Last week’s Tips & Tricks described the Haas control’s capability to vary machining accuracy according to the operation being performed, or more specifically whether it is necessary to have the machine slowing in corners to achieve micron level positioning when the operation is roughing?
In the same way, the Haas controlled machine tool is capable of varying its rates of acceleration and deceleration according to the values of user defined setting 191 – Default Smoothness. This setting can be changed from Rough, Medium or Finish and this corresponds to the more commonly used terms of Roughing, Semi-Finishing or Finishing, the machine control defaults to Medium but the user is free to alter this setting according to their particular requirements and the change will have a global effect on all future programs.
However the G-code G187 which allows the user to vary the accuracy in last week’s Tips & Tricks is actually a dual function code which when specified with a P value provides the facility to alter the smoothness with which the machine operates within a specific program. The three possible alternatives are P1, P2, or P3 and their refer to Rough, Medium or Finish accordingly and hence in line with the accuracy, the user can alter the performance characteristics of the machine’s axis drives to reduce cycle time and increase productivity.