SU775196A1 - System for mean-thickness control of parts galvanic plating - Google Patents

Description

I

The invention relates to the field of electrochemistry and can be used to automate the processes of electroplating.

The system of monitoring the average thickness of electroplated coatings on parts is closest to the invention in terms of technical essence and the achieved result. It contains stationary measuring electrodes with shunts, power sources, each of which are connected to j to one from the baths and to the control computer II.

A disadvantage of the known system is that for measuring the average current density and determining the thickness 2o of the coatings on the parts in the working bath, it is necessary for each time to determine the configuration factor in the working bath for different parts, i.e. to carry out complex and laborious measurements, which limits the use of this device in practice.

The purpose of the invention is to improve the accuracy of control by automating measurement processes.

This goal is achieved due to the fact that the system is equipped with a coating thickness measurement sensor permanently installed on the measuring electrode of the working bath, with the outputs from the shunt of the measuring electrode and the thickness sensor being connected by the control computer.

FIG. 1 is a block diagram of the system; in fig. 2 is a block diagram of a calculation algorithm for calculating the average coating thickness on parts using a control computer.

The electroplating thickness control system consists of an electrochemical degreasing bath 1, a power source 2 thereto, a shunt 3 for measuring the current of the bath, a measuring electrode 4 permanently installed in the ECM bath with shunt 5 in its circuit, and anodes 6; a working bath 7 with an electrolyte, in which the anodes 8 are permanently installed, a sensor 9 for measuring the thickness during deposition on the measuring electrode 10 with a known surface area B., made of metal foil (for example, gold or other hardly soluble matter), cathodes 11 (suspension with details), and power point 12, additional power source 13 for etching the coating applied to the measuring electrode 10, shunt 14 for measuring the current through the working bath, shunt 15 for measuring the current through the measuring electrode Electrode, control computer (UBM) 16, which includes input devices 17 and 1 information output and processor 19; coating thickness recorder 20, amplifier 21 with output in the form of contacts 22, setting device 23 of initial coating thickness, comparison circuits 24 with a relay output in the form of contacts 25, which provide connection through normally closed contacts 22 of auxiliary electrode 10 of sensor 9 to an auxiliary source in etching mode power 13. The device operates as follows. At the beginning of the process, data 1 (see Fig. 2) is entered into the control computer by the ECO baths and the operating one (the average current density on the parts or the bath current is the current through the measuring electrode L3 of the thickness sensor, for mode 3iJ3- const a previously removed relationship for the working bath B. Changing the loading area b of the suspension from 60 to 100% with a configuration coefficient k: etc. When the suspension with 11 parts is fed into the electro-chemical degreasing bath (ECHO) in the latter with the help of control computers 16 determines the area of the parts to be covered 5d (pos. II of Fig. 2), for example, by measuring the current j, through shunt 3, the current through the measuring electrode 4 Zie with a known surface area 5 and determining the iC configuration factor of the parts on the suspension 11, entering these data to the control computer 16 and calculating the surface area of the DB by the formula, the value of which is remembered. At the end of the degreasing process, the suspension 11 with details follows the technological process and goes further to the main working bath 7. The preliminary nan process of passage of the coating is in a mode of stabilization of the Ztse current (pos. III of FIG. 2), through the measuring electrode 10 sensors 9 thickness C nj-const) and lasts about 1 - 10 s. At the end of this mode, the bath current is measured by shunt 14. the value of which enters the UBM 16 and is remembered (pos. IY of Fig. 2). UVM calculates the value of b .. (St.) on the basis of a certain value of the surface area 5d in the bath 1 of the ECHO (pos. At Fig. 2). After that, the working bath 7 is put into operation (pos. YI, fig. 2), i.e. the stabilization of the current set by the technological process of the bath CJj, defined as the product of the given current density rd by parts by the area bd and the surface of the parts defined in the bath. The current value du3 (pos. YII of Fig. 2) of the coating thickness on the measuring electrode 10 is measured. The current value of the average thickness of the coating on the parts is determined (Pos. YIII of Fig. 2) through the current thickness of the coating on the measuring electrode 10 of the sensor 9 of thickness According to the formula (1): ь.ычЫЛЛ Current bath e. is calculated according to the ampoule curve Zy.yych, previously removed in the working bath. bfeys D are the load area functions for parts with a configuration factor kL, and they are calculated based on the area d of parts for a given load determined in an ECM bath. After coating of a given thickness, the suspension 11c is discharged by parts into other baths specified in the technological sequence. In the absence of the suspension 11 in the bath 7 (more precisely, the absence of current dj,) the additional power source 13 is connected via the contacts 22 of the relay amplifier 21 to the measurement electrode. 10 of the thickness sensor 9 and the process of etching the applied coating from the measuring electrode begins until the current dyg thickness of the coating on the measuring electrode is not comparable with the set value c1t, after which the comparison circuit 24 with the relay output is triggered and the measuring electrode contacts 25 disconnects from an additional power source 13. Thus, the coating deposited on the measuring electrode to the initial value during the absence is provided. the arrival of a new suspension with details. The etching method is mainly used for relatively easily electrically etched coatings, such as zinc, copper plating, etc.

Claims (1)

Invention Formula A control system for the average thickness of electroplated coatings on parts, containing permanently installed in the preliminary preparation and in the working bath, measuring electrodes with shunts, power sources, each of which is connected to one of the baths and to the control computer, characterized in that in order to increase control accuracy by automating the measurement process, it is equipped with a coating thickness measurement sensor permanently mounted on the measuring electrode of the working bath, with the outputs from the measuring electrode shunt and thickness sensor connected to the inputs of the control computer. Sources of information accepted in the attention during examination 1. USSR Copyright Certificate 1 600217, cl. C 25 D 21/12, 1978, .- - r-f--, 775196 -.f- CutHOfl: Hem jodan HOto ptHcuna