Manufacturers of mass-produced parts and products, such as vehicles, rely on automated inspection machines for quality control and rejection of defective parts. Consumer demand as well as considerations of safety and efficiency have led to the development of inspection systems that rely on machine vision coordinated with robotics and computer aided design to achieve precision and quality. One such inspection system is the coordinate measurement machine (CMM). However, due to the relatively high costs of CMMs, less accurate and less expensive conventional industrial robots equipped with contact sensors are often used for inspection of parts. CMMs and robot-based systems operate by moving the sensor around the part to take measurements while the part is stationary. The inspection process is done off-line, preferably in an inspection room. It may take several hours to complete the inspection of a complicated automobile engine part. During this inspection time, bad or defective parts may be produced on the assembly line.
Researchers at University of Michigan have developed an inspection system for inspecting parts during a manufacturing process. The apparatus comprises a conveyor line for moving a part during a manufacturing process and a plurality of sensors and cameras mounted on stationary supports around the conveyor line. The conveyor line may be a part of or adjacent to the production line. The sensors measure a characteristic of a first part and produce an inspection output, and can be reconfigured for inspection of at least one different characteristic of a second part or for re-inspection of the first part at a different stage of the manufacturing process. The apparatus may include a computer system that receives the sensor inspection outputs and produces operator-accessible information.
Applications and Advantages
- Coordinate measurement machines
- Inspection done online (i.e during the manufacturing process)