CB CNC Part 8 / Stacking PSU’s & Drivers for Control Box

Ok it’s been a little since I make a video in relation to the leadscrew CNC machine. I’ve just been distracted with real life, the recent Christmas holiday and other project on the main channel, one of which is actually running at the moment. I’m using the other CNC machine to sharpen the plane iron so you’re going to hear this in the background for a little while, while that doing that, I’m trying to multitask. If it turns out that the noise in the room is too annoying I’ll just put a voiceover this. But I’m at the stage now where I want to build the controller for the new CNC machine. My plan is to dismantle the bigger machine and stick with a smaller machine. I want the controller to be future proof, so I’m going to try and throw everything at this build.

I’ve got a rough diagram of how I think this is going to fit together. And I’m basing some of this on pre-existing stuff. I will link to all the sources in the description and on the website, and so on where credit is due. I definitely wouldn’t be able to do this is if wasn’t for the information available out in the public domain to work with this.

If the first controller box I made was anything to go by, I wouldn’t take that diagram as a reference just yet. The first thing I want to do is combine some of the components into modules which I can assemble onto a board – that will act like the removable mounting panel in an electrical enclosure.

Now’s a good time to mention I’ve been provided with some components by stepper motor online – in the form of these drivers and several PSU’s. So many thanks to them.

Anyway I rushed to mount the PSU’s and motor controllers, and later when I was sleeping, in bed, I realised they were all wrong.

I should have really installed this the other way around, it would have made accessing the screw terminals a lot easier.

I should have staggered the terminals of the PSU’s so I could install them facing upwards, making them a little more accessible.  I should also reduce the space between all the components so the overall size of the enclosure is not the same size as the CNC machine I am trying to replace.

I’ll just go pause the other CNC machine so we can hear what these power supply units sound like.

All the lights turned on so that’s a good start.

I’m taking the 6mm ply mounting plates off the PSU’s. I want to replace them with 1.5mm thick aluminium which I’m going to cut from some 40mm angle bar I had leftover from the drag-chain install.

I carefully cut the angle bar in half along its length, so I was left with one piece which was of 40mm wide, and another around 36mm

I then modelled the mounting face of the 3 power supply unites based on a combination of their online PDF diagram and my calliper measurements. I then worked out where to scribe and punch marks for the mounting holes.

I made sure to measure from the same edge in case I make a mistake with cutting.

I’m just de-buring the back.

Ok that looks a hell of a lot better. You case I can access all of the terminals from the top. There is a cm gap between each of the PSU’s which should be enough to let air circular around. On the opposite side I’m just going to put these cable tie self-adhesive tacks, which you normally put inside computer cases.

Somewhere in the middle.

I’m undoing this as well.

You can see the difference in spacing. I think I’ll just put 5 to 8mm between each one. As long as there is a fan near by that should be more than enough for air to circulate around.

Ok I’ve cut some pieces of angle aluminium to 150mm. It’s about 24-25mm… about that much. And all of these are going to be bolted on like that. So I have mounted these on. They are more or less ok, and I managed to drill one hole in the wrong place. It’s pretty sturdy although not perfectly square. And all these terminals can come out of these sockets, I can then screw whatever wires I need in, and then put them back. So even though they are quite close together I can still access the screws.

The contactor and trip is on a bit of din rail or dim rail. The VFD over here is pretty much ready to go where it needs to go. I’m not sure where to put this terminal block but I know I’m going to need one to break out all the cables to the different fans and so on. I could fit it onto the aluminium frame on the side like this, but I also noticed that  these machines screws here line up perfectly with the holes, so it could go at the back.

Wow that’s pretty perfect.

So the next thing I need to do is cut out a board which I’ll use as the mounting plate for the enclosure. And I’m going to have to do a bit of trial and error, to work out the best way to put these components together to make the most of the space that I’ll end up having in the control box.

In the next video I will start mapping out the different components of my mounting board, and figure out how to wire this motor contactor unit.

Leave a Reply