- June 11, 2017 at 10:56 am #35617
I’ve printed all of the New parts about 3 months ago. I assembled the frame and never got around to wiring so the frame has just been sitting. I find time to set it up and find stress cracks in most of the parts. 3 different brands of PLA. Has anyone had an issue with this and/or have a suggestion? I really don’t want to print them again just to have them crack again. I do live in southern Arizona where it is really dry. I’ve attached files.
Any help is appreciated. I’ve thought of trying printing the parts in PETG.
Attachments:June 11, 2017 at 6:14 pm #35659
Dui, ni shuo de duiParticipant
Wow, that’s bad luck…
Never had such an issue, I think it might very well be weather related. Guess PLA doesn’t suits all parts of the world, I never had that kind of problems here.
I think you have no choice but to switch to another material, ABS, nylon or PETG, just choose the most rigid you canJune 11, 2017 at 9:24 pm #35675
A very interesting problem … Unusual is that structural cracks pass through the filament layers as if they were tensile stresses. Can not it be a problem in too much tightening screw connections? An alternative solution to the problem would probably be to use a more supple material, just beware of a larger shrinkage of ABS – I have proven to print these parts with a scale coefficient 1.063
Please excuse my English terminology – Engineering is not the focus of my profession, I miss professional vocabularyJune 12, 2017 at 6:40 am #35690
I’ve had it happen to a few, but in my case it’s been overtightening that caused it. I’m in Idaho where it’s really dry for part of the year and pretty cold for part..June 12, 2017 at 7:23 am #35695
All of them look like overtightening except the roller mount, still could be over tight but it is not cracking from the screw hole and it is flat on flat. I can’t imagine how such large cracks happen on that plane of a 3d printed part. Once the part is printed I can’t imagine anything other than direct sun effecting it so much. It can handle hot cold and humid pretty well as far as I know. My friend had a 3D printed part (pretty sure it was PLA) glued on the outside of his car in San Diego, it was still there when I left. It made it through the heat and the rain.June 12, 2017 at 8:24 pm #35767
Should all of the big bolts go into the holes smooth or should it feel like its threading itself into the plastic. All of my parts felt really tight during assembly. Maybe my printer isn’t printing to scale and all my parts are just a little too small. I might try to print one or two small pieces at like .5 or 1% bigger and see how the bolts fit. Thanks for the comments and info.June 13, 2017 at 6:27 pm #35873
Dui, ni shuo de duiParticipantShould all of the big bolts go into the holes smooth or should it feel like its threading itself into the plastic. All of my parts felt really tight during assembly. Maybe my printer isn’t printing to scale and all my parts are just a little too small. I might try to print one or two small pieces at like .5 or 1% bigger and see how the bolts fit. Thanks for the comments and info.
Yeah, they feel like they thread themselves. At least on mine.June 20, 2017 at 2:29 pm #36399
You could try drilling them out slightly (if you re-print) to avoid any extra stress internally on the holes that might lead to failure. I am also in Arizona (Phoenix – 118f outside currently) and normally the ambient temps in my shop (not cooled when I’m not in it) and ultra low humidity do not adversely affect my printed parts.
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