feeds in corners: any good answers?

[klaus]

What is the deal with the job setup's button for changing a feed on an arc move? I have machines that suffer from interpolation error in the mainly 2D machining that I do. I get the feeds cranked and want to slow down the finish pass corner feeds, to combat the stretching or cutting of radii. If I use the adjust feed on arcs function, Mastercam will process the complete NCI file and slow down my roughing lead in/out arc moves, my helix ramping entries and any other arc moves that I do not really want slowed down. Is ther a way (not in my controllers) that I can get Mastercam to slow arc feeds only on certain operations defined by myself?

[Allan Brown]

You should research the High Feed C-Hook in V7/V8 to see if it meets your requirements. The file Hfapp.doc (or Hfapp_v8.doc) is helpful.

In general, High Feed optimizes feed rates based on a constant volume calculation. Settings for Cornering Acceleration will also adjust feed rates on arcs and at sharp corners, thereby reducing servo lag error.

Two more limited and tedious methods, for the record:

1. The Change at Point menu provides a method of modifying feeds on contour toolpaths.

2. In V8, the Graphical Toolpath Editor allows editing of feeds at individual lines in the toolpath.

[This message has been edited by Dave Thomson (edited 06-05-2000).]

[Karl Oram]

Dave's suggestion to us the High feed would be a more accurate way of modifying the feed rates for your cutter path as it looks at volume and angle change for it's calculations. The area you noted in the job set up will change feed rates on any arc movement regardless.