JPS58144498A - High speed plating apparatus - Google Patents

Abstract

PURPOSE:To make it possible to reduce the irregularity of a plating thickness, in a plating chamber consisting of a cylindrical electrode and a non-conductive holding member of the electrode having an outflow and an inflow ports of a plating liquids, by specify the cross area ratio of the outflow and inflow ports of the plating liquid. CONSTITUTION:A plating chamber 1 is constituted from a cylindrical electrode 3, non-conductive holding members 6, 7 having an outflow and an inflow ports provided to the upper and the lower ends thereof and a lid 10a hermetically closing the upper opening part of an internal chamber 8 formed by the electrode 3 and the holding members 6, 7 and integrated with a shaft 10 for holding an object W to be plated. The outflow and the inflow ports 5, 4 of the plating liquid are provided in such a manner that the ratio of the cross area of the outflow port 5 to that of the inflow port 4 is adjusted to 1.5 or more. By this mechanism, the flow of the plating liquid on the surface of the object W to be plated becomes uniform and a plating thickness of high speed plating to a long cylindrical body can be made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called high-speed plating apparatus that performs chromium plating or other electroplating on the outer peripheral surface of a long cylindrical body in a plating solution flowing at high speed.

Generally, in the case of the high-speed metallurgy method, in order to increase the critical current density, it is necessary to provide a relative flow velocity between the electrode and the workpiece (object to be plated) to create a turbulent flow state and suppress the growth of a diffusion layer. It is said.

The relative flow velocity that causes turbulence is said to be 0.8 m/see or higher, and methods for obtaining the relative flow velocity include plating hydraulic perforation,
A work rotation type or an electrode rotation type is considered. Among the above, the work rotation type or electrode rotation type is often used in laboratories because it is possible with a relatively simple mechanism, but there are problems with the power supply method to the rotating part, and carbon brushes may wear out. It has a defect that makes it unable to withstand long-term use. For this reason, when high-speed plating is used for mass production, the reality is that most of the plating is of the hydraulic permeable type. However, in the case of hydraulic transparent plating, when high-speed plating is performed on the outer circumferential surface of a long cylindrical body, both ends of the plated object become thick.
The central part has a thin plating thickness distribution, which has the disadvantage of non-uniform plating thickness.

The present invention provides a high-speed plating device to solve this problem, and includes a cylindrical electrode and a non-metallic plate having one or more plating liquid inlets on the side surfaces provided at both the upper and lower ends of the electrode. Relating to a high-speed plating device comprising a plating chamber formed by a conductive holding member and a lid, and characterized in that the ratio of the plating solution outlet diameter cross-sectional area to the plating solution inflow diameter cross-sectional area is 1.5 or more. It is something.

Hereinafter, the apparatus of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the apparatus of the present invention.

In FIG. 1, reference numeral 1 indicates a plating chamber installed on a surface plate 2 on the floor where plating processing is performed.

The plating chamber 1 includes a cylindrical electrode 3 and non-conductive holding members 6 and 7 having one or more liquid inlets and outlets 5.4 (here, two each) on the side surfaces provided at the upper and lower ends of the plating chamber 1. The upper opening 9 of the internal chamber 8 is formed by these electrodes 6 and the non-conductive holding members 6 and 7 (the opening 9 is the upper non-conductive holding member which is the entrance and exit for the object W to be plated). The opening (coinciding with the opening in B) is sealed with a lid 10a integrated with the shaft 10 that holds the object W to be plated.The liquid inlet 5°4 mentioned above is tangential to the cylinder. The non-conductive holding members 6 and 7 are provided on the upper and lower lids 11 and 12.
, and are integrally connected using bolts 16 and nuts 14. The plating chamber 1 is fixed to the surface plate 2 with the lower cover 12 using bolts 15. Furthermore, the seal between the cylindrical electrode 6 and the non-conductive holding members 6, 7, and the seal between the upper non-conductive holding member 6 and the lid 102L integrated with the shaft 1o are all performed by the non-conductive holding member 6, 7. This is done through the fitting section 7 provided with a K ring groove and Q IJ ring, and the bolt tightening pressure is applied to seal the upper and lower ends of the cylindrical electrode 3 and the non-conductive holding members 6 and 7.

In the device of the present invention, the liquid inlet 5.4 described above is
It is provided so that the ratio of the diameter cross-sectional area of the outlet port 5 to the diameter cross-sectional area of the inflow port 40 is 1.5 or more.

The reason why this ratio is set to 1.5 or more is based on the practical results described below.
When the aperture cross-sectional area ratio becomes less than 1, the flow resistance of the plating solution becomes large and a large pressure is applied to the pump, causing problems.The resistance of the plating solution outlet 5 causes non-uniformity of the plating solution flow, resulting in an increase in the plating thickness. This causes variation.

・On the other hand, it has been confirmed that when the aperture cross-sectional area ratio is set to 1.5 or more, the plating surface of the object W to be plated becomes uniform in flow (flow speed, form, etc.) and the variation in plating thickness is reduced. It is something.

In this way, when performing high-speed plating on a long cylindrical body using the apparatus of the present invention, in order to make the plating thickness uniform, the internal chamber 8 provided in the non-conductive holding member 6. It is necessary that the ratio of the cross-sectional area of the plating solution outlet side 50 to the plating solution inflow side 40 diameter cross-sectional area of the plating solution inlets 5 and 4 that communicate with each other is 1.5 or more.

Example Using the apparatus shown in Fig. 1, the diameter cross-sectional area of the plating solution inlet and outlet was set such that the ratio of the outlet 5 to the inlet 4 was 0.5°1°0, 1.5.
, 2.0, and 3.0, and then applied Or plating to the outer peripheral surface of the object W to be plated, in which piston rings with an outer diameter of 77 φ, a width of 3.0 g, and a thickness of 165 mm were laminated. It was carried out under the following conditions.

Bath composition: Silica fluoride bath Temperature: 75°C Current density: 20 OA,/dm2 Plating time: 20 minutes, 40 minutes As a result, 20 An Or plating layer with a plating thickness of 100 μm was obtained by plating for 40 minutes, and a plating thickness of 200 μm by plating for 40 minutes, but the plating thickness varied in the above cross-sectional area ratios as shown in Figure 2. Ta.

In FIG. 2, the plating thickness variation on the vertical axis indicates the variation with respect to the standard plating thickness. Further, the curve α is for a plating thickness of 100 μm, and the curve β is for a plating thickness of 200 μm.

As is clear from FIG. 2, uniform plating can be obtained when the cross-sectional area ratio is 1.5 or more.

[Brief Description of the Drawings] Fig. 1 is a longitudinal sectional view showing an embodiment of the apparatus of the present invention, and Fig. 2 is a chart showing the results obtained in the embodiment of the present invention. The relationship between the ratio and variation in plating thickness is shown. Agents 1) Akira's agent Ryo Hagiwara - Figure 1

Claims (1)

[Claims] It consists of a cylindrical electrode, a non-conductive holding member having one or more plating solution inlets on the side surfaces provided at the upper and lower ends of the electrode, and a plating chamber formed by a lid, and has a diameter cross-sectional area on the plating solution inlet side. A high-speed plating device characterized in that the ratio of the diameter cross-sectional area of the plating liquid outlet side to the diameter of the plating liquid outlet side is 1.5 or more.