CAST FIXTURE FOR COMPOSITE WORKPIECES AND METHOD AND APPARATUS FOR MAKING AND BREAKING UP THE FIXTURE

摘要

A cast metallic fixture for workpieces including twin turbine blades has two spaced-apart walls which surround portions of the exterior of a workpiece and several webs which connect the walls to each other. The fixture is made in a casting mold which has one or more inserts extending into the interior of a workpiece which is placed into the cavity of the mold preparatory to pouring of a molten alloy which is then caused to harden and to thus form the fixture. When the fixture has served its purpose of holding the workpiece in a grinding machine, it is broken up by subjecting its walls to bending and tensional stresses to destroy the webs, whereupon the walls are moved apart to afford access to the workpiece. The webs can be destroyed by melting simultaneously with or in lieu of the application of mechanical stresses to the walls of the fixture.