Nylon Causing PEI Layer to bubble?

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dchincom
Posts: 23
Joined: Sun Dec 13, 2015 2:04 pm

Nylon Causing PEI Layer to bubble?

Post by dchincom » Wed Jan 18, 2017 2:56 pm

I've noticed a trend, and I'm not sure if anyone else has observed this. But it seems every time I print with Bridge Nylon, I damage the PEI layer on my bed. It seems that the PEI will bubble. I never see this happen with ABS or HIPS. My only thought is that the Mini Bridge Nylon settings have the bed temp at 110. Is it possible that this temperature is messing up the PEI adhesive on the back?
Maybe it's because I'm removing the model off the bed before the bed completely cools down?
Do I even need the bed at the profile's 110? I'm already needing to use Purple glue to keep the Bridge Nylon model stuck to the bed while printing.

Thoughts?
Dower

Daniel
Posts: 70
Joined: Tue Nov 17, 2015 6:22 am

Re: Nylon Causing PEI Layer to bubble?

Post by Daniel » Wed Jan 18, 2017 7:22 pm

Nop, PEI sheets often bubble, if your are under warranty, contact lulzbot support they will send you a new one ;)

dchincom
Posts: 23
Joined: Sun Dec 13, 2015 2:04 pm

Re: Nylon Causing PEI Layer to bubble?

Post by dchincom » Wed Jan 18, 2017 8:03 pm

Daniel wrote:Nop, PEI sheets often bubble, if your are under warranty, contact lulzbot support they will send you a new one ;)
I understand it would happen at any time, this is the third time I've replaced my PEI sheet. It just seems interesting that I see more bubbling so far after working with Nylon than all the times I've used ABS. Maybe it's just a coincidence...

Daniel
Posts: 70
Joined: Tue Nov 17, 2015 6:22 am

Re: Nylon Causing PEI Layer to bubble?

Post by Daniel » Thu Jan 19, 2017 9:57 am

I think the solution to fix reccuring bubbling is to install a thicker PEI sheet, I have a 0.04" one from mc master carr (the stock PEI sheet is 0.01"), and it seems ok since few months.

https://www.mcmaster.com/#8685k41

dchincom
Posts: 23
Joined: Sun Dec 13, 2015 2:04 pm

Re: Nylon Causing PEI Layer to bubble?

Post by dchincom » Thu Jan 19, 2017 10:11 am

Daniel wrote:I think the solution to fix reccuring bubbling is to install a thicker PEI sheet, I have a 0.04" one from mc master carr (the stock PEI sheet is 0.01"), and it seems ok since few months.

https://www.mcmaster.com/#8685k41
That's interesting. I'll need to try that. How did you stick the PEI sheet down? It doesn't look like it has the adhesive backing, like the one's you get from here. Also, did you need to tweak the build height at all to accommodate the extra thickness?

Daniel
Posts: 70
Joined: Tue Nov 17, 2015 6:22 am

Re: Nylon Causing PEI Layer to bubble?

Post by Daniel » Thu Jan 19, 2017 12:05 pm

You have to use « 468 MP » tape, it's heat resistant :

http://www.digikey.com/products/en?keywords=3M9720-ND
https://www.amazon.ca/TapeCase-squares- ... s=3m+468mp

Btw, you can buy PEI sheets on amazon.com too
Last edited by Daniel on Thu Jan 19, 2017 12:05 pm, edited 1 time in total.

ttabbal
Posts: 298
Joined: Wed Nov 11, 2015 4:20 pm

Re: Nylon Causing PEI Layer to bubble?

Post by ttabbal » Thu Jan 19, 2017 12:05 pm

For thicker PEI that comes with adhesive, I got one here by emailing resources@cshyde.com and requesting a 40mil thick 170mm x 170mm (that's the size of the glass for a Mini). They custom cut one for me and had it out quite quickly and the price was reasonable.

There are some threads here detailing replacing the PEI. It's pretty easy. Put the bed in the freezer for about 15min, pull the PEI off. Then use adhesive remover and a razor blade to remove the adhesive. Now thoroughly clean the adhesive remover from the plate. I used windex to clean everything, then alcohol as a second pass to make sure. Don't forget to wash your hands as well, everything needs to be very clean. Then peel and stick. I went slowly from one side pressing down with a plastic putty knife as I went to try to get it as flat as possible. The added thickness helps here, it wants to be flat.

Now, when re-installing the bed the spacers on the corner washers are just a bit short. I put a #6 washer under each one to space it up a little to account for the now thicker bed. Don't force it, one user has already reported breaking the bed tightening too much. I press the bed plate down with one hand, while tightening the screw till it's snug. Just enough to hold it all in place.

Now do some tests starting with a Z-Offset of about 0.1mm. That starts things a bit high, you then need to dial it in based on filament and how much "squish" you want on the first layer. Nylon might need to be closer, PLA will stick if it manages to touch the bed. :)

mikronano
Posts: 63
Joined: Wed May 13, 2015 2:42 pm
Location: Chicago, IL

Re: Nylon Causing PEI Layer to bubble?

Post by mikronano » Thu Jan 19, 2017 3:19 pm

dchincom wrote:Do I even need the bed at the profile's 110? I'm already needing to use Purple glue to keep the Bridge Nylon model stuck to the bed while printing.
Pretty much all nylons are really strong plastics. So, when you manage to keep them stuck on the bed then you can be sure that they'll exert a much stronger pull up force at the edges and corners, when they shrink, than ABS or HIPS. Added to that the fact that taulman nylons exhibit excellent layer to layer bonding. They just don't delaminate as opposed to ABS.
But 110C is just too much. I believe you can easily work with 80C or 90C at best. It works for me. That will also help with keeping the bubbles down.
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alexmit
Posts: 19
Joined: Wed Jul 20, 2016 10:44 am

Re: Nylon Causing PEI Layer to bubble?

Post by alexmit » Thu Jan 19, 2017 4:03 pm

Daniel wrote:Nop, PEI sheets often bubble, if your are under warranty, contact lulzbot support they will send you a new one ;)
Not in my case. I was doing 4-5 prints a week (not all nylon) over a 4 month period when mine bubbled like crazy. I was told the PEI sheet is a wear and tear item that would not be replaced under warranty.

Daniel
Posts: 70
Joined: Tue Nov 17, 2015 6:22 am

Re: Nylon Causing PEI Layer to bubble?

Post by Daniel » Thu Jan 19, 2017 9:18 pm

It's the reason why I used 'often', someones don't have any trouble. I had at least 3 new pei sheets under warranty

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