IES79070B2 - Electroplating - Google Patents

Abstract

An electroplating bath (1), (80), (81) has an anodic contact (60) for electrically contacting a secondary anode stub (40) and a cathodic contact (61) for electrically contacting cathode support bars (10) of an electroplating jig. A primary anode bar (70) supports baskets (71) containing anodic material below the level of electroplating solution in the bath (10, (81). There are two electroplating tanks (80, 81) and an interconnecting pipe (85) with a value (86) to achieve a substantially uniform electroplating solution in each tank (80, 81). A sensor (92) senses the temperature of the electroplating solution and control means (94) activates heaters (93) and/or a heat exchanger (90) to achieve a solution target temperature of 20 to 24°C.

Description

The invention relates to electroplating and in particular to an electroplating jig, an electroplating system, and method of electroplating a plurality of articles.

There are many steps involved in electroplating. A number of these steps are rate limiting as regards the speed of production. Various attempts have been made to improve the rate of production while maintaining quality. One such known improvement involves the use of a jig for mounting an article or articles to be electroplated.

There are, however, various problems involved in the use of such jigs as they are generally limited to use with specific articles.

There are also problems in that, over time they become damaged and/or consumed in the electroplating process. Furthermore, the electroplating process is, in general, difficult to operate in such a way as to optimise the rate of production of electroplated articles while maintaining product quality.

This invention is therefore directed towards providing a solution to at least some of these problems.

Statements of Invention According to the invention there is provided in electroplating jig for use in electroplating a plurality of articles in an electroplating bath, the jig comprising a support frame having a cathodic support means and an anodic support means, the cathodic support means comprising a cathodic rack for supporting articles to be eletroplated, the anodic support means comprising means for supporting secondary anode means for use in electroplating the articles, the cathodic racks having adjustable mounting means to accommodate a range of different articles to be electroplated.

Preferably the anodic support means includes a secondary anode bar which extends below the level of the electroplating solution in the electroplating bath.

Ideally the cathodic support means comprises a plurality of spaced-apart cathodic mounting brackets for supporting cathode rods, the secondary anode bar being supported on the cathodic mounting brackets by brackets of insulating material.

In a preferred arrangement the anodic support means includes an anodic stub at least at one end of the frame which is electrically connected to the secondary anode bar.

Preferably an anodic stub is provided at opposite ends of the frame.

Preferably the or each anodic stub supports the secondary anode bar.

According to one aspect of the invention the or each cathodic rack comprises a pair of uprights and a number of transverse support rods extending between the uprights, at least some of the transverse support rods being movable relative to the uprights to accommodate a range of different articles to be electroplated, rod mounting means being provided for mounting a movable transverse support rod to accommodate a range of different articles to be electroplated and releasable locking means for locking a movable transverse support rod to the adjacent upright.

Preferably, for ease of adjustment, the mounting means is slidably movable along the upright.

In one embodiment of the invention a sleeve is provided at both ends of a transverse support rod for engaging the uprights and the releasable locking means engages the sleeve to lock a transverse support rod in a desired position relative to the associated uprights.

Preferably the locking means includes a locking sleeve on the upright, the locking sleeve being movable along the upright and releasable locking means for locking the locking sleeve in a desired position.

Typically the releasable locking means is a locking screw.

In another arrangement the rod mounting means comprises a number of elements which are interengaged to lock onto an upright.

In this case preferably the interengagable elements comprise a pair of half sleeves, one of which is carried by the transverse support rod, the sleeve elements being wrapped around the upright.

In one embodiment of the invention the mounting means and the locking means are integral. In this case preferably the locking means comprises a locking bolt having an upright engaging head portion, the head portion being drawn into engagement by a nut which is fastened to the locking bolt.

Preferably a plurality of hook means are provided for each transverse support to support articles during electroplating.

In a particularly preferred embodiment of the invention the hooks are releasably mounted on the transverse support.

In a preferred arrangement the transverse support is substantially insulated except at a hook engaging part thereof.

Preferably the transverse support has a projecting part which is not insulated at the tip thereof to engage a hook when the hook is mounted to the transverse support.

For ease of mounting, preferably part of the hook is movable to engage an uninsulated part of the transverse in the mounting position of the hook.

