The Shop > CNC

3D printer Ender 3 pro oval hole problem

(1/4) > >>

picclock:
Ender 3 pro oval hole problem

Hi
I'm struggling with this. The holes I make are ovalled and diagonally offset  - see picture. Internet help seems pretty useless as the advice boils down to tighten the belts or square the frame - neither of which are applicable. A

The printer frame is square and the xyz dimensions calibrated. If I print a square it comes out square with equal dimensions across the diagonals, and the desired size within 0.1mm.

Yet the holes are all over the place. The test piece has holes 1 to 15mm, is 100mm long and 25mm wide.
The major axis of the oval is around 340 degrees. On the 11mm hole the diameter at approx 340 degrees (top view) is 11.04mm, at 0 degrees (y direction) its 10.89mm, at 90 degrees (X direction) its 10.53mm, which is typical.

I've tried an earlier version Cura slicer, 3.41, which always produced good results on my now defunct Prusa, and the results were the same. I'm beginning to think it might be a mainboard problem. Its a Creality 1.1.4 motherboard, using ATMega 1284P processor.

I have a new SKR V1.3 card on the way with 2209 drivers and a touch screen, so if it is this its not going to be an issue for long.

Any other ideas very much appreciated.

Best Regards

picclock

Joules:
If everything is OK when printing square parts, it looks like your bed is moving on the springs somehow.   It certainly exhibits drag I would associate with belt stretch or binding, or a hotend rocking as the top and bottom of the holes have very similar displacement regardless of size.  Check the hotend assembly is tight and you can’t rock it side to side with your fingers.

Joules:
Just try printing some cubes again, but rotate them 45 degree to see if the sides distort.

picclock:
Hi Joules

Thanks for the springs idea, its something I hadn't  thought of. I've just compressed them well up, but now I will have to butcher the Z endstop (microswitch) holder for head adjustment. I'm not too worried about it as I've a 3d touch levelling sensor on order.

I have already checked the head for tightness, although I would imagine this would show up with unsquare prints if there was an issue like this.

I am impressed by the sturdiness of the frame and generally good engineering for a pretty low cost printer.
Do you have one and does yours print round holes ??  :lol:

I'll post my results when done.

Best Regards

picclock

 

Joules:
No Ender 3 here, I think I posted in the past my test prints for checking holes.  In extreme cases I will print a test ring, then draw an eliptical hole to compensate.   My worse case for out of round components was due to a ballrace going bad at the rear of my printer, the drag from that caused racking and lots of head scratching till I found it.

Navigation

[0] Message Index

[#] Next page