Glass thickness question
Posted by WZ9V
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Glass thickness question November 20, 2016 11:33AM |
Registered: 10 years ago Posts: 293 |
I have a 200x300mm PCB style heated bed which is supported at the four corners. What thickness of glass should I use for that size bed?
I'm currently using standard window pane glass from the h/w store and I'm seeing a bit of sag in the middle when printing things that are close to the 300mm length.
I'm currently using standard window pane glass from the h/w store and I'm seeing a bit of sag in the middle when printing things that are close to the 300mm length.
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Re: Glass thickness question November 20, 2016 12:46PM |
Registered: 9 years ago Posts: 288 |
If you intend to have an inductance probe the the glass needs to be less then 4mm.Quote
WZ9V
I have a 200x300mm PCB style heated bed which is supported at the four corners. What thickness of glass should I use for that size bed?
I'm currently using standard window pane glass from the h/w store and I'm seeing a bit of sag in the middle when printing things that are close to the 300mm length.
or that is what understand from probe specs.
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Re: Glass thickness question November 20, 2016 01:31PM |
Registered: 10 years ago Posts: 293 |
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Re: Glass thickness question November 20, 2016 02:16PM |
Registered: 12 years ago Posts: 1,450 |
I have found that although 3mm glass is O.K. at 200mm by 200mm, above that things get much less good. and even 4mm is too thin at 300mm by 300mm and even using glass is marginal and aluminium becomes the choice. At your 200mm by 300mm I would prefer to use aluminium but would use 4mm glass as second best.
Mike
Mike
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Re: Glass thickness question November 20, 2016 05:17PM |
Registered: 10 years ago Posts: 293 |
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Re: Glass thickness question November 20, 2016 08:46PM |
Registered: 11 years ago Posts: 1,171 |
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Re: Glass thickness question November 20, 2016 09:34PM |
Registered: 10 years ago Posts: 293 |
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Re: Glass thickness question November 20, 2016 09:49PM |
Registered: 11 years ago Posts: 5,780 |
Quote
WZ9V
What thickness aluminum would be good?
1/4" cast aluminum tooling plate supported on a 3 point leveling system eliminates the need for glass. It is flat, easily leveled, and thermally conductive so it heats up very evenly.
Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]
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Re: Glass thickness question November 21, 2016 09:13AM |
Registered: 12 years ago Posts: 1,450 |
Going back to your original posting you say that your bed is supported at four corners.
If a flat plate has supports on all four corners then it is quite likely that opposite corners are causing the bed to adopt a saddle shape - sagging in the middle.
I would still recommend using a metal bed, but going to a three point mounting could also get the flatness to a livable level.
Mike
Quote
WZ9V
I have a 200x300mm PCB style heated bed which is supported at the four corners. What thickness of glass should I use for that size bed?
I'm currently using standard window pane glass from the h/w store and I'm seeing a bit of sag in the middle when printing things that are close to the 300mm length.
If a flat plate has supports on all four corners then it is quite likely that opposite corners are causing the bed to adopt a saddle shape - sagging in the middle.
I would still recommend using a metal bed, but going to a three point mounting could also get the flatness to a livable level.
Mike
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Re: Glass thickness question November 21, 2016 10:50PM |
Registered: 10 years ago Posts: 293 |
Yes a saddle shape is what I'm seeing along the 300mm Y axis. It's most noticeable on parts that use most of the 300mm distance. On shorter parts it is much less noticeable.
The project I'm working on (P-47 wing section) needs a flat base so that they can glue together without gaps. A saddle shape as described above would perfectly explain why I get gaps at the leading and trailing edges when joining two center section pieces together.
The project I'm working on (P-47 wing section) needs a flat base so that they can glue together without gaps. A saddle shape as described above would perfectly explain why I get gaps at the leading and trailing edges when joining two center section pieces together.
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