GB2053967A

GB2053967A - Selective plating of pin or socket connectors

Info

Publication number: GB2053967A
Application number: GB7926126A
Authority: GB
Original assignee: Standard Telephone and Cables PLC
Current assignee: STC PLC
Priority date: 1979-07-26
Filing date: 1979-07-26
Publication date: 1981-02-11
Also published as: ES493700A0; ES8106024A1; GB2053967B

Abstract

A method of selectively plating components with precious metal e.g. pin or socket connectors with gold is described so as to reduce the amount of precious metal used to get good contact when components are mated. The components 3 to be plated are placed in recesses 2 in a non- conducting medium 1 and plating solution is passed through the recesses e.g. via inlet 8 and outlet 11 forcing the components into contact with a cathode plate 6 at the bottom of the recess. A high rate and highly selective plating is achieved. <IMAGE>

Description

SPECIFICATION Selective plating of pin type connectors This invention relates to a method of selective plating of components and in particular to pin and socket connectors.

For male pin connectors and female socket connectors used in computers and other switching devices it is necessary to plate the connectors with a precious metal such as gold to enable good contact when the two connectors are mated and to reduce the corrosive wear on the connectors.

Conventional plating using barrel techniques gives a relatively even coating of the precious metal over the entire surface area of the pin and socket connectors and in additon to the amount of precious metal wasted it is also a comparatively slow process.

An object of the present invention is to provide a method of selective plating with a precious metal such as gold which is more economical than the methods hitherto used.

According to the present invention there is provided a method of electro-plating components with a precious metal, in which the components to be plated are placed in recesses in a solid nonconductive medium between two metallic electrodes which are used as the anode and the cathode for the application of the electro-plating current, in which an electroplating solution which contains one or more compounds of the precious metal to be plated on to the components is pumped through the recesses when the components are in place, in which the direction of the pumping is such as to urge the components into contact with the cathode but not with the anode, and in which the rate of electro-plating solution flow causes the components to be plated at high speed.

According to another aspect of the present invention there is provided a method of selectively electro-plating small components of substantially tubular form with a precious metal, in which the components to be plated are placed in narrow tunnel-like recesses in a solid non-conductive medium between two flat metallic electrodes which are used as the anode and the cathode for the application of the electro-plating current, in which an electro-plating solution which contains one or more compounds of the precious metal to be plated on to the components is pumped through the tunnel-like recesses when the components are in place, in which the direction of the pumping is such as to urge the components into contact with the cathode but not with the anode, and in which the anode and the cathode are energised with direct current while the solution is being pumped past the components, the arrangement being such that the components receive substantially thicker piatings at their ends which face the anode than at their ends which are in contact with the cathode.

As already mentioned, the method referred to above has been specially developed for plating pin and/or socket connectors of pin-like form with gold. Hence in accordance with a more specific aspect of the invention, there is provided a method of selectively plating pin and/or socket connectors of substantially cylindrical form with gold, in which the connectors to be plated are placed in narrow cylindrical tunnel-like recesses in a solid nonconductive medium, the recesses having crosssections only slightly greater than those of the connectors, the non-conductive medium being placed between two metallic electrodes which are used as the anode and the cathode for the application of the electro-plating current, in which an electro-plating solution which contains one or more gold compounds is pumped through the tunnel-like recesses when the components are in place, in which the direction of the pumping is such as to urge the connectors into contact with the cathode but not with the anode and in which the anode and cathode are energised with direct current while the solution is being pumped past the components, the arrangement being such that the connectors receive substantially thicker coatings at their ends which face the anode than at their ends which are in contact with the cathode.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Fig. 1 shows schematically apparatus for carrying out the invention; Fig. 2 shows a male pin connector with the plating profile achieved by the method of the invention; Fig. 3(a) shows a split bore female socket connector, Fig. 3(b) shows the plating profile achieved by the method of the invention on the socket connector of Fig. 3(a); Fig. 4 shows a simple large-scale apparatus for carrying out the method of the invention; and Fig. 5 shows an alternative position of the anode and the plating profile achieved by this placing.

