Dimension of printed part

[Orrhomariani 0]

Hello, I have several Ultimaker 2+ and I have differences in the final dimension of a printed part. How can I modify the calibration of each printer internally to balance and obtain the same dimension for the same 3D object?

thanks !

[gr5 2,235]

This is tricky to answer.  In my experience the obvious thing to calibrate is the x,y, and Z "steps/mm" value which in my experience is spot on for these printers.  More likely (I think?  not certain) the error would be where the hole drilled through one or more pulleys is off center such that, for example, the x axis might print too large/long for half a rotation (about 3cm) and then print too short for the other half.  Such that if you printed a 1cm cube it might be fine in the center but too large if placed 1cm to the right or too small if 1cm to the left.

 

I guess you first need to explain exactly which dimensions are a problem.

 

Is it vertical holes?  As that is a different issue.

 

I also guess I would print a pattern right on the glass with maybe 5mm spacing (or do imperial units if you don't have any good metric measuring devices).  Then check them all to see if some are too small and some too large and if so try to get a better set of pulleys.  If they are consistently large or small then it's pretty easy to fix with the steps/mm parameter but I think you can't edit that in the default Ultimaker firmware and instead you would want to get the tinkerGnome version of Marlin also known as tinkerMarlin (search this forum for that so you can download and install).

[gr5 2,235]

Oh, another common problem is that shipping really sucks and a lot of these printers show up at the customer where the frame is a parallelogram instead of squared off.  If you look down from the top sometimes you can see that things are crooked.  This makes it so that when you print circles or cylinders they come out as an ellipse in the diagonal direction.

 

The best fix is to loosen all the frame screws, square it up and retighten.  Or just ask a friendly elephant to push the farther edges together just a bit.

 

You (and we) really need to know what dimensions you are talking about and which of the many possible causes the problem is caused by.

[Orrhomariani 0]

. It Is for dental . Thank you for your answer. When I print a cube of 1cmx1cmx1cm on several printers I get a cube that does not have the same measurements because of the shrinkage. I would like to modify each printer individually to apply a magnification factor so that I don't have to modify my part each time in Cura. Your idea of modifying the firmware seems very interesting. Do you think I should continue in this way?

[gr5 2,235]

Yes.  The firmware is here.  You can always go back to the official firmware.  So install tinkerMarlin:

https://github.com/TinkerGnome/Ultimaker2Marlin/releases/tag/V19.03.1

 

Get the only one that matches your machine.  From your description it would be near the end of the list.  It should *not* say dual.  It should say "plus": 

Tinker-MarlinUltimaker2plus-19.03.1.hex

 

The hex file is the firmware.  Then you connect a USB cable from your printer to your computer.  Then you have many options on installation.  I'd try cura first although it's the most likely one to have trouble seeing your printer.  In Cura 14.X or 15.X it's pretty easy.  In latest cura do PREPARE mode, then click on the printer drop down and then "manage printers" and then UPDATE FIRMWARE and then custom firmware option.  Often it can't see your printer for a few possible reasons.  You need the USB driver which should be bundled with Cura.  At least it used to.  On windows you can check if there is a com port in device manager that is added when you connect the usb cable.  You can connect and unconnect a few times and you should see a COM port added.  In the old days it was like COM3 but now typically it's a larger number like COM17 and cura doesn't look that high I think.  So if you see the COM port in device manager but not in cura then you need different software.  You can google about how to install firmware for arduino (as it's an arduino computer inside the UM2+) and there's tons of help for you there.  Or use printrun software here: 

http://koti.kapsi.fi/~kliment/printrun/

 

Which should have less trouble connecting to your printer and installing new firmware.

 

Once installed the rest is easy - find the steps/mm settings for all 4 axes and if your cubes are say 5% too small than increase steps/mm by 5%.

[gr5 2,235]

After you adjust the steps/mm power cycle the printer to make sure it's saved permanently.  I think by default it only changes it temporarily and you have to do some kind of save operation.  Although maybe it *does* save it.  Anyway if you have questions about that post them here and I will answer or tinkergnome himself will answer.