated parts, constitutes a fire risk. A well designed 3D printer should be designed to be as safe as possible, especially one used in the home... Yes, the recommendation is, when printing, to watch the 3D printer at all times and never leave a print unattended. However, with some print times lasting hours and days, this is not always feasible, nor practical. So, some inbuilt safety features should be included, to at least mitigate the risk of fire, to some extent.

Is the use of thermal fuses1,2 a good idea3?
Would you use more than one?
Where should one place a thermal fuse? Next to a particular component, or free standing, in the air, to get an average, rather than highly localised temperature?
Against which components should a thermal fuse be placed? There are a number of places to choose from, such as next to:

The hotend?
The heated bed?
The extruder?
Each of the stepper motors?
The power supply?
The RAMPS stepper motor drivers?

Of lesser import, which type should one use4, radial or axial?

Has anyone added thermal fuses to their 3D printers? Or has anyone examined where the thermal fuses are placed in commercial 3D printer designs, if used at all?

Background

I have recently found myself having to repair rice cookers and fans in Thailand. In those, it is very often the thermal fuse (axial thermal fuses for the rice cookers and the square "radial" types for fans) that requires replacing, as they have blown before the device got hot enough to start a fire. This got me thinking about their use in a 3D printer.

Footnotes

1 We are not talking about the standard, replaceable, thermo-fuse,or fuse, which blow upon a current surge, short-circuit, etc. These are thermal fuses that contain metal connector within them that melts (permanently) at a specific temperature (typically ~135°C), thereby breaking the circuit.

2 Nor am I referring to resettable fuses (AKA PPTC, multifuse, polyfuse or polyswitch)

3 Would a thermal fuse be preferable to thermal cut offs, in the case of fire?

4 The thermal fuses used in rice cookers are the axial type, and in the motors of fans are the radial type.

Whether you should use a thermal fuse or not depends on what other safety measures you've taken. You can't look at the safety features of a printer in isolation, you need to look at what other measures are in place.

The main fire hazard in printers is unfortunately (still) the fact that some manufacturers use underrated connectors on their boards, and that some users put bare wires in screw terminals or use inadequate torque when tightening terminals. As the wire works itself loose, it starts arcing and burning the connector. A thermal fuse does not help in this situation (unless you place thermal fuses near all of the connectors, which is impractical). Instead:

Properly tighten screw terminals, check them, and consider using proper wire termination (crimp lugs).
Use strain relief on wires. Make sure wires don't rub against anything, and guide them so they do not bend in a tight radius. Since the extruder (or print bed) is constantly moving, those wires are subject to fatigue.
Make sure connectors (especially those for the heated bed) are rated for the current running through them, and solder wires directly to the board if necessary.

Using a regular fuse may protect against wires shorting against each other should their insulation be damaged. Fuses are usually already integrated into the main board.

Most firmwares include some variant of thermal runaway protection, a feature that monitors the heaters and shuts the printer down if it notices something gone wrong. This protects against:

The thermistor coming loose/reading incorrect values/etc...

but not against:

Bugs in the firmware itself
Failure of the MOSFET

Most printers use MOSFETs to switch power to the heating element. Unfortunately, when MOSFETs fail, they usually fail closed (i.e. conducting). This means that, even if the firmware detects something has gone wrong, it won't be able to do anything about it. Solid State Relays (TRIACs) can fail in the same way.

To protect against this, mounting a thermal fuse (or resettable bimetallic switch*) on the heated bed may be a good idea. However, thermal fuses with ratings up to the operating temperature of a hotend do not appear to be available so this is not an option.

Attaching the fuse physically to the part it is monitoring is the most reliable, but for instance with the hotend (if you wanted to protect it all) this might not be feasible to the high temperatures involved so you'd have to settle with monitoring the air temperature close by.

Also consider thermal balancing. A thermal fuse is unnecessary if the component can not overheat to begin with. For instance, most MK2 heated beds struggle getting up to even 100C, so even with a shorted MOSFET they present no danger. However, if you have a powerful high wattage (mains-powered) heated bed, you should definitely install thermal protection.

E3D supplies their hot ends with 25W, 30W and 40W heaters. The 25W heater is the safer choice, since it limits the maximum temperature the hot end can get to, while with the 40W heater you can reach higher temperatures (and reach them faster). Barring a very unlikely scenario in which simultaneously (1) the power supply fails and starts supplying excessive voltage and (2) the MOSFET and/or firmware fails, a heater that is sized appropriately to the load it is driving can never pose any danger.

I don't think it's common to install thermal fuses on steppers, stepper drives or the power supply (which should have its own protection). For every possible location to place a thermal fuse, you can probably think up a failure mode in which that fuse would save the day, but at a certain point it just becomes overkill. The stepper drivers would likely burn out well before the steppers would get hot enough to pose a threat, and overheating of the stepper driver would probably (violently) destroy it but afterwards it should not pose any threat.

Axial v.s. radial does not matter, just use whatever is convenient for your situation.

* Note that some bimetallic switches short one of the leads to the (metal)
 case when tripped, which poses a danger, especially with mains-powered heaters.


How to calculate the proper layer height multiples? We all know, that the best layer hight is, when you have multiples of full steps. If it is not, sometimes steps get skipped and end up bad layer-to-layer adhesion when one height step missed a tiny bit and then the next catches up, creating an extra-thick layer. For example, this was printed somewhat deliberately, and here, the extra spaced layers are perfect for delaminating the print with just a fingernail:

The Ender 3 I have uses the following Z-Rod:

Diameter 8 mm
4 flutes
ca 13 Threads per inch

That is according to the table, a 2 mm pitch for one thread.
As a result, it's an 8 mm pitch for each of the 4 threads.

The firmware (Marlin) I use claims in configuration.h that the NEMA17 motor would be using 400 Steps per mm in Z. configuration_adv.h tells that the microsteps on the Z-axis motor are 16.

In the printer's menu, Babystepping is in increments of 0.049 mm (though some rounding error seems to be there: 5 Babysteps are 0.250 mm).

that the NEMA17 motor would be using 400 Steps per mm in Z. configuration_adv.h tells that the microsteps on the Z-axis motor are 16.

Easy. There are 400 microsteps in a millimeter, and 16 microsteps in a full step. So, there are 400/16=25 full steps in a millimeter. So a full step is 1/25th of a millimeter, or 0.04 mm. Your layer height should be a multiple of this.

As your leadscrew has a lead of 8 mm (i.e., a full rotation will move the Z-axis by 8 mm), a full step is either 8/200=0.04 mm (for a 1.8 degree stepper) or 8/400=0.02 mm (for a 0.9 degree stepper). So, apparently, you have a 1.8 degree stepper (and this is the most common type of stepper).


Prusa MK3S weird 'Blobs' on PLA print surface This is the first time I've run into this problem and it seems very confusing. I wanted to print a simple functional part out of PLA and although the first few layers were fine, the 6th/7th layer started to have some weird 'blobs'/deformations on it. I don't know how to fix it and the problem didn't go away after changing the filament. I suppose the problem is related either to my settings or the printer. It is very weird, I fully calibrated the printer right after the first fail.

Settings:

nozzle 215 °C
bed 60 °C
speed 100, 50 mm/s for bridges
cooling 100 %, but no autocooling in order to print faster
using PrusaSlicer

Photo:

After hours of trying to fix the problem by trial and error I found that getting the nozzle slightly higher by approximately 0.1 mm was the solution. I cleaned the rods from dust, tightened most of the screws again and calibrated the printer.

I don't encounter this problem anymore even while printing at 150 mm/s speeds.


Connecting Sain Smart Mechanical End Stops to Ramps 1.4? I have Sainsmart Mechanical End Stops, and I'm building a Prusa i3 Rework.

I've recently gotten the x-axis to move, but it needs to stop when it gets to the end and it does not do that; I end up having to pull the plug.

From what I understand, there are two ways to wire ends stops in general, but you have to change the settings in the firmware to make it work right.

There are 3 connectors on the board:

S (signal)
- (ground)
+ (VCC)

My Sainsmart Mechanical End Stops have 4 connectors!!!

According to their website, left to right with the white connector facing you, they are as follows:

S
Normally Closed (NC)
Normally Open (NO)
VCC

Now it seems to me that if I take those connections and connect them as follows it should work...(ramps on the left, sainsmart end stop on the right):

S (signal) -> S
- (ground) -> Normally Open (NO)
+ (VCC) -> VCC
nothing -> Normally Closed (NC)

...but!  Screwing this up by either using the wrong firmware of selecting the wrong wire frys your board, so I thought I'd ask here.  Sources please.

The multiple connections are redundant. Your picture indicates the wires labelled as "SIGNAL, GND, GND, VCC". This is correct if the board is a "standard" mechanical endstop v1.2. The two middle pins are both ground, but you only need to use one of them.

You can simply connect signal to signal and ground to ground. That is sufficient for the endstop to work. You only need to connect VVC to VVC if you want the LED that's on the board to function.


My first attempt at pausing a print and changing filaments resumed from the wrong position -- how do I troubleshoot? I'm attemping my first print where I pause the print, change the filament, and resume to achieve a two-color print.  My first attempt failed when the printer resumed printing over a centimeter away from where it should have on the X axis.  My second attempt was much better, but still resumed about 1.5mm off-target.

Here's specifically what I did:

Loaded the STL in Cura, the design has a 1mm "base" with an additional 1mm design on top of the base.
I used Cura's "Pause at Height" feature to specify the printer should pause after completing the first 1mm.
I sent the print to Octoprint, via the Cura plugin.
The pause began and went as-expected for the first 1mm.  It paused after finishing the layer, as expected.
To switch filament I used the controls to raise the nozzle by 1cm, then moved it to home (X/Y, away from the print).  I swapped filaments, hand-feeding the 2nd color until the old color was no longer coming out the nozzle, then gently cleaned up the nozzle.
I lowered the nozzle back to the height it paused at (down 1cm), then resumed the print.  The printer moved the X/Y back to the print and resumed.