The apparatus shown schematically in Fig. 1 consists of an insulating block 1 which has holes 2 drilled in it. The components to be plated are placed in the holes. In the case of cylindrical connectors these holes are also cylindrical. A pin connector 3 is shown inside one of these holes in Fig. 1. Insulating blocks 4 and 5 are clamped onto the block 1 with perforated stainless steel plates 6 and 7 in between as shown in Fig. 1. The diameters of the perforations at least of the plate 7 are smaller than the dimensions of the components to be plated. The steel plates 6 and 7 are connected to a d.c. supply (not shown) so that plate 6 is a cathode contact and plate 7 is an anode contact. A plating solution 9 is pumped by a pump 10 (see the Fig. 4) through an inlet or inlets 8 into the apparatus.The solution passes through the perforations in the anode contact, over the components placed in the holes in the insulating block, through the perforations in the cathode contact and out of the apparatus by means of outlet 11. The passage of the solution through the holes presses the components onto the cathode through the holes presses the components onto the cathode so ensuring good contact. Application of a voltage across the anode and the cathode results in the selective plating of the components.

By way of example only the plating profile of gold achieved on male pin connectors and female socket connectors will be described. The components were loaded into the holes in the insulating block 1 and after assembly of the apparatus a solution containing 12 g per litre of gold was pumped through using a peristaltic pump. Anodic and cathodic contacts were made to the stainless steel plates, and a current of 250 mA was passed for 1 minute. After disassembly the components were found to have the gold plating profiles shown in Fig. 2 and Fig.

3(b).

A 1 mm diameter male pin connector shown in Fig. 2 had a coating of gold less than 1 ym thick in the region A and at the head B a thickness up to 1 5 ,tom. A split bore female socket connector of diameter 1 mm shown in Fig. 3(a) had a coating of gold of similar thicknesses to the male pin connector and a plating profile is shown in Fig.

3(b). This method of plating leads to a good internal coating of gold in the bore of the female socket connector as the plating solution flows through the split bore of the socket connector in its passage through the apparatus.

This distribution of the plating occurs because the connectors, by being urged into contact with the cathode plate, each becomes effectively part of the cathode.

In a large-scale process the components may be easily loaded automatically into the holes and the high plating solution flow rate past the components gives a relatively fast rate of plating.

In Fig. 4, which has been referred to briefly already, the anode plate 7 is shown partly cut away to reveal the insulating-block 1 with its holes 2, also known as pots, and receive the components to be plated. In this case there are a number, four as shown, of inlets 8 for the plating fluid.

Fig. 5 shows a portion of the apparatus of Fig. 1 in which the anode 7 is placed as a laminate in the insulating block 1. The components 3 to be plated are inserted in the recesses in the insulated block, through the perforations in the anode, which, in this case are of larger dimension than the components.

Plating is achieved in a ring round the component shown in the drawing as P.

It is also possible for irregular shaped components to be plated by the method as described above.

Although we have described our plating method in the application to gold plating, it is also applicable to plating with the other precious metals such as platinum which are used in high quality connector manufacture.

Claims

1. A method of electro-plating components with a precious metal, in which the components to be plated are placed in recesses in a solid nonconductive medium between two metallic electrodes which are used as the anode and the cathode for the application of the electro-plating current, in which an electro-plating solution which contains one or more compounds of the precious metal to be plated on to the components is pumped through the recesses when the components are in place, in which the direction of the pumping is such as to urge the components into contact with the cathode but not with the anode, and in which the rate of electro-plating solution flow causes the components to be plated at high speed.

2. A method of selectively electro-plating small components of substantially tubular form with a precious metal, in which the components to be plated are placed in narrow tunnel-iike recesses in a solid non-conductive medium between two flat metallic electrodes which are used as the anode and the cathode for the application of the eiectroplating current, in which an electro-plating solution which contains one or more compounds of the precious metal to be plated on to the components is pumped through the tunnel-like recesses when the components are in place, in which the direction of the pumping is such as to urge the components into contact with the cathode but not with the anode, and in which the anode and the cathode are energised with direct current or current pulses while the solution is being pumped past the components, the arrangement being such that the components receive substantially thicker platings at their ends which face the anode than at their ends which are in contact with the cathode.

3. A method of selectively plating pin and/or socket connectors of substantially cylindrical form with gold, in which the connectors to be plated are placed in narrow cylindrical tunnel-like recesses in a solid non-conductive medium, the recesses having cross-sections only slightly greater than those of the connectors, the non-conductive medium being placed between two metallic electrodes which are used as the anode and the cathode for the application of the electro-plating current, in which an electro-plating solution which contains one or more gold compounds is pumped through the tunnel-like recesses when the components are in place, in which the direction of the pumping is such as to urge the connectors into contact with the cathode but not with the anode and in which the anode and cathode are energised with direct current or current pulses while the solution is being pumped past the components, the arrangement being such that the connectors receive substantially thicker coatings at their ends which face the anode than at their ends which are in contact with the cathode.

