Bubbles Under Brand New Heated Beds (Yes Plural)

I recently had to order a new heated bed for my TAZ 6. So far, I have ordered from Amazon three different times and they have all arrived with issues. First one arrived shattered, second and third ones arrived with bubbles under the PEI (see attached pics).

I’ve only been using PEI for a year and a half and the original bed that came with my TAZ 6 didn’t have a single bubble under the PEI for over over 6 months of use. My expectation is that a brand new bed should look like the one that originally came on it. Are my expectations set too high? Is the attached picture look like a brand new bed should?

Before anyone says contact Lulzbot - I did. Their solution was to send me PEI and have me replace it. On a six month old bed I would accept this solution, but on a brand new $160 bed, I feel it should arrive ready to go out of the box.

My Lulzbots Taz 6 is new, have used it for 2-3 prints only and I’m seeing lots of bubbles in the bed.
Will be sending support team a note with details to check what are their recommendations.

If the fulfillment is through Amazon, then they could be storing improperly.

I’d return, get a refund and order direct from Lulzbot.

I have two more coming from Amazon Friday - Hopefully one of them is good. If not, I agree I may have no other choice than to get one from Lulzbot and hope it doesn’t have the same issue.

2 more beds arrived today (#4 and #5) - both did the same thing. I took a time lapse video showing what happens: https://www.dropbox.com/s/94s2n3foiq3pkpe/magLatch_DoorSide_20180316232445.mpg?dl=0

The way the bubbles are all around the edges would make you think something is tweaking the glass, however, the washers are not tightened down that much. Is there anyway to make sure my bed isn’t tweaked? Does anyone know where I can find the torque settings on the washer screws? I looked at https://ohai.lulzbot.com/ but the most I found was “DON’T OVERTIGHTEN!”

I’m running out of ideas.

Issue solved…

The reason I bought an entire bed vs replacing the PEI sheet was because I had a chunk out of my original bed. Since I couldn’t get a quality OEM bed after 5 tries, I decided I’d try to find a solution with my old bed. After I took the old PEI off, the glass was perfect. Turns out the chunk was in the PEI only; it looked worse than it was. Yesterday I had Amazon overnight me a $22 1mm Gizmo Dorks PEI sheet with adhesive and put it on my bed. This PEI sheet is amazing - I only have one print in, but it seems far superior to the OEM PEI. http://a.co/9euijmK

Here is my first print, not a single bubble: https://www.dropbox.com/s/coh9ezzra4vhrje/handle_v1_20180317183129.mpg?dl=0

It looks like the adhesive was not baked to remove any moisture in it. So it steams out and causes gas bubbles.

That makes total sense and would explain it. Hopefully Lulzbot is reading these forums…

While it is a published part of Lulzbot’s procedure to bake the sheets and adhesive – I think they have either stopped doing it, or changed to shorter bake time, or aren’t storing them right afterwards, or something…

When I received my two-piece bed for the mini a few months ago, the same thing happened: Both beds (I ordered 2 glass/pei sheets for the modular bed) looked perfect until it heated up, then tons of tiny bubbles formed within minutes. Definitely not as bad as yours, the bubbles were smaller, but still not right. I complained and sent photos, so they sent a replacement sheets for ME to install. Ok, I ate the labor to remove and re-install, and guess what? The replacements did the exact same thing – they looked perfect until the first heat to 100c, then hundreds of bubbles immediately formed all over the sheet.

I plan on giving the GizmoDorks 1mm sheet a try when I get ready to replace again.

Lulzbot support has historically been great for me, however this issue has taken them down a couple of notches. Their responsiveness was quick, but their offered solutions were the same as yours - sending me a new PEI sheet. I couldn’t bring myself to invest so much time repairing a brand new bed I just spent $160 dollars on.

In the end though, I am glad things happened the way they did, I absolutely love my 1mm Gizmo Dorks PEI bed.

How do you like the Modular bed upgrade?

Not as much as I thought I would. I bought it so I could easily switch to bare glass for Ninjaflex, instead of using gluestick over PEI. But it turns out removing/reinstalling the 4 screws and washers (and being careful to not drop and lose the spacers) isn’t really all that convenient. So I am mostly still using gluestick instead of flipping the bed.

Another issue… The modular bed and washers are 2mm higher, yet uses the same firmware - which means the “failsafe” probing code that keeps a dirty nozzle from pushing down too far pushes 2mm further than it should. I fixed that by compiling custom firmware, but most owners won’t want to do that. Future models that have the modular bed as standard equipment will have correct firmware values here, but retrofitting an existing model means compiling custom firmware or living with over-deflection when the nozzle contact fails.

All in all, if I was making the decision today I would save my money and stick with the standard bed. It does make replacing the PEI a bit easier though, since you don’t have to mess with the heater or wiring when replacing the surface.

