PETG vs PLA

[RAGII]

As I wait for my Prusa printer to arrive I am looking at getting some more filament to play with. I currently have a few rolls of PLA (white and translucent green) and am looking at getting a couple more. I purchased a gift card from MakerGeeks when they had the 25% off sale on them. They now have the 30% off after Christmas sale going on. With this combination I can now get 2 rolls from their Grab Bag program for a total investment of under $19.00.

I was thinking of getting some PETG thinking it will be stronger/more durable than PLA. After doing some reading on this, it appears that PETG may be less impact resistant than PLA, but stronger, more heat resistant, and more flexible. The combination of these does not make sense to me.

I was considering printing some small 2" quad frames, firewalls, and MPCNC mounting fixtures to start with.

Any insights on PLA vs PETG?

Thanks

 

[jhitesma]

I love PETG. It does take higher temps to work well, it can be printed with a teflon lined hot end - but you have to be careful because you'll be running temps right at the limit and risk melting the PTFE liner. I'd suggest having some replacement PTFE on hand just in case.

PETG tends to string more than other filaments, more retraction and faster retraction usually help with this and I've got it printing with almost no stringing that way.

It's stronger than PLA in that it will flex and deform instead of shatter, it's also definitely more heat resistant. Same parts printed in PLA and PETG left in my truck will deform under their own weight in PLA but in PETG will hold up.

The downside of PETG is that it's not as stiff so for some structural type of parts where it's extra strength would be nice - it's not always suitable.

TPU is kind of the same only to a higher degree...it's really tough and hard to break...but...it's very soft. So it will deform and pop right back. Great for things like camera pods and bumpers...but useless as something structural.

Nylon is also softer and more flexible - not as bad as TPU but more than PETG...however it's stronger than either.

I've heard that PETG isn't supposed to be as good at impact resistance...but in my experience it's better than PLA.

I've had better luck with makergeeks PETG than their PLA overall. Their PETG performs like any other PETG I've tried. Their PLA however needs higher temps than other PLA's and doesn't like all metal hot ends as much. Not sure what they do different with their PLA but it's definitely a bit different than others.

I actually use PLA for my 2" quad frame because it's lighter than PETG. It's not as strong - but on something that small there's so little mass that there isn't much damage in crashes. I've yet to break an arm or anything major on a PLA 2" quad. The only thing I've broken is a FC mounting post or two - even in hard crashes that bent motor shafts. Also the extra stiffness of PLA appeals to me on a 2" quad frame, I could try doing mine in PETG...but I worry it would be extra weight and less stiffness in exchange for more strength - that isn't really needed.