I started 3D printing with PETG rather than PLA because I looked at the specifications and liked PETG. Researching materials I got interested in TPU and PolyCarbonites as well.
PETG
Printing with PETG is a little trickier than PLA. I’ve had prints that warped in PETG so I tend to run the bed fairly hot, starting at 75 C and going 85 or 90 C depending on the size (time), amount of surface on the print bed and overhang. For the most part at 85 C keeps PETG stuck to glass with hairspray quite well. I’ve found prints pop off easily the glass has cooled to about 50 C and break loose on their own at around 40 C. You really must have a heated bed.
TPU – NijaFlex
The results from this amazing material is a ‘fun’ print. The NijaFlex I used was 85 Shore hardness. Since it was green I selected ‘Flippy’ the frog as my from Thinigiverse for the ‘benchie’. I have a whole bunch of little frogs (I scaled it to 25 and 33 percent) from learning how to print with NinjaFlex.
The flexible nature seems to do best if printed slow. Very important I found is to slow down travel. I’m still not sure about retraction but it seemed with my direct feed extruder on the A8 Cura worked best with 5 to 10 mm of retraction. I think it simply slowed the process down because that is a lot of retraction but maybe it is creating enough suction to make a difference when you pull that far out. If so then maybe retracting fast would be good? Many posts recommend no retraction but that seems to be in reference bowden setups. Anyway, I still have a lot to learn but got some nice prints with from my efforts so I am confident I can figure it out if I need to.
Running low temperature and the bed heat didn’t seem important. I still used 65 C but the NijaFlex stuck quite well to the glass and hairspray.
Poly Carbonate – PC
Here is my new jewel. From what I read PC required an enclosure and very high heat. However, I ran across a 1KG roll on EBay for $14 USD and figured at that price it was worth a try.
The nozzle temperature was surprisingly low, only 230-260 C. I’ve found 225-235 seems to work well so I’m even going below the manufacturer’s recommended temperature. What seems to matter is the heat bed temperature. PC seems to warp easily, which is why an enclosure seems to be important. The manufacturer recommended a bed temperature of 100 – 110 C so after losing a couple of prints to warping and falling off I moved up to 110. For a longer print job I build at least a 5 layer raft with a brim to provide room at the bottom as well for warping in addition to the brim for more surface connection and that seemed to protect my larger prints. An enclosure would be nice but it appears I can print PC with my A8.
PETG is still a good choice for many things as the PC is very hard and not available in very many colors. I’ve seen Blue, Black, White, and Clear.
PLA
I had some samples of different colored PLA I purchased so I decided to burn some PLA one day. I quickly learned how useless small amounts of filament are. I will never buy a sampler pack again!!!
What I discovered is that PLA can be a lot of ‘fun’ and I was turning out nice looking prints so all of the color choices in PLA is a positive. I also found it warps and actually does better with some bed heat, higher than the manufacture recommended. The bed temperature is lower than PETG but I found 65-70 C seemed to help things stick better. If you got it you might as well use it.
I also found PLA warped very easily. I applied a little heat from a heat gun to soften a hole where a post was to be inserted. I didn’t use much heat at all but there was clear warping from what little I did use. Apparently even moderate heat is too much.
I really don’t know what I would use PLA to print considering all of it’s shortcomings. I must say it prints nicely but that is just skin deep.
Summary
I ran through a few of the printing experiences I’ve had to date and tried to cover why one material might be used where another wasn’t up to the task. PETG has a lot of advantages over PLA but not anywhere near the choices in colors. It is also much stringier and requires a heated bed, though I didn’t do well with PLA without bed heat. You can use a heat gun to help clean up strings which is a lot different than PLA. PETG can still be warped but it takes more heat than PLA so a quick blast of hot air turns the strings into little balls that can be removed leaving little to no evidence.
PolyCarbonate is much harder than PETG and can take higher temperatures. Running my bed at 110 warped PETG parts but the PC replacements don’t seem to be showing any signs of warping from the heat.
TPU is a lot of fun but a hardness of 98 is only bendable, I wouldn’t call it flexible. On the otherhand shore 85 (the NijaFlex) was quite flexible. ‘Flippy’ the frog jumps if you hold him just right. I’ve seen Shore 40 (rubber-band) and will be notified if it ever actually becomes available. I look forward to printing with that.
And finally PLA, which I simply don’t see as very useful. Other than ease of printing it has little going for it. I don’t think PETG prints as nicely as PLA but the difference is minor and PETG is durable where PLA is not. I am satisfied printing with PETG instead of PLA.
