METHOD FOR CONTROLLING DEPOSITED QUANTITY IN VACUUM DEPOSITION PLATING

PURPOSE:To minimize a waste part in changing by increasing the quantity of heat supplied to an evaporation bath and decreasing the opening degree of a shutter in a previous lot and suddenly increasing the opening degree in changing, when changing to a lot of greater METSUKE (unit, 200-2000g/m ) quantity at the middle part of a coil in continuous vacuum deposition plating. CONSTITUTION:After metal 1, such as Zn is melted in a melting furnace 2 and fed to an evaporation vessel 3 by suction and heated by a heater 5, the metal is introduced into a vapor duct 7 through a shutter 6 to plate a steel belt 8 by vapor deposition. At the change point which is two lots before the lot where METSUKE (unit) quantity is increased at one lot before, first power to the heater 5 for a metal deposition bath is suddenly increased. To compensate the increase of the evaporated quantity, the opening degree of the shutter 6 is gradually decreased to maintain the same METSUKE (unit) quantity as that of the previous lot. Next, at the change point to the lot of the in creased METSUKE (unit) quantity, when the opening degree of the shutter 6 is suddenly increased, the evaporated quantity is suddenly increased to increase METSUKE (unit) quantity. As the evaporated quantity is suddenly increased, the opening degree is gradually decreased to compensate it.