Machine Vision and Inspection

This system is widely used by machine makers in the manufacturing industry as a method for checking the quality of products or components on a production line. They can be found all over the world and in a number of different environments.

A factory in England produces stainless steel washers of various sizes. The production line is very basic. Washers are punched out of large sheet metal where they are dropped onto a conveyor belt ready to be packed into bags. One day, a worker found a bag containing a washing machine without a hole in the middle!

A vision inspection system could be introduced to identify this kind of fault before the faulty washer is packaged. A camera, placed at a point along the conveyor would be triggered to take a picture of a washer as it passes underneath. The image from the camera is relayed to a computer system that is pre-programmed by an engineer to interpret the image of the washer and decide if it is acceptable or faulty. A washer identified as faulty could be removed further down the line allowing only acceptable ones to be packaged.

This is a vision system almost at its most basic. They can do an awful lot more! Taking the washer example further; the computer system could be programmed not only to detect the presence of a hole but also check the size of the hole, the size of the washer’s outer diameter, the quality of the punched hole’s edge, roundness, scratches, colour and a whole lot more besides. Moving on from simple washers, a camera system can be used to take measurements and check the quality, alignment and presence of extremely complex assemblies.

A more recent use of vision systems is for robot guidance. Many modern car production lines rely on cameras to guide the robot arms in manouvering components like windscreens carefully into place on their vehicles.

This is only a very simple overview of what is an often a complex and vital part of the manufacturing process. In further articles I hope to go into greater depth of what makes up a vision system and how it integrates into the production line.