Building my Repstrap Smartrap 3D Printer... and the setbacks (Part 3)

ATX Power supply to power my Smartrap 3D printer

I think there are a lot of advantages buying a complete kit when you get your first 3D printer. It will be less expensive and you will not have problems with incompatible parts as opposed to buying individual parts from all over the place (unless you can source all the parts exactly as in the BOM). You will also be able to start printing faster.  At least until you get it working reliably, you can start customizing and improving it which is not how it went for me.In my case, the customization part comes during the build since I was trying to make parts work together (again, this is because I can't source the exact parts in the BOM).

When it comes to power supply, things went smoothly.  There's a huge difference in price between the ATX and the industrial 12V power supply so I went for the ATX.  The instructions on how to use it for a 3D printer are also straightforward but unlike most people, I saved the 5V and 3.3V supply wires. I already mentioned that my Arduino Mega had a busted voltage regulator and that's what I need the 5V supply for. Then I plan to use the 3.3V supply to power some LEDs to light my build area.

I got one that is 700W. Should be more than enough for the 3D printer even for a heated bed. 

700W ATX power supply

Before I got cutting the wires and lose the warranty, it's good to test it first, of course.  I used a small piece of wire to connect the green wire to the ground wire to turn it on.

Yup, it turns on. :p  But what about the voltages?

So far, so good.  Time to open it.

All that's needed was to cut the wires coming out. They are color coded so I just combined the wires of the same color.  There were more ground wires so I bunched them into two just in case I find a need for it later on.

Finally, I used 16 gauge wire and soldered it to the 12V wires and the ground wire. The other end will go to the RAMPS board.

Improvement

The power supply is working great but after using it for a few days, I found myself always unplugging it from the mains when I needed to restart the printer. So I added a small switch which is what I should have done the first time =).

I used the same green and black wires I connected when I tested the power supply and soldered them to the switch.  Then I drilled a hole for it to go through.

Whohoooo! This part was the smoothest part of my build so far.  Time to try and print! :)

To make it easy to follow this series, the links are here:

• Part 1 - Sourcing parts and building the base/frame
• Part 2 - Electronics  
• Part 3 - Power supply
• Part 4 - First prints and modifications