Anyone Tried a Removable PEI Bed?

A forum dedicated to the stock LulzBot TAZ 3D Printer
idiot
Posts: 122
Joined: Thu Jul 02, 2015 7:53 am

Re: Anyone Tried a Removable PEI Bed?

Post by idiot » Tue Apr 19, 2016 2:22 pm

moejt wrote:Interesting, this stuff is supposed to be heat resistant and it's glass transition is way higher than anything it gets close to. I'm shocked to hear it warps.

So basically the community started with Ultum 2300 (30 percent fiber glass infill) and got cheap and moved to. Small layers on glass.

Am I seriously the only one dealing with bubbling? A typical build plate is $50. And they all tend to have weak points. I'd gladly spend $100 on a far superior build plate.
No, my PEI has bubbles all over and the glass itself is bowed (.1mm sag in the very middle which gets as low as .18mm on the left hand side of the bed). I now print everything at the front of the bed which is the only properly flat and unbubbled section I have. Luckily everything I've been working on the last few months has been pretty small.

It's something I've been meaning to contact Lulzbot about for months but I guess it's not something that's covered by warranty? The bubbling in particular which was probably caused by me.

moejt
Posts: 68
Joined: Wed Sep 09, 2015 11:46 am

Re: Anyone Tried a Removable PEI Bed?

Post by moejt » Wed Apr 20, 2016 11:58 am

The bubbling is covered by warranty. They will get you taken care of.

I've already had mine really replaced. I could probably do it again but to what point? I'm looking for a better more permanent solution and I'm willing to pay for it.

It's a choice.

kcchen_00
Posts: 1701
Joined: Thu Feb 19, 2015 12:42 am

Re: Anyone Tried a Removable PEI Bed?

Post by kcchen_00 » Wed Apr 20, 2016 4:59 pm

It's covered the first and second time... possibly a third, but eventually they cut you off. :) Citing normal wear. I guess they figure you should have learned after the second time to take care of the PEI... Or you shouldn't be going through that many beds in a year.

billyd
Posts: 234
Joined: Thu Mar 12, 2015 11:06 pm

Re: Anyone Tried a Removable PEI Bed?

Post by billyd » Thu Apr 21, 2016 11:41 am

You can add a sheet of PEI to this bed using typical 3m tape that Lulzbot uses:

http://www.thingiverse.com/thing:1021403

moejt
Posts: 68
Joined: Wed Sep 09, 2015 11:46 am

Re: Anyone Tried a Removable PEI Bed?

Post by moejt » Wed May 18, 2016 11:36 am

Necro posting my own thread.

I have been contacting vendors. The best I have been able to find is Ultem 2300 12"x12"x0.25" for $109. The price is fine with me, however I have found that nothing will come close to the flatness required. Which means that a method to flatten it during print/use is required. I hate the idea of adhesive as so many of us deal with bubbling.

So now I acknowledge and agree with what everyone else and Piercet have been saying (I should learn not to question the guy).

I've been brain storming magnets.. But this would require attaching them to the bottom of the PEI sheet which would defeat the purpose of avoiding adhesive.

I'm now starting to believe that Piercets vacuum idea is the best route. I am eating my words, lol.

Time to find someone with a CNC machine to create channels in an aluminum plate for me. 1/4" PEI probably wouldnt be necessary at this point, something lik e1/8" would be more than enough.

kcchen_00
Posts: 1701
Joined: Thu Feb 19, 2015 12:42 am

Re: Anyone Tried a Removable PEI Bed?

Post by kcchen_00 » Thu May 19, 2016 12:02 am

How about two sheets of 2-3mm PEI back to back? Bow side being the "back"...

moejt
Posts: 68
Joined: Wed Sep 09, 2015 11:46 am

Re: Anyone Tried a Removable PEI Bed?

Post by moejt » Thu May 19, 2016 9:23 am

At that point wouldn't it just be better to do a 3mm sheet on glass? 2 sheets back to back would still require adhesive and if they are both bowed opposite of each other, you'd be dealing with twice as much internal static stress compared to 1 sheet on glass.

I guess my objective is 2 fold. A removable bed would be nice. But more importantly I want to get rid of adhesive so as to eliminate issues with bubbling (all while maintaining a flat build surface).

My PEI bubbles and pulls off the glass during a print. The ABS prints create enough tension that it literally will lift the PEI. The prints turn out great, the stick factor is great, but my PEI bed can't handle the stresses. The weak link isn't the stick between the PEI and the ABS but instead is in between the PEI and the glass. I don't believe all bubbling issues are caused by user errors. I follow proper part removal instructions. But as I said, I notice the prints doing it mid print before I ever get a chance to damage the PEI by removing the part. I think it's just an inherent design flaw.

Im still under warranty and could maybe get another replacement. But at this point I feel like it's just sticking a bandaid on the issue.

With that said. A thicker piece of PEI taped/glued onto the glass may be enough to resolve the issues with bubbling. Maybe it's as simple as a thicker piece won't flex as much and thus won't pull up from the glass during printing.

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

Re: Anyone Tried a Removable PEI Bed?

Post by ttabbal » Thu May 19, 2016 9:35 am

I kind of liked the idea of laminating PEI resin directly onto an aluminum plate.

As for magnets having adhesive too, true, but you could just pull it off and replace it easily. I suspect it would be unlikely to have more than one let go at a time, so it shouldn't effect the in-progress print much. I do like the vacuum idea though, it's a bit over-engineered, but that's what we do around here, isn't it? I know, do both! :D

kcchen_00
Posts: 1701
Joined: Thu Feb 19, 2015 12:42 am

Re: Anyone Tried a Removable PEI Bed?

Post by kcchen_00 » Thu May 19, 2016 11:33 pm

moejt wrote:At that point wouldn't it just be better to do a 3mm sheet on glass? 2 sheets back to back would still require adhesive and if they are both bowed opposite of each other, you'd be dealing with twice as much internal static stress compared to 1 sheet on glass.

Well... my understanding is that thicker sheets of PEI bow when heated. So if you can "cancel" out the bowing, then the PEI can be clipped to the glass bed with out adhesive.

I was originally thinking about epoxying the PEI to a CF sheet. But the CF would reduce the effectiveness of the silicone heater.

The bubbling I think is inevitable... LB is starting to admit that as well. I went through 3 beds before my warranty. The third, they didn't want to replace citing normal wear. I tried different removable plates, but ended up going back to PEI. Currently trying a little thicker PEI sheet with 3M 467MP adhesive. I'm hoping the thinner adhesive will be easier to remove when it bubbles. Overall its holding up pretty well.

moejt
Posts: 68
Joined: Wed Sep 09, 2015 11:46 am

Re: Anyone Tried a Removable PEI Bed?

Post by moejt » Fri May 20, 2016 1:59 am

Exactly my point kcchen. I've gone through 2 sheets and agree that the bubbling is inevitable. I've also tried other build plates and none of them are as good as the PEI.

I'm looking for the ultimate solution. I'm currently looking into getting a Vaccuum plate similar to what piercet described machined. It's between the vacuum and Magnets. But honestly I think the Magnets would be a more expensive and less versatile route.

Looking through McMaster, I'm finding 303 aluminum plates with a thickness of 3-4 mm. They seem to be the most reasonably priced option. . I'm not overly familiar with aluminum. Will a sheet this thick flex? Obviously we wouldn't be wanting flex.

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