25mm primo core clamp issues

@vicious1 I’m in the last stages of my 25mm build. I was seeing some play as well but was able to eliminate it by tightening the clamps, but I worry that I might have overtightened them.

Should I reprint the core parts? I’d need to get some more PLA first.

Also, what’s the benefit of the new trucks you just released?

Here are the new trucks: New MPCNC for 2020! - Primo - and what they do.

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Thanks!

All the new core files are up. I just double checked.

If it is snug, leave it alone, if you break a part, reprint them all.

at the print in Cura on layer high line 485 (CORE) hes getting out of control,
hope thats not bad
cause its my last filament :frowning:

hey, guys,

I have successfully crossed the Alps and am now back here :smiley:

Thank you very much that you have taken up this topic so intensively!

The new core and the clamps were printed to me in the meantime. Yesterday I installed and tested the parts directly.

default assembly
I have assembled everything, the rail is still about 1mm away from the stock.

altered assembly
By this method I could bring the situation a lot closer. The rails X- and Y-axis were only slightly wobbling.

After I installed the core, it has probably stretched so far that the core only wobbles a little bit. At the moment I would say it should fit.

Do you have any other experiences with the new version?

It would be interesting to know if the adjustment only works for me, all other rail clamps are working fine and can be adjusted too much like for the trucks.

I will continue to assemble the MPCNC, if I can still help just let me know.

Cheers Chris

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Hey how,

Sorry, I have bad news…

I have connected the steppers to test the movement.

The core is wobbling again. I have retightened the tension bolts again, it can’t get any tighter. It didn’t do much good either, one layer is not in contact (~0,5mm distance).

It is impossible to move the core, but with small steps the core wobbles and it rattles very hard.

SmartSelect_20200901-183501_WhatsApp

Must be something with the pipes, hardware or printer. Mine is super rigid.

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Please run both tests.

Good evening,

i have spoken with my friend. Sorry, I had in my mind that the calibration test (XY axis distance and square) was correct.

He has printed it again today and the following deviations have occurred.
X +0.9mm
Y +1.3mm

The steps/mm were adjusted and we got the following measurements:
X 150.1mm
Y 150.1mm

diagonal of the small square 149.8mm

The measurements showed a deviation of less than 0.6mm. We are currently reprinting the clamps.

Tomorrow I will install the clamps.
I will get you up to date.

Good night
Chris

If you are not printing the new Core, you need the modified clamps that I did not make. My clamps will not fix the issue without also replacing the core.

If the printer was that far off you should also check the z axis and extruder. 150 should be correct so I suspect something else is wrong like loose belts. Steps per mm are exact numbers (except the extruder).

Hey how,

we printed the clamps again after the print test had been adjusted

Now the bearings are also in contact with the rail. We left the core in the V1 for the time being - the deviations are probably not that dramatic.

I have already printed a few test drawings. They look good so far.

When changing the direction the Y-axis swings back, but I would say it is because of the length (1200mm).

Cheers Chris

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