The Power Supply Part1

When I ordered my first parts the naked PS that should fit to the Prusa MK3 should costs about 40€. Again, just the PS with no enclosure, Power Fail circut board or cables.

So you can order a prebuilt MK3 power supply with all features for about 40€. Given the costs for the PS itself, the power fail board, switch and the effort to design and 3D print the parts I would rather go with the complete PS for this price.

So I went for a 9.99€ PS from ebay with the same specs. 24V 250W(240W has the original).

First I wanted to have a more beefy PS(320W/12.5A or 360W/15A), that I could use to power the water cooling and some LED strips as well. But the common cheap PS over 10A usually have a fan installed, a cheap noisy fan to be precise. Also I would have to step down the 24V to 12V for the "silent" water pump I picked.

Nothing on this power supply matched to the one that Prusa uses, except for the Voltage and Amps specs.
The outer diameter is bigger, the holes for the screws, nothing fits.

Not even the holes that are used to mount the PS to the frame. Which is important for a usual MK3 as this makes the frame more sturdy. But in my case, I wanted to mount the PS outside of the Ikea enclosure anyway. So this was the only point that was not a problem.

So I started to import the original Prusa STL files in Fusion 360 measured the dimension and looked for a good spot to cut the part in two.

Then I move the parts apart until the dimensions matched with my cheap power supply. Then I simply extruded the cut surface about the same distance and joint both parts together again.

Next I need to sticht the holes for the screws that clamp the PS to the 3D printed parts. Once that was done I removed the strengthening on the backside.
Then I extruded the back wall to the point where the screw holes on my PS are covered. I added some new strengthening and the holes that fit to my PS.

The advantage of doing it this way was the I did not had to change any more complex parts from the original design.

To put this together you need some M3x10mm counter sunk screws and some round headed M3x8mm screws that go into the PS. Be careful, do not use M3x10mm or longer as the screws might damage the inner circut board or create a shortcut.

As you can see there is plenty of room for the cabling inside.

One part I needed was the power switch. I wanted to have a switch that has two ways and switches both connections, as in most countries you don´t know which cable is phase and neutral when you plug it into the wall.

And it also needed to fit into the gap in the printed part. So this snap in version just did fine.

But to mount it to the Ikea Lack table you need another part that Prusa provides with the files for the Ikea Lack enclosure. But this bracket needed to be modified as well to fit to my PS.

Same process as above. Measure the dimensions, cut and extend on 2 axis. To make it look good I removed the side wall and created a new one once the part had the new size.

And this is the printed result.

Now I had to wire everything together.

IMPORTANT! This is main voltage. Leave this to an expert, you can risk you life and the life from others by electric shock or fire if you don't know what you are doing!