Integration of Machining Inspection Sensors and Software

Abstract

<p>Ideally, the nominal design of a part or assembly, created with 3D Computer-Aided Design and Manufacturing (CAD/CAM) software, can be consistently fixtured and machined. In reality, process conditions vary, and feedback and correction methods such as integrated on-machine inspection, analysis, and process adjustment, are required.</p> <p>On-machine inspection based on touch trigger probes is well established, but limited motion control computing capability restricts analysis to simple arithmetic. This prevents on-line use of known whole part mathematical analysis software that implements the part salvaging intentions of modern Geometric Dimensioning and Tolerancing (GD&T) standards. Additionally, no CNC integrated method exists for geometrically adjusting nominal tool paths so that an in-tolerance final part is produced. Machine tool support for high data rate sensors such as laser scanners is also lacking.</p> <p>This thesis reports progress towards bidirectional integration of machine tool mounted inspection sensors with GD&T analysis software, and subsequent toolpath adjustment. The concepts are demonstrated using a fixture consisting of three datum spheres and a workpiece. The fixture is clamped in the CNC machine, datum spheres are measured, and after mathematical data fitting and registration, an in-tolerance final part is produced. To facilitate multiple tests, a tool path is split into four and machined in four poses with measurement and tool path adjustment for each pose. Preliminary integration of a laser scanner with axis scales and computer software was also accomplished.</p>