December 19, 2015
Description
I made a box to mount on a separate 24V power supply
Until now, my 3d printer has been given 12V to the heat bed, so it takes approx. 20 minutes to heat it up to 100 C (while covering it with some insulation on top).
After that it struggled keeping that temperature.
When i designed and built my printer, everything has found a place in the very compact base of the printer, so there was no space left for an extra power supply.
I left the 24V power supply out of the printer housing and left it separate, but only with one cable connected to the printer.
The box houses a solid state relais, a heatsink and a fan. You can mount the SRS two ways; with the top or bottom facing the square hole (in case you don't use a fan or heat sink)
The cable contains the following signals:
The fan in the box is powered by the fan voltage already supplied for in the power supply
Because this PS is powered by the 220V signal behing the on/off switch on the printer itself, it automatically powers on when the printer is powered on.
--- IMPORTANT NOTE: ---
The setup with the solid state relais did not work out ok!!
I let Marlin control the heatbed with PID settings and while i used a fan and heat sink on the SRS, the thing completely melted down :-(
Now i have replaced the SRS with a 30A car fuse and let Marlin control the bed using the bang-bang method instead of PID (to prevent relais switching too much).
It works perfectly now, and also eliminates the use of a fan and heatsink! :-)
Bed heats up to 100 C in approx 5 minutes now, is very stable and even 120 C is no problem!
Note that my heat bed is not a regulat 12V heat bed, it can be configured for 24V when connected differently, so that's what i have done ;-)
License:
Creative Commons - Attribution
wd73_
