GB1510787A - Apparatus for automatically measuring internal stress in an electrodeposit - Google Patents

Abstract

1510787 Automatic control systems LUCAS ELECTRICAL Ltd 18 July 1975 [20 July 1974] 32232/74 Heading G3R [Also in Division C7] Internal stress in an electro-deposit is automatically measured by apparatus comprising means for holding a flexible, conductive test strip 12 e.g. clamp 11 on rotary magazine 10, probe means 13 spaced from the holding means, an electrodepositing bath 14, means for effecting relative movement between the bath and holding means to immerse the strip at least partially in the bath e.g. pneumatic piston/cylinder 22 for raising the bath 14 on table 20 on vertical supports 21, means for moving the probe means 13 e.g. stepping motor 25 to determine the distance of a portion of the strip from a datum position before and after a predetermined amount of electro-deposit has been provided on one surface of the strip (the other being covered e.g. by lacquer resist), and means for comparing the distances e.g. memory registers (31 and 32) Fig. 4 (not shown) and arithmetic processor (33) to determine the amount of strip deflection, Fig. 3, to obtain e.g. from an output selection unit (34) a measurement of the internal stress. By moving the bath as shown, no movement of strip occurs between measurements except that produced by internal stress in the electro-deposit. The probe means may be a horizontally movable table 15 with mounted support 16 carrying an energy emitter e.g. light source, (17) Fig. 2, (not shown) and a spaced energy sensor e.g. photoelectric cell (18) arranged to produce a signal when the strip 12 intercepts an energy beam passing therebetween; or a proximity device. Internal stresses may be regulated in an electro-depositing operation e.g. electro-plating or electro-forming by an automatic dosing arrangement, Fig. 6, comprising the above apparatus, means e.g. pump (43) for continuously supplying electrolyte from the operation e.g. an electro-plating bath (35) to the bath 14 e.g. via lower inlet conduit 23, at least one dosing material supply e.g. tensile and compressive stress inhibitors from respective tanks (35, 36) via supply pipes (38, 39) (fitted with respective solenoid control valves (40, 41) for the operation, and means e.g. control unit (44) for controlling the dosing material supply in response to signals (related to the amount from output unit (34) of strip deflection from the apparatus. The electrolyte may be continuously recirculated e.g. via upper weir outlet 24 to the electro-plating bath (35).