22 mars 2016

Progresses on OboXL3D

The two heat beds are working ok.
Both are driven by their own electronic switch and power supply.
The electronic switches are  driven by the Rumba main board.
Only one temperature sensor is used as current Marlin firmware does not seems to allow more than one bed temperature sensor.
Below the bed, I have added some thin aluminium to enhance thermal isolation.
Bed comes to temperature pretty quickly, so far so good :)

10 mars 2016

Hot bed for OboXL3D

Given the large size of the printer (600mm), for the heat bed  I decided to use two pad (from china), with dimensions each 300x300mm.

The problem is that each pad requires roughly 300w power supply.
So instead of a *big* power supply of more than 600w,  I decided to use 2*350w power supply at a reasonable cost (35€) each.
To control these power supply, instead of using SSD relay with doubts about the end of life, I use two electronic boards with  mosfet.
That works perfectly already on my other printer 3D, and it decouple the electronic+heat head+motors+fans from the Bed power supply.  More than 10A is used by bed, reste of electronic requires only 1A. A large current consomption from BED does not impact the rest of the printer.

The Bed regulator control board schematic comes from here:
and I adapted in on prototype PCB with strips.
*Be careful to NOT link both GND , or you may damage all*

Each power supply is 350W, model meanwell  LRS-350. I printed the protection case and adapt plusgs and swtich.  See http://www.thingiverse.com/thing:1221600

Orange power supply is 12V, for electronic board, motors, heat head, fans.
Black power supply is 24V and for each PAD of the heat bed.