GB1464096A - Method of effecting an abrading process - Google Patents

Abstract

1464096 Abrading E G FELDCAMP 10 June 1974 [12 June 1973] 27824/73 Heading B3D A method of finishing an aperture in a component, such as an extrusion die, drilled passage in a valve block, or window of an anti-friction bearing cage, comprises placing a billet of an abrasive compound in a chamber of a press 12, forcing the abrasive compound through the aperture, and receiving the abrasive compound in a confined space 18 whereby to reform it into a billet for subsequent re-use. The press has a ram 12 movable along vertical guides 13 above a platen 10 having a stepped bore in which is a replaceable plate 15 having a bore 11 aligned with a bore in a replaceable wax recovery gallery 14. The box 11 in the plate 15 is flared and, in operation, encompasses the workpiece aperture and contains a body of the abrasive compound through which back pressure is applied to the abrasive in the workpiece aperture. A recovery cylinder 17 is pivotally mounted on a projection 23 on a plate 16 secured beneath the platen 10. A hydraulic rotary actuator 26 is operable to pivot the container between an operative position, as shown, in which the container is releasably secured by a hydraulically actuated latch 20 engaging a lug 19, to a horizontal position wherein a billet of the used abrasive compound can be ejected from the container for re-use. The container 17 has a hydraulically operated piston 22 connected to a ram 25 supplied with hydraulic fluid at a pressure proportional to that applied to the press 12 so that as the abrasive compound is forced through the workpiece aperture, a back pressure is applied in the container 17. The container is slightly smaller than the chamber of the press so that a billet formed in the container is easily received in the chamber of the press. Billets of successively finer abrasive may be used ranging from a grit size of 150 to 1000, the abrasive being silicon carbide grit mixed with plasticized petroleum wax. The finished aperture may be cleaned by using a billet of clear wax and washing. In another embodiment, the recovery cylinder is horizontal and has a side entry for receiving used wax and an end plate which is removable for ejecting the billet.