I'm guessing either I shouldn't move the printer head away from the print when changing filament, or perhaps need to re-home after the new filament is in.

What should I do to resume a print precisely where it paused?  Is there a better approach?

You are out of luck:

Print gcode is written in relative coordinates. If you move the printhead manually, the printer does not know this, and will just follow its relative path from the new position - which is what commonly is called layer-shifting.

To try to mitigate this, there are ways, but they are a little tricky:

If your printer has a change filament option, then choose that - this saves the absolute position of the printhead before moving it to X0Y0, then usually extracts the filament and waits for the new filament to be inserted and the printer waits till given a resume-OK. Then it will move to the saves absolute position, and resume the code from the point it paused.
If your printer has a pause option that moves the printhead to X0Y0, this can be used, using a manual extraction. Resuming the print will be easy.
Some slicers support to call "Change filament at layer X", which will call a move to X0Y0 and pause, allowing manual change even if the normal pause behavior is not to move to X0Y0.

As you see: NO manual commands are given here! You can not move the printhead up/down/sideways without having a good chance of inducing a layer shift.

The Pause behavior can be adjusted in the firmware.


Best/Simplest/Easiest way to secure a lid This is a part I designed, a kind of a frame:

Into the frame I want to be able to place a flat object of variable (but uniform) thickness - like paper, glass, sheet metal, etc. The inserted object should then be covered by some kind of a lid and secured. The lid should keep the inserted object pressed against the "ledge" you see in the frame. The object in the frame will be repeatedly replaced, so the lid will be repeatedly taken off and placed again. When placed, the lid needs to hold, not fall off randomly.

What would be the best/easiest/simplest way to secure the lid? Considering ease of printing, so ideally no supports, as little additional separate parts as possible (but adding a few is not a big problem), etc. The side of the frame you see in the picture can be modified, stuff can be added.

Considered:

threaded inserts in the corners of the frame, screws through the lid. Screws are a little impractical. Threaded inserts for screws big enough to be practical when handled repeatedly take up a lot of space both in area and depth
rubber bands stretched from one side across the lid to the other side. Rubber bands seem a little weak to hold the lid securely, but I guess it could be done.

What methods would you choose?

Don't know how big your parts are, but if repeated use is a concern and you need pressure that screws can deliver, consider screwing on some toggle clamps if you have the real estate.

You could also make a 3d printed version of one that's sized to your needs.  There are some models available.


How to fix WoW models in photon workshop I am using an AnyCubic Photon Resin Printer. I have used the (WoW model viewer to export a miniture that I am hoping to 3D print.
However, when I look at the model in photon workshop, certain parts appear in a different colour, and those parts are printing incorrectly on the final version. For example, if you look at the model below the headpiece feathers printed as a solid block all the way to the base of the model.

Looking at the slicing file, this is what photon workshop exported. I believe the issue may be that, because these are models deisigned for games and not 3d printing, they have only one surface and what I am looking at in Blue is what the photon workshop considers to be the inside of the model. Would ye be able to recommend any steps that I could do to adjust the models to allow them be 3D printed?
https://mega.nz/file/p6I00JZK#qhQplzOTh6w7yZxbGw2vtRRKc-iVDp_QHOvaWfPtULs
The above link is the object as exported from WoW Model viewer.

I believe you've identified the primary problem with this model. The single surface features are going to interfere with printing this object.

The image above is the result of loading the model into Autodesk Netfabb. The red segments are reversed normals, but also single surface components. There are others, visible when rotating the model.
One portion is uncertain, above the flap on the back. It could be a component of the flap or a reversed normal of the body's back.
To resolve this problem, it would be necessary to add thickness to those features.
I loaded the model into Meshmixer and identified one feature, the rear flap. It's loaded with reversed normals when viewed from the "outside" or rear of the model.
Using the select tool, it was easy enough to highlight those triangles and proceed to Edit, flip normals. That was followed by Edit, Extrude, to a thickness of -0.02 mm which presented this result:

There are a few "floating" features in the model. One which pops out is over the protective garb over the shoulder. Those would have to be anchored by adding features or moving that specific feature to properly intersect the body.
There are a few others, zero thickness portions that resemble solar panels. I suspect they are artifacts rather than intentional model features. Those can be removed in Meshmixer using a similar method, Select, Edit, Delete
The hanging hook is a collection of intersecting faces and present a challenge. It's not my model, but I'd be inclined to completely remove that feature, or remove most of it and add a simple cylinder to attach it to the model.
There are programs other than Meshmixer which will allow one to perform such manual repairs/modifications, but my skill set does not include presenting the answer for those packages.


Issue with Z homing on Ender 3 Pro with Marlin I've just changed the motherboard on my Ender 3 Pro with a MKS GEN_L v1.0 and flashed the latest Marlin version on it.
I've calibrated my bed manually using the default XY and Z auto home commands on OctoPrint and a piece of paper.
I'm happy with the calibration, however whenever I launch a print the Z axis moves up from the calibrated position by about 4 mm and starts extruding.
I've checked my Z endstop status with M119 and it's triggered at the right calibrated position.
How can I correct this?

I've actually found what the issue was. It turns out that my Z steps were way out of whack (i.e. 4000 steps/mm instead of 400). Apparently, that's the default value in GitHub for version 2.0 of Marlin. Not sure if that's a typo or a valid value, anyhow setting it to 400 fixed it.


How to access BIGTREETECH firmware I recently purchased a BIGTREETECH SKR mini E3 V1.2 and need to adjust some of the settings in configuration h to accommodate for my custom built 3d printer. In the past I've used the RAMPS 1.4 board and adjusted the firmware in the arduino IDE. What is the best way/recommended way to do this for the mini E3 V1.2.

Thanks.

The previous answer is good, but here's one specific for Bigtreetech.

Install platform.io. I use the command-line interface (CLI)
Modify your marlin files. You can clone existiing firmware for your board from the BigtreeTech Github for your board.
Remove microUSB card from your Bigtree tech board
Plug microUSB card into microUSB reader, and the microusb reader into the computer. You should be able to read your microUSB card
Enter the command in the root directory of your Marlin files: platformio run -e STM32F103RC_bigtree_USB. At least, this is the one for my board. You should have to run this in one folder before the Marlin folder.
It creates a file called firmware.bin in the directory .pio/build/STM32F103RC_bigtree_USB/firmware.bin. Copy it to your microUSB card, replacing and deleting any existing .bin. You can use the name firmware.bin.
Remove microSD card from computer and plug into board.

In your Marlin Configuration.h file, there should be a variable called something like MACHINE_NAME. If you make that name custom, then it will appear in the Octoprint terminal when connecting to your board, letting you know that you have updated the firmware.


Infill not reaching perimeter I've got several examples like the image below where the perimeter either doesn't bond to, or doesn't reach the infill. I tried adjusting the infil overlap parameter in Slic3r from its default of 25% to 30%, but it doesn't seem to have made a difference. This is on a new Tevo Tornado that's all stock + a petsfang bullseye cooler.

Edit

neither speed variations, nor temp variation seems to impact this issue. I'm beginning to suspect that it's related to some sort of play in the y axis, as if you look at the defect in the picture, it's the most pronounced running north/south in the picture, which would be layers along the x axis (meaning their relative position would be impacted by y axis movement instability). I'm replacing the leveling springs with PETG standoffs tonight (I have a BLTouch) and will try again then.

I tried 25, 30, and 50% infill overlap as per a comment request, and that (50%)seems to have improved another issue where the infill on a first layer would often not reach the perimeter shells.

I tried the following print speeds with all of the following temperatures- 190/60, 193/65, 193/70, with 3 perimeters.

That's default behavior. I've also gone to

Perimeters - 80
Small perimeters - 20
Infill - 90
Solid infil - 25
Top solid infil - 20
Bridges - 70
Gap fill - 25

With no visible change in this outer perimeter behavior (the faster set of numbers is what I print with in general).

This has nothing to do with the infill overlap, the image you've added looks as if the issue is related to non-bonding perimeters (it looks as if it is in between the 2nd and the 3rd perimeter). If that is the case look into this question.

I've had this same issue, the problem is that if the perimeters do not touch, this is most probably caused by insufficient filament flow which can be a result of a too high of a print speed (or too low print temperature) of the inner perimeters.


PLA printings always ~0.22% larger I was trying to print parts for a small CD-ROM drive based plotter based on this thing https://www.thingiverse.com/thing:3521286

But as tolerances are very small and need to match the existing parts, I realized that my printed parts are actually a little bigger, I made a test with a part like this:

   _                          _
 /   \                      /   \
 \  .------------------------. ___
    | [O]________________[O] |  ^
    | |                    | |  |
    | |                    | |  |
    | |                    | |  |
    | |  |<--- 62mm ---->| | |  |
    | |                    | | 70mm
    | |                    | |  |
    | |                    | |  |
    | |                    | |  |
    | |                    | |  |
   _| [O]________________[O] | _v_
 /  '------------------------'  \
 \ _ /                      \ _ /

Side View:

      [X]                [X]
 ___[XXXXXXXXXXXXXXXXXXXXXXXX]____

A squared and mouse-eared frame with two protruding 4mm cubes on each corner with inner distances of 62mm and outer of 70mm between each adjacent cubes.

I discovered that, after measuring many times and averaging distances, my model printed 0.227..% larger.

I've heard of shrinkage factor for ABS or Nylon, and people compensate scaling their models while slicing.

But what about PLA?

Im using:

Anet A8
Stock marlin firmware (not the Anet one)
Flashforge natural PLA 1.75mm
0.4mm Nozzle
0.2mm layer height
0.4mm line width
210ºC extrusion temp
60ºC Bed temp
40mm/s print speed
Fusion 360, Cura 2.7 or 4.3 and Octoprint.

