SD3 to SDXXXL (Page 1 of 2)

Going that big I would highly recommend moving to a wider spacing on the z-axis rods.  Even better might be 2 sets of rods at eache end with 2 z-axis motors. No matter what you build that bed out of it is going to have alot of flex at each end of the x-axis.

Will keep an eye on this. it will be an impressive build

I try to keep the rebuild price down but 2X Z motors sounds better than one, but probably wont be as eazy as splicing some wires together ?

If you get a ramps board, there are 2 z-motor connections on a single stepper driver so I'm sure it's the same as a split.

My only thought is - thats a fairly big unsupported span. Personally, I would have considered jumping up to 10mm Smooth Rod.. I think if you go dual-extruder you'd definately see sagging...

Keen to see how it eventuates though - good luck on the build!

You can do that - or you could run multiple PCB MkIIB's if you wanted to avoid the issue with the big bulge on the silicone beds.
Alternatively, you could make ONE build plate, but etch onto it 2 seperate heater coils... and then power them as required.

http://bassompierrescientax.pagesperso- … icone1.htm

2 heater solution does sound good but i will probaby need custom glass bed to avoid warping
so i imagine that big glass does not like to be heated from one end only.

eazy solution would be small glass - small print and big glass both heaters etc,

new rod's from ebay - i think China

since there is a lot of bed to heat my thought is why not use a water block and pump heated water into it. yes it adds to the machine complexity by adding a pump but my thought is that all you would need to do is heat the reservoir and it should keep the bed at a good constant temp. And an immersion heater should get you up to the 80-85c water temps pretty quick.

anyone know if this would work? or if its a terrible idea?

unfortunately, water heating would also limit your max temperature. you actually would like to operate hotter than 80C if you can help it, especially with a larger print area.

I personally think that multiple heating pads are the best option.

China FTL

might have to source from mcmaster. more expensive, but at least they have actual precision ground hardened rods instead of just chromed mild steel hardware store rods. and they know how to ship them.

You can order silicone beds in any size you want from china, but you usually have to use a separate thermistor.  My qu-bd gets over a 100 in under 3 minutes. Do you need to heat it up faster then this?

mcmaster told me to "sod off" so i'm getting these rod's locally.
but my printer is trying to piss me off ... since yesterday the bed maximum temp reached 69c and thats it ... any ideas ?

So i have to come up with double bed solution sooner than expected.
two qu-bd's maybe and separate power supply for them and solidstate relay ?

ebay has also 200x400mm 220v silicone pads available .... but 600w .... nice and toasty for sure

not a bad idea.