Perfectly flat borosilicate

[Farr0wn3d]

Does anyone know where I can order a sheet of perfectly flat borosilicate? Boro is easy to find but finding actual float glass is hard

[Matt_Sharkey]

The stuff the Makergear is selling is fine, but if flatness is what we want, how about MIC6 Aluminium tooling plate.

http://www.mcmaster.com/#86825k11/=z75x8c

[Farr0wn3d]

Yes the stuff that makergear sells is "fine", in that, the surface is great for sticking to and its durable. but I have approximately 120 microns in height difference from centre to edge X and 150 centre to edge on Y. I'm smashing my first layer in the centre while it doesnt even adhere on the edges of large prints. I would go aluminum but I dont see that holding up very well when it comes to scraping prints off. I'd considered having a sheet of aluminum decked at a machine shop and using build tak on it. but my first choice is float borosilicate if I can get my hands on it.

[Tim]

My glass plate was as flat as I could ever want it. Luck? The glass plates are relatively cheap, so maybe it's just a matter of ordering, say, three of them and using the one that's flattest.

[PcS]

If you want flat glass look for float glass. But even then it would need to be ground and polished to get it flat. At least as flat as you are looking for.

[jimc]

Mic6 alum is a tooling plate. Its cast, stress free and milled flat. You cant get anything flatter really. Its far more durable than glass is. I cut them them to size and glass bead one side, spray with hairspray and print. Been running them about 2 years now. On another note, are you sure its the glass thats bowed up in the middle and not the top gantry bowed down? The more belt tension you have the more that will bow.

[wmgeorge]

I would think aluminum would scratch and mar a lot easier than glass. I have access, maybe to stainless steel plate has anyone used that instead of glass or aluminum?

[ednisley]

stainless steel plate

For equal volumes, steel weighs three times more than glass or aluminum, so you must reduce the Y-axis acceleration to reduce the motor torque required to move that thing.

Density:

• Glass - 2.5 g/cm³
• Aluminum - 2.7 g/cm³
• Steel - 8 g/cm³

A sheet 1/3 the thickness of the glass plate will have about the same weight, but would curl like a potato chip when heated. Remember that you must maintain a flatness under ±0.05 mm across the whole thing to improve on the glass you've already got.

In the unlikely event you have an old-old M2 with the high-resistance Z-axis motor, the poor thing can't lift much additional weight. Plan on upgrading that before you add a steel plate.

If you have 0.15 mm difference across the entire plate, then split the difference: the initial gap will vary by ±0.07 mm across the entire plate. That's fine if (and only if) you have the initial gap set correctly with a properly aligned platform and you're using a suitable adhesive.

[jimc]

Stainless has poor heat conductivity. Alum will gouge if you pry your parts off the bed with a screwdriver and hammer but what the hell would you use somethig like that for. Put it this way, anything that would gouge or mar the alum would crack the glass. There is also a much more even heat distribution with mic6.

[wmgeorge]

All good points. What thickness aluminum plate? I see Online Metals carries, something like $51 (plus shipping) for .250 thick by 12x12 inches.