I’m glad I asked. I was considering the modular bed as a replacement and possible upgrade in the near future; I definitely will not go that route now. Because of all the defective beds I’ve received, I’m pretty good at swapping out the beds now. I think I’ll stick with what I have, again, that 1mm PEI is amazing.

Thanks for the detailed reply Scott, sounds like you just saved me some $$ and a big headache.

My Taz 6 also gets these bubbles, and it’s even worse when I print ABS and the bed needs to get up to 100 degrees. Unfortunately, Lulzbot doesn’t replace this unless it’s within the first 30 days of use. I could deal with the few bubbles from PLA, but now that I frequently print with ABS the bubbles are going more towards the center and “staining” the bottom of my prints.

I just purchased the modular bed and the first thing I’m going to do is heat it up to 100 to make sure the bubbles don’t appear.

Don’t try to get get bubbles under the PEI… its really hard to clear them.

The bubbles develop primarily from removal of prints when the bed is still too hot. The adhesive weakens and bubbles form between the PEI sheet and glass bed. Lulzbot recommends part removal when the bed gets to 50C. Get a flat spatula type tool to get under the object… slowly work your way around the object, it’ll eventually come off the bed. Whatever you do, try not to pry the object off the bed. Ultimately, the PEI will form bubbles and it will need to be replaced…

Anyway… there’s tons of advice on using the PEI bed. Once you get the hang of it, the PEI is a great surface for printing. No tape, hair spray or abs-juice… just the right bed temp.

Everything you say is correct, and is exactly my experience with previous PEI sheets. But something was wrong with the sheets I received recently. The brand new sheets developed bubbles as soon as heated the first time - before any printing was done! Either there was a bad batch of adhesive, or there was moisture trapped in the adhesive. It was actually fascinating to watch, the sheet looked perfect - then when heated to 100c, bubbles started forming minute-by-minute as I watched. No printing or print removal involved.

My PEI sheet bubbling got so bad after about 18 months that I finally decided to remove it. Freezer method mad it easy. Soaking the remaining adhesive layer with 90% isopropyl and scraping it off with a fresh window razor made short work of the goo (man, that stuff stinks as it degrades). The glass underneath is flat, pristine, and glossy.

Before installing a new PEI sheet, I thought it would be well worth trying to print on the glass with and without glue stick. So I wouldn’t have to drastically adjust the Z-Offset, I snipped off four triangles from the old PEI sheet to use as spacers under the bed, bringing the height nearly back up to where it would normally be with the PEI sheet on.

NinjaFlex directly to glass is great. So far, printing ABS onto glue stick on glass is hasn’t failed me (I used an enclosure). Polycarbonate is fine on glue stick for smaller parts, as well. I learned the part cooling fan on the new Aerostruder is simply too much for ABS and PC, so leave it off.

I’m actually in no hurry to put a new PEI sheet on since I use glue stick most of the time anyway. Perhaps I’ll run into something that will make me want to put the PEI sheet back on, but for now, I’m wondering if dealing with the bubbles is worth the “holy grail” of printing surfaces.

Well… I’m in the camp of “If it ain’t broke, don’t break it” :slight_smile: An enclosure should makes a world of difference when printing ABS and other warp-prone materials.

I’ll get around to building something one of these days, but for now I need the help of PEI… after the last few years, I’m pretty familiar with how picky the surface can be and deal with it.

@ScottW - yeah, that is strange… I’ve been buying PEI sheets from Amazon/Zoro and have a roll of the adhesive. I’ll say that the PEI applied by the factory is the nicest. I just wish they would go to a thicker sheet. My experience with the thicker sheet is that it spreads force of removal across a wider area of adhesive. Giving the PEI a little longer life.

What will eventually happen is that the ABS will adhere a bit too well to the glass, and when you go to remove the part, a big chunk of the glass bed will come up with the part. Then you go buy a new bed.

I strongly recommend never printing directly on glass unless you like buying new beds.

I had the same issue with the original bed and they sent a PEI sheet. But I was having more issues with the heating. Printed out a grid of 50mmx50mm squares and took 9 readings per square with my highly sophisticated thermometer gun from Harbor Freight. The temps were all over, sometimes I would get a 20C change in just one square. the whole left side of the bed was, on average, 15C cooler than the right ( at 110C).

With the new bed I get less than a 5C difference anywhere on the bed. Makes a huge difference in the first layer.

So up to your needs, of course, but I found the modular bed worth the price. Also, I kept the PEI sheet, so I have a replacement if I ever need it.

This was for a TAZ 6.

I took several hours to completely clean my heated bed and properly install a new Lulzbot brand PEI sheet. 2 prints later and I have small bubbles all over the surface. I plan to contact Lulzbot about the issue, but I’m afraid they’ll write it off as operator error on my end.

I’ve ordered the modular print bed in hopes to alleviate the issue, but I can’t help but be disappointed that I spent about 6 hours meticulously installing a new PEI sheet to wind up with bubbles almost immediately. I just wish I had seen this thread sooner.