Real time machining control system including in-process part measuring and inspection

An in-process machining control for a machining system of the type which includes a bed, means for rotating a part to be machined, a longitudinal slide, a cross slide carrying a cutting tool, a computer numerical control having a part program and providing output signals, a position feedback signal for modifying said computer output signals and providing control signals for controlling the position of the cutting tool in accordance with said part program, comprising:

• non-contact detector means for continually determining an instantaneous actual dimension of the rotating part immediately behind the tip of said cutting tool and providing an actual dimension signal representative of the instantaneous actual dimension of said part at a given Z-axis position;
• means for comparing said actual dimension with said part program and producing an error signal representative of the difference between said instantaneous actual dimension of said part and said part dimension for the corresponding Z-axis position;
• means responsive to said error signal for modifying said position feedback signal;
• and
• X-axis drive means responsive to said modified position feedback signal to cause said cutting tool to be moved so that said part is actually machined in accordance with said part program.

An in-process machining control for a machining system of the type which includes means for rotating a part to be machined, a cutting tool, a computer control having a part program and providing tool position output signals, a position feedback for modifying said tool position output signals and providing a control signal for controlling the position of the cutting tool in accordance with said part program, comprising:

• non-contact detector means for providing signals representative of the upper and lower edges of the rotating part immediately behind the tip of said cutting tool and at a given Z-axis position;
• signal processor means responsive to the signals from said detector means for providing an actual diameter signal representative of the instantaneous actual diameter of said part;
• means for comparing said instantaneous actual diameter signal with said part program and producing an error signal representative of the difference between the instantaneous actual diameter of said part and the desired part dimension for the corresponding Z-axis position;
• means responsive to said error signal for modifying said feedback control signals;
• and
• X-axis drive means responsive to said modified feedback control signal to cause said cutting tool to be moved whereby said part is actually machined in accordance with said part program.

An electro-optical measuring system, comprising:

• first and second spaced-apart light source units arranged to direct light toward a body the limits of a parameter of which is to be measured so as to shadow the edges of said body which define the limits of said parameter;
• first and second spaced-apart light sensor units disposed opposite said first and second light source units for receiving light therefrom, signal processor means responsive to the output of said light sensor units for calculating said parameter;
• and
• means for simultaneously and correspondingly moving said light source units and said light sensor units toward and away from each other to accommodate a range of sizes of the body to be measured.

A system for measuring the profile of a thread on a body, comprising:

• optical ranging sensor means disposed at a preselected elevation with respect to the body and the thread to be measured and providing an output;
• drive means connected with said optical ranging sensor means for moving said optical ranging sensor means across the profile of said thread;
• means responsive to the output of said optical ranging sensor means for measuring changes in elevation of the thread as said optical ranging sensor means moves along said body;
• and
• means responsive to the measured changes in elevation for translating said changes into actual dimensional features of the thread.

A method of measuring the profile of the surface of a body having a thread thereon, comprising:

• coating the surface of the body with a material to make light scattered from said surface uniform;
• moving an optical ranging sensor means at a fixed elevation along the surface of said body to provide an output;
• calculating from the output of said optical ranging sensor means the changes in elevation along the surface of said body;
• and
• translating and calculated changes in elevation into actual dimensional features of said thread.