Problems with eSUN PETG material

[nssorensen 2]

I  have problems when printing with PETG material (I only tried material from eSUN)

What happens is that occasionally the printer leaves "holes" in my print (i.e it doesn't dispense material)

I'm not sure what can cause this (picture attached)

In this particular case:

1) The bed was leveled prior to the print

2) The bed was cleaned prior to the print

3) The eSUN filament is unpacked a couple of days ago (i.e new)

4) Settings similar to Ultimakers CPE material.

 

Anyone has any suggestions?

 

Thanks,

 

[riotguards 0]

What temp are you setting your nozzle at? I've got the same material red PETG and i've found it works but its very fussy.

 

My settings are 235 nozzle, 60 for bed and i use hairspray for the glass bed for adhesion, also when you print do you hear a ticking sound from your feeds? maybe a tug on your filament line?

[rien1959 1]

Whit PETG you need very slow printing speeds. It is heating up real slow, so try with a low speed and if that works, slowly turn up the speed. A temperature between 215 and 235 C and bed temp of 60 C is a good choice. Try a starting speed of 20 mm/s. If that doesn't work then you have to clean the nozzle and try again. When you did find the right speed, you will see that the print will start to shine.

[nssorensen 2]

I'm using a noozle temperature of 250 and a plate temperature of 85 (eSUN recommend this temperature) and I read somewhere that PETG needs a high bed temperature.

I do use glue on the bed but I did not change the speed but used the "default" for CPE material in Cura 4.0.

Will try a lower speed.

 

[riotguards 0]

I've been using hairspray and found it works really well at coverage, not sure about glue but it might start peeling after baking on the bed for awhile

 

I would also recommend trying a lower temp as PETG doesn't need an a crazy amount more than PLA to start coming out (like i've found mine to come out around 180 ish but its instantly solidifies after leaving the nozzle)

 

Take my advice with a pinch of salt as I've not been in the game for long, just giving my two cent.

 

Edited April 14, 2019 by riotguards

[AndersK 59]

I found reducing flow rate for initial layer helps a lot. PETG is sticky and like to form blobs on the extruder which can pull the material off the plate sometimes. Your photo look like you might suffer from that.

I'm setting flow rate to 80% on initial layer. Roughly same temp as you are and bed at 70°C, below that a bit of warping occurs.

[geert_2 557]

For PET from the brand ICE, I usually print between 215°C and 225°C, slow at 25...30mm/s, and with a bed temperature of 80...90°C. No fan if the model allows it.

 

If I need to use a fan for overhangs, then a higher nozzle temp works better. If I need a fan, then I need to use glue to prevent warping, otherwise I print on bare glass. Most of the time I use the "salt method" (=wiping the glass with salt water, and let that dry into an almost invisible mist of salt stuck to the glass), which slightly reduces bonding for PET, but it makes it much easier to remove the models afterwards, with less risk of chipping the glass. (While for PLA, the salt method increases bonding.)

 

PET goo accumulating around the nozzle, and then sagging and leaving brown blobs on the print, is something I also see. The effect lessens when printing slower and cooler.

 

[nssorensen 2]

Thanks everyone for your suggestions.

I ended up reducing the print speed down 20 mm/s and that did help.

As geert_2 pointed out - I also did notice a lot of goo's accumulating so I ended up cleaning the nozzle on a regular basis during the print.

I guess the next thing to try is a lower print temperature.