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Does the Mk4 require calibration?  

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SgtCaffran
(@sgtcaffran)
Active Member
Does the Mk4 require calibration?

I recently received and set up my Prusa Mk4 printer. It's my first FDM printer although I'm not new to the concepts of engineering, CAD design and 3D printing in general.

But one question did come up recently when designing a model with very tight tolerances: do we need to calibrate our Mk4 printers?

If so, which calibrations make sense for a Prusa machine? I'm currently checking my extrusion multiplier with this test: https://www.printables.com/model/294234-overunder-extrusion-test

 

Respondido : 13/08/2023 7:51 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Does the Mk4 require calibration?

While there are sporadic reports of people who say that calibrating esteps on their Mk3S helped them, the vast majority of users (including myself) probably never saw the need for any calibration, and I pretty sure the same is true for the Mk4. On the other hand, adjusting the extrusion multiplier for different filaments if you run into issues is certainly a good idea.

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Respondido : 13/08/2023 9:24 pm
HA60_Design
(@ha60_design)
Active Member
RE: Does the Mk4 require calibration?

I would say it does. I printed a standard calibration cube and X/Y were both not the correct size. I'm currently in the process of trying to get pronterface to connect with the MK4 so I can fiddle with the M92 steps.

 

What this does is it takes filament shrinkage into account. If X brand of filament always shrinks by .1mm on the X axis and .15mm on the Y when you tell it to print 1mm of filament (as is my case), then you tell the printer that for every 1mm you actually print 1.1mm. The model then shrinks its normal amount but becomes the size you want.

 

I did this on a £200 old Ender 3 pro, and every part was stupidly accurate, as I need them to be.

Respondido : 14/08/2023 1:47 am
Rainer
(@rainer-2)
Reputable Member
RE: Does the Mk4 require calibration?

Normally you don't change anything in the steps. Belt tension and flow rate first.

How big are the discrepancies?

 

Respondido : 14/08/2023 1:37 pm
HA60_Design
(@ha60_design)
Active Member
RE: Does the Mk4 require calibration?

.1mm on the X and .15mm in the Y. I’ve checked the belts (they were both wrong from factory) and flow rate I don’t believe would chance a difference like this. If all 3 axes were the same difference, then I believe that would be the case (as you’re I dreading the amount of plastic produced in all directions)

Respondido : 14/08/2023 3:38 pm
wizbongre
(@wizbongre)
Eminent Member
RE: Does the Mk4 require calibration?

Building on this, is there a recommended regular maintenance/calibration process to be considered?

After about a month of perfect prints from my self-assembled MK4 I'm having a few major issues that started almost overnight, mostly with filament blobbing on the nozzle and sometimes catching the print. I suspect its mostly self-inflicted as I got a V6 adapter and messed around with different nozzles likely undoing the good work I did when originally building it!

Last night I stripped out the nozzle assembly again and then decided to check the belts - both were too loose. I've adjusted them (using the online app and my phone) and seem to have got back to decent prints overnight again.

However, I've still got a lot of filament blobbing on and around the nozzle - I'm still too new to 3d printing in general to know what is causing this...

Respondido : 15/08/2023 10:43 am
Rainer
(@rainer-2)
Reputable Member
RE: Does the Mk4 require calibration?

0.15 is a lot.  None of my printer has such a deviation. Especially no Prusa.

What kind of filament do you use? Is the diameter of the filament constant and was it taken over in the Slicer?

If the flow fits, the dimensions are usually ok. Try lower and higher and see what happens.

There is a very good thread for adjusting the printer. A lot of background knowledge is also conveyed there. But unfortunately only in German.

I found two more cubes that I printed with Galaxy Black Pla.

X/y/z

19.97/19.96/20.01

19.97/19.95/20.00

Respondido : 15/08/2023 11:30 am
wizbongre me gusta
chmax
(@chmax)
Eminent Member
RE: Does the Mk4 require calibration?

> There is a very good thread for adjusting the printer. A lot of background knowledge is also conveyed there. But unfortunately only in German.

Could you please post a link to that?

Respondido : 15/08/2023 1:34 pm
wizbongre me gusta
SgtCaffran
(@sgtcaffran)
Active Member
Topic starter answered:
RE:

So I recently received some new filament from Auropol. It's a relatively unknown brand but also produced in the Czech Republic so I was hoping for Prusa quality.

The filament at least appears to be less than 1.75mm and the tolerances are hard to measure. The first print did not look pretty. The second print was a lot better after adjusting the filament dimension in Prusaslicer. Then I noticed a bit of bulging on top surfaces so I slightly adjusted the extrusion multiplier. Looking good!

However, today I printed a similar model as the "Califlower" from Vector 3D and noticed that several dimensions were not spot on. Dimensions of 100mm are printed in X and Y orientations and on inner and outer perimeter.

Because you can measure both inner and outer perimeters, you can actually calculate the middle line and determine the accuracy of the printer without taking into account the line width.

In this case I got 0.20% and 0.06% deviation from 100mm on the two axis. What can we do to fix this kind of deviation?

Also, all of the bars should be 5mm but each one measures 4.94/4.95mm, in both directions. I don't understand how to fix this one either, if I increase the extrusion multiplier then I get bulging on the top surfaces again...

Esta publicación ha sido modificada el hace 1 year por SgtCaffran
Respondido : 16/08/2023 7:56 pm
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