within the global Johnson Matthey family that would be:

1) Technically equivalent to rings stamped from sheet
2) Substantially more efficient to produce

This paper will share the Johnson Matthey assessment of several alternate manufacturing techniques, circa 1989, that led to the selection of Hot Extrusion of Seamless Tube as our primary method of manufacture resulting in the production of over 1/2 million T.O. of heavy wall platinum tube that the North American jewelry industry has converted into over 2 1/2 million wedding bands from 1991 through 2002.

                                                   Table I
                                       Stamped Ring Blank
• Cast Ingot
• Machine ingot to remove surface distress
• Anneal if necessary (homogenization alloys prone to                          segregation)
• Roll to desired thickness (reduction / anneal schedule                       appropriate for work-hardening rate of alloy)
• Blank washers in as-rolled condition
• Machine to remove disturbed micro-structure (alloy & size                dependent)
• Anneal washers to ductile condition
• Press washer to pre-form geometry (potentially multi-stage)
• Anneal pressed washer
• Draw back pre-form to desired ring blank height (band width)
• Anneal to restore ductility
• Ring roll cylinder to finished OD / ID ring blank dimensions

Platinum Guild International USA 2004   All Rights Reserved

2 of 25