2017-10-17

Custom Deskproto strategy

Project history

  1. current posting
  2. next step: add command line arguments and extensively test the strategy
  3. Next project: subdivide rotary axis operations to keep toolpath-distance constant while getting near the center of rotation

Why?

I have two problems with CNC machining either wax, plastic or soft wood:
  1. I lack experience with how much surface finishing detail I need. So I want a finishing strategy that graducally gets finer (distance of parallel toolpathes) until I stop. Without however milling the same path serveral times (like every second path when I do a tpd=tool-diameter/4 and then a tpd=tool-diameter/8 parallel strategy or every 15th path if I do a tpd=tool-diameter/3 and then a tpd=tool-diameter/5 operation.)
  2. I cannot machine the same part of the surface for too long a time. It will eithrer melt (wax and plastic) or catch fire (wood). It needs time to cool down. Duering that time however, I can maching other parts of the geometry that are far away.

How?


Since the existing toolpathes did not offer such a strategy, I came up with a small Java program.
You would start with a Deskptoro CAM project containing one (e.g. "parallel along X") or two (e.g. "parallel along X", then "parallel along Y" or "along A")  FINISHING passes.
These would be marked by adding "REPLICATE" to their names.

The program will then make copies of these operations with the starting point offset by toolpath-distance / 2.
After these it will add copied operations with the starting point offset by toolpath-distance / 4 of the original and the copied operations.
Then it will do the same with toolpath-distance / 8.

The result is a finishing strategy that gradually increases surface quality and can be paused and aborted at any time.
At the same time it does not operate on the same part of the geometry until it has worked on all other parts.
Thus giving the part time to cool down where a simple parallel-strategy with a smaller toolpath-distance would mill over the same place dozens of times, thus heating up the surface and either melting plastic or wax or setting soft wood on fire.


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