I have watched most of the YouTube 3D printer “top guns” in regards to the best filament for my needs. I have an Ender 3 v2 so I can only print PLA, TPU (which I don’t need now) or PETG with out modifying it. The one thing the video heads have in common is that they are all different. Everyone seems to have a different opinion of these filaments
Some say PLA is the strongest but has poor outdoor and heat properties, PLA+ is not as strong but more flexible and some “may” have better heat resistance.
PETG is stated to have the best of both PLA and ABS properties, more flexible then PLA but has the outdoor properties closer to ABS but according to one guru it will shatter on impact. Is it stiff enough and durable for practical outdoor parts or will it bend to easily.
CNC Kitchen has done a lot of testing but I get mixed messages even from him. Any suggestions.
The reason why there is no clear answer is there is no clear answer.
I know that sounds stupid but it remains true. It is like comparing wood and glass. Glass is very strong but it does not tolerate impacts. Wood is also very strong but in a very different way it’s flexibility gives strength.
Pla is ridged and tough it will not bend easily and tends to break shortly after it flexes. PetG is flexible it will bend before it breaks.
This is similar to carbon fiber in resins compared to Kevlar in resin. CF will not bend and will fragment as it fails. Kevlar will bend and fuzz but takes a huge force to separate.
It really depends on what you are doing. A hammer would be better in PetG or nylon these resist shattering. A gear maybe better in pla as it will not bend and cause the gear to jump teeth.
Neither is best they are just different.
A rubber tire is stupid strong. Go beat a hammer on a tire, it will be unchanged after 100s of impacts. You will give up before it does. Beat a chunk of steel, it will dent and change.
We still don’t build bridges from rubber. Rubber is perfect for a tire Steel for a bridge. Neither is better or worse. It all comes to the application.
I have some items that will be outdoors so My understanding is that PETG is much better for this.
One other question. I have seen on You Tube that PETG has much better layer adhesion (others say no) so it should be stronger then PLA but isn’t BUT other “talking heads” say it will shatter under some conditions which seems strange since it will bend before it breaks. Very confusing.
PLA needs very specific conditions to break down. There are loads of people who have tried to compost PLA or set it in gardens burried it. It simply takes many many years to decompose. I have my first print on my deck for years now it is fine. The PL glue holding it not so much. It seems more dependent on the fillers.
This is a good video that demonstrates that ‘strength’ is not so simple. Every material has different properties and the usage defines what material is best.
So it degrades in 10 to 50 years instead of 10,000 years. Still not bad.
My main concern is if I printed some parts in PETG how much abuse can it take before it is ruined. PLA is stiffer and PETG bends before it will break, is suppose to have better layer adhesion but can it take an impact. Some say no but since it is suppose to be more flexible and bend before cracking you would think it could take some impact abuse.
My experience with Petg is it is fairly flexible and will take banging around well. I also like ASA and nylon they both do well with sharp impacts that would break pla. I never found PETg to shatter it kinds pulls? hmmm not finding the right words, peels maybe. It kinda separates.