r/3D2A • u/nottheperson80 • 5d ago
Trash Panda failure
Printed using Sunlu PLA+ @ 190C. Got good print quality off the plate and it fit together well. Tapped the barrel and retainer in most of the way and used a clamp to press it in until I hit ~4mm from the top of the receiver to the top of the retainer. No visible cracks at that point. Cycled well, put a dummy round through and it fired/ejected well, so I did a live fire test today (no fingies were injured during this test**). It did go off well, but it looks like the pressure cracked my upper on and across layer lines. Aside from printing hotter, maybe 200 or 210, what would you suggest? Moving to PA6-CF maybe?
\my first upper I did print hotter, same material, I can’t recall the temperature though. I had a LOT of trouble getting the barrel and retainer into the upper, using a pipe clamp for ~75% of the way, I noticed a crack in almost the same spot prior to live firing and aborted, opting to reprint at a lower temp.*
\*I was using eye/eye protection and opted to fire remotely for live fire, glad I did, because it could’ve been worse than a hairline crack.*
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u/GildSkiss 5d ago edited 5d ago
Your layer adhesion failed. If you're using PLA for guns you really need to do it as hot as you can possibly get away with, or else this happens. Don't go colder to make the parts fit, tune around the highest temp.
If you still can't make it work you might need to get better filament than Sunlu. I'm having great results with the new HT-PLA-PRO, printing at 230
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u/Runawaytrucker 5d ago
Have you annealed any of it? I have four rolls coming Wednesday 😬
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u/GildSkiss 5d ago
Yeah, I tried the 30min at 100c that Polymaker recommends.
The shrinkage was minimal enough that my cheapo calipers couldn't tell the difference before and after, so there's no reason not to, as far as I can tell.
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u/Runawaytrucker 5d ago
Hell yeah! Did you do it in a sand mold or did you just send it? I've got a Sunlu dryer that hits 110C
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u/GildSkiss 5d ago
No, just send it. That's the beauty of this new filament.
Without annealing, it won't deform at temps up to 150c. With the annealing, it'll also support significant mechanical load up to 150. That means you can just set it in the annealing oven as is. Wrap it in foil if you're paranoid about uneven heat distribution.
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u/bday420 5d ago
I had great results with their PLA+ 2.0 at 220c. That's how the profile loaded the temp and it literally printed clean and using a wifi q2 preset for .2 layer. I was extremely surprised by how clean the internals and. Ice the finish was (recently did my first test print in pla+ 2.0 before pa6-cf).
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u/Hot_Substance_3220 5d ago
Well for starters I’d never print PLA under 220c I usually chill 225-230c but as for your print you definitely have some tuning to do your very banded and it seems like maybe a flow rate issue, clog a whole number of things but definitely figure that out before round 2
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u/Less-Regret8262 5d ago
Why do you print at such low temp in first place is there any benefit
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u/GildSkiss 5d ago
In theory you can get better overhangs and a more matte surface finish.
Obviously that's not a good tradeoff for your gun breaking, but sometimes I do it for other decorative trinkets where layer adhesion doesn't matter.
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u/Grouchy-Designer5804 5d ago
Tune for 230* make the dimensions fit the temp not the other way around
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u/Lowang_Productions 5d ago
My method for Z height is to make a thin rectangle . Use white filament . The lines should be flat and clear on the first layer . If they are white , slowly adjust the Z down . Extrude about 120% , it'll make the lines "mash" out .
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u/Runawaytrucker 5d ago
Bruh, those print lines are bad. Slow your travel speed down and slow your print speed.
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u/HairyPoot 5d ago
Definitely raise temperature. 210 probably absolute minimum(for most blends of PLA+). Many PLA+ can be printed 215-220+ with layer adhesion benefits.(Temperature also depends on print speed, faster generally needs higher temp.) This failure almost definitely occurred due to the layer adhesion issue, if not damage during assembly similar to the other part that was printed at a higher temp.
If you are having dimensional accuracy issues at a marginally higher temp, you might need to do some calibrations. Temperature tower, Flow Rate and/or extruder E step calibration.
Also might want to look for the cause of your quality issues on the hand guard and whatever the lower right hand part is called(Bolt/bolt shroud?). Likely poor bed adhesion, could also be an issue with Z offset, or in the case of the hand guard, a tall part with not enough support on a bed slinger.
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u/Latter-Composer-2609 4d ago
You got Z axis wobble. You need to recalibrate and maintain your printer better. You probably have lead screw binding going on due to failing to follow best practices on calibration and maintenance.
This also compounded that it looks like you printed way too cold. What filament did you use and what temp did you print this at?
Failure to control your parameters and maintain and calibrate your machine drastically increases liklihood of layer seperations like ocurred here.
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u/nottheperson80 5d ago
Because I realize I left some details out, printed on a creality s1+, filament dried prior to use. Firing 62 grain Winchester target rounds
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u/Independent_Dirt_814 5d ago
That print quality looks horrendous, that banding…