(19)

(11)

EP 0 642 599 A1

(12)

(43) Date of publication: 15.03.1995 Bulletin 1995/11 (21) Application number: 93910285.0 (22) Date of filing: 26.05.1993

(51) International Patent Classification (IPC):  B24C 3/ 32( . ) B24C 11/ 00( . ) C23C 16/ 27( . ) B24C 5/ 08( . ) C23C 16/ 02( . ) (86) International application number: PCT/GB1993/001082 (87) International publication number: WO 1993/024676 (09.12.1993 Gazette 1993/29)

(84) Designated Contracting States: DE FR GB IT NL (30) Priority: 26.05.1992 GB 19920011107 (71) Applicant: BRITISH TECHNOLOGY GROUP LIMITED London SE1 6BU (GB)	(72) Inventors: JOHN, Phillip Juniper Green, Edinburgh EH14 5DQ (GB) WILSON, John Ivor Barrett Balerno, Midlothian EH14 7DG (GB) DRUMMOND, Iain Cameron Edinburgh EH12 8UN (GB) (74) Representative: Gaskin, John Shield  Patents Department British Technology Group Ltd 101 Newington Causeway London SE1 6BU London SE1 6BU (GB)