Mechanical build, part 2
After running a few motor tests with the setup from the previous part, I knew I had to change a few things about the build. For both sides to move evenly, a drive belt on each side would have been necessary, so that the belts could be moved simultaneously via a suitable coupling. However, that would have made the build unnecessarily complicated, and it would also have required identical parts. Unfortunately, with the printers salvaged from the bulky waste, I didn’t have any identical parts available. So a new idea was needed. I quickly figured it would be better to mount the drive belt in the middle between the two Y rails, so that, with a cross brace connecting the two linear carriages, a single drive belt in the middle would be enough to move the carriages on both guides at the same time.
At first I used the aluminium round rods from the hardware store as guides. The first tests with the linear carriages mounted on the aluminium rod guides ultimately led to the decision to use the steel shafts from the printers as guides for the linear carriages instead. That completed the Y axis for the time being.
So I could move on to building the gantry for the X axis. For this I first made two support pieces out of wood. Initially I screwed one linear carriage (following picture, left) to each of these support pieces. Since the first tests with the steppers showed that the movement was too rough, I later went for 2 linear carriages (following picture, right) per support piece.
All that was still missing in between was the cross brace connecting the two support pieces, which you can see in the second picture. With this first version of the X-axis gantry I was already able to run the first test with the steppers. The following video shows the first test of this setup.
Here, too, I initially attached the drive belt to the cross brace provisionally with electrical tape. This makeshift fix was later to give way to a permanent solution: the drive belt is clamped between a piece of plywood and the cross brace with two screws and nuts.
In the next part I’ll report on the rest of the mechanical build of the CNC router.
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