OpenBuilds ACRO Z Axis

This is a Z-Axis for OpenBuilds ACRO system. I designed it with a few key requirements in mind:

• has to be sturdy enough to able to carry a small drill. I drill small holes (2mm in diameter, 15 mm deep, plywood / MDF) with it. This was very important to me. This is why I tried to get the drill to be as close to the 20x40 bar as possible.
• simple tool changing. For example, I want to quickly go from using a drill to using a laser.
• should not deviate from original ACRO design too much
• most parts should be be 3D-printable or easily sourceable.

I am very happy with how it turned out and I hope you like it too.


Here's a brief story about how I built it:


Step 0 — Design process.



This z axis was primarily designed to carry a small drill, so my main goal when designing it in a way that would get the drill to be as close to the center of the 20x40 extrusion as possible. I think this design gets as close to that goal as possible if we're talking using openbuilds hardware.

Step 1 — Cutting the extrusions.

So to give you some context, I'm doing all of this in a 1 bedroom apartment and I don't have any large tools. So my best option was to use a hacksaw (btw I didn't have a hacksaw either so I made one).

To make the cut as good I could, I used a modified extrusion cutting jig designed by Grégoire Saunier.



The shortest profile you can get is 250mm and the size I needed 2 parts at 124mm. So I figured I'd just cut them in half using the jig and they would come out perfect. I was wrong of course — parts looked good after the cut but were not equal lengths. So I made this other little jig and finished the job with a file.





That got the job done well.

Step 2 — Printing the parts.

Printing all the printed parts was pretty straightforward, except for the biggest one — the shell. That part has a pretty large surface and it warped during the process. I wasn't too bad so I ended up using the warped part, but if was printing it again I would have probably added some brim.

Step 3 — Assembly.

Unfortunately, I don't really have pictures from the assembly process. It's pretty straightforward, you just put things together in the right order — nothing too complicated.





Final results.