Paul Lang

This is my general development blog. Random 3D printing, networking, game design, AI, and basically any other random stuff you can think of.

Adventures with PETG

I'm a long time user of PLA. It's decently strong and rigid, easy to print, and easy to find. I currently don't plan on using anything styrene based, as their very toxic for us and the environment. I do sleep next to my printer so that's a factor too for me. These include HIPS, ABS, and ASA.

Welcome PETG to the table. It's closer to Nylons in it's strength. PETG is also more flexible then PLA and ABS are. It has a much higher glass transition temperature (Tg) then PLA, so it shouldn't melt in your car. It loves to stick to everything so beware! It's known to take entire chunks out of glass!

Personal Experience with PETG can be found below.

Atomic Filament PETG Filament

What you should know about PETG

  • It's more flexible than PLA/ABS
  • Closer to Nylon in strength
  • Close to PLA in printability
  • Sticks really well to things, sometimes too much
  • May require temperatures that require an all-metal-hotend
  • It likes to stick to the nozzle and doesn't like to bridge

How to Print PETG

Printing PETG requires more finesse then PLA does.
I highly recommend that you print several test objects and play with getting the correct settings.
Some things that you should know about printing PETG:

  • Use a low retraction value
  • Slow down the speeds, especially on the first layer
  • It likes to be printed further from the bed then PLA and others
  • Use a cooling fan
Settings I Use
Setting Value
Nozzle Temperature 240 C
Bed Temperature 40 C
Retraction Distance 1.5 mm
Coasting/Wiping Off
Default Speed 35 mm/s
All Other Speeds 50 %
First Layer Hieght 130 %

My Experience

I ordered an all metal thermal throat and nozzle from Microswiss, allowing me to go over 240C - the temperature at which PTFE found in normal extruders starts to degrade.

I ordered some Gun Metal Grey PRO PETG from Atomicfilaments for 30$/kg. It arrived and then waited in a box for a few days - dying to be used for it's first project. Eventually I had something to print with it. I loaded the filament into the nozzle and started out with the classic benchy. The first thing I ran into was adhesion issues. After fiddling with the leveling and temperature settings, I finally got it to stick. The first layer went great. After that came the soul crushing click click click of the extruder skipping steps.

A Sheared Nozzle

I tried to remedy this first by upping the stepper motor current. Next I tried pushing it by hand.... and it wouldn't budge. This isn't good, it means that the actual extruder has nothing to do with this issue, and the problem is some form of clog. I removed the filament and reinserted it, making sure to manually push a bunch of filament through. With no sign of a blockage I started another benchy. Going great aaaaaand click click click.

This is the point where you start going mad. I tried different temperatures, 245C, 240C, 230C, 250C, 260C. I tried the atomic method to remove blockages. Nothing helped. As a last resort I took the nozzle out of the hotend, and got out my pliers and butane torch. I did my best to burnout any gunk in the filament. I put it all back together, when more disaster struck - the nozzle sheared straight off.

Microswiss has been great to me, they often respond to my emails in 15 minutes. I messaged Microswiss about the incident, even though I believe it was my fault. I didn't ask for a replacement, but they sent me one anyway. I also asked about how to bed the throat out of the heat block as it was jammed with what was left of the nozzle. They recommended that I use two M6 nuts and jam them together to get the throat out, which worked out great!

I had a discussion with the guys at Atomic Filament, and they recommended after reinstalling the new nozzle into the heatblock, making sure the heat throat went further into the MK8 extruder. This allowed it to dump more of it's heat into the metal extruder (and then the heat sink). Luckily this worked!

Since discovering this PETG is no longer an issue, I've printed many things included PUBG Helmets and Pans without any issues. Temperature is the biggest thing that I have to change, most other settings are near PLA for me.