JPH0535855U - Plating device - Google Patents

Abstract

(57) [Summary] [Purpose] To eliminate variations in plating thickness due to fluctuations in the wetted area between batches when immersion plating a small part of the tip of a metal piece. [Structure] The change in voltage between the metal piece 1 and the anode 2 when the plated area 5 is changed at a constant current is measured, and a conversion formula for the inter-electrode voltage and the plated area is obtained. Measure the inter-electrode voltage when a constant current is applied at the beginning of plating and estimate the plating area by the conversion formula. Next, the plating power source is controlled by the product of the estimated area and the specified current density, and plating is performed for the specified time. That is, plating can always be performed at a constant current density even if the batch is changed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a plating apparatus, and more particularly, to an apparatus for plating a part of the tip of a metal piece by controlling the liquid level.

[0002]

[Prior Art]

 In conventional plating equipment, the anode is set in a plating tank filled with plating solution, part of the tip of the object to be plated as the cathode is immersed in the plating solution, and a constant current power supply is used for a certain period of time. , Was configured to plate.

In this plating apparatus, when performing continuous plating by batch processing, in order to reduce the variation in the thickness of the plating film, the height of the liquid level of the plating solution, the height of the object to be plated, and the accuracy of the plating jig. Etc. must be strictly controlled.

[0004]

[Problems to be solved by the device]

 In this conventional plating apparatus, when the length of the material to be plated dipped in the plating solution is short, the actual wetted area is greatly affected by fluctuations in the crawling height of the liquid and the plating film It becomes a major controlling factor of thickness variation.

The solid-liquid interfacial tension is more strongly governed by the surface state of the solid than the surface tension of the liquid, and it is very difficult to control this constant. Even if the solid surface is in a dry state, it immediately adsorbs steam. Alternatively, even if it is immersed in a liquid in advance, it is difficult to make the wet state constant because of variations in surface roughness and physical / chemical adsorption capacity.

Therefore, when a plating film having a constant thickness is applied to a part of the tip of the object to be plated, there is a problem that the thickness variation of the plating film increases as the plating length is shortened.

[0007]

[Means for Solving the Problems]

 A plating apparatus of a first invention is a plating tank, an anode and a metal piece as a cathode set in the plating tank, a power supply for supplying a constant current between the anode and the metal piece, and the anode. It includes a voltmeter that measures the voltage between the metal piece and a calculation control unit that calculates the plated area of the metal piece from the signal from the voltmeter and controls the current supplied to the metal piece. It is a waste.

A plating apparatus of a second invention is a plating tank, an anode and a metal piece as a cathode set in the plating tank, and a power supply for supplying a constant current between the anode and the metal piece. A voltmeter that measures the voltage between the anode and the metal piece, a sequencer that calculates the plated area of the metal piece based on the signal from this voltmeter, and a vertical movement of the metal piece based on the signal from this sequencer. And a movable means for causing the movement.

The voltage between the cathode and the anode is represented by V = I [R (boundary) + R (liquid)].

The R (boundary) is governed by the true contact area of the solid and the surface coating resistance of the solid, but variations in the surface coating resistance can be ignored immediately after controlled plating pretreatment. R (liquid) is governed by the amount of ions in the liquid, but this also does not change suddenly in a short time if it is a plating liquid in which a conductive salt is controlled. Therefore, the main cause of the voltage fluctuation between the electrodes in a short time can be regarded as the fluctuation of the true contact area (plating area) of the solid.

That is, the voltage between the cathode and the anode is measured, the plating area is estimated and the current is increased or decreased (the cathode current density is kept constant), the plating time is controlled according to the voltage, or the voltage is kept constant. By vertically moving the object to be plated (making the plating area constant), it becomes possible to form a plating film having a constant thickness.

[0012]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of the first embodiment of the present invention.

In FIG. 1, the plating apparatus includes a plating tank 13 filled with a plating solution 3, an anode 2 set in the plating solution, a metal as a cathode which is the anode 2 and an object to be plated. A power supply 10 that supplies a constant current to the strip 1, a voltmeter 11 for measuring the voltage between the anode and the metal strip, and a signal from the voltmeter 11 covers the metal strip 1. It is mainly configured by an arithmetic control unit 12 that calculates a contact area 5 and controls a current supplied to the metal piece 1. The process will be further described below with reference to the process chart shown in FIG.

First, a metal piece 1 to be plated is immersed in a plating solution 3 and a constant pulse current I _p is supplied from a power source 10 controlled by a calculation control unit 12 including a sequencer and a CPU, and an anode is also provided. The voltage V _m between 2 and the metal piece 1 is measured by the voltmeter 11. Then, the output of V _m is input to the arithmetic and control unit 12, the plated area S is estimated by a predetermined conversion formula S = f (V), and then the product of the cathode current density D _k under the plating conditions is calculated. The plating current I _a is calculated. Next, based on this I _a , the arithmetic control unit 12 controls the plating power source 10 to plate the metal piece 1 for a certain period of time.

Further, it is possible to control the plating time for adjusting the thickness of the plating film to a predetermined thickness according to the area S.

FIG. 2 is a block diagram of a second embodiment of the present invention. In the second embodiment, a constant current is supplied from the power source 10A to start plating on the metal piece 1 so that the inter-electrode voltage V _m measured by the voltmeter 11A becomes a predetermined voltage. The pulse motor 6 is controlled so that it can be moved up and down by the pulse motor 6 to change the height of the metal piece 1 so as to keep the plated area 5 wet with the liquid surface 4 constant.

As described above, according to the second embodiment, since the area to be plated and the thickness of the plated film are made constant only by controlling V _m , there is an advantage that the control unit can be simplified.

[0018]

[Effect of the device]

 As described above, the present invention can control the plating conditions for each batch, so that there is an effect that variations in plating thickness between batches can be reduced and defective plating thickness can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a process drawing for plating using the first embodiment.

FIG. 3 is a block diagram of a second embodiment of the present invention.

[Explanation of symbols]

 1 Metal Fragment 2 Anode 3 Plating Solution 4 Liquid Level 5 Plated Area 6 Pulse Motor 10, 10A Power Supply 11 Voltmeter 12 Calculation Controller 13 Sequencer

Claims (2)

[Scope of utility model registration request] 1. A plating tank, a metal piece as an anode and a cathode set in the plating tank, a power supply for supplying a constant current between the anode and the metal piece, and the anode and the metal piece. It is characterized by including a voltmeter for measuring a voltage between the voltmeter and an arithmetic control unit for calculating a plated area of the metal piece by a signal from the voltmeter and controlling a current supplied to the metal piece. Plating equipment. 2. A plating tank, a metal piece as an anode and a cathode set in the plating tank, a power supply for supplying a constant current between the anode and the metal piece, and the anode and the metal piece. A voltmeter for measuring a voltage between the voltmeter, a sequencer for calculating the plated area of the metal piece by a signal from the voltmeter, and a moving means for moving the metal piece up and down by a signal from the sequencer. Characteristic plating equipment.