Material build up on the print head during prints

[AndyP 0]

I recently attempted to print a bearing out of Ultimaker's PC filament and had to cancel the print half way through. The filament had started to accumulate on the print head which lead to the silicone gasket at the bottom being split into two pieces. I changed the gasket and cleaned up the PC filament from the print head. Was there something wrong in my print settings that lead to this happening or could it be a flaw in the model? I have not played around yet with the print settings of the S5 Pro, just use the default or engineering options on Cura.

[Dustin 87]

Sounds like you might have had bed adhesion issues? 
Hard to say much without pictures.

I would refer to this guide though to help!
https://support.makerbot.com/s/article/1667337602519

[RogueWave 15]

Had a very similar issue, too much filament "inside" print core head causing  build up, once again, "Inside" Print Head!

Yes looks like a adhesion started the issue. 

[AndyP 0]

Attached are some pictures to help. The first print came out perfect, just had an issue with the raft so I removed it and tried printing the object again. The two filed labeled "Failed" are the results of the second print. I cancelled the print after checking on it and noticing the shift that happened, removed the print core and saw the build-up. This has to do with the adhesion to the print bed?

[jirodriguez72 18]

When running materials that print hotter (PC, CF-Nylon, etc.) I find that I have to turn down the flow rate and/or temperature a bit. You have a pool of melted material in the print head that is under pressure from the filament feeding into into it. So if your temp is too high you can end up over-extruding quite a bit and then dragging the print head through the still soft/molten plastic (especially on smaller parts). Over time that will build up and can grab the entire part and break it loose from the print bed, leading to "flooding" of the print head - which is what it looks like was starting to happen to your print head. Since the feeder gears are so far away from the print head a retraction does not instantaneously relieve the pressure on that pool of liquid plastic so you have to fine tune the temp. and flow to allow for good layer adhesion, but not end up with over-extrusion.

 

Best of luck!

[AndyP 0]

16 minutes ago, jirodriguez72 said:

When running materials that print hotter (PC, CF-Nylon, etc.) I find that I have to turn down the flow rate and/or temperature a bit. You have a pool of melted material in the print head that is under pressure from the filament feeding into into it. So if your temp is too high you can end up over-extruding quite a bit and then dragging the print head through the still soft/molten plastic (especially on smaller parts). Over time that will build up and can grab the entire part and break it loose from the print bed, leading to "flooding" of the print head - which is what it looks like was starting to happen to your print head. Since the feeder gears are so far away from the print head a retraction does not instantaneously relieve the pressure on that pool of liquid plastic so you have to fine tune the temp. and flow to allow for good layer adhesion, but not end up with over-extrusion.

 

Best of luck!

Thanks for the detailed response, I appreciate it a lot! Next time I print with those materials I will attach pictures of the results.

[jirodriguez72 18]

No problem.... FYI this is a NylonX piece using Aquasys-120 dissolvable support material for ref. Other than dissolving the supports the only cleanup we have to do is a little bit of light scraping with a razor blade across the surfaces to remove a few stray blobs. This is a pump impeller that is 10" on the OD and we spin these to 3600 RPM under load in water.