Multiple head beds

How to connect multiple heat beds(say 4) to RAMPS 1.4?
Whats the better way for controlling multiple heat beds?

DONT!

4 beds at 11 amps each = 44 amps...
Also you get cold spots in the middle as the heated areas have a border.
Ramps has 3 mosfets... no way to control 4 beds and hot ends and fans without addons.
No firmware has support for this. (that I know of... ) DC42 will now jump in and add it to his controller in an effort to make you buy one.


use one large bed, probably mains powered and use a AC SSR to turn it on/off (Solid State Relay)

It is also recommended that your bed be fixed and the machine move around that. IE delta or CoreXY type machine

Edited 1 time(s). Last edit at 05/31/2018 10:28AM by Dust.

You could put 4 independent Kapton heaters under a big plate of aluminum, but the aluminum spreads the heat anyway, no matter how many heaters are ON.
Maybe use 4 heaters with 4 aluminum plates and cover it all with a single glass/mirror tile ?

As Dust already said, you can't control them directly from Ramps. You'd need external Mosfet modules and plug/unplug the ones you want to use. The problem is, you can only use one thermistor, but you could place it in the center.

If you want to use 4 heaters to save energy, better use one big heater and cover the parts of the bed, that aren't in use, with something isolating.

Quote
Dust
DC42 will now jump in and add it to his controller in an effort to make you buy one.

RepRapFirmware has supported up to 4 independently-controlled bed heaters for several months already.

But it's easier to use a single bed heater with a thick heat spreader, if you don't mind it taking longer to heat up and especially to cool down.

Edited 1 time(s). Last edit at 06/01/2018 01:15PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].