Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Masking system

During the early preliminary trials it was observed that the blasting process produced a distinctive pattern across the leather. The centre portion was well roughed and is bordered by a well-defined area, which forms a clear interface between the well-roughed area and the untouched leather. Depending on the angle of approach, there is a varying amount of damage to the surrounding grain reinforcing the need for varying degrees of protection to the upper material. A simple mask provided an extremely well defined edge to the roughed area and in fact may introduce a potential weakness into the leather. Experiments with non-contacting masks revealed that significant damage to the upper material did take place.

Further experiments showed clearly that there needs to be actual contact between any sort of masking device and the upper material to produce the best roughing results. Even allowing small amounts of dust and debris to pass over the upper material results in unacceptable damage, typically resulting in a matting of the surface grain. Several different designs of mask were evaluated. The adopted solution used a rotating satellite disk of 60mm diameter, which traces a path around the feather line of the lasted upper both acting as a guide for the venture nozzle and as mask to protect the upper from over roughing. The disk is maintained in contact with the work-piece using passive compliance. Extensive tests have been carried out and the results obtained are considered excellent, with a well-defined transition between the processed area and the cosmetic surface showing no visible sign of abrasion.

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Reported by

Herschel Building
United Kingdom