I’ve been making 3D printed parts for years now, all functional. Drill jigs, cutting jigs, antenna parts, all sorts. For most of these years I have only printed with PLA+ which is to be honest not the best choice, however it DOES work. You just need to know it’s limitations. The below antenna is one of 5 I made and every element mount, the dipole box and the N type box are all 3D printed in PLA+. I use this antenna portable (sometimes 2, I’ve yet to put any actual RF up 2 more and 5th one a friend uses) and it works great:
However I have noticed some stress fractures in the tops of some of the element mounts. PLA+ is very rigid and a bit brittle. It also will distort in the heat of a parked car in the sun.
More recently I have got a new printer, the Bambu Lab P1S with AMS which I have actually experimented with and switched to using PETG, which I already knew is a stronger material.
Bearing in mind the above you may ask “Are 3D printed parts strong enough?”
Well this week I have come to the conclusion the answer is pretty much yes!
For one of my current antenna projects (will they ever end???) I have designed and printed some drilling jigs (nothing new there) but have decided as they will be used a few times I would turn some small brass bushes to press in so the drill doesn’t wear way any plastic and make the hole fit sloppy.
Here is one. You can see it is 60mm wide and the brass bush has a 6mm external diameter:
I wasn’t happy with that jig so decided to tweak the design and print it again. But I didn’t want to turn another brass bush so needed to get it out. It’s pressed in and wasn’t keen on coming out at all.
No problem, I’ll just break the plastic at the ‘weak’ point where it is fitted and it will fall out.
Erm, nope. I tried by hand squeezing the legs together and trying to break it like a wishbone. All I got was sore dented hands. That PETG just refused to snap on me. I do print with decent wall counts but the fill on this wasn’t excessive as ‘only’ a drill jig.
Time to resort to more forceful persuasion!
First I crushed the legs together in the drill press vice (because it’s more handy than my 6 inch vice) and I did break it at the middle point, but it still refused to let go of the brass bush.
So next I lay it across the jaws and split it sideways with a cold chisel (as that was close at hand too).
This did the job:
I must admit I was very pleasantly surprised at the length I had to go to in order to break this! When you look at the amount of material at the break below (that bush is 4mm tall) it’s really quite impressive.
So my conclusion is when asked “Are 3D printed parts strong enough?” is that yes they are if printed in the correct material and with an eye for manufacture at the design stage and with correct settings at the print stage.
PETG isn’t even the strongest material we can quite easily get and print with. But it is very readily available and as cheap as PLA/PLA+ pretty much. Some of the stronger materials like ASA need more consideration on fume handling etc so for now I am pretty pleased with the performance of PETG and only wish I had made the switch before!