Ramp rates angles or lengths?

[gundog]

Is there a rule of thumb for ramp rates maybe X times the diameter or an angle that is preferred? Is there a calculator or chart for different materials? I have gotten some poor finish results on soft plastic at times in the area of the ramp in. I have always just guessed how far to ramp in.

Thanks Mike

[wberminio]

Mike
Check out Brady's column:http://www.shopbotblog.com/index.php/2008/03/a-ramping-the-vr-command-and-how-to-tune-your-tool-for-maximum-performance/

[Brady Watson]

Is there a rule of thumb for ramp rates maybe X times the diameter or an angle that is preferred? Is there a calculator or chart for different materials? I have gotten some poor finish results on soft plastic at times in the area of the ramp in. I have always just guessed how far to ramp in.

Thanks Mike

Mike,
It's pretty much a guess...I know what you mean about ramping into certain plastics where the chips birdsnest and clump together for some reason. The only thing I could suggest is trying a 2-flute spiral-O instead of a single, since it will most likely be center cutting compared to the single spiral-O. Not sure if you have one in your collection, but you should if cutting plastics. I forget the Onsrud series number off the top of my head, but I want to say it is 52-624 (for 1/4").

-B