The printed model is pretty flat, has no curvatures or artifacts either.

Would this be an error of constants on my printer a known artifact from PLA?

You are not taking into account die swell.

When printing with a 3D printer hot plastic is forced through a nozzle, which leads to the expansion of the material. The result is, that with 0.4 mm nozzle and 0.4 mm intended line width, the material will actually deposit some fraction of a millimeter wider. In your test case, that is 0.22%. If you'd print a double-sized test piece, I expect 0.11%, and in case of a half-sized 0.44% - in other words, it is a static offset.

Because of this, it is usually better to demand wider lines than the nozzle is, forcing the die swell effect to become negligible in the wider line. I managed this with about 110% of the nozzle width on my machines.

Further Reading: Why is it conventional to set line width > nozzle diameter?


Extrusion stops during print I changed the filament (PLA) in my Wanhao Duplicator I3+. I ended the first try to print when I saw that the 'lines' were too thin. I re-sliced with a higher temperature (195°C instead of 190°C). Now the print started without a problem but after about 25% no more filament came out of the extruder. What can be the reason and how can I resolve it?

The filament is from Vertex, grey. The object that I use to test is a 20 mm hollow cube from Thingiverse that I have used for the previous filament too.

I am not sure that this is a clogging problem since the print starts with no problems. It just stopped after 25%. When I started another print I was able to finish by increasing the temperature.

I redid the print in order to reply to some questions posed in the answer of @kdtop. The print started but the output was not consistent and sometimes stopped. The temperature is 195°C and sometimes 'drop' to 194°C. First I pushed the new real so that the extruder did not need to pull so much. When this did not solve the problem I changed the temperature to 200°C. Now the output became consistent and my print finished. It was not as good as the one that I did with my previous filament. The top was not as neatly closed. Only the last 2 layers covered more or less for 100% the surface (perhaps 200°C is too high for this?).

For me the solution is to higher the temperature to 200°C (or perhaps 205°C).


RF100 Settings after reinstalling firmware I have an RF100 v.1 printer with stock software (again) onboard.

After my attempt of changing firmware, the X-axis motor decided to stray printhead away out of the borders of the printer and somehow motor wires broke out of the adapter.
I fixed the wires and reverted to stock firmware, though now whenever I auto-home or press "Home" button on Ultimaker Cura, printhead goes wild top and left reaching borders and starts buzzing like crazy.

current condition:

Head is TOP LEFT with X=100 and Y=100 on the table being under head Z=0;
screenshot

Even with these beautiful tiny settings, I cannot print anything because printhead goes too far TOP RIGHT by itself.
Ideas?

Everything was fixed by thorough googling and flipping the whole wire-set of the motor. It started to twirl in a right direction.
Sorry for the time


Turn off heated bed in Repetier? I have a printrbot simple metal with the heated bed upgrade. I think theirs a problem with my board, so long story short, I'm just trying to print without actually heating up the bed. The problem I am faced with is when I try to print from Repetier, it's still trying to connect the heated bed. I can't find any settings for shutting this off anywhere. How can I bypass this so I can still print? Thanks!

A workaround would be to post-process your gcode files manually removing all M140 and M190 instructions (the one setting heated bed temperatures).

You can do that manually by opening your GCODE file in a text editor and searching for M140 and M190, but I recently had the same problem with Slic3r (Prusa edition) and I wrote a one-liner that does that automatically for me.


Connecting disconnected pieces in Fusion360 Stencil. Sketch entire model then extrude I am trying to make stencils of Japanese Kanji characters with my 3D Printer.

I am very new to Autodesk Fusion360 so I am running into some barriers:

I am having trouble sketching a rectangle and then a text character and extruding them separately. If I extrude one they both disappear. Therefore I have to sketch one, then extrude, then create the next sketch object.
How can I create both sketches and select different ones to extrude?
I am having this basic problem where my stencil has parts that are disconnected (see example below). I've tried sketching lines and thin rectangles to connect the pieces but they both didn't work. I once again can't extrude after it's created.

How can I connect the pieces after extruding? How can I connect them inside a text object?

As I see it, for a stencil you want the brown part with the white part(s) cut out.

This is easily doable. You can do this one sketch at a time, extrude it, and cut it out of the brown part.

To connect the inner brown parts to the rest of the brown, you'll need to cut a thin rectangle in the white character so that the inner brown pieces are connected to the outer brown pieces.


Adhesion problems with masking tape I have been playing around with the bed for a while and I still can't get the first layer to stick properly. I think I am getting the bed leveled good, I use the paper method. But yet I find myself with the filament lifting off and getting pulled away with the nozzle or some balling in rare situations.

I use masking tape, which I found for $3 at Dollar general. I heard something about shine being a factor, but why is that important? And is more expensive masking tape worth it? I don't want to buy it because I would hate for it to tear when I take off a print.

I also use some glue stick, which seems to sometimes not help, almost like it doesn't allow the filament to stick. I don't think I was adding too much, maybe I was. But is glue stick needed? Does it really make that much of a difference?

So other than that I don't know what to try. I can't get the first layer to work properly. Maybe it is my speed, what is a good speed to print at for the first layer, I am doing 60 mm/s, just like the rest of my print.

Any advice from there with first layers would be great. I am tired of wasting time and filament over failed first layers. But when I do get the first layer done, the second+ layers all work fine, no issues.

Here are the specs of my printer, that should be helpful for people:

Printer --> Anet A6
Print area --> 220 x 220 mm
Heated bed? --> Yes
Bed temp --> 50°C
I use masking tape on bed
nozzle dia. --> 0.4mm
Nozzle temp --> 210°C
Print speed --> 60 mm
Material of choice --> PLA
Fan is on after 3 layers

I think that covers everything, Let me know if I need to add anything else.

Masking tape (and blue painter's tape) is coated with a wax-based release agent in order to prevent the tape sticking to itself on the roll. This release agent must be removed with an organic solvent in order to obtain good adhesion. Isopropyl (rubbing) alcohol is good for this. Acetone will also work, but it is a much stronger solvent (which is not necessarily a good thing).

For blue painter's tape, rub freshly applied tape with solvent until the blue dye starts coming off. Then give it a quick wipe between prints to remove any fingerprints, etc.


How does Prusa3D firmware respond to an open or shorted thermistor during a print? I have a Prusa3D i3m3s.  The problem occurred once before with firmware 3.6.1.  Last night I upgraded to firmware 3.7.1 and repeated the problem almost exactly.

The symptom is that at what appears to be the same point in the print in the two failure instances, the extruder stops extruding.  There are a few wisps of filament on both failures.  The print continues to completing.  At the end of the print, the firmware issues an error because the MMU2s can not properly retract the filament.

On analysis, the filament is tightly jammed into the extruder and hot end, almost as if there has been heat creep.  Slow, strong, and steady tension on the filament will withdraw it from the extruder system.

The hot end heats normally, and maintains temperature.  When hot, plastic extrudes properly from the hot nozzle.

The thermister wires are damaged from an earlier problem.

The damage points to a thermister-related problem, but a shorted or open thermister is easy to detect in firmware.  I would expect it to throw an error and stop the print.

My question is:  Does the Prusa3D firmware detect open/shorted thermisters and stop the print?

If a photo is required, I can post that tomorrow.

This sounds like a problem I had with my hotend cooling fan a couple years back. To answer your question, from what I'm reading, the Prusa3D firmware detects thermal runaway if the hotend temperature drops for more than 45 seconds, it detects an open-circuit by reading 16 °C or less (MINTEMP error), and detects a short by reading 310 °C or higher (MAXTEMP error).

Couple questions that might help better troubleshoot the root of the problem:

have you measured the thermistor's resistance while cold or hot?
have you made sure your hotend cooling fan is at an appropriate speed while heated?
have you made sure your print cooling fan duct isn't pointed at the hotend block due to being jostled?

You might find that there are some fairly simple solutions to a handful of overheat problems. I bought a cheap knockoff all-metal heatbreak and immediately ran into problems, but solved them by printing a better heatsink shroud and upgrading to a 40 mm fan. If you've upgraded to an all-metal hotend, you might run into issues with PLA specifically if you're not printing enough material fast enough, as PLA is somewhat sensitive to heat creep through the filament itself in the throat of the hotend.


The bottom of the printed objects has waves after replacing the nozzle I had a problem with my nozzle on my homemade printer. The problem was that the nozzle with a 0.4 mm diameter wasn't putting out any plastic. I replaced the nozzle with a 0.2 mm one and now the bottom of my model is looking like this:
I tried to change flow,temperatures and speed.
But nothing helped it keeps making this waves. At the old 0.4 mm nozzle there everything was okay.

Without more detail is difficult to say with certainty what the root cause of the problem is, but it looks like too much material is being deposited on the bed.

A few things to try/check:

Make sure the nozzle is not leaking.  If it is, you should see fused plastic coming out from the seal nozzle/hot-end and/or hot-end/heat break and trickling down.  This is often the case when the nozzle hasn't been tightened enough, or it has been changed with the hot-end being cold, or if the internal PTFE tube has been dislodged upwards (does not apply to all-metal hot-ends).
Make sure you changed the appropriate setting for the nozzle diameter.  This is not "flow" it is a separate setting.  If you haven't, your printer is now extruding ~4 times as much filament as it ought.
Recalibrate your nozzle height.  This should be done at each nozzle change, as each nozzle is slightly different from the other, and it is possible your new nozzle now sits too close to the bed.

EDIT: also, the picture is too low-res to be sure, but looking at the skirt, it looks like the extruded plastic comes out in blobs.  If it is not due to leakage, then I would suggest to also check that the filament is not slipping through the gears of the extruder.  If you have access to a suitable thermometer, you could also check that the hot-end temperature is stable at the level it should.

