Gap sensing benefits in Conform/spl trade/ extrusion machinery

The work presents the results of production trials of a gap sensing system for continuous extrusion machinery. It is critical to maintain a precise pre-defined extrusion gap for the efficient running of the continuous extrusion process and to maintain product quality. A high temperature capacitive gap sensing system is designed and implemented on a copper extrusion machine in a production plant. The results from the successful gap sensing production trials are presented and the benefits of the gap sensing system are demonstrated. First it is shown that machine setup times prior to production can be reduced from 35-40 minutes to 5 minutes with active gap sensing. The sensors can be used for on-line direct gap measurement and control, and for the first time provide a detailed view of extrusion zone gap behavior during a full production cycle. The gap sensor is used to evaluate the relationship between gap size, and waste levels. It is shown that there is a linear reduction of waste levels from 20% to 2%, when the gap size is reduced from 1 mm to 0.15 mm.