Printing PA-CF
@lemcott During flow tuning test for this PA-CF filament, I print a 30x30mm square 3mm high with 2 bottom, some infill and 10 top layers (Ellis' tuning guide), but it comes loose. Probe offset is good (nice first layer squish). print surface is textured PEI sheet, its clean and I am using 3dlac as well. It still comes off (i literally never had issues before). Bed temp is 50C. Should I try higher bed temps for this stuff, or perhaps it needs a larger surface (ie, use a brim)?
18 Replies
Glue stick
I print on unheated G10 using Elmer's purple glue stick
Pei is fine, so is kapton. Just use gluestick
Better cleaning and more 3dlac. I dont have a glue stick. This material prints beatifully. Its giving me a boner.
first functional print, 4 parts for the rear corners for the sheet to fit in.
still need to go through PA tuning, bridging etc but thats not important for these parts. i'll do that tomorrow
Chopped fiber is soooo good at hiding the crimes of additive
haha I had ChatGPT translate that 
you explain this joke to me? The context is 3d printing with PA-CF filament. The joke is this: Chopped fiber is soooo good at hiding the crimes of additive.
ChatGPT
The joke seems to be a play on words related to the use of chopped carbon fiber (CF) in additive manufacturing or 3D printing, specifically with PA-CF filament (polyamide with chopped carbon fiber). Let's break it down:
Chopped Fiber:
In the context of 3D printing with PA-CF filament, "chopped fiber" likely refers to the short carbon fibers that are mixed into the polyamide material. These fibers enhance the strength and stiffness of the printed parts.
Hiding the Crimes of Additive:
The term "additive" in this context is likely a play on words. "Additive" usually refers to additive manufacturing, the process of building objects layer by layer (commonly known as 3D printing). However, the term "crimes of additive" is a humorous exaggeration, implying that there might be some issues or challenges associated with the 3D printing process.
So Good:
The phrase "soooo good" is used sarcastically or humorously to suggest that chopped fiber (in this case, carbon fiber) is exceptionally effective at covering up or hiding the potential problems or challenges that may arise in the additive manufacturing process.
In essence, the joke is a playful way of acknowledging that chopped carbon fiber, when used in the context of 3D printing with polyamide, can be highly effective at improving the mechanical properties of printed parts. The humor comes from the exaggerated notion that these fibers are so good that they can "hide the crimes" of the additive manufacturing process, as if there were some misdeeds or issues to cover up in the first place. It's a lighthearted way for enthusiasts in the 3D printing community to appreciate the benefits of incorporating chopped fiber into their prints.
Just an observation, it seems that I need to bring my flow rate (extrusion multiplier) down to 0.9. Normally I am around 0.94 to 0.98. Extrusion length has been calibrated.
you explain this joke to me? The context is 3d printing with PA-CF filament. The joke is this: Chopped fiber is soooo good at hiding the crimes of additive.
ChatGPT
The joke seems to be a play on words related to the use of chopped carbon fiber (CF) in additive manufacturing or 3D printing, specifically with PA-CF filament (polyamide with chopped carbon fiber). Let's break it down:
Chopped Fiber:
In the context of 3D printing with PA-CF filament, "chopped fiber" likely refers to the short carbon fibers that are mixed into the polyamide material. These fibers enhance the strength and stiffness of the printed parts.
Hiding the Crimes of Additive:
The term "additive" in this context is likely a play on words. "Additive" usually refers to additive manufacturing, the process of building objects layer by layer (commonly known as 3D printing). However, the term "crimes of additive" is a humorous exaggeration, implying that there might be some issues or challenges associated with the 3D printing process.
So Good:
The phrase "soooo good" is used sarcastically or humorously to suggest that chopped fiber (in this case, carbon fiber) is exceptionally effective at covering up or hiding the potential problems or challenges that may arise in the additive manufacturing process.
In essence, the joke is a playful way of acknowledging that chopped carbon fiber, when used in the context of 3D printing with polyamide, can be highly effective at improving the mechanical properties of printed parts. The humor comes from the exaggerated notion that these fibers are so good that they can "hide the crimes" of the additive manufacturing process, as if there were some misdeeds or issues to cover up in the first place. It's a lighthearted way for enthusiasts in the 3D printing community to appreciate the benefits of incorporating chopped fiber into their prints.
