Patent ID: 9690282
Date: 2017-06-27
CPC Classifications: G05B,Y02P

Claim:
1. An automated computer-implemented method for controlling a computer numerically controlled milling machine to fabricate a machined object from a workpiece having a Z-axis, said machined object being configured to facilitate subsequent finishing into a finished object, the method comprising: defining a surface of said finished object; defining an offset surface, said offset surface being outside said surface of said finished object and separated therefrom by an offset distance, said offset surface defining an inner limiting surface of said machined object; defining a scallop surface, said scallop surface being outside said offset surface and separated therefrom by a scallop distance, said scallop surface defining an outer limiting surface of said machined object; and— calculating a tool path for said computer numerically controlled milling machine which produces multiple step-up cuts in said workpiece at multiple heights along said Z-axis, said multiple step up cuts in said workpiece resulting in said machined object, wherein: surfaces of said machined object produced by said multiple step-up cuts all lie between said inner limiting surface defined by said offset surface and said outer limiting surface defined by said scallop surface; and a number of multiple step-up cuts in said workpiece at multiple heights along said Z-axis and areas cut in each of said multiple step-up cuts are selected so as to minimize the amount of workpiece material that is removed from said workpiece during said cuts while ensuring that said surfaces of said machined object produced by said multiple step-up cuts all lie between said inner limiting surface defined by said offset surface and said outer limiting surface defined by said scallop surface; and directing said computer numerically controlled milling machine along said tool path, said calculating said tool path for said computer numerically controlled milling machine comprising calculating a first step height along said Z-axis of a step-up cut from a bottom of an initial cut for a collection of mutually azimuthally separated points distributed all along a curve representing an intersection of a step forward edge wall defined by the initial cut with a step floor surface also defined by the initial cut, said calculating a first step height along said Z-axis of a step-up cut from a bottom of an initial cut for a collection of mutually azimuthally separated points including: for each one of said collection of points, drawing an imaginary vertical line, parallel to said Z-axis to extend through said point and intersect at a scallop curve intersection point with said scallop surface; ascertaining a lowest height of a scallop curve intersection point corresponding to any of said collection of mutually azimuthally separated points; and selecting said lowest height of a scallop curve intersection point to be the first step height along said Z-axis of a step-up cut from a bottom of an initial cut.