Getting “A” Turned On

Late Saturday night I found some time to to work in Aspire software to create a little project I could run using the 4th axis on the Taig. Little did I realize what an intense learning experience I was about to endure.

The first challenge was to learn how Vectric Aspire creates a forth axis tool path. I do a little reading and I dive right in. After working for a couple of hours burning the midnight oil, I realized I was making something far more difficult than it needed to be especially for a first project.

A shallow pocket and add a shallow pocketed name inside of that and see if the shop computer and MACH3 can make it wrap around a cylinder. That’s all I really need.

I had a piece of inch and a quarter aluminum bar. I figured this would be the perfect victim for my first attempts. So on Sunday I began setting up the mechanical side of this experiment out in the shop.

You can see I had to be super cautious around the three jaws so I wouldn’t crash into them. I also discovered what I think is a clever trick for zeroing the Z axis. If I touch off on the top of the tail post I am exactly 0.450 inches above dead center.

All the above was the easy stuff. The hardest time I had was to figure out the MACH3 setup for 4th axis. The first run I showed in the previous post was way off base. I will probably have to write a story for the THMS main site with some more pictures of a real project. I can save someone a lot of trial and error from my experience.

With quarter stepping I am set up for 160 pulses per degree. So “A” moves in degrees (per minute) while “X” moves in IPM. You should see what happens in a diagonal move. It all works very well when everything is properly set. I just had one heck of a time finding the combination. The MACH 3 instructions hint but do not give a good solid how-to. Soft limits are a problem too for “A” axis.

It seems to me there must or should also be some compensation on rotational speed the farther the cut is away from the axis center. (The arc length increases in proportion to the increase in radius for every step.) I have no proof of that speed change (yet). Maybe it is not that critical… but I have to assume it would be…

The following 30 second video is showing the real setup running with the correct MACH3 variables. I was too busy to shoot any action cutting video. Next project I’ll do better and feel a lot more confident.

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