What kind of aluminium grade for a heated 3D printer bed?
I'm replacing my standard MK3 Aluminium printing bed with a custom sized bed paired with a silicone heater. I came across a few on Amazon and they all have grades such as 6061, 3003, 5052 etc. I know these mean the composition of the Al alloy and their end purpose but I'm not sure what they mean in terms of being used for a 3D printer. Can anyone here advise me on this?
As @fred_dot_u states, MIC 6 is the way to go. Take a look at Aluminum Sheet Between Heater and Glass and Where to buy an aluminium plate for heate bed. You don't say where you are based outside the US, but I have found some reasonably priced suppliers in the UK.
Various grades and alloys of aluminum will have characteristics related to ease of welding, resistance to corrosion, malleability, and other aspects. For a heated bed on a 3D printer, you'd really want to have something resistant to warping and something that can be assured to be planar across the surface, that is, flat.
The terminology you'd want to use for your search is "MIC 6 Cast Aluminum Tooling Plate" and the results are many.
From a rather comprehensive web site:
Flatness tolerance is maintained within .015" on 1/4"-5/8" thickness and .005" on 3/4"- 4" thickness. Thermal Cycling can be performed up to 800° F under controlled conditions.
You would want to confirm from the seller that the surface has been prepared, as some sites appear to sell un-finished tooling plate, but I've not been able to clarify that. Most appear to provide either no specifications regarding flatness or give a figure such as that above.
Thanks. Where can I order one from? I checked ebay and amazon and they don't seem to have one listed.
I hit ebay as part of the research for your question and found a number of suppliers. My country is USA and that may be a factor. The link in the text of the answer is a location for purchase as well. For eBay, I used "MIC 6 Aluminum" which makes me realize that you're not US based, as you have aluminium in your post.
This seems like massive overkill - can you point to printers using this as a bed? These tooling plates seem like they are really intended for use in welding jigs or CNC milling machines where they could be exposed to extreme heat an/or physical stress, far more abusive than a printer. Also they are very heavy and expensive. Most aluminum beds I've seen are thin sheetmetal. I could see going a little thicker than typical to avoid warping, but it seems like thin aluminum sheet paired with glass would be much more economical. I don't know if the allow would matter.
I agree about the overkill aspect. I have suggested this particular product due to reading about others' experiences with warping from thinner aluminum beds and the answers posted to other forums. A bed of this type, perhaps 3 mm thick, paired with a piece of glass may be a more attractive solution. Glass was not under consideration in the question, hence its omission.