Getting ABS to stick to PEI Bed

Help with printing with specific plastic filaments.
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TomsCables
Posts: 87
Joined: Mon Apr 14, 2014 8:45 am

Getting ABS to stick to PEI Bed

Post by TomsCables » Tue Oct 22, 2019 3:03 pm

Hey Folks,

Just wondering if anyone can give me some tips to get ABS plastic to stick to this new PEI bed surface?

I've had great success with small parts sticking 2"x2" square and rectangle shapes.

Larger shapes make bacon as I call it, the first layer does not fully adhere and becomes wavy and each subsequent extrusion just builds on to the wave.

Currently running it a 270C extruder, 100C Bed, no fan and extruding the first layers at 15mm/s with a 0.35 nozzle on 0.2 layer height.

Here is an example of a part that didn't' want to stick.
IMG_3916.JPG
On the short extrusions (the Left/Right side of the M) it does fine. It seems to do it on longer extrusions.

kcchen_00
Posts: 1721
Joined: Thu Feb 19, 2015 12:42 am

Re: Getting ABS to stick to PEI Bed

Post by kcchen_00 » Tue Oct 22, 2019 8:14 pm

The temps seem off... Try 250C and 110C. Try scoffing up the PEI with a green scotch brite pad.

TomsCables
Posts: 87
Joined: Mon Apr 14, 2014 8:45 am

Re: Getting ABS to stick to PEI Bed

Post by TomsCables » Wed Oct 23, 2019 9:19 am

I tried adding a brim to the print to help it stick but even the brim was popping off after about four extrusions. Not layers, just the forth time around the brim shape it would twist

This blue colored ABS just wanted to warp up something serious.

I have cleaned the PEI with alcohol.

I will try your suggestions and report back.

Would running a slower first layer help? Just thinking that a slower speed would give the extruded plastic time to set and might eliminate some of the stress that's causing it to warp.

kcchen_00
Posts: 1721
Joined: Thu Feb 19, 2015 12:42 am

Re: Getting ABS to stick to PEI Bed

Post by kcchen_00 » Wed Oct 23, 2019 11:01 pm

Make sure the print fans are off when printing ABS to help with adhesion.

If your slicer allows for variable cooling, I like to set the fan to 8% after the print has reached 3mm (10 layers at .3 layer height). Also drop the bed temp to 100C or 90C after the print reaches 6mm... the base should have solidified enough to resist warping.

TomsCables
Posts: 87
Joined: Mon Apr 14, 2014 8:45 am

Re: Getting ABS to stick to PEI Bed

Post by TomsCables » Fri Oct 25, 2019 12:16 pm

Ok, we made a little progress.
I couldn't find a scotch brite pad but I did have some steel wool handy so I lightly scrubbed the bed with that.
Wiped it down with 90% isopropyl alcohol again. Set the temp to 250 and the bed to 110 and this time we got wrinkles not bacon.

I have attached a few pics here. The black plastic is the wrinkles. The white plastic is this same issue I have been having with it "making Bacon" This was with white ABS back on the old PET (Green Bed) with enough abs glue added to it to choke a horse and I was still having this issue then. Its got to be a setting that I have set wrong. This issue shows up on long extrusions on the first layer.
IMG_3926.JPG
Looking from the top
IMG_3928.JPG
This is the part flipped over.
IMG_3309.JPG

kcchen_00
Posts: 1721
Joined: Thu Feb 19, 2015 12:42 am

Re: Getting ABS to stick to PEI Bed

Post by kcchen_00 » Fri Oct 25, 2019 7:49 pm

Not sure what's gong on there... try lowering the extrusion temp by 5C.

TomsCables
Posts: 87
Joined: Mon Apr 14, 2014 8:45 am

Re: Getting ABS to stick to PEI Bed

Post by TomsCables » Mon Oct 28, 2019 11:41 am

Little update here.

I set the extuder to 240 and the bed to 110C and I still had the wrinkles. Oh and I adjusted the layer height from 0.28 to 0.2. I have a .35 and a .3 nozzle I couldn't remember which one I had in the machine.

I went back and upped the initial extrusion layer From 100% to 110% and this helped it stick.

Now I was still seeing the wrinkles but it was sticking to the bed and not lifting off in the wrinkles.
I noticed the leading edge of the extrusions didn't look smooth, on further examination you could see plastic squirting out on each of the waves almost like its over extruding in that area. What you are seeing in the picture is the extruder just made a pass and there is extra plastic outside of the extruder path that will be under the next extrusion. This might be whats making the wavy initial surface.
IMG_3932.JPG

Anyone seen this behavior?

JoeBowler300
Posts: 119
Joined: Thu Apr 28, 2016 12:20 am

Re: Getting ABS to stick to PEI Bed

Post by JoeBowler300 » Mon Oct 28, 2019 8:19 pm

Yes I’ve seen that before, almost like the bed is too hot in certain places, not an even heated bed. The following layers filled in and the print came out looking good. Seems especially true when printing with a small nozzle and large flat area. May be nothing to worry about, may be chasing a red herring.

kcchen_00
Posts: 1721
Joined: Thu Feb 19, 2015 12:42 am

Re: Getting ABS to stick to PEI Bed

Post by kcchen_00 » Tue Oct 29, 2019 8:31 pm

Hmm... probably a good idea to start checking that everything is tight on the printer. Check any printed parts for cracks or wear. Clean the rails, and check the belts.

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