The invention provides an electroplating system having a plurality of separate stations for performing operations associated with electroplating and a hoist for moving an electroplating jig from one location to another, the system including at least two electroplating tanks and an interconnector for interconnecting electroplating solution in the tanks to achieve a substantially uniform electroplating solution in the tanks, each tank having an anodic contact and a cathodic contact at least at one end of the tank for electrically contacting an anode of the jig and a cathode of the jig respectively.

Preferably the electroplating jig is the jig defined above.

Ideally, the electroplating tank has an anodic contact and a cathodic contact at opposite ends of the tank, each for electrically contacting secondary anode and the cathode of the jig.

In one arrangement, the electroplating tank includes primary anode means on opposite sides of the tank, the primary anode means comprising a primary anode bar and a basket for containing anodic material, the basket being releasably hung from the primary anode bar below the level of the electroplating solution in the tank.

In this case, preferably the primary anode means includes a hoist connection means for removal of the bracket from the electroplating tank to replenish the anodic material.

Ideally the interconnector comprises a pipe means between the tanks, the pipe means being fitted with a valve means to control the flow of electroplating between the tanks.

Preferably the inlets from the electroplating tanks to the pipe means are located at a position between a quarter and a half of the height of the electroplating solution in the tank.

In a preferred embodiment of the invention the inlets from the electroplating tanks to the pipe means are located at a position approximately one third of the height of the electroplating solution in the tanks.

The electroplating system preferably includes an electroplating solution conditioning system including heat exchanger means for heating and/or cooling the solution to achieve a target temperature of from 20 to 24° C in the electroplating tank.

In a preferred embodiment the conditioning system includes an electroplating solution temperature sensor, heating means for heating the electroplating solution, and control means for activating the heating means to heat the electroplating solution if the temperature falls below a target temperature.

Preferably the cooling means comprises a heat exchanger through which the electroplating solution is passed, the heat exchanger having a cooling fluid inlet and valve means responsive to a control means for closing off the cooling fluid supply if the temperature of the electroplating solution falls below a target temperature.

The invention also provides a method for electroplating a plurality of articles using an electroplating jig of the invention or an electroplating system of the invention.

Brief Description of the Drawings The invention will be more clearly understood from the following description thereof given by way of example only with reference to the accompanying drawings in which:Fig. 1 is a perspective view of an electroplating jig according to the invention with articles for electroplating in position; Fig. 2 is a side view of the jig with the articles removed; Fig. 3 is an end view of the jig of Fig. 1; Fig. 4 is a perspective view of a detail of the jig; Fig. 5 is a side view of the jig hoisted from a trolley ; Fig. 6 and 7 are perspective, partially cross sectional views of cathodic and anodic support details of the jig; Fig. 8 is a perspective view of a trolley used with the jig; Fig. 9 is a perspective view of one arrangement for mounting a transverse support to an upright; Fig. 10 is a cross sectional view of a hook mounting detail of the arrangement of Fig. 9; Fig. 11 is a perspective view of another arrangement similar to Fig. 9; Fig. 12 is a perspective view of another transverse support in position on uprights; Fig. 13 is an elevational view of a hook for use with the support of Fig. 12; Fig. 14 is a cross sectional view of the support and hook; Fig. 15 is a perspective view of another transverse support mounting system; Fig. 16 and 17 are perspective views of an alternative transverse support mounting system; Fig. 18 is a perspective view of the jig in position in an electroplating tank; Fig. 19 is a view of a detail of the electroplating tank; Fig. 20 is a cross sectional view of the electroplating tank; and Fig. 21 is a plan view of part of an electroplating system also according to the invention.

Detailed Description Referring to the drawings there is illustrated an electroplating jig for electroplating a plurality of articles 2 in an electroplating bath 1. The jig comprises a support frame 5 which is lifted by a hoist (not shown) from a trolley 6 into the bath 1.

The support frame 5 has a cathodic support means and an anodic support means. The cathodic support means comprises a pair of longitudinally extending cathode support bars 10 with a number of drop arms 11, to each of which is mounted a cathodic mounting bracket 12. Thus there are, in this case, four spaced-apart cathodic mounting brackets 12, each having a plurality of mounting holes 13 to receive longitudinally extending cathodic support rods 15, on each of which is hung a cathodic rack 20 by means of support hooks 19.