Final thought: have you ever succeeded printing with that filament spool?  It is unlikely, but it may be for example a defective one, or a mis-labelled one (so your printing temperature may be wrong).


Extruder clicking Tronxy x5s Whenever it start printing the extruder starts clicking, I tried adjusting the voltage with no luck, it's still clicking. And it doesn't extrude a lot of plastic sometimes it even stops extruding but the extruder is still turning. Can someone help?

The clicking you are hearing is either the stepper motor skipping steps or the hobbed gear losing grip on the filament.

Either way, it means that the filament opposes an unusually high resistence to be pushed forward.

A key information to be able to diagnose your problem is whether the clicking is on the firsts couple of layers or throughout the print.

If it is only for the first 1-3 layers the problem is likely to be the printing bed too high (or deformed), so that the nozzle touches it and the bed acts a "lid" on the nozzle preventing the molten plastic to get out.  If this is the case, adjust the printing bed to be flat and level (and the nozzle at the right height when homed on the Z axis.

If the problem persists throughout the full print the problem is likely to be related to one of the following:

the extruder not managing to get a firm grip on the filament (worn teeth, slack spring, ...)
the stepper motor being underpowered (this seems not to be your case, given that you have already adjusted the voltage)
a clog, adhesion, or restriction in either the bowden tube or the extruder, for which the best solution is disassemble, inspect and clean (eventually changing the bowden tube if it has been deformed).


How can I program a 3D printer to move using Arduino? I search about that topic, but all what I found, was the mechanical part of the 3d printer. But I didn't find, how to program it using arduino.

I want to make a cartesian 3d printer. I don't have a printer yet, but I will buy all the components that I need actually.

I know, how to control stepper motors, but I don't know, how I can program it in order to make the shape that I want.

This is my question: what I need to learn in order to let this 3d printer make this shapes?

Yes.
Look up Arduino Ramps 1.4

http://reprap.org/wiki/RAMPS_1.4

Following the programing is all done for you in the firmware. That said you can edit it. Just open the firmware files -- it is compiled when you upload them. Generally however one usually sticks to the preferences header alone..

http://reprap.org/wiki/List_of_Firmware

Over all you are trying to reinvent the wheel. When I started 5-6 years ago it was barely a thing. Now you buy a proven kit and get to the printing. That said if you are truly interested in designing check out.

https://www.facebook.com/groups/cncbuilddesign/

If you want help on picking a kit. Or what I really think you are looking for. A good place to start. This is one of the larger 3d printing groups. Full disclosure I run this one, but at 6k members I don't recruit.

https://www.facebook.com/groups/3DPrinterHobbyists/

I got my start in reprap IRC

http://reprap.org/wiki/IRC

Be aware there are trolls that now camp the IRC looking to sell you a printer. I would not engage with them, their printers are usually overpriced and sub par.

Best of luck.

Most of all I think you need to know it's Reprap all the way. Reprap forums, Reprap printers, Reprap kits, Reprap community. All the commercial printers started off the reprap project. Even if you buy a makerbot (don't) it's Reprap in it's roots.

https://vimeo.com/5202148


Layer lifted and separated from ESD PLA I'm using the default Ultimaker Cura draft profile but with the nozzle temp at 220 °C because this is a special ESD filament.

All was going well after some troubleshooting thanks to some users on 3DPrinting.SE but this happened over night:

What would cause an entire layer to lift off the main body, continue to print and then turn to spaghetti?

The red circled part was supposed to be part of the blue outline.

The spool kept getting caught on itself and tightening. I unrolled some of it and rewound it and the print came out perfect. @anttix was almost correct with the clog theory.


Are stepper flex couplings important? How important? TL;DR:

On my particular printer design, it definitely appears the company switched from flex couplings to solid couplings on purpose to improve the printer, and to prevent well-meaning users from adjusting the previous flex couplings. Whether or not this is a good design overall, is left for the reader to decide. It's certainly simple and cheap to use the motor itself as one of the leadscrew thrust bearings, but in the future I might add a micro-adjustable bearing block in place of the motor, and then couple the motor to the leadscrew with a flex coupling. That would be more typical of the way it's done on CNC machines, where the stepper bearings are isolated from any machine loads.

Original post: I bought a Artillery X1, supposedly the latest V4 version. It's my first printer, but I have experience with CNC machines. Although the pictures and YouTube videos all show the Z axis steppers connected to the leadscrews with flexible (spiral type) couplings, the printer I got has solid couplings.

I thought flex couplings were important to prevent binding, so I was going to buy some flex couplings. But as I look at the printer, it appears the leadscrews actually are supported by the stepper motor itself at the bottom...there are no thrust bearings, so the weight of the printhead is supported by the stepper motor directly through the coupling. Since the spiral flex couplings can compress slightly, is the use of solid couplings deliberate in order to make a more precise machine? If I install flex couplings, will it make my printer worse by introducing "spring" into the system? Is this a typical design, or do other printers have thrust bearings or "hang" the leadscrews from the top?

There are a lot of reviews and videos about this printer where people noticed the leadscrews were internally touching the end of the motor shaft inside the coupling, and people thought that was wrong, so they spaced them back apart. Now, I wonder if the shafts touching was a deliberate design decision, and maybe the company even switched to solid couplers to prevent people from adjusting the couplers back. Please help me solve this mystery of the solid motor couplings.

EDIT: I found a related application where the axial rigidity of the stepper couplings matter. In the following YouTube video the author deliberately jams together the lead screw and stepper shaft in order to eliminate spring from the flex coupling. This tends to solidify my theory that this printer uses solid couplings deliberately, and other printers with similar Z axes could potentially benefit as well. The X1 uses floating support bearings for the X stage to prevent binding, which probably helps.

Also, in this YouTube video the author describes how he deliberately decided to use rigid couplings on this printer to improve his Z axis and references other sources which come to the same conclusion.

Yes and No
Let's start with the obvious: Flex couplings or rigid couplings are a deliberate choice in designing the printer. Each has its benefits and drawbacks. So let's look into the 4 types of drive-train setups that I know to be possible:

Spiral couplings make it possible to operate the machine with a slightly misaligned motor to the shaft (<1°) but can add a measurable slop, which can be seen as a systemic error.
Rigid couplings have minimal slop but need to be much better aligned by the user in setup.
No coupling at all - direct drive to the shaft - has no slop at all, but is both more expensive and needs the most diligent work on setup.
Geared. You could couple the motor with the Z-Axis via gears, allowing to trade speed for detail and vice versa. It also can allow mounting the motor 90° to the printer, but it also adds some backlash and slop. Because good gears are expensive, this is really rare.

Using spiral couplers right
A spiral coupler can actually be used in two ways:
Keeping the leadscrew tensioned into a position.
This butts both parts together, it reduces the slop induced by the coupler to the minimum, but you need to forcefully make sure that the parts push together. You lose some of the misalignment-correction.
Decouple vibrations from one shaft to another.
This keeps a little gap between the two. The slop can be larger, but you get the benefit of the shafts on both sides not transmitting all the vibrations 1:1 to the other shaft and you get more self-realignment if the motor and shaft are not perfectly coaxial.
What is better?
Well, it depends. If you want the perfect drive, you'd go direct drive. If you want the finest motor control (by virtue of getting the steps to a much smaller rotation), you might use gears. But the spring-coupler allows you to do the setup easier for a consumer that might not be the most reliable in setting it up himself. Making the spring-coupler butted can increase repeatability and reduce slop to almost the same as a stiff coupler but not lose the ability to have a slightly crooked setup that still works.


How can I tell if BLTouch is triggering? MY new BLTouch doesn't seem to be actually sensing anything, and I'm not sure how to test it.
Quick background: I have a bit under a decade of experience with printing generally, but essentially none with firmware or any of the specific hardware. I recently got a new Ender 3 Pro, and successfully printed with it for a month.
I recently decided to upgrade my Ender 3 pro motherboard and add a BLTouch. I installed an SKR Mini E3 v2.0, tested briefly (long enough to satisfy myself that it worked as expected, but nothing extensive). I bolted on a BLTouch (not sure if 3.0 or 3.1), built and installed a cable to the dedicated "Z-Probe" port (same pinout as the BLTouch: brown, red, yellow, black, white), and updated the firmware with the binary firmware file from the controller board manufacturer. I have no other mods to electronics.
Right now, I have the following behavior:

During startup: BLTouch extends and retracts several times
In the LCD menu for BLTouch; select CMD:Self Test: BLTouch turns red, extends and retracts several times.
In the LCD menu for BLTouch; select CMD:Extend: BLTouch extends.
In the LCD menu for BLTouch; select CMD:Retract: BLTouch retracts.
In the LCD menu, select Auto Home: behaves as expected (moves the axes until they hit endstops).

So far so good, but then this:

In the LCD menu, select Bed Level: performs Auto Home procedure (as above), moves the BLTouch over the corner of the bed, extends the probe, lowers the Z axis until it hits the endstop. BLTouch probe moves back in. On the way down it turns solid red, then flashing red, then eventually retracts, then the carriage hits the endstop. Process ends.

So, What next? I'd like to check that the BLTouch is actually sending a signal to the board, but I'm not sure how. I've reviewed a bunch of online tutorials and the documentation for the mainboard and the BLTouch, without finding an answer.
Available tools: I have a multimeter and a very cheap oscilloscope. I haven't gotten the maple console installed, but do have a (probably?) functional alternative through the Pango slicer.

Problem is solved, though I still don't know how to test the BLTouch.
I had reversed the power connection (black and white wires) at the connection to the extension cable. Swapping that connector back around restored expected behavior.


Can a sandstone 3D print be printed as a solid object? I've been asked to prepare a 3D model for 3D printing in sandstone. I've been told that it needs to be 3" tall and the walls have to be at least 2 mm thick. It's an absolute pain in the neck having to make sure everything is the right thickness. So, I was wondering, can the whole model just be printed as a solid object, with 100% infill, and does that work for sandstone?

