Building the C-Bot 3d Printer : Part 35 : Updating the heated bed controller

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A few weeks ago the relay controlling my heated bed had a meltdown, literally.  Magic smoke released.  It’d been running for a year, and I guess it was time.  Since I never wanted that to happen again, and I was tired of the “click click click” sounds it made I decided to go solid state.

After querying  the C-Bot Google Group for this issue, this board was suggested: (ebay link, $12.69):  It’s a HA210NO6 mosfet in a nice breakout board.  And it has the longest product name ever: “3D Printer Power Module for Higher Power Heated Bed upgrade RepRap RAMPS 1.4″.  I’m guessing that’s a direct translation from the Chinese…

mosfet_module

But I didn’t like the idea of all the exposed electronics, so I built a nice little enclosure for it in Autodesk Maya, which includes an active cooling fan in the back.  According to the specs (Ebay link) and the current I’m drawing the passive cooling via heatsink should be enough, but better safe than sorry.

This pic shows the three stage prototyping process I went though:

mosfet_enclosure

It includes a top-hole for a screwdriver to access the terminals inside, plus other top-holes giving your hex-wrench easy access to the bolts below.

Each box took about an hour to 3d print, using a .6mm E3d-v6 volcano nozzle on the C-Bot, 450 micron, 60mm/sec-ish.  The final two were in MakerGeeks HD Vivid Blue PLA (& dishwasher safe to boot!).

After an hour or so of splicing & soldering, the electronics were in place, and it was up and running without a hitch:

mosfet_in_action

You can download the enclosure from Thingiverse here.

Heats up in no time, and no more “click click click” like the relay used to.  A red LED shows it has power, and a nice soothing blue LED kicks on when the bed is heating.

When I find a bit more time I’ll look into configuring RepRap Firmware to use PID to control it, rather than the default bang/bang.


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Modular Panel System & new garage shelving
New Commission: Denali
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