A straightforward and low-cost pre-inspection measurement method for small gears

On-line or rapid inspection of parts is essential in streamlining manufacturing processes. A novel pre-inspection method for measuring small gears is proposed. This method requires little specialist equipment outside that normally found in a laboratory or on a shop floor. Gears are measured using a standard optical microscope. These are then processed using an image processing algorithm to give a percentage error in tooth profile. This allows only gears of sufficiently high quality to be “passed on” to more sophisticated inspection techniques. The technique is used to analyse sub-centimetre diameter gears produced using WEDM. It is found that the technique provides a simple but effective method of determining how close a gear is to the required geometry. While the result is basic, it is extremely quick and inexpensive to perform alongside the manufacturing process. This method provides a capability to small companies and production lines for pre-inspection of gears before detailed analysis without purchasing specialist equipment.