sliptonic wrote:I did get this working and it produces very nice paths! I sent you a pm about specific implementation issues.
When clearing a circular hole, it does a helical descent, then rapids out, moves over the step width and repeats with progressively larger helices.
I'm curious if users would also like to see the alternative strategy where it spirals down a step, then spirals out to the full width, rapids back and repeats.
Is there ever an advantage of one over the other?
End-mills generally is not made to plunge and might wear out quicker with the helical decent, so I would guess that for certain tool material combinations, the alternative strategy could be preferable.
So speed vs tool-preservation I guess.
Ugh, I just wrote an hour long response to this and the forum software made it disappear.
I'm a machinist and a mechanical engineer. I want to help make this path code awesome.
End-mills are specifically made to plunge, unless you buy the non-pluging type.
Helical descents are awesome. There's no need to rapid out of the first hole you've made. End mills are slightly mis-named. They are made to cut using the flutes too!
In fact, the most modern machining techniques attempt to use the flutes as much as possible. It's found to be much better for tool life, faster at material removal, better at avoiding tool vibration (which kills tool life and surface finish).
So we often make a pocket by starting with a helical ramp down to the depth we want to cut, which is often 1/4-3/4". Then we start making adaptive clearing passes. The goal of adaptive clearing is to avoid cutting corners as much as possible because corners force you to slow down the feed rates because the cutter engagement is going from around 10-20% to 70-100%. This is bad for speed, bad for tool life because it often induces vibrations, and bad for surface finish. If you've listened to a cutter entering a corner at high speed, if sounds like a huge bird chirp. It's not good.
Using a larger depth of cut also spreads the cutting forces along a larger portion of the tool, which makes tool wear slower and more even than if you only take for example a bunch of 1/16-3/16 inch passes. This kind of shallow step concentrates all tool wear onto the very end of the tool and a very short portion of the flutes.
Modern techniques for outer profiles often involve approaching the stock from the side with full flute cutter engagement and then cutting at a reasonable step over for that depth, then stepping up from the lowest Z level to a higher Z level. It's more efficient at material removal.
Also, rest machining is a must. The path planning software needs to know what material is left after the previous operation to intelligently plan the next operation.
Cutter compensation is essential to making accurate circular interpolation for bores and shafts.
+1 for keeping terminology consistent with the machinists world. They've been around longer than computers. Use their language for a tool build for their work.
this was all more eloquently detailed out in my first attempt.