| 摘要 |
In production of jewellery there is a comprehensive metal preparation operation stage. This involves a dilute acid dip (25), a three-stage rinse (26), a concentrated acid dip (27), a hot rinse (28) and a drying stage (29). The concentrations and durations of these dips provide an extremely clean metal blank which is very suitable for reception and adherence of enamel. Enamel is wet-filled and there is direct flame heating for firing of the enamel. Both the enamel firing stage (32) and an annealing stage (24) are carried out by direct application of heat which has been found to be extremely effective and with a low defect rate. For plating, there is a sequence of steps involving a detergent dip (40), a rinse (41), an acid de-grease (42), and a rinsed step (43) which further prepares the jewellery item for nickel plating (44). After removal of all excess nickel the item is further plated, eg with gold. |
