Gaps in Carbon Fiber Print
These are a series of 10mm tower prints that I'm using to try to get my Carbon Fiber settings correct.
The tower on the left looks nice and smooth. The other prints have "gaps" in the outer shell (and I'm assuming inconsistencies in the infil).
I thought this was due to the hobbed pulley being incorrectly tensioned against. In experimenting with that, I ground the hobbed gear smooth (I have purchased a couple of steel ones).
However, I am still having the issue. It crops up at irregular times.
I've slowed the print settings way down, because I heard that CF has problems with clogging or choking at faster speeds. Also, I don't need to print things quickly.
I've increased the temp to 250c to print, and that seemed to have a slight reduction in the gaps.
Today I printed several towers ranging from light tension to heavy tension on the hobbed pulley, and it really doesn't seem to make a difference.
The belts are tight. The z-axis does not appear to skip or hang.
Any thoughts?
Re: Gaps in Carbon Fiber Print
i guess you use a hardened nozzle to print the carbon fiber stuff. did you retune your hotend's PID parameters with the new nozzle?
but it's only one piece of the jigsaw puzzle.
dem inscheniör is' nix zu schwör...
Re: Gaps in Carbon Fiber Print
I've tried a ton of things, but I did not think to retune the PID. I didn't think the nozzle would need that, but I'll give it a shot
I'm going to go give that a shot.
Re: Gaps in Carbon Fiber Print
Hi Ty,
You say that you wore the hobbed gear smooth, and that you bought some steel ones.
are the steel gears the same size as the brass ones?
the only steel ones that i have seen, are larger in diameter, which is likely to cause a couple of issues.
1, unless you revise the number of steps per millimeter for the extruder, a larger steel gear will cause over extrusion
2, a larger diameter gear will make loading the filament more difficult, as the filament will not line up with the PTFE liner in the extruder... (note this may only become aparrent when you next change the liner, because the current liner may already be worn larger...)
If you have found a source of identical dimension steel extruder gears I would be interested in knowing where and how much they are.
best wishes, Jon
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Gaps in Carbon Fiber Print
If you have found a source of identical dimension steel extruder gears I would be interested in knowing where and how much they are.
Joan - I had an extruder kit delivered recently from PR and that included a steel filament drive pulley. I didn't need it, so I put it to one side and didn't measure it, but it may be that PR have sourced these instead of the brass ones.
May be worth having a chat with support.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Gaps in Carbon Fiber Print
Thanks Peter,
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Gaps in Carbon Fiber Print
Hi Peter, I did as you suggested and the online helper, (Honza) said that new orders are shipping with steel wheels, so I ordered one, to be added to my multifilament order... I will save on shipping be having them delivered together,
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Gaps in Carbon Fiber Print
I did notice that the steel hobbed pulleys were fractionally larger. However, a slight (very tiny) shave on the area around the PTFE liner seemed to do the trick. I have not seen issues with over extrusion, but I am concerned that somehow this is an under extrusion (by definition, there isn't enough extrusion). I will disassemble the extruder tonight to look at the PTFE liner to see if there is any rubbing there. Good thought.
I will have to order some correctly sized pulleys from Prusa. The shipping is a little killer (I had a PINDA probe issue when I first got the printer), but I bet I need a correctly sized pulley.
I did not autotune the PID yet. I thought there might be a function within the printer menu, but there is not. I'll go digging tonight.
Re: Gaps in Carbon Fiber Print
I started up a print using conventional PLA, and it seems to be printing fine.
Is a .4mm nozzle too small for Carbon Fiber PLA?
Re: Gaps in Carbon Fiber Print
OK, this is literally the same file, but printed with straight PLA instead of CF PLA.
That's a 15cm PLA tower that looks almost perfect. No gaps, nothing. Incredibly strong.
So, does anyone have any suggestions for getting consistent quality out of Protopasta Carbon Fiber?
Re: Gaps in Carbon Fiber Print
you need a nozzle bigger then 0.4 mm for abrasive materials, a 0.5/0.6 mm harden steel or olsson ruby and print at 260 degrees.