Just an observation, it seems that I need to bring my flow rate (extrusion multiplier) down to 0.9. Normally I am around 0.94 to 0.98. Extrusion length has been calibrated.I feel like I could've explained that in a lot less words 
first "real" print in PA-CF after going through all the tuning etc.
looks like in lower left corner PA is not correct even though in the tests it was looking good. No biggie for this part but I need to double-check that when its finished
PA is set to 0.04 but in hindsight I could have gone to 0.05 and prefer the higher setting before lines become separated. I picked the first without bulges.
ow I had a 'zero' too many; 0.004 
I print this without fan, but my longer bridges hang. Bridge extrusion is at 0.8, no fan. I can bring extrusion down to 0.7 and give it 10% fan? What would you suggest?
correction: its at 0.9 flow
speed 50mm/s
I print this without fan, but my longer bridges hang. Bridge extrusion is at 0.8, no fan. I can bring extrusion down to 0.7 and give it 10% fan? What would you suggest?
correction: its at 0.9 flow
speed 50mm/sif the printer is enclosed I would use a cooling fan for sure. not just on overhangs.
you shouldn't need a lot of cooling, 10% of a 4028 is a good start for general printing, go up in 2% increments for overhangs and faster moves like infill/supports until they look good too.
I also use z hop and wipe
but many call me a madman
nah sounds good. I always do zhop
and prevent cross perims
I;'ll try the fan
@lemcott the horizontal lines, is that because its not dry enough?
ambitious-aqua•13mo ago
Wet filament sometimes does that, but this doesn't look terribly wet either
I did have a little bit of stringing in another print as well. Next print will dry the spool some more
Better pic
Yeah that doesn't look wet to me, but I don't want to rule that out that quick. Wet is usually more blips/blops and stringing with steam coming out of the nozzle.
Also: don't get too attached to the idea of a PA-CF Eva hotend... Nylon creeps and it is worse around heat. But that's a totally different issue for the future you.
Seeing a lot of surface gapping along with the missing perimeters, it's hard to say for certain of this is slicer or mechanical
Yeh I’ve been dealing with creep since I got this printer. It’s annoying af. All thermoplastics creep and nylon is maybe worse than abs or asa, I’m not sure. I do think cf20 makes it a little better? Either way not much choice. Will use heat inserts and use m3 washers where I can. They help a bit too. Im just hoping this will be better in terms of resonances. Spools are in the dryer again until I get home later today. That would be the second run of 10 hour drying.
ambitious-aqua•13mo ago
Creep is super dependent on the PA blend used for the filament. No personal experience with ePA-CF, but I'd guess it creeps.
You could anneal your printed parts to make them somewhat more resistant to creep, but it only goes so far. High fill % helps at first, but since carbon fibers are porous, they'll help to suck in moisture through capillary action, making the PA more creepy
Seems lately ePACF, PA12-CF, and PCCF are all I am printing in these days. My VC500 was built with a specific intent of printing fuel injection parts. I too started with PACF, but have switched to PCCF. Higher glass temps and zero creep. Perhaps not as good at hiding print artifacts as PACF, and the PC gloss tends to show the layers, but damn these parts are strong. I can stand on the diameter of one horn and it does not break or distort, slips right back on the studs
black 90mm horns are Priline Superhard PCCF blue are Gizmodork pure PC. Printing is WAY cheaper than buying to find the right tuning length. Then, I 'might' purchase aluminum (purely a 'shiny bobble' thing) once the right length is determined. The rail cover (with pocket to hide injector wires) is PACF
zoom in.... look how smooth that rail cover is!
Still snaps on as originally dimensioned
The point here is finding print temps.
to get the PA to print right, I had to work my bed to handle higher than 110°C bed temps to stick well, regardless of surface or adherent used. PACF I'm printing at 285-295°C with a bed temp at 115°C The PC is closer to 280 and 95 respectively. I use NANO Polymer Adhesive on the bed almost exclusively. you REALLY need to watch the bed temps at part removal. If you let it cool to room temp, the PC is now part of your smooth PEI sheet! Cooling my flex plate to 5-10 degrees below print temp I pull it out and over to the table . The table will cool the plate a bit quicker than the part. The temp diff it the trick to get your parts to release cleanly.