Vision sensors in hostile environments

The paper provides an overview of a number of in process monitoring applications for vision sensors, particularly in hostile manufacturing environments such as arc and spot welding, molten metal pouring, wood processing and electronics. When vision sensors are mounted right in the manufacturing process, rather than after the fact, instant data to detect process becomes available for closed loop control and instant response. Each in-process monitoring environment has it's own specific needs regarding sensor performance specifications, environmental factors, operator interface requirements and different industrial practices. A description of typical user interfaces, including integrated systems capabilities, is provided. Specially designed sensor environmental protection for hostile in-process applications is a major issue. Considerable development effort on packaging vision sensors to survive harsh environments is described. Specific environments encountered include high temperature (both of the sensor environment and the surface monitored, including molten metal), high electromagnetic fields and metal splatter found near weld guns, dirty environments and saw mill applications operating in high ambient light levels. Results of testing to validate sensor performance in hostile environments are described. Results outlining the values found by users who have implemented vision sensing in process are discussed. Depending on individual applications, these cover a spectrum from quality and/or productivity increases, faster response to process changes, and cost reductions. Examples are provided from automotive assembly, foundry, and wood processing industries.