I have been running Mach 3 ver 1.84.001 for a couple years…love it but recently have been dramatically increasing my X,Y feeds to 250 ipm for melamine and am noticing  that the inside and outside corners of my parts are being rounded off. I have to eliminate this problem. Any body have some ideas. Much appreciated.

Hi, i-marc

You may be in Constant Velocity mode (G64), Put a G61 in the top of your G-code file for Exact Stop mode (G61), That maybe It.

You can check/set it in your Comfig file or use MDI line G61 also.

Hope this Helps, Chip

You can possibly reap the benefits of both modes by customizing the settings for your particular application.
Here is a VERY interesting read pertaining to the two modes, the associated settings and their intended funtions.
http://www.machsupport.com/docs/Mach3_CVSettings_v2.pdf
RC

Mach 3 runs in two ways - either Absolute Stop, or Constant Velocity.

To get a precise right angle on a cut, then the x axis must cut - to above the line (to allow for tool clearance) then stop. The Y axis must then start. This happens when you jave the machine set to Absolute Stop - see General Configuration - second column.

In Constant Velocity - which is designed to smooth out changes between multiple straight lines, - the computer  calculates the acceleration of the next line, and as the last line slows down, to a stop, it feeds in the acceleration of the next - i.e. it never stops - constant velocity.

You can never, however , get rid of the rounding on an inside angle, because of the tool diameter.