Experiencing repeating layer drift then return printing pc.
I am printing a 60mm diameter 2mm wall thickness 319mm long tube in pc. It needs to be as close to perfect as possible for an engineering application. I’ve printed out 6 now and I get repeating layer drift at exactly the same height every time, 245mm. The tube drifts sideways about a mm and then seems to return to true over a few cm – please see pics.
I’m using a 20mm inner and outer brim, and have tried including ribs for stability, it doesn’t seem to be a bed adhesion issue. Particularly because of how accurately the problem repeats. It occurs at exactly the same height every time.
When I print in PLA the tube comes out without error.
I’m thinking now it’s some sort of hardware issue due to the precise repeatability of the problem.
Have thoroughly cleaned and lubed z lead screws and rails.
Seems unrelated because different height but might be a clue – when I move bed right to the bottom and move bed up by 10mm at a time, I get a clicking sound that occurs every time in second 10mm bed movement. Only one click, but every time. No other clicks throughout bed movement. Only on up movement of bed, not down. This places the click at 300-320mm so have so far discounted but thought it might be a clue.
Would seriously appreciate any help, need to get this working and fast. Thanks all.
Hello, this seems very similar to the cooling problem some users are experiencing with the H2S: H2S layer twisting at specific height. Maybe you can try redirecting the air flow as suggested in this thread. Hope this helps. Good luck!
Hi there!! Thanks heaps :)). This was the problem.
I read the thread and did two things (recommended in the thread by other users and Bambu support) to get a successful print:
Moved the tube to the back and rear left of the build plate (away from the chamber heating fan/vent).
The fault was at 245mm so I added the following g-code command at 200mm - “MS141 S0.” (From other thread). This switches the chamber heating fan off at this height.
The problem disappeared.
The print looks good but I’m thinking maybe layer adhesion might not be as good after 200mm coz of reduced chamber temp. It did stay reasonably high in any case however coz it was a 6 hour print and chamber had already warmed everything up a lot.
I’ll continue to monitor the other thread and if someone finalises a working shroud for the chamber heating vent which means you don’t have to turn the chamber heating fan off I will try this to ensure best possible layer adhesion.
