Shifted / Offset layers in print

Hi everyone,

I am printing in flexPLA and at some points the 3D printer creates shifts in the layers, only in the X-direction.
See the pic attached for an example.

There can be many causes:
http://reprap.org/wiki/Shifted_layers

The belt tensions are exactly right and the motors work fine.
I suspect a backlash in one of the C-clamps causing at some point too much friction.
Or can it be something simple like the arms needing oil?

Has anyone else had the same problem?

https://d2py9w124w2itd.cloudfront.ne...b/DSC01927.JPG

Hi

Yes, I have seen exactly the same issue.

Since I don't know what kind of printer you are using, it is tough to know if my slipping parts are the same as yours. Set screws on D shafts can do that.

Bob

Have you repeat the print and did it happen again?

Typical issue could be your nozzle slamming your print. Make sure nozzle is cleaned and doesnt have a huge junk of crap sticking on it.

It happens in about 1 out of 10 prints that I do.
I reassembled the print arms and checked the electronics - one of the heatsinks on the motor stepper drivers is missing so I am suspecting that this motor is skipping steps causing the offsets. I will put on some thermal paste and see if it resolves the issue.

Hi

If you have rate dependent thermal motor shutdown, the answer may be to drop the speed. If it's purely thermal, it should happen when the printer has been on for a while. In that case, you may have to much current headed into the motors. The little paste on heatsinks do very little for the drivers. You can get a little more benefit from a fan. Even there the benefit is less than you might think. The way the chips cool and the pc board layouts don't generally work very well together.

Bob

Dont just put the heatsink, put also a fan or make sure it is running free. Sleeves bearing clogged up easily and needs to be cleaned frequently.

Hi Bob, thank you - it happens when the printer has been on for a long while, and indeed the cooling paste doesn't help very much. So when I turn it off between prints to let it cool down it works as normal again. Thanks!

Hi

Put a fan on it. Running the chips hot shortens their life.

Bob

Make sure nozzle is cleaned and doesnt have a huge junk of crap sticking on it. In that case, you may have to much current headed into the motors