Wednesday, January 26, 2011

Sketching the CNC

So, at this point, I have a scanner that I'm going to use as a base, with a stepper controlling the movement along one axis.
This is the scanner I'm going to use as the base.
I also have a stepper motor, a metal rail and a pulley system that will be used to move along the other axis.

A stepper motor from an old printer.
A metal rail & old printhead.

I was thinking about the possibilities how to create the XY-controlled CNC from these parts, and came up with three sketches.

I admit, I'm very bad at drawing, but anyway, I decided to share these sketches with you.

My first idea on how to construct the CNC was not a very brilliant one:

First idea of the CNC, a very shitty one. The laser points up.

The surface to be engraved would be held upside down over the CNC byt something, and the beam is pointed upwards from the scanner. Well, you can imagine how this would make the whole set-up and engraving process a pain in the ass. Especially with heavier items.

Next idea, already a bit better one:

2nd sketch of the CNC.

Now the scanner is held upside down, and the engraved surface is lying beneath it. The rail is sticking a bit out from the side (it's wider than the scanner). The laser points down. The problem with this one is that it limits the engravable things a bit. It would be hard to put bigger items under it, like a guitar, a synth, or things like that.

With the third idea I think I nailed it.

Third and probably the final sketch of the CNC.

Now you can put whatever items under it. The metal rod & pulley system is held high by a big piece of something. I just wonder how the scanner motor & tray will pull it off with all that weight. Obviously I'll need to make it as light & balanced as possible. Or then I need something to hold the rail from the other end...
I have no idea yet how I will do all of that. These are just the first ideas I came up with.


  1. Best of luck with this project, i'm attempting something like this myself and have been trying to source parts for years now. I finally got my hands on some old HP scanners and will be gutting them very soon. One point to note, the stepper motor you have here is not very good for detailed work, the 048 in the middle of the part number meand 48 steps per revolution or 7.5 degree steps. Try to source some 1.8 degree steppers instead, giving you a much higher resolution of 200 steps per revolution.
    Best of luck!!

  2. Thanks! I actually already planned a simple gearbox that will make the resolution better than even a 1.8 degree stepper. I'm planning to make it from some plastic printer gears I have. But I've been concentrating on other projects lately... I'll post some details on it if/when I get it ready. Of course, using a stepper with a better resolution would be the easiest solution!