Thick Sheet Thickness?
April 26, 2011 10:10AM
I am new to the forum though have been building my Prusa on and off for the last few weeks and buying the parts as and when I can.
But I am now stuck on a question I can't seem to find an answer on:

For the thick sheet is there a limit to the thickness of the material (within reason) that you can use? I was about to set off on the route of cutting some MDF but a friend, with a machine shop, has offered to make me the 225 x 225 and 225 x 140 from 8mm aluminium. Would this cause any issues?
Any help would be appreciated.

Re: Thick Sheet Thickness?
April 26, 2011 11:53AM
The extra mass would be bad for the performance of the machine. You want a material that is light but stiff.

Re: Thick Sheet Thickness?
April 26, 2011 12:16PM
Thanks for the quick reply and thanks for the parts from previous.
Back to the drawing board then.
Re: Thick Sheet Thickness?
April 26, 2011 12:29PM
If your friend can hog out the bottom of the metal, and leave ribs for support, I think it would be ok. I've been looking at putting lead weights on by belts to counter the inertia of the extruder. PLA bushings are probably not a good idea if you are going to put any significant weight on there though, so consider bushings, or have a look at the linear bearing clip that just posted to thingiverse.
Re: Thick Sheet Thickness?
April 26, 2011 04:58PM
I like the look of the linear bearings. I will give that a go if/when I get this thing going. I'm suffering a blip in confidence in the project at the moment but will keep plugging away.
The good news is that my friend offered to mill down the whole thing to 5mm which hopefully will get me going

Thanks for the help and advice
Re: Thick Sheet Thickness?
April 26, 2011 10:04PM
8mm aluminum would be perfect for a heated bed. Stick some nichrome to the bottom with kapton tape. Or some resistors! You'll probably want to drill a hole for the thermistor for better contact. Hook it up and away you go!

Erm, what *is* the standard method of insulating the bottom so you don't melt your bearings anyway?

I'm building it with Baling Wire
Re: Thick Sheet Thickness?
April 26, 2011 11:27PM
8mm seems like overkill (and added weight). I use 3mm with a 2mm glass sheet cliped to the top. I have printed PLA linear bearing holders undreneath that I separate from the print bed with a 18mm square block of wood (using countersunk wood screws).
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