layer shifting after noise

[JLM]

I have noticed on my larger prints when the print bed moves fast from front to back, (long distance) from one corner to the other it sounds like the print head or print bed hits something. Then the object I am printing gets messed up. After I hear this noise the printed object has a shifted layer effect. I know the print head is not hitting anything. It only happens when the bed/head moves fast between print times. I have the default print speed set at 3800 and solid infill speed set at 80% so it is not like I am printing at blazing speeds here. The sound it makes is definitely a thump. I though it was my wire harnesses fetching up on the under cartridge rail but I tied them up and it still does it. Most very time the bed moves fast front to back it a effects the print. see attached picture.
But if I print really slow with no long travel it prints fine.I am using a new machine Makergear assembled for me. I have 28 hours on it so far.

[jimc]

yes its not your print speed but your xy travel speed. i assume you are using s3d? in your process settings the xy speed is usually default to something like 18000. drop that to 9000-12000. if that works out for you then great. if not we may need to lower the acceleration as well but try the speed first.

[JLM]

Once again Jimc you nailed it!

I turned down the xy default speed from 18000 down to 9400 and I had no issues at all.

This is a replica of the DDG 1000 I drew up on Geomagic design. I still need to attach the back with 4-40 machine screws and print the bottom half in red. To be continued....

Thanks again for your awesome help.

[jimc]

josh and jin actually figured out that its a bug in the marlin firmware that somehow doesnt show itself unless you run really fast travel moves which happen to be the default of s3d. i have my acceleration turned down a little and have always run my speed from 12,000-9000 and i have never had a skip since i made those changes 2 years ago.

nice job on the print btw