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PETG first layer advice  

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dandychookies
(@dandychookies)
New Member
PETG first layer advice

Hi everyone,

Well I've had my printer assembled for about 2 days now, and after a few test prints with PLA, I wanted to do a run of parts incase I break something one day.  Call me paranoid if you have to but Australia is a long way from the Czech Republic!

I printed a test object in PETG and played with the live Z till it seemed to be doing pretty well.  Then I coated the plate in glue stick, and started on a full tray of parts.  I watched the first layer carefully, and it was really mixed.  Some parts went down perfectly, sometimes it struggled, particularly with circular outlines of the holes.  Some PETG lifted up and got stuck on the nozzle so I paused the print, wiped the nozzle with a rag and resumed.

Once I got going everything worked OK, the parts seem like they should be functional, and for the most part are quite pretty.  I was just looking for some advice on the first layer.

 

Here you can see some of the centers of the R4's are missing:

 

This inconsistent layer has me quite confused.. it's perfect at each end, but sketchy in the middle?  Is there a way to improve on this?

 

After a couple of layers everything looked fine, One part (up the back, just to the right of the extruder)  I think it's the extruder body back plate, there is a hole in the first layer there around the R4.. it did manage to continue and recover from that.

 

All in all though, it made it though a fairly mammoth 25 hr print run with no real issues.. I'm pretty impressed.  Extremely impressed.

Thanks for any thoughts on this

Postato : 23/07/2019 10:00 am
Neophyl
(@neophyl)
Illustrious Member
RE: PETG first layer advice

You need to be a bit closer to the bed to close up those gaps in the first layer.  Have a look for the Live Z adjust thread on here and do it for your  petg (different z value to pla usually).  

Postato : 23/07/2019 12:08 pm
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(@)
Illustrious Member
RE: PETG first layer advice

PETG is fickle. Windex sprayed down and spread evenly, then left to dry is one of the favored release agents. Much better than glustik, which often prevents adhesion. Some PETG  I've printed even works best on a bare clean bed. Other PETG sticks like superglue.

Wash the glustik off and try the Windex approach.

And, I agree with Neo your live z is a bit high. You might want to check if you are also using the 7x7 mesh method.

Questo post è stato modificato 5 years fa 2 tempo da --
Postato : 24/07/2019 12:46 am
dandychookies
(@dandychookies)
New Member
Topic starter answered:
RE: PETG first layer advice

Thanks for the advice guys.  I feel like its at least partly due to the glue stick.  I was at the shops today and picked up some windex, so I'll give that a go.

Given I'm such a beginner I'm too concerned about crashing the nozzle into the bed, but I'll try tweaking down the z height a bit too.

Thanks again!

Postato : 24/07/2019 2:52 am
Peter M
(@peter-m)
Noble Member
RE: PETG first layer advice

I could also not get petg stick to the bed, glue stick did not help.

A clean bed with nothing on worked best.

Also use the petg prusa setting here the temperture hotter, and printed better.

Postato : 24/07/2019 4:04 am
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