How Does the Haas High-speed Machining Option Work?

The high-speed machining option in the Haas control works by analysing the change in vector direction, or change in angle, from one block to the next. When the change in vector direction is very small, as with code produced by using a small cut tolerance value, the control can interpolate the motion at a higher feedrate than when the change in vector direction is greater. The greater the change in vector direction, the more the control must slow the motion to stay on the programmed path. 

For this reason, you never want to drive your cutter into a sharp internal corner. The machine motion has to come to a nearly complete stop to change direction at such a sharp angle in the span of one block of motion. In that brief period of hesitation in a sharp corner, any tool pressure or tool deflection will be reduced and may result in small gouges at the surface intersections. 

You should always model a fillet radius larger than the radius of the cutter being used, or select a cutter with a smaller radius than the required fillets. This allows the machine to make the large change in direction over more blocks of code. The machine motion will be much smoother and faster, and produce better finishes in those areas.