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


Identifying PLA/PETG or ABS I received a roll of Black filament as a present, and struggled to print with it, experiencing extreme under-extrusion (and slippage of the hobbed gear). Higher temperatures seemed to work better, particularly in freeing up the extrude rate.

The filament is advertised as PLA, but without any temperature recommendations that I can find on the vendor's website (or the amazon listing). Amazon reviews have a fairly wide range of temperatures, but the listing aggregates several colours. There is a suggestion that the filament may be PETG, or ABS.

I have tried using acetone, and it dissolves roughly the same as some ABS I have, my PLA shows some weakening but doesn't dissolve.

Below about 215°C, extrusion is borderline non-existent. I printed at 225°C with a fan, and it extruded kind of OK, but adhesion was poor. 240° without a fan seems a bit on the hot side (see photo). Even 255°C seems to extrude OK without burning. There is no smell I can observe (but I have a cold). It burns with a small blue flame, and minimal smell (kind of like natural gas).

One factor against it being ABS is that with the bed at 60°C, printing both a benchy and the heat tower below, there was no warping. Bed adhesion remained good.

Is there anything I can do to better identify this filament and decide the best combination of fan/temperature without wasting too much time?

255° to 225° heat tower, seems different to the ABS i've used:

There is a trick. However I would like to mention that chances are that the random spool you pickup from most stores, especially no name brands, are either completely lying to you about its material or is mixed / cut with cheaper fillers. All about finding a good brand. Course rarely does one actually need pure PLA, a mixed material will often perform as well without you even noticing. Aside from the temp difference. Not to say it is right.

Now the trick is this. While I don't advise ever breathing in potentially carcinogenic plastic smoke. You take a lighter. Burn it. If it smells sweet it is PLA.

From this link from digital trends about PLA VS ABS you can see why it has this smell.

  The thermoplastic is also more pleasant on the nose, as the sugar-based material smells slightly sweet when heated opposed to the harsh smell often associated with ABS. However, while PLA might seem like a better overall choice at first glance, it features a far lower melting point than ABS.

Also not responsible if you burn yourself or your property. At your own risk.

Just warming it with lighter might work too. But just burning a small section. It will be real clear.

Or you could just drop a bit into aceton and see if it melts. PLA will mostly just look like crud after being treated is aceton. ABS is 100% dissolve.

We see from these forums that PETG does not dissolve via Aceton. So you can test you material. If it does disolve it is ABS. If it smells sweet when burned it is PLA. If it melts at 240 and does not dissolve it is likely PETG.

Solid forums
3d printboard

We are a bit lost on a test for PETG. However we do know its melting point. Which is 240-260c. I would say it is likely you have ABS

Once we know the material we can get to the meat of your question.

Best way to proceed is to start with simple calibration prints. The thin wall. Cube, and part fitting. Once those pass you are good to go. Other than buying simplify3d I do not know of any short cuts. Back when I used slic3r I kept a spread sheet. I would change a temp by 5 degrees and give it a quality score. Repeat with speeds. Far as fan, I would expect that it wont effect much. Maybe need to calibrate your PIDs.

Once you have it dialed in, all you will need to do is calibrate the temp when switching materials. Remember you need to calibrate even between different colors (okay its best to.. I often skip) I usually do the temp adjustments live on the printer. Increase and degrease a few degrees. For me the goal is to have the plastic as cool as possible. That allows for highest quality prints (ie less oozing and such)


What do the pink colors in Slic3r preview signify? If it signifies a problem, how do I fix it? What does the pink color in Slic3r preview mean? Yellow is my model, green is support, and pink is..?

If the pink color is some kind of warning, how do I fix it?

In slic3r preview, salmon (pink) represents infill, yellow represents perimeters, and green represents support material, including skirt and brim.


Problems with bed leveling of Creality CR-10 Mini So I've had my CR-10 Mini for some months now, and I've been continually having strange problems with bed leveling. Basically, after leveling the bed and printing a part, the bed is no longer leveled for printing again.

Just now, I auto-homed, leveled the bed to where there was a pretty good amount of friction between the nozzle and a piece of paper, and started a print. The first layer didn't look like it was getting squished just that little bit that it should be, so I stopped the print, auto-homed again and checked the leveling with the paper. Low and behold, there was no friction at all between the nozzle and the paper. I re-leveled again and restarted the print, and then the first layer went down OK.

So what I'd like to know is why the heck am I having so many leveling problems?!? I've checked to make sure all my set screws are tight, my belts properly tensioned, and the rollers on the bed adjusted to slide smoothly but still have a good amount of grab. Help?

The Creality CR-10 Mini is a portal printer using a single Z lead screw at one side of the portal to move the whole X axis gantry. This implies that the X gantry needs to be very stiff when raised and lowered from one side and also have a minimum of play on the rollers (especially on the lead screw driven side).

I have seen many complaints from experience of people complaining that the gantry is not stiff enough, or that there is too much play on the rollers on either side of the gantry to result in a skew gantry. Consistent leveling is very hard on such machines. A colleague of me added an extra stepper (and split the original stepper connector) to have it raised and lowered from both sides. Do understand that this is also not optimal, missed steps on one of either sides can also cause the X gantry to become skew. A better solution is to create a belt driven extra lead screw that is powered by one stepper, you will not experience a skew gantry as the gantry is integrally moved.


Second layer of ASA print 'runs' I am using a Prusa i3 MK2 to do a print in ASA, and I'm having a problem where on the second layer the plastic 'runs' into lines across the direction the head travels. It looks like the plastic is being repelled by the previous layer and running together due to surface tension, but I may be wrong about this.

I thought I had managed to solve this problem previously by reducing the temperature to 230 °C (1st layer) / 225 °C (other layers), but having changed some of the other settings this is no longer solving the problem. I have tried reducing the temperature as low as 215 °C / 210 °C, and this is still happening.

Here is a photograph of the first and second layers:

The direction of head travel for the first layer was bottom left <-> top right, and for the second layer top left <-> bottom right.

The settings were based on the standard Prusa i3 MK2 Slic3r settings bundle for ABS filament with a 0.05 mm layer height, modified as follows:

print temperature reduced to 230 °C / 225 °C
fan speed increased slightly to 15 % as on 10 % the fan doesn't start.
layer height for first 14 layers: 0.2 mm
extrusion widths set to Slic3r defaults
various print speeds reduced, mainly the travel speed.
number of top and bottom layers reduced because of the increased layer height.

The reason for increasing the layer height for the first 14 layers is that the print is a piece of mixed raised text and braille lettering intended to be inset into a larger sign. I want fine detail for the top layers with the lettering, but high speed for the lower layers that are more structural. I am inserting an M600 change filament manually into the G-Code file at the point where the lettering starts.  I have so far managed to produce one successful print - see the image below. The reason I am still playing with the settings is that the good print wasn't in high enough quality, and there was some slight stringing between letters.

The good print was based on a 0.1 mm layer height for the lettering, modified to 0.15 mm for the lower layers, with a temperature of 230 °C / 225 °C.

I've now worked out the reason for the plastic 'running' on the second layer. It is because of the way that I prepared the G-Code file, using the option in  Slic3r which lets you alter the layer height for certain layers in the print. The problem with this appears to be that there are other settings which are not altered at the same time for the thicker layers. So the first half of the file ends up printed using the settings that work for a 0.05 mm layer height, but with the layer height set to 0.2 mm.

I have prepared a new file by rendering two G-Code files, one using the Prusa settings for a 0.2 mm layer height, and the other using a 0.05 mm layer height. I then merged these manually by looking for the layer change at 2.8 mm in both files and appending the end of the 0.05 mm file to the start of the 0.2 mm file. (I found the layer changes by using Slic3r's custom G-Code option, and adding custom comments into the G-Code which included the layer number and height on every layer change). Then I inserted an M600 'Change filament' instruction at a height of 3.05 mm, where the writing begins.

When I print this file, the problem with the plastic running together on the second layer disappears.


Anycubic i3 Mega incorrect Heated Bed temperature Reading It's been about a month since I've started using my Anycubic i3 Mega and everything has been going great. But today, I left it alone to print a 3DBenchy and it suddenly stopped mid-print. I didn't see it stop but once I came to the printer, the motors and the bed were at ambient temperature suggesting that it has stopped for quite a while. I was surprised that the Bed Temperature registered at over 200 ºC (although it wasn't at all hot) and tried to stop the print. However. I wasn't able to stop the print (It said stop failed) and I couldn't change the temperature, so I just switched the PSU off.

After leaving it for a few minutes, I turned the printer back on and the Bed Temperature still registered at absurd temperatures although it wasn't hot at all as seen on the Image Below.

I then tested the Hot End as the temperature seemed normal and it does seem to work and I was able to get some filament to be extruded out normally.

Any ideas on what happened here? It was working fine for an entire month and was working fine for the day, but mid-print it just suddenly broke. I've also uploaded a GIF to Imgur to show how the bed temp fluctuates a lot. Any help would be appreciated :)

The first value, which is in your pictures 179 and 184 °C, is the measured value. The 0 °C value is the set value. It looks like the temperature reading from the hotbed is not working correctly. So there are two possible issues:

The cable on the backside leading to the hotplate might be damaged. This seems to be a common issue with this printer. You could check if the cables show any obvious damage.
The hotbed thermistor is broken. On the leads on the backside you can measure with a multimeter the resistance between the green an blue cables. Typical readings are in the range of 100 kΩ. If you touch the thermistor, usually it is placed in the mid area of the heatbed, the resistance should change.


How are delta movements calculated? On a Cartesian printer movements are really simple. If we assume the printer has 100 steps/mm on each axis, then a move of 10mm on a axis is just 1000 Steps on that axis.

