Welcome to the SeeMeCNC Community

I really need to do something about evening up the temperature across the bed for some large parts i need to print for work.
with the bed set to 100C, i can still touch 50mm in from the edge, its only about 60C

I was thinking about a 4mm mild steel plate rather than aluminium?
my reasoning was:
- we have a surface grinder- so it will be perfectly flat, and i can clean it up form time to time.
- on bigger jobs, i can wait till the jobs about 5 mm high and put magnets on the raft corners to hold the job down.
has anyone tried printing onto steel? and is the thermal conductivity of the steel going to be enough to sort out the temperature anyway?
I'm happy to give it a try- but if someones already 'been there, done that' it would be good to know.

Cheers

Jason

I have not tried it but...

I don't think you'd want to print directly onto the steel, given most steel is impregnated to some degree with oil, my guess is you'll have adhesion problems, you'll also want something on top of it to retain some of the heat, otherwise your basically sticking a big heatsink on your heated bed and you will probably have issues getting up to temperature.

If you do try us let us know how it works.

I am using 24V heatedbed, 10mm aluminium, boroglass, PEI sheet sandwich - works ok

Steel is not the best thermally conductive thing in the world, but it certainly is better than glass.

Remember that when you have a heat spreader in between it is a good idea to wait a while until the heat reaches the top of the plate.


Magnets is a really good idea. I like it. I was using lead diving weights, but magnets will be better. However magnets are known to demagnetize with heat. But go for it, magnets are cheap nowadays, and yours may not demagnetize.

If you have the ability to do it, go for it, and please report back so others may benefit from it.

+1 for aluminum. http://www.sandsmachine.com/alumweb.htm

If you need physical intervention to keep parts from curling and unsticking, chances are that something else is at play. More even heat by any means would be an improvement, and a larger thermal mass would smooth out inaccuracies caused by printing on top of the bed thermistor (which I think causes a lot of this headache, the bed turns off because it's reading the hot-end, and when it's done printing that area and it reads an actual bed temperature again, it's cooled enough everywhere else to make it unstick)

MakiBox before its collapse used a stainless steel sheet (small build volume) about .83 mm thick that was bonded to a pcb heater. That worked really well with ABS that was being tested then. All you had to do was sit back and let the build plate cool and at a certain point the printed object would pop loose due to differing thermal coefficient of expansion according to the theory. I'm working on hacking it to my Deezmaker Bukito in my copious spare time. Cheers

Thanks for the replies, I'll skim down a square of steel and give it a try, before committing and getting a disc Watercut.
Maybe a copper conducting layer between the glass is the way to go.