OK to use standard glass bed?

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tommymc
Posts: 3
Joined: Sat Mar 07, 2020 12:40 am

OK to use standard glass bed?

Postby tommymc » Sat Mar 07, 2020 1:08 am

I have been ramping up 3D printing projects with my N2.

I had a lot of trouble with a large ABS print (12'' x 12") where corners would warp up off the stock N2 Buildtak bed.
After trying hair spray, kapton, etc. I finally found the best solution that would hold down the corners - I use Elmer's extra strength glue stick which works very well, and washes off with just water. The problem is it works too well, and after a few prints I broke my bed plate trying to remove the part ($$).

Since it was on the weekend and I was due to my model at a trade show on that Monday(!), I panicked and went to Michael's to have a couple of picture frame glass pieces cut as an ad-hoc build plate. What I found is that the standard glass plate with glue directly on it seemed to work just as well as the stock N2 plate with Buildtak that I broke.

Also, an advantage I discovered was that when the regular glass cooled, it contracted and with a lot of popping and cracking noises, and the part was easily removed because the bond was broken by the contracting glass. (I calibrated the head with plate heated to my target temp.)

So my question- is it OK to use this standard glass as a bed or is there something I should be aware of short of impending disaster or glass shattering? I don't see how the more expensive temperature-stable bed glass matters with a heated bed while printing? Has anyone else had similar experiences?

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Vicky@Raise3D
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Joined: Fri Mar 25, 2016 3:54 am

Re: OK to use standard glass bed?

Postby Vicky@Raise3D » Mon Mar 09, 2020 11:15 pm

I would suggest at least use a glass which can stand high temperature up to the highest temperature you will use for heated bed and also we are using borosilicate glass in case it gets damaged, it won't be broken into thousands of too tiny pieces which will be hard to clean out.

tja
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Joined: Mon Oct 17, 2016 10:24 pm
Location: Essex, UK

Re: OK to use standard glass bed?

Postby tja » Thu Mar 12, 2020 12:36 pm

Cheap float glass may not be as flat and certainly won't be as strong as the glass that came with your printer. Pyrex (borosilicate) glass was developed to withstand large thermal shocks, something that ordinary glass is notoriously bad at. Considering the rapid and unven heating & cooling cycles within a 3D printer, borosilicate glass is a wise choice for printer manufaturers. However, there are many people printing with ordinary glass/mirror glass and getting perfectly good results. Just be aware of the obvious safety risks and act accordingly.

Of course, it doesn't have to be glass. Prusa and others have used a flexible steel plate for a while and Wham Bam now have a similar offering. I have just received my order from them for my N1 printer so I know that they have a range of sizes, including a size to fit your N2. I haven't tried it yet, but I'm looking forward to not having to use a chisel to get my PETG parts off the Buildtak ;)

Do your parts really have to be ABS? I print engineering parts mostly and my favourite material is PETG. Stringing can be an issue at times, but is usually easily resolved. With half the shrinkage of ABS I very rarely get warping. Similarly PLA is a useful material for some of the engineering models I design. I used to be a bit snobbish about PLA, thinking it was just for toys, but I'm past that phase now.

Are you controlling all the temperature variables of your printer? I have just put a cheap ebay thermometer inside my printer to monitor the internal air temp. I always let my printer warm up for an hour or so before I start printing, but recently decided that I should be moniotoring/controlling this variable as it's just as important as the heater bed temp.

tommymc
Posts: 3
Joined: Sat Mar 07, 2020 12:40 am

Re: OK to use standard glass bed?

Postby tommymc » Thu Apr 30, 2020 11:43 am

Thanks for the insight.

I have had to use ABS to print large enclosures that I weld together with solvent. I haven't found anything that will glue PLA, and had mixed results using crazy glue with PETG (and those strings...)

Good idea about warming up the printer way ahead of time. Maybe that even explains why I get the most warping near the bed. Thanks!!


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