GB1454092A - Method of removing a burr from an electrically conductive article - Google Patents

Abstract

1454092 Removing burrs by gas plasmas ROLLS-ROYCE (1971) Ltd 10 Jan 1974 [17 Jan 1973] 2522/73 Heading B3V [Also in Division H5] A burr 23 is removed from an electrically conductive article 20 by exposing the article 20 to a gas plasma 21 at a temperature of 5000- 50,000‹ K. and using means capable of exothermic reaction with the burr 23. In one embodiment, Fig. 2, a metal workpiece 20 having a burr 23 is positioned in a plasma flame 21 generated by a plasma torch 1 comprising three concentric, silica tubes 2, 3, 4, each provided with a gas inlet 5, 6, 7, and a water cooled R.F. induction coil 9 of copper surrounding the outer tube 2. At the start of the operation, argon is supplied through the three gas inlets 5-7, whereafter oxygen is supplied through the torch inlet 7 and the R.F. power turned up to its maximum value. The burr 23 is converted by the plasma to a material which can be blown off or removed by brushing. Powders may be added to the gas or coatings provided on the workpiece or elsewhere to provide substances which chemically react with the burr material. The gas plasma has a pressure of 0À1 atmos to several atmospheres, including atmospheric and may alternatively be produced by nitrogen, oxygen or chlorine gas or sulphur or phosphorus vapour. The operation may be controlled by varying the power supplied to the plasma pulsing the plasma source or controlling the duration of the exposure of the workpiece. In another embodiment, Fig. 4, gear-wheels 110 to be deburred are conveyed by an indexing table 101 to a working station below a plasma torch 119. Each gear-wheel 110 is mounted on a carrier 102-(105) each provided with a friction roller 108 which is rotated by an electric motor 113 via rollers 111, 115 when the carrier is at the working station. The operation of the torch 119 and motor 113 is controlled by an electric circuit (Fig. 7, not shown).