Movements that are not aligned with one axis are also simple. Moving from x,y = 0,0 to 10,10 would be 1000 steps on x and y.

On deltas even for simple moves more than one motor has to move. And just calculating the amount of steps on each axis needed to reach the destination probably gives a curved move.

So what is the algorithm to calculate the steps for a given move for a delta printer?

There are two main special steps to the technique used by most open-source 3d printer controllers:

Divide each linear gcode segment into lots of very small subsegments ("Segmentation")
Use some basic trigonometry or the pythagorean theorem to tie extruder position to carriage height for each of the three towers ("Inverse Kinematics")
to find the target position for each small segment

The inverse kinematics are surprisingly simple. A virtual 90 degree triangle is constructed from two known lengths to solve for the unknown third length:

The fixed delta arm length is the hypotenuse of the triangle
The horizontal distance between the column joints and end-effector joints is calculated from the XY coordinates of the nozzle and the fixed position of the column, to determine the length of the lower side of the triangle
The length of the upper side of the triangle is calculated from the previous two via the pythagorean theorem
The length of the upper side is added to the nozzle Z height to get the necessary carriage height

I think the best open-source reference here is Steve Grave's Rostock Kinematics document, rev3 available for download here: https://groups.google.com/d/msg/deltabot/V6ATBdT43eU/jEORG_l3dTEJ
Some relevant pictures:

These inverse kinematics calculations are performed for each carriage to get a "carriage space" target position, and this is performed for every path sub-segment.

The results from these steps can then be reinserted back into the standard linear path interpolation techniques for the printer, in which it fires steps in the necessary ratios and at the necessary rates to produce the desired straight-line motion and acceleration/velocity profile. (How THAT is done is a different question.)

The net effect is that the printer will move through a series of small "linear" carriage movements (linear meaning constant* speed with respect to time) that collectively approximate the necessary curved (quadratic position with respect to time) carriage motions required to produce a straight-line end-effector move.

*(Constant speed before acceleration slowdowns are applied in order to obey dynamics constraints, anyway. Again, that's the subject of a different question.)

Segmentation is very similar to the process of using a polygon to approximate a circle. If the facets are small enough, the polygon is a good approximation. Higher Segmentation rates produce less path-following error.  The primary conceptual difference between drawing circle arcs and Delta motion paths is that the so-called "faceted arc" with Delta Segmentation is constructed in height-vs-time coordinates instead of the X-vs-Y coordinates you'd use to draw a circle on a computer screen.

This system is used in large part because support for Delta style printers was originally bolted onto GRBL-based motion planners which were written exclusively for straight-line motion paths in Cartesian printers. It was a relatively minimal modification to the existing codebase compared to implementing full quadratic path interpolation.

Techniques have evolved over the years. And alternate approaches are often used: for example, the dc42 fork of RepRapFirmware performs exact path-following without segmentation, by recalculating the proper time for the next step after every step. This is functionally equivalent to approximating a circle with a polygon facet count so high that every pixel on the screen gets its own facet. So it is exactly as accurate as the positioning resolution of the motors allows. The downside is that this segmentation-free technique is fairly processor-intensive, so it only works on relatively fast controllers, not the older 8bit Atmega AVR that powers most existing consumer/hobbyist printers today.

Other techniques are possible. The academic parallel robotics control literature is a whole other world of mathematical techniques and complexity in order to produce generalized control algorithms that work for a wide range of robot mechanisms. The version we use in open-source 3d printers is quite simple and application-specific in comparison.


Calibrating E steps for new filament Is it a good idea or do I need to calibrate my E steps after I switch to a new filament due to the different types I use (to make my prints accurate)?

E.g. calibrate when switching from PLA to ABS/PETG?

No that will not be necessary.

However, you could use calipers to measure the diameter of the filaments (e.g. at 5 positions over a few meters) and calculate the mean diameter, if there is a significant difference between the new and the currently used filament you could change the diameter in the slicer (or the flow modifier), you do not need to calibrate the steps per millimeter every time you change filament.

You only need to calibrate the steps per millimeter if you change something in the extruder hardware setup, e.g. different extruder, different stepper driver, a new gear, etc. As long as the hardware is not changed a calibrated extruder setup will move a certain amount of filament regardless of the diameter variation (per rotation of the extruder gear an amount of $2 \times \pi \times (gear\ radius)$ mm of filament.


Issues with connecting Pronterface to Anet A8 printer I was recently told I should probably update my printer's firmware from the current version (ANET_A8_20160701V2.0) to Marlin (going to use v1.1.9). To do this, I dutifully downloaded both Pronterface and RepetierHost trying to connect with either one of them to my printer. I've checked the Device Mangler (Manager) and found the USB does connect and is recognized on COM5, yet neither software are connecting. The software sees COM5 as active as well, but I get back an error stating "access is denied" for some reason. What might I be doing wrong?

After some trial and error, I discovered you need to set the baud rate to 115200 in the printer settings. I went through and tried each of the baud settings available until it connected. Glad I started with Pronterface, as RepetierHost has a lot longer baud list :o) Setting the baud rate is not inuitive as to the issue, as getting back "access denied" to me implied something else was going on. After that, was able to run direct commands to the printer through the USB port without issues.


What is the strongest filament type? I'm looking for a filament that is strong, doesn't crack and doesn't break easily and is impact resistant. I'm currently using PLA and it's strong, but, I'm looking for something that doesn't snap or break when dropped.

PEEK may well be the strongest filament out there (and it has other interesting properties to recommend it), but it is very difficult to print and requires a printer designed to operate at high temperatures. If you are still using PLA, your next port of call should be PETG. It is a lot stronger than PLA (although it will shatter if hit hard enough) and it is almost as easy to print. It also gives off hardly any fumes and it can be printed without an enclosure.


Brand new Ender 3 does not extrude any filament during printing I bought an Ender 3 two days ago and assembled it today. I think I did it properly, tested the movement of all axes which works for all axes. Then I performed the calibration as described in the manual. I used a piece of paper and adjusted the bed until it barely fits underneath the nozzle for all four corners. Afterwards, I wanted to print my first model so I selected the cat from the usb stick which came with printer. And now comes my problem. I let the printer run for 15 minutes. It moved and moved and moved but there was no filament on the bed. The nozzle and bed were heated properly. The one thing which I noticed was that the stepper which feeds the filament turns for like 30° and then flips back: to me it looks like the filament can not be fed in. After canceling the print the extruder moves back to the home position which is like 5 mm off the bed and then suddenly the filament flows out of the nozzle.
What part of the configuration I'm missing?

I am a fairly new user of an Ender 3 and had similar issues on a couple of occasions.

The main reason was as @0scar suggested - the nozzle was too close to the build plate preventing the filament from exiting - and the back-pressure was causing the filament to jump back, giving the extruder a "shudder" as it slips on the filament. Lower your build plate as suggested by @0scar. The paper should only just drag.

The fact that filament oozes after the hot end/print heads moves to home suggests you don't have a blockage... but you will if you don't adjust this.

It is better to have the nozzle slightly too high, so the first level does not stick and gradually raise the bed up while you are running the test patterns. Only turn the adjustment knob about 1/8 of a turn before checking - you are dealing in tenths of a millimeter here. Also remember that changing the front setting is going to change the back settings too because the plate will tilt.


3D Printed Sphere, How to Remove Roughness I have a model of an eye that I custom made in Blender 2.83 that when printed only creates roughness on the printed object near where I had the supports.  The supports are not the cause of the roughness (at least not completely) since the supports don't even touch the parts of the print where the majority of the roughness and bumps are (refer to my photos of the print)
The roughness is only near the bottom part of the sphere as it prints upwards (refer to photos)
What I'm looking for is a technique or any suggestions for printing this without the roughness so it's smooth like in the rest of the print.  I'm also curious what is causing the roughness.

Eye Model in Blender

Blender Scale Ratio: 0.001
Blender Units: mm

Eye Model in Prusa Slicer
Layer Gif

Prusa Slicer Main Settings (Higher Res)

Variable Layer Heights For Smoothness

Eye Model Prints Photos
Eye Model Small Version 3D Print (Notice it's smooth on top of print)

Eye Model Small Version 3D Print Trouble Area

Eye Model Small & Large Version With Support (Notice roughness on the sphere)

Example of Support Used On Small Print

Smooth on inside of print

--------- Print Details ---------
Printer: Prusa i3 MK3s
Filament: PLA Galaxy Silver (Prusa Reserach)
Slicer Software: Prusa Slicer
Print Temperature First Layer: 205 degrees
Print Temperature Other Layers: 190 degrees
Notes: The suggested temperature for the filament is 205-215, I've adjusted after careful calibration given my environment to a lower temperature to reduce stringing.  I created a tower at different temperatures and discovered 190 was the perfect setting to reduce stringing in my case with this material.  Refer to my screenshot below.  I do not think temperature has anything to do with this since the print is smooth inside and near the top without any issues.
Temperature Tower Test For Filament Photo:
(Note stringing in the cone test areas at 225 to 205)

--------- Prusa Slicer Settings Photos ---------
Filament settings

Extruder Settings

Support Settings

While Trish is completely right that the roughness can't be completely eliminated (you can't print a perfect spherical surface with discrete layers), the situation can be improved dramatically. The most telling photo in your question is the one of the removed support structure.
The part of your sphere that's seriously rough is all severe overhang. In this region, the outer wall of layer N+1 barely overlaps the outer wall of layer N, if at all, and without support would be printed mostly or entirely over thin air, failing to attach to anything and sagging/curling down randomly according to tensions in the extruded material, air currents, etc.
Now, with support material that's not entirely the case. Every so often (looks like a 2 mm grid) there are support lines under the overhanging outer wall. These will anchor it every so often and keep it from curling or sagging too much, but they don't actually constrain it to the place the slicer wanted the wall to go, and they don't provide a surface for the extruded material to press against to get the desired (e.g. 0.4 mm wide by 0.1 mm thick) extrusion cross section; instead the cross section will tend to be circular as a result of tensions within the molten material.
In order to get a decent surface over support material, you need what slicers call "Support Interface" or "Support Roof" (these are the names Cura uses; I suspect it's similar in Prusa Slicer). This feature builds a top surface as part of the support material itself for the supported part of the model to rest upon and press against. Of course that can make support harder (potentially a lot harder) to remove, and depends on tuning the Z distance between the model and the support as a tradeoff between quality and difficulty of removal, but it should get you much better results.