4. A method of selectively electro-plating small components of substantially tubular form with a precious metal, in which the components to be plated are placed in narrow tunnel-like recesses in a solid non-conductive medium, in which two metallic electrodes are used one as the anode and one as the cathode for the application of the electro-plating current, one electrode, the anode, being placed as a laminate in the insulating block and the other, the cathode, at the base of the insulating block, in which an electro-plating solution which contains one or more compounds of the precious metal to be plated on to the components is pumped through the tunnel-like recesses when the components are in place, in which the direction of the pumping is such as to urge the components into contact with the cathode but not with the anode, and in which the anode and the cathode are energised with direct current or current pulses while the solution is being pumped past the components, the arrangement being such that the components receive substantially thicker platings in the region where the anode extends through the insulating block than at their ends.

5. A method of selectively electro-plating small components of substantially tubular form as claimed in claim 2 in which the two metallic electrodes used for the anode and the cathode are perforated, the diameters of the perforations of the cathode being smaller than the diameters of the components to be plated.

6. A method of selectively plating pin and/or socket connectors of substantially cylindrical forms with gold as claimed in claim 3 in which the two metallic electrodes used for the anode and the cathode are perforated, the diameters of the perforations of the cathode being smaller than the diameters of the pin and/or socket connectors to be plated.

7. An apparatus for selectively electro-plating small components of substantially tubular form as claimed in claim 4 in which the two metallic electrodes used for the anode and the cathode are perforated, the diameters of the perforations of the cathode being smaller than the diameters of the components to be plated.

8. A method as claimed in claim 5 or 6, in which the two metallic electrodes are meshed.

9. A method of selectively plating small components of irregular form with a precious metal, in which the components to be plated are placed in narrow tunnel-like recesses in a solid non-conductive medium, the recesses having dimensions slightly greater than those of the components, the non-conductive medium being placed between two metallic electrodes which are used as the anode and the cathode for the application of the electro-plating current, in which an electro-plating solution which contains one or more compounds of the precious metal to be plated on to the components is pumped through the tunnel-like recesses when the components are in place, in which the direction of the pumping is such as to urge the components into contact with the cathode but not with the anode, and in which the anode and the cathode are energised with direct current or current pulses while the solution is being pumped past the components, the arrangement being such that the components receive substantially thicker plating at their ends which face the anode than at their ends which are in contact with the cathode.

1 0. A method of selectively electro-plating -smali components of irregular form as claimed in claim 9 in which the two metallic electrodes used for the anode and the cathode are perforated, the diameters of the perforations of the cathode being smaller than the diameters of the components to be plated.

1 A method as claimed in claim 10 in which the two metallic electrodes are meshed.

12. An apparatus for selectively electro-plating small components of substantially tubular form with a precious metal by the method as claimed in any one of claims 1 to 8.

1 3. An apparatus for selectively plating pin and/or socket connectors of substantially cylindrical forms with gold, including a solid nonconductive medium with narrow cylindrical tunnel-like recesses, the recesses having crosssections only slightly greater than those of the connectors, said solid non-conductive medium being positioned between two metallic electrodes which are used as the anode and the cathode for the application of the electro-plating current, the two metallic electrodes being perforated, the diameters of the perforations of the cathode being smaller than the diameters of the pin and/or socket connectors, means for pumping an electroplating solution containing one or more bold compounds through the tunnel-like recesses when the connectors to be plated are placed in the recesses, the direction of the pumping being such as to urge the connectors into contact with the cathode but not with the anode, and the anode and the cathode being energised with direct current while the solution is being pumped past the connectors, the arrangement being such that the connectors receive substantially thicker coatings at their ends which face the anode than at their ends which are in contact with the cathode.

14. An apparatus for selectively electro-plating small components of irregular form with a precious metal by the method as claimed in any one of claims 9 to 11.

1 5. A pin connector made by the method as claimed in any one of claims 1 to 8 or by the apparatus of claim 12 or 13.

16. A socket connector made by the method as claimed in any one of claims 1 to 8 or by the apparatus of claims 12 or 13.

1 7. A method of selectively electro-plating small components of substantially tubular form with a precious metal substantially as described herein with reference to the accompanying drawings.

1 8. An apparatus for selectively electro-plating small components of substantially tubular form with a precious metal substantially as described herein with reference to the accompanying drawings.