Jig fixturing on CNC

I use the CNC for repetitive processes that I repeat once a month or so. I want to remake my jigs based on some cool new ideas and wanted to double check if they are appropriate for this machine.

I’d like to make a jig that has 1 inch wings on the front and sides so that the whole thing will slot on top of the cnc bed, like putting a lid on a box. This would mean that the jig is always installed at the same location every time. And if the location is always the same, I could set the program to corner datum and use the homed position as my X and Y. That would mean the only manual calibration I’d need to do is set the Z axis off the material.

The jig would slot on kind of like this, probably not with wings all the way around. I’m thinking 10 inch wide, 1 inch tall wings. I measured the CNC and the wings wouldn’t touch any part of the CNC table, only the spoilboard.

Before I create the new jigs I wanted to double check that this idea would work. @dannym what do you think?

  1. Is the homed position reliable? Is there any reason the homed position would move or change?
  2. I would need to surface the spoilboard once to confirm it’s level. I wouldn’t need to surface it every time I use these jigs just once to make sure the current spoilboard is generally flat. Are there any objections to me surfacing the spoilboard one time?

I think if you square the gantry every time it will improve your accuracy. You can also use your bit to run up and down the x and y axis against the edge of your jig. You can then change the offset the radius of your bit. Once you are offset. You would be directly over your corner of your jig.

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Thanks Joe! Yes, I’ve made squaring the gantry part of my set up routine. It helps a lot. I think I will go ahead and give this a try!