PETG on a PEI printbed (Lulzbot Mini)

Help with printing with specific plastic filaments.
ScottW
Posts: 462
Joined: Thu Dec 10, 2015 1:00 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by ScottW » Mon Feb 29, 2016 6:08 pm

After some difficult removal of PETT, I was really concerned about PETG sticking "too well" to the PEI. But the PETG I have used (Esun and GizmoDorks) has been a dream, sticking great during print (75C bed) and removing very easily when cooled to 50C. I think it does help to remove it "warm" (i.e., 50C) and not let it cool all the way.

If you continue to have trouble and the Z-offset recommended by others doesn't resolve it, then either try some Esun brand *or* try some Glue Stick as a barrier between the PEI and PETG. (I like the Elmers Disappearing Purple Washable Glue Stick -- it is what I use now as a barrier for PETT, and as an adhesive surface for Taulman910.) Goes down easily, cleans off easily with a wet cloth.

kingjamie
Posts: 35
Joined: Sat Feb 06, 2016 12:00 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by kingjamie » Mon Feb 29, 2016 8:28 pm

Quick question I have seen issues with stringing on the initial layer but the second a so on layers are perfect. I'm using the purple glue with print head at 245 and bed at 80. Any idea to reduce the stringing? Note I've got the first layer slowed to 20% of 3600mm/m.

ScottW
Posts: 462
Joined: Thu Dec 10, 2015 1:00 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by ScottW » Mon Feb 29, 2016 8:37 pm

Lower temp (I use 240c) seemed to reduce stringing a bit for me, but a larger layer height seemed to make the most difference. I had way less stringing with 0.32 layers than with 0.18 layers. A cool environment helps too. But I'm not sure there is any way to completely eliminate it.

kingjamie
Posts: 35
Joined: Sat Feb 06, 2016 12:00 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by kingjamie » Mon Feb 29, 2016 8:53 pm

Thanks I'll adjust that. I've been printing with fans off but not sure how to turn them on for the first layer I had it at 75% for layer 1 but it never came on.

Thinkdifferent
Posts: 9
Joined: Mon Feb 29, 2016 8:04 am

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by Thinkdifferent » Thu Mar 03, 2016 8:08 am

A short update:
with 0.2 mm Z-offset and 50°C ist works fine - so far I could remove every object without detroying my PEI.
The only problem I have is the print quality regarding the first 2 layers: the skirt is "empty" until short before the object is going to be printed (this is a general, not a PETG problem...), and there are some lumps on the first 2 layers, which tend to be included in the printing: at these locations the print doesn't look very accurat. The remaining layers look very well!

ScottW
Posts: 462
Joined: Thu Dec 10, 2015 1:00 pm

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by ScottW » Thu Mar 03, 2016 9:35 am

Thinkdifferent wrote:A short update:
with 0.2 mm Z-offset and 50°C ist works fine - so far I could remove every object without detroying my PEI.
The only problem I have is the print quality regarding the first 2 layers: the skirt is "empty" until short before the object is going to be printed (this is a general, not a PETG problem...), and there are some lumps on the first 2 layers, which tend to be included in the printing: at these locations the print doesn't look very accurat. The remaining layers look very well!
The easiest fix for insufficient priming is to increase the skirt. If you're using Cura, go to expert settings and increase the Skirt "Line count" to 2, or increase the Skirt "minimal length". For S3D, the number of "skirt outlines" can be increased on the "Additions" tab.

Another option (which I use) is adding some code to the start script.
In Cura, look for the line that says "G1 Z2 E0 F75", and add these two lines immediately after:
G1 Z2 E5 F75
G92 E0
Or if using S3D, add these four lines at the same place:
G1 Z2 E5 F75
G1 Z2 E4.5 F600
G1 X15 Y15 Z10 F5000
G92 E0

Both of these extrude a little "blob" of filament at the left-front corner of the bed before the skirt starts. Note that the default "end" scripts retract 5mm when the print completes, so when doing multiple prints back-to-back this simply gets the filament back where it should be. The extra lines are required in S3D because it moves "down and over" when starting the print, so without the lateral move that would push the head into the "blob" it just extruded.

Thinkdifferent
Posts: 9
Joined: Mon Feb 29, 2016 8:04 am

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by Thinkdifferent » Sat Mar 05, 2016 2:51 am

Thanks a lot!
Today I will change my PEI. Maybe I will order S3D - but before spending 150 $ I have some other questions, regarding the combination LB Mini and S3D. This should better be a new post...
(copying filament profiles from CURA to S3D, auto-levelling, interrupting the auto-levelling between multiple prints...)

suntorn
Posts: 36
Joined: Sun Feb 15, 2015 1:14 am

Re: PETG on a PEI printbed (Lulzbot Mini)

Post by suntorn » Sat Mar 05, 2016 7:04 am

Thinkdifferent wrote:Hi,

I've got heavy problems with my PETG, printing on a PEI printbed (Lulzbot Mini): as I tried to pull off my print, I needed to use force. This ended in a destroyed PEI-sheet...
I use PETG from RepRapWorld (brand is REAL).
My former settings: 240° C, printbed 90° C.

As my printbed is destroyed only in the middle of the bed, I have 4 more efforts, to test other settings.
Should I use hairspray on the PEI? Or UHU glue-stick, to NOT GLUE the filament? Printing without heated bed was not successful: the object did not stick on the bed.

So - what are the best settings? Temperature and layer? Although the MINI has a self-levelling printerhead, I have the feeling, that the nozzle touches the bed - other to ABS and PLA...

I would appreciate any kind of help!!!
I am printing perfect prints using a esun petg. Using .5mm nozzle, cura settings for tglaze, and nozzlw temp of 240° (e3d v6) and pei bed temp of 50°.

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