Can you program for constant chip area infeed method with a gear form tool in a cnc mill?

[Azoth]

Before looking for a programming job I'm trying out mastercam to see if I can get it to output ergonomic operations and toolpaths that are catered to the machinist's workflow. The type of stuff I as the machinist end up rewriting by hand at the control.

One thing I need mastercam to replicate is toolpathing for constant spindle load in various operations.

Right now I want to make a custom tool (a 7 tooth tall 8 D.P. gear hobbing cutter) to 2D Mill some gear racks and have mastercam calculate decrementing radial depth of cut based on constant chip area so the spindle load is constant throughout the operation. As the machinist I know I can't use higher speeds without wearing out my cutter, and I can't feed faster or take large RDOC because the mill, toolholding, and work holding are no where near as rigid as traditional gear cutting machines so the only way to reduce cycle time is adaptive RDOC. At the machine I went by trial and error starting with a finish and semifinish RDOC of .010" and experimentally increasing RDOC out from there.

 

Is there a method in mastercam to do this? Model the finished geometry and specify the finish pass RDOC and tell it to work backwards to give larger RDOC on each rough pass out based on the described tool geometry and part stock to maintain constant chip area?

[Aaron Eberhard]

Out of the box, you're not going to get that level of intelligence.  You would need a custom add on written to take that surface area of your engagement into account and create your passes that way.   The same problem exists in thread milling & full engagement t-slotting, but normally it's not a enough deal so the easy solution is just to create two or three toolpaths with different rough & finish parameters, but you'd have to calculate the amount yourself.  With a T/slot or thread-mill, though, the variation is generally not so large that it really matters.

Your reseller should be able to help you out, or you can reach out to Byte on here (https://theebyte.com/), or give me a shout as I have some resources that do custom add ins as well.

[Azoth]

Okay thanks. I haven't even gotten to the gear tool yet because right off the bat I ran into an issue with the way mastercam calculates it's facing toolpaths (it prioritizes from the center out with symmetric tool overlap off the sides of the part, but straight ignores my stepover distance which leads to an awful toolpath that leaves a mere sliver on last pass because they made it prioritize tool overhang over my specified radial tool engagement). The only solution I'm seeing is to manually offset the toolpath by drawing a separate wireframe or just draw the toolpath, which at that point why am I even using cam? Do I really have to hand edit my cam's gcode in "state-of-the-art" software if I want optimized toolpaths?

So yeah the chances of it being capable of calculating toolpaths based on constant chip area was starting to look like a long shot, thanks for confirming.

Obviously the 3d surfacing toolpaths that can't be done at the control make mastercam valuable, but I'm just shocked with how lacking mastercam is in the fundamentals.

[AHarrison1]

I think you are basing your comments on the little knowledge and experience you have with Mastercam.

[Aaron Eberhard]

1 hour ago, Azoth said:

Okay thanks. I haven't even gotten to the gear tool yet because right off the bat I ran into an issue with the way mastercam calculates it's facing toolpaths (it prioritizes from the center out with symmetric tool overlap off the sides of the part, but straight ignores my stepover distance which leads to an awful toolpath that leaves a mere sliver on last pass because they made it prioritize tool overhang over my specified radial tool engagement). The only solution I'm seeing is to manually offset the toolpath by drawing a separate wireframe or just draw the toolpath, which at that point why am I even using cam? Do I really have to hand edit my cam's gcode in "state-of-the-art" software if I want optimized toolpaths?

So yeah the chances of it being capable of calculating toolpaths based on constant chip area was starting to look like a long shot, thanks for confirming.

Obviously the 3d surfacing toolpaths that can't be done at the control make mastercam valuable, but I'm just shocked with how lacking mastercam is in the fundamentals.

You would likely benefit from some instruction from your reseller.  Barring that, sounds like this would be a great time to post a file and ask for assistance from this awesome community