Process features

The abrasive paste extrusion process uses two opposing cylinders to extrude a semi-solid abrasive paste back and forth through the passages formed by the workpiece and fixture (figure 1 ). By repeating the extrusion from one cylinder to the other, the paste produces an abrasion when it enters a restricted passage in or around the part. The machining action is similar to a grinding or honing operation, with the abrasive paste lightly polishing surfaces and edges.

The process is abrasive only in areas of flow restriction. When the paste is forced into a restriction, the viscosity of the carrier polymer temporarily increases, rigidly holding the abrasive grains in place. They abrade the passages only when the polymer is in this state of increased viscosity....