Best bed levelling system?
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@kungpaoshizi said in Best bed levelling system?:
@deckingman said in Best bed levelling system?:
@claustro said in Best bed levelling system?:
.................. I am afraid about aluminum bed for 3 reasons cost, availability and thermal reaction.................
Aluminium tooling plate is the best solution because the bed needs to be flat, and it needs to be stiff enough, and it needs to have good thermal conductivity. This question gets raised with monotonous regularity.
Aluminum doesnt remain flat though. Glass is preferable.
Of course aluminium tooling plate remains flat - why do you say it doesn't? For reasons that I and others have stated, you really don't want to fix a heater directly to glass because local hot spots will cause it to crack. Glass on top of aluminium is perfectly acceptable (it is what I use in fact), as are various other surfaces like PEI but glass as an alternative to aluminium is completely unacceptable.
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@kungpaoshizi said in Best bed levelling system?:
Aluminum doesn't remain flat though
There's a very big difference between a thin piece of rolled or sheared aluminum and a thick piece of cast and milled tooling plate. Tooling plate is cast so it doesn't have the same internal stresses and it is milled flat afterwards. It should heat and expand quite evenly and with a proper mount would never change shape or expand noticeably in Z.
A thin piece of rolled or sheared aluminum on the other hand would behave like a bag of snakes. So you're right there.
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@kungpaoshizi Here are two videos of the bed flatness (and every other flaw that translates to variation in distance between nozzle and bed) in my corexy printer at room temperature and at 100C. The bed plate is 8mm thick cast tooling plate with a 0.7 mm thick PEI print surface (and adhesive under that). The plate sits on a three point kinematic leveling system and is lifted by two belts driven by a single motor.
It's flat enough to print edge to edge on the bed with a first layer thickness of 200 um.
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Well, while we digging out videos, here is one did a couple of years ago https://www.youtube.com/watch?v=U733PMTou7M. I use glass rather than PEI on my aluminium bed but no form of levelling or flatness compensation.
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@mrehorstdmd nice, i guess ive been brainwashed by the cheap printers these days
