The conception and development of a three dimensional laser machining system that can shape and contour ceramic shuttle tiles is described. The inputs are an unshaped billet of raw material and a Computer Aided Design (CAD) representation of the tile. The output is a machined and inspected tile. Experimental research was performed to develop tile cutting algorithms for the laser. Computers, lasers, and a five axis positioner were integrated to perform the cutting. A machine vision system was developed to inspect the tile without contact.
The three dimensional laser machining system had to satisfy two requirements: (1) it had to have the ability to cut to a desired depth within a material while controlling all parameters important to the cutting such as laser power, material feedrate, and assist gas type and flowrate, and (2) ablation of the material while minimizing melting and vapor deposition was necessary to prevent changing the physical characteristics of the surface. Over 2,900 exposures were made and laser cutting algorithms were developed to enable the design of laser tools in a CAD/CAM system.
A five axis Computer Aided Manufacturing (CAM) system was employed to automatically generate the toolpaths. The prescribed geometry was entered into the CAD system, descriptions of the laser tools were applied to the geometry and Computer Numerical Control (CNC) programs were generated to operate the positioner and the laser.
A three dimensional machine vision system was developed to scan the cut surfaces and compare them to the desired geometry. An analysis of the difference between the desired and actual shapes is capable of producing corrective machining steps.