Shapeoko upgrade (8) – Aluminium Z-plate

A new day, a new project. Today: cutting a plate for the final version of my Z-stage out of 4mm aluminium.

Why have a plate and belt drive at all instead of direct drive? Well I mentioned this before: firstly I simply find it prettier. Secondly because of weight distribution on both sides of the X-axis makerslide. Thirdly the aluminium plate doubles as a heatsink, which I wouldn’t have if the motor was mounted on top of the linear rail axle.

A few months back, I made a temporary plate out of acrylic, because obviously the Shapeoko was down so the lasercutter was the only option at my disposal. It worked, but over time the acrylic had started cracking under the weight of the motor on the back. As if that weren’t enough, I had to fabricate a makeshift contraption with clamps just to keep the drag chain from scraping over the belt. So yeah this project was long overdue…

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This literally is my second job since the recent overhaul, so cutting aluminium right out of the gate was kind of a risk, but hey I felt confident.

And I have to say, boy was I right! The difference with how I used to cut aluminium vs. now is literally night and day. The rigidity mods and sturdier drive system on all axis seem to have paid off big time and I couldn’t be happier. Milling was fast, smooth, with no noticeable chatter and therefor much less noise. It was great. Believe me: it was huge! Very clean lines, OK. Very nice profile cuts. It must have been the most tremendous buttery smooth experience the world has ever seen! And you know I know my butter…

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Joking aside, cutting really went like a dream, and I felt immediately there was room for improvement in the DOC and feeds/speeds department.

Perceptive readers will have noticed the motor mount is placed relatively far away from the axle hole. This was a deliberate choice so that the drag chain can go underneath the plate instead of over the top. Just watch the pictures below and tell me that this isn’t an elegant solution!

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I had bought 3 belts with slightly varying lengths, and that also turned out to be a smart move, as I ended up having to use the longest of the three.

You’ll also notice that the plate sticks out slightly to the front of the Z-assembly, which unfortunately was NOT a deliberate choice… In fact it is a mistake that I fixed in the linked file at the bottom of this article.

Luckily, router clearance was OK, if only by a hair. But I will re-machine my Makita mounts shortly, and I intend to move the router closer to the axis, so we’ll see how that works out. By the way, I took this opportunity to check whether my axis are well calibrated. Should have been 76mm wide. Judge for yourself.

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Well, here’s a final shot. I’m getting there:

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Download the Z-plate svg here.

 

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