Xjyuk

We've been doing some printing with PETG filament on Ender 3 Pro printer and the result were awful:

Here are settings we used:

• Extruder: 240 °C


• Bed: ~70 °C (± 10 °C)


• Speed: 80 mm/sec

There are a few types of problems that we had:

1. 
   Initially filament did not stick to the bed - those 3 items in the middle of the picture are example of this issue. This got fixed by increasing temperature of bed to 80 °C.


2. 
   At some point a piece would get dis-attached from the bed and would move around together with the extruder around - two prints in the upper right corner of the picture were cancelled for this reason.


3. 
   Models are very rough, like a cheaply made snowball - that tiny model in the upper left is suppose to be a cattle-bell. Could you tell?

Additional info

Filament that we used indicated

• extruder temperature 230-240 °C


• printing speed 40-90 mm/sec


• no info about bed temperature

Question(s):

• What are some optimal, tried and tested options for printing PETG? _{(Temperatures, speed, etc)}


• What are some caveats/difficulties of working with PETG to look out for? _{(For example, I've read that PETG likes slower speeds. Is that true?)}


• Is it possible that the model of 3D printer does not work well with this type of filament? _{(I don't have much experience printing so I can't know)}

Slow down!

80 mm/s is much too fast for PETG. Try 45 or 50 mm/s instead, even for infill, supports, and other less-visible areas.

None of your prints look like they are sticking well to the bed. You didn't specify the bed material. For many bed types, you might have success with Aqua Net hair spray.

Like any material, if it isn't solidly sticking to the bed, the print won't be good.

This probably is not related to your problem, but you may need to reduce the drive gear pressure or "pinch" of the filament. PETG seems to be softer than PLA or ABS, and I've had problems where it was rolled out like pie crust by the filament feed gear to the point where it would not feed. Reducing pressure, reducing retraction, and increasing the minimum extrusion between retractions helped.

The Ender 3 can print PETG just fine - even better results than with PLA in my experience. But you do need the right settings. 230-240 °C is too low, especially at the extremely high speed you're trying - you're going to get serious under extrusion and likely stringing.

My PETG settings are 80°C bed, 250°C hotend, and normal 30/60 speeds (probably could do 60 everywhere if you're ok with lower surface quality), and lowering fan speed to 40% or lower. Full speed fan will prevent bonding, and is not needed to avoid warping like it is with PLA.