Method of Forming Parts on a CNC Machine

A method of forming parts of selected profiles from workpieces mountable on a porous spoil board disposed on the worktable of a CNC router machine having means for applying a negative pressure on the underside of one of said workpieces mounted on a spoil board disposed on said worktable, providing a pressure differential across said mounted workpiece, and a cutting tool displaceable along x, y and z axes to form said selected profiles, comprising:

• loading a multiple sequence cutting program into the control of said machine wherein a first cutting sequence consists of
• comparing the surface area value of each part with a predetermined area value;
• adjusting the cutting depth of the cutting tool of the machine to provide less than a through cut where said surface area value is less than said predetermined area value, and a through cut where said surface area value is equal or greater than said predetermined area valve;
• mapping the cut path of said first cutting sequence;
• calculating the area of said cut path;
• and
• storing the value of the calculated cut path area,
• and wherein a second cutting sequence consists of:
• mapping the location of each part in said second cutting sequence;
• calculating the surface area of each part in said second cutting sequence;
• and
• calculating the ratio of the value of the calculated surface areas of the parts in said second cutting sequence to the stored value of the calculated cut,
• loading a workpiece on said worktable;
• activating said negative pressure applying means;
• operating said machine to execute said program;
• unloading said workpiece including cut parts upon execution of said program;
• and
• one of fly-cutting and replacing said spoil board where said ratio is not greater than a predetermined value.