Where to enable user interface encoder in Marlin? I am trying to configure Marlin for a Ramps 1.6 board. I have an I2C 4x20 character LCD enabled. I have the LCD working with

#define LCD_SAINSMART_I2C_2004

I have a separate encoder, with push button, but I can't find where to enable it. It seems that combo display-encoder-buzzer boards are enabled as a set. Some common name, like the define I used for the display. But I can't find any useful information that includes a I2C LCD with an encoder.

I'm looking for a configuration that would enable my LCD and encoder, or just some way to enable the encoder by itself.

For some configurations I found the following. But when I connect my encoder to those pins nothing happens when I try it. So I think I need to enable them somewhere.

//encoder pins
#define BTN_EN1 31
#define BTN_EN2 33
#define BTN_ENC 35

It seems that ULTIPANEL must be defined. The code for the encoder was included long ago with the Ultipanel (display and encoder) and does not exist on its own.

#define LCD_SAINSMART_I2C_2004   //  I2C LCD

#define ULTIPANEL                // enable code for encoder.

//encoder pins
#define BTN_EN1 37
#define BTN_EN2 35
#define BTN_ENC 31


Under-extrusion in vase mode So I found a vase on thingiverse and I wanted to print it, so obviously I did. I used craft ware to slice the model using there 'vase mode', and sent the Gcode to my Anet A6 printer. In the end I found weird underextrusion (I think that is what happened) at the starting points that seem to have appeared. I don't know what to think of this and I don't know what happened or how to fix it.

This sort of failure is best diagnosed by observing the failure. It probably isn't underextrusion, there is no reason to get variation in extrusion just along one edge.

Did you really get a proper vase-mode? You can check in your slicer, or with gcode.ws and make sure that each layer only occupies a fraction of the part, with many small steps (rather than one step after printing a slice of the whole part)

It seems the failure is close to a sharp transition in the wall. Have you got enough cooling, or a low enough extrusion temperature? It could be that the plastic viscosity and surface tension are conspiring against the shape. Printing slower might possibly help too (both on the failure, and to allow the part to cool between layers).

Finally, you might have a mechanical problem which is interfering with the print just at this point, and that might include the extruder binding in some way. This could be hard to spot during the print, so check over all the moving parts, and all the fixings.


Can OctoPrint web interface be turned off during a print? Can I turn off the web interface (i.e. shutting down my computer) during a print? The Raspberry is online still.
Am I correct to say that G-code has already been uploaded via WiFi to my OctoPi, and so turning off my computer now (web interface) will not disrupt the print?

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


Arduino and Ramps powering up I want to run two stepper motors using Arduino Mega 2560 and RAMPS 1.4. But, somehow I burned the Arduino while I was connecting the motor and plugging the board to the computer.
Can I plug external power supply and USB connection to the computer at the same time?
Additional info from comments
I am using RAMPS 1.4 with Polulo red stepper drivers and Arduino Mega R3. I am only using two Nema 17 stepper motors and not using any hotbed or anything else other than the two stepper motors for the x and y axes. I am feeding 11.9 V supply to the RAMPS board. When powered on, can I plug the USB to my computer?
Suppose I have connected two motors on the X and Y outputs of the RAMPS, and the external power supply is on, then can I connect my Arduino to my PC using USB? Will it burn my board or not?
My only trouble is that when the board is on load, connecting the USB to computer motors would take power by Arduino pins instead of the RAMPS external supply.

I had a similar issue building my Prusa i3 Mk2s clone.  I was constantly hooking & unhooking my Arduino from my PC while the printer was plugged into the mains.  At some point it had enough & it released some "magic smoke".  Later on I found out this was the power regulator on the Arduino.
You shouldn't need to plug in the USB and the external power to the Arduino at the same time, but if you did, it is smart enough to only use one.
That being said, by default the RAMPS passes 12V straight to the Arduino in order to power it (the Vin pin).


Should I enclose my 3D Printer? I have a home built RepRap with all sides open..

Would there be any advantage to enclosing the print area in acrylic?

It is hard to tell whether you personally should enclose your printer. However, you asked for the advantages and I will name some of them on which one can base a decision.

A 3D printer enclosure

helps to keep the temperature of the whole print at controlled levels, if you use a heating element, thermocouple and pid regulator. This is one of the most direct uses of the enclosure, which can be achieved by almost no other means. One could sloppily say it does for the whole print what the heatbed does for the initial layers. Controlling the temperature can be beneficial for layer adhesion and can help against delamination problems. This can go as far as fixing cracks and complete delamination (Thanks to @J. Roibal for bringing these cracks to my attention in the comments)
keeps dangerous fumes controlled. Here you can find a scientific study about it, published in Atmospheric Environment 79, titled 'ultrafine particle emission from desktop 3D printers, on exactly that topic. You can embed a filter with a fan in your housing to filter the air from all dangerous fumes that are created when melting certain plastic types. It could just circulate the air inside the chamber or get the filtered air out of the housing. This is another use which cannot be achieved otherwise (afaik).
can keep humidity away from your printer. This is helpful for filaments that attract water (and don't print well under that circumstance). This should be realized separately for stored filament, too, adding some silica gel to regulate humidity. (Thanks to @Obmerk Kronen in the comments)
minimizes losses of your heatbed. This happens in at least two ways, - the heated bed will also heat the surroundings, that is the inside of the enclosure. By raising its temperature, the temperature difference and hence heat loss is minimized. Also wind, introducing high fluctuations in the transfered (i.e. lost) heat is minimized. In that sense, it also
shuts out any wind for print temperature stability. Also dust and particles that could be blown on the print will be shut out (thanks to the addition of dust/particles: @Obmerk Kronen). This is a benefit that comes without having a heated chamber or filter.
helps to keep the printer clean in between use. Your axes will thank you being free from dust.
reduces smell and noise. If you use the printer in you living area, that alone can be a great benefit.
makes sure that your printer is safe during storage, nothing will fall on it.
can look pretty nice and add to the style of your printer, even if selfmade ;-)

There are obviously also downsides, as: connected work/money to make it, increased space used for the printer, and, if not well made for that purpose (which it should be), increased difficulty in repairs and maintenance of the printer itself (i.e. to get the printer out of the enclosure).


Any possible issues with adding heat/cool down cycle in the end of print (PLA) I'm printing with anycubic i3 mega on an ultrabase bed. When I first got the printer the prints were easy to remove from the bed after it cools down, I didn't need to put any extra effort. However after I used 70% isopropyl to clean it it seems I removed some kind of extra coating as all next prints were sticking to the bed firmly even after the bed cools down. So I tried to heat the bed up to 100 degrees and then cool it down and wait until it gets to something like 35, at that point print comes off quite easily (really helped me with some big parts with huge initial layer) so I wonder if I should just add that extra heating cycle to the end of each print job.
Is there any possible problems with that?
PS my understanding is that PLA should be okay with short temperature spike since it is being melted with twice as high heat. However long exposure to that temperature might cause some deformation (eg if I throw the printed part into dishwasher).
Another possible concern is that extra heating cycle could potentially shorten life of the ultrabase, but not sure if it is the case.
UPDATE
so after some experiments I printed at least a dozen calibration cubes adjusting several parameters along the way as it seems each of them contributed to the issue

I decided to reset initial layer thickness which I noticed was set to 0.25 when normal layer was 0.2. Since it was thicker for better adhesion I thought I don't need it since I don't have problem with sticking to the bed :)
second thing was the flow adjustment and enabling some layer filling settings in cura (filtering small holes etc). Ended up at 91% flow rate which gave me much cleaner top layers as well as the bottom ones.
and finally I played with Z offset, I did bed leveling recently so it was flat (did single layer tests to check that) but it might have been a little bit too high, so adding an offset seems like a good way to compensate for it. The thing I was looking after as a feedback here is the squeezing bottom layers issue, so I stopped once I got initial layers a bit smaller than the ones on top, went back a few values and ended up with 0.125 mm which sounds quite big to me but it allowed to get initial layer very clean and consistent with next layer so I think I got it right.

I can say it is easier to remove the cube from the bed now (used to be very difficult and I was using a mallet almost every time in the beginning) but it still doesn't come off on its own. I also noticed that now all three dimensions are almost identical (Z was about 0.5 less). And all X/Y/Z are ~19mm after cube cools down (the model is 20mm) so I wonder if I need to fix that one now

Heating PLA even to 60°C will make it pliable and may affect dimensional accuracy; 100°C is likely to make that severe. Being stuck to the bed and thus constrained by it might help some, but I think it's a bad idea.
If your PLA is hard to remove, you probably have bed leveling issues. PLA should remove easily after cooling from reasonable print-time bed temperatures of 40-60°C to room temperature as long as it has not been extruded against the bed with excessive force (from being too close and having nowhere else to go).


Can anyone suggest what technology and 3D printing material is most suitable for printing of dental models? I'm looking for a 3D printer for applications in the dental field, for printing digital dental models (not for itra-oral use parts).

Resolution and finish are the main requirements that we consider necessary.

Any suggestion?

