Posted: 8/25/2026 8:44:05 PM EDT
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I am having an issue printing theFTN.6 Rimfire suppressor. Has happened last three attempts. Sunlu PA6-CF. Completely dried in Sunlu E2 and heated during print. 65c chamber temp and 300c nozzle temp. It prints fine until it gets to the threads. Then a blob of filament starts to build up on one side of the print until the hotend hits the blob and knocks the print over. It seems to start as the threads begin to print. My assumption is this is likely cause by warping as the start of the threads are cooled. Anyone run into this before? Attached File |
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not sure if it relates, but we designed our own threads with a 45 degree angle as thats better than 60 used in typical threads... when printing in plastic. Zero issues with threads and buggers or strands of crap on them. Not sure why all the designers are sticking with 60 in plastic-when you can do whatever you want. Unless thats the interface thread that connects to the barrel? Maybe its time for somebody to make that.. |
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Im guessing you are printing too fast and your layer times are too short. What layer height and print speed? You should be like 30mm/s on the high end. Your problem is heat build up. You're printing in ideal conditions for strength but its a double edged sword as its also more likely to cause heat artifacts, one of which is curled edges at the top of the print. You have plenty of options to solve it. Just need to figure out which you want to do. You can slow the print down. You can decrease the nozzle temp ten degrees. You can create a sacrificial tower across the build plate, you can decrease layer height, etc etc. Usually experience dictates what you do based on your current settings. While I love the super capable printers we have today, it lets people skip a lot of the learning curve that most people naturally had to progress through before dealing with more advanced materials. This can come back to bite later when you are having failed prints with filament that is $40-80/kg when you could learn it with ABS for $10/kg. ABS is a great learning filament for PA6-CF. It actually warps more, has similar print temps, and has an even narrower thermal envelope in which max strength is obtained without heat related artifacts. 
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I just ran our new batch of Sunlu pa6. In the bambu H2s it ran perfect and looks perfect, I just used the generic built in specs in Orca with out changing a thing. I did not even bother to dry it. Naturally, I ran the wrong part and discovered that with just minutes left in a 8 hour print. So good news is that will be used for strength testing . UPDATE, this stuff is really strong. Normal test could not break or chip the part. We have a tension test to see if it will pull apart along the print length, will do that later. |
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Thanks for all the input on my questions. I slowed print speed from 30mm/s to 20mm/s, dropped nozzle temp to 295 and adjusted layer height for the portions where the threads were printing. I also adjusted some Z hop settings. Extended the print time by about 4 hours but it all looks good now. Probably won't be going down the rabbit hole of tapping threads by hand at this point. |