Re: [CAD_CAM_EDM_DRO] Radius Compensation---Leadin

Art Fenerty wrote:

> Hi all:
>
> Can someone explain Lead-in's on radius compensation.
>
> If I have a program which cuts a sqaure contour for example.
>
> X10Y0
> X10Y10
> X0Y10
> X0Y0
>
> and I wish to do it in Radius Compensation, ex.
> G42D1
> X10Y0
> X10Y10
> X0Y10
> X0Y0 What would be my leadin values after G42D1. As it is I get a proper cut except for the start and I suspect I don't understand the Lead-in values. (This all assumes a 6mm bit is in Slot1) . Shouldn't I get a nice Square with rounded edges with a 3mm offset.

Look at http://206.19.206.56/rs274.htm under How to use Cutter Diameter Compensation
to see an example of how I did it. Basically, you have to define a special point off the
workpiece, where the cutter won't gouge anything. This has to be at least one cutter
diameter from the point where the tool will contact the work. When you specify the
G42, it will then gradually interpolate in the offset compensation during the move, so that
the offset compensation will be fully in at the end of the move. The second concern is
that the actual movement must not have an inside corner, as this will cause EMC to
report an error. So, the choice of the point to begin the offset leadin from is pretty
tricky. Exiting offset compensation (G40) is done similarly to this.

Jon