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

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


When 3D printing a hollow box, what is the best course of action? If I need to 3D print a hollow box that can not have any light permeating into the box, what would be the best course of action? Should I 3D print the hollow box as a whole or print out the 6 sides individually and put them together at the end? And if I do the second option, what would be the best way to put the pieces together (design/connect grooves or use glue)?
I am very new to 3D printing so any feedback would be very much appreciated!

That depends very much on what your goal is with the box. If it needs to be hollow and you don't need any access to the inside (and also prefer it to be printed in one piece) than the answer provided by user77232 would probably be the best.
Alternatively, if you need access to the inside of the box you would probably be best off printing the box in two pieces. A box and a lid. This way you can print the box without support and also save on material that would otherwise be used as infill.
The amount of light coming into your box also depends on the translucency of your material and brightness of the light source. To find the required wall thickness would be a matter of testing with the desired material.


Interesting project for a child A member of our hackspace wants to get their 8- and 11- year old kids1 excited about 3D-printing and CNC cutting and makering in general. We have a weekly open training where people can design and print/CNC/laser an item of their choice like a dogboned box or a two-piece sword and hilt, or a name tag, or whatever. I need a few ideas prepared so we don't spend half our lesson on Thingiverse or in Fusion (more like a quarter)! I'm not a parent and my youngest friend is probably in their twenties.

What we have:

a full bed 1200x1800 mm CNC (preferred, because it's loud and fast)
Prusa mk3
cheapo 80W 500x300 mm laser
Fusion 360 based workflow, easy :)
Arduinos and stuff

Ideas we've had: a minecraft creeper, done as a simple-ish box.

1: the (girls) are not interested in my normal kids' goto, which is: swords, shields. They are interested in: minecraft, dragons, horses. _o_/

edit: this is NOT an opinion-gathering post, though there may be more than one "correct" answer.  We need specific applications of 3d printing for a young audience. This collection of answers will be useful to evangelize making to a whole new generation!

As @fred_dot_u mentioned above, keychains are a simple, personalized item to make.  In terms of interesting projects, things that I found intriguing when I first encountered 3D printing were objects that could not be made by other means, such as those "geared bearings" (Google: geared bearings 3d print).  Given the popularity of figet spinners a while back, they could be an interesting item.   A captive ball in a box, or three joined rings, can also be set up as a 3D print, and could have the same effect, while being easier for the kids to design.

EDIT:  Some links to versions of items along the above lines.  Thingiverse tends to slowly break links, though, so these might not last:

Geared Bearing
Captive Ball
Three Rings
Triple Gear
Self-aligning Bushing Keychain


Aluminium cube - fan and hotend mount - is it worth it? Has anyone used one of these aluminium cubes?

It is used to mount the fan for the hotend, when used on a delta effector, like so:

Are they a good idea?

Without actually buying one and trying it, compared to the traditional fan mount, I imagine the pros are

Additional heatsink surface area

and that is it, I could think of only one tenuous advantage...

However, I would imagine that the cons are:

Additional weight on the effector1, for the push rods to move around, i.e. slightly higher inertia;
Probably restricted air flow, and;
Unnecessary additional cost

Therefore, as the cons appears to outweigh the pros, are they worth upgrading to from, say, a typical plastic fan mount:

Does anyone have first hand experience? Are there any other additional benefits, and/or is heat dissipation that much better?

1 Of course, the lightest solution is with the fan mounted, such that it hangs off the top of the effector, but with no air flow guide and hence less effective heat dissipation.

I think its only advantage is that it serves to move money from the folks who buy it to the folks that sell it, and that's an advantage purely for the folks that sell it.

"Additional heatsink surface area" is quite doubtful - it would have poor coupling to the actual heatsink. If the actual heatsink is correctly designed, there's no need for additional area, anyway. This design clearly does limit airflow to the top and bottom fins - the bottom one, in particular, is not a good place to limit airflow for best function, and yet it's severely occluded by the design of this block.

Save your money.

Edit - I think the plastic one shown is also less than ideal - the close coupling to the edges of the heatsink reduces the effectiveness of the heatsink, which would otherwise be dumping heat into the airflow past those edges. A better design (IMHO, gut engineering) would be spaced off the ends/edges of the fins about as much as the space between fins, not touching them. Axial fans perform poorly with backpressure, and that would also reduce backpressure.


CR 10 mini not detecet as Serial interface (Win 10) I want to use my secondary Win 10 PC for Octoprint (Direct connection to the Printer via USB) but Windows detects the Printer as "Unknown USB Device (Device Descriptor Request Failed)" Im 99.9% sure the cable is not the problem cause it works perfectly fine on any other device. Ive tried installing multiple Driver versions (including the one that came with the printer) but no luck yet. I also tried different cables/USB ports, no luck either.

 (Device Manager)

 (Properties)

From Properties->Events->Information I get this:

Device USB\VID_0000&PID_0002\6&23938f4b&0&4 was configured.

Driver Name: usb.inf
Class Guid: {36fc9e60-c465-11cf-8056-444553540000}
Driver Date: 06/21/2006
Driver Version: 10.0.18362.1
Driver Provider: Microsoft
Driver Section: BADDEVICE.Dev.NT
Driver Rank: 0xFF0000
Matching Device Id: USB\DEVICE_DESCRIPTOR_FAILURE
Outranked Drivers: usb.inf:USB\DEVICE_DESCRIPTOR_FAILURE:00FF2000
Device Updated: false
Parent Device: USB\VID_8087&PID_0024\5&2564d19a&0&1

I use linux, so I am not familiar with Win10 stuff. But, it seems that the device driver has asked the USB device for its identifying codes (PID and VID) and got no recognisable response. Could be a bad cable, but you seem to have checked that. Could be a fried USB interface chip, so check whether you have any luck trying to connect to any other computer. If you can find someone with a linux machine (or you have something you can run linux on), the logs will tell you a lot more about what has been tried and what failed (or not).

Note that the parent USB device is VID=8087 (being Intel Corp.) and PID=0024 (being the Integrated Rate Matching Hub) - see https://devicehunt.com/search/type/usb/vendor/8087/device/0024.


Scaling/size issues in delta printers So here How to achieve dimensional accuracy of printed parts the Cartesian printer approach to accurate sizing is covered. And deltas get a footnote of being a whole other ball of wax - so let's look at that wax ball.

I'm currently resurrecting, or erecting, depending how one looks at it, a poorly documented Chinese printer (purchased in China by a Chinese student and abandoned in the US after graduation) that appears to be based off a Rostock mini. Z 204mm, X Y 100mm radius or 200 mm diameter, Bowden tube.

It appears to be equipped with an absurdly small nozzle (lacking a good way to check that precisely yet, feeding suggests possibly 0.1mm, and no, the vertical resolution is not nearly enough to make that in any way reasonable), which is obviously fixable if the rest of it can be made to work.

Yesterday we got it to the point of (very tediously with tiny nozzle) spitting out a test cube, which was 17 by 17 by 20 mm - undersized in XY, accurate in Z. The last bit makes me pretty sure the steps/mm are right on the steppers, but obviously something is off in the geometry (measured, no documentation for this exact printer can be found, at least by non-Chinese-speaking/reading me - it being utterly un-branded does not help.)

A second test cube was produced with scaling set to 20/17 (1.176) in the XY directions, and that seems to be accurate at least to non-precision measurements. I'm now contemplating "what likely needs tweaked, and in what direction" for the delta geometry - I'd say the rod eye-to-eye measurement (85mm, IIRC) is fairly decent, the offset from rod mount at carriage to rod center is not too terrible, and I have low confidence in the rod mount at printhead to nozzle - so that's the one I suspect most.

tl, dr:But I lack an intuitive understanding of how each of those parameters (offset at carriage, offset at printhead, and arm length) would affect the printed size. I'll come back and edit in what we currently think each is. Rather than depending on scaling in the slicer I'd like to seek the "right numbers" but when at the limits of available measurement precision, having an idea how and in what direction incorrect offsets or arm length affect the print size would be good, rather than just blindly changing numbers and hoping.

I also have some other "print quality" issues and a bed leveling issue which will be other questions when I can sort that out.

Issues in X-Y size on a Delta are usually the result of an incorrect diagonal rod value in the firmware.  This should be easy to fix assuming the rods were built together.

The formula for this is (20 in this case is your test print X-Y):

New DELTA_DIAGONAL_ROD = 20 / measured_length * Original DELTA_DIAGONAL_ROD

I found this information (here), this site also has more information on setting the radius and other delta specific issues.

If you encounter issues with the size of the rods you should build new ones using a jig.  There are several (here's one) I found on Thingiverse but they require printed parts and they do all the rods horizontally which I think would be tough to keep equal. I would use something similar to this picture but with a longer rod/bolt so you can fit all rods on the same time.  When I did my Kossel Mini I used a piece of the extrusion with bolts coming off of it to keep the rods consistent.

For the other issues you mention you should open another question specific to each issue.


Layer shifting on product printing after raft support structure First post here, so please forgive me for any silly mistakes.

Recently the y-axis (I think, forward-backward) has started skipping forward when printing the first layer of my print. It prints the raft with no issues at all, sticks the bed nice and flat and the raft is perfect every time.

Then it starts to print the actual item, but every time it starts to the print the back right corner the Y-Axis jumps or skips on the gears and makes a loud grinding noise. The amount it jumps varies on the print, but always jumps towards the front of the print. It doesn't matter on the size of the print or the position, it always jumps forward never back.

The printer is a Makerbot Replikator clone, from eBay. The X & Y moves the extruder. I have tried upgrading and downgrading the software (which uses Makerbot software) I am unsure if I can update the firmware.

Any help much appreciated.

UPDATE:
Image has been attached of the failed part, excuse the colour, I use it for my test prints. This is orientation it printed on the bed. First 3 blocks printed fine, 4th one jumped  It printed in the following order 1. top-left, 2. bottom left, 3. bottom right, 4. top right.

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

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

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

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