Repeatedly skipping same layer while printing

brandonbrayRRS · March 18, 2016

Hi,

We've just set up our first printer, Ultimaker 2+, and for the most part it's worked great. But it consistently skips one layer while printing. I've posted about it as a reply to another thread that sounded similar, but it hasn't shown up. So I'm starting a new topic to hopefully have it seen and see if if any of you can help.

In the picture below, you'll see a sample part with a skipped layer approximately 11.5mm (.45") from the base, making it layer 191 or 192, as every layer is .06mm thick according to my settings. Just below it is a ridge where I expect some PLA has squished out from the build plate not dropping enough or at all for that layer. After the gap, the printing continues as normal and the final height is to print. All other dimensions are to print, as well.

After consulting the troubleshooting page, it appears the build plate's linear bearings could be binding on their shafts, as the skipped layer is very consistent from part to part. I attempted to adjust the bearings as explained on that page, but it hasn't seemed to help. Is there a more reliable way to adjust the bearings, or something else I can try?

Thank you for your help!

Best regards,

Brandon Bray

Edited March 18, 2016 by Guest

Labern · March 19, 2016

There have been a few reports lately with lumpy bearings and or sloppy z axis nuts.

I would first check your model in layer view just to make sure its all good.

Then raise and lower the bed up and down by hand to see if you can fee a tight spot. its normally repeated at a set distance as the balls complete one round of the inner race inside the bearing.

Next you can raise and lower the bed small amounts without the z axis turning to check the play in the z nut.

You may needs to remove the linear bearing individually from the bed and raise them on there own to feel any problems.

If you want to print something in the mean time just put a weight on the back of the bed and see if that helps.

Jomet · March 20, 2016

I have the same problem. With a micro meter I measured the move of the bed and saw that it was not linear. The combination of not so solid bearings and a nut without anti backlash gives these gab. My nut has a backlash of 0.15 mm.

The bed remains for a momend at the same position so you put 2 layers on the same position. This gives you also an edge at the outside of your print.

I ordered a nut with anti backlash and waiting for it. When I have build up the system I will post the result here.

Jomet · March 24, 2016

Today I made my first prints with the anti backlash nut and it was a great succes. no gap and a smood surface. Every layer seems to have an equal thickness now.

Labern · March 28, 2016

Today I made my first prints with the anti backlash nut and it was a great succes. no gap and a smood surface. Every layer seems to have an equal thickness now.

Looks great. Where did you get the anti-backlash nut?