Each of the cathode racks 20 supports a plurality of articles to be electroplated. A rack 20 comprises a pair of spaced-apart upright rack bars 26 with a number, in this case three, transverse rack bars 27 extending therebetween.

To accommodate a range of different articles to be electroplated the cathode racks have adjustable mounting means. In this case the transverse support rack bars 27 are movable relative to the upright rack bars 26 to accommodate different articles to be electroplated. In the arrangement of Figs. 9 and 10 the transverse support rack bars 27 have sleeves 28 at both ends for slidably engaging the uprights 26 to adjust the position of the transverse support bars 27. Releasable locking means are provided for locking the sleeves 28 in a desired position relative to the uprights 26. The locking means is in this case provided by a locking screw 32. In this way the cathode racks are readily adjustable to accommodate a wide range of articles. Thus, the same rack can be used to accommodate a range of articles, set-up time is thereby minimised and the rate of production is optimised, particularly when a range of articles are to be plated.

The articles 2 are support on the transverse rods 27 by hooks 100. In the case illustrated in Figs. 9 and 10 the support bar 27 is coated with the exception of contact points 101 with the hooks 100 which are also coated except at the contact points 100 and article engaging tips 102. In this way electrical contact is maintained without sacrificing the insulation of the supports 27 and hooks 100.

Referring to Fig. 11 in this case the locking means includes a locking sleeve 103 which is slidable along the upright 26 and is locked in a desired position to support the sleeve 28 of the transverse bar 27 by a locking screw 104.

Referring to Figs. 12 to 17 various arrangements are illustrated of transverse support bars, mounting means, and hooks. In all of these versions an extra dimension is provided by virtue of the fact that support hooks 105 are readily mounted to and de-mounted from a transverse support 106. The hooks 105 are movable from the release position illustrated in Fig 13 to the support-engaging position of Fig. 14. The support bar 106 has a projecting section 107 with an exposed tip for electrical contact with the hook 105 in the engaged position illustrated in Fig. 14. The remainder of the support bar 106 is covered with an insulating material 109 as illustrated in Fig. 14.

In this way, any number of support hooks 105 may be mounted on a support bar 106 to accommodate a inside range of articles to be electroplated.

Referring particularly to Fig. 15 in this case the mounting and locking means are integral and comprise a bolt 110 with an inturned section 111 to engage an upright 26. The bolt 110 is retained in an upright - engaging position by a lock nut 112 which draws the bolt 110 into engagement with the upright 26.

Referring to Figs. 16 and 17 in this case the mounting sleeve is in two half sections 115, 116 which are drawn together in an upright engaging position by a locking screw 117.

Referring particularly to Figs. 6 and 7, the anodic support means comprises an anodic stub 40 which is mounted at one end of the support frame adjacent to the cathode bars 10. The anodic stub 40 is mounted between a pair of oppositely directed channel supports 41, 42 which are attached to the adjacent cathode bar 10. Blocks 45 of electrically insulating material are housed within the support channels 41, 42 to ensure that the anodic stub 40 is electrically insulated from the cathode bars 10. A cranked anodic drop arm 47 is connected to the anode stub 40 and a longitudinally extending anodic support bar 48 extends from the lowermost edge of the drop arm 47 to support a number of secondary anode plates which are hung by secondary anode hooks 49 from the anodic support bar 48.

Thus, the secondary anode bar 48 extends in use below the level of the 5 electroplating solution in an electroplating bath. The anodic support bar 48 is further supported at the low level position by brackets 49 of insulating material attached at one end to a cathodic support bracket 12. In this way the secondary anode plates are efficiently and effectively supported between the cathodic racks to optimise the electroplating process, io Referring to Figs. 18 and 20 one electroplating bath 1 is illustrated with a jig according to the invention in position in Fig. 20. The tank has an anodic contact for electrically contacting the secondary anode stub 40 and a cathodic contact for electrically contacting the cathode support bars 10 of the jig. Such electrical 15 contacts may be provided at one or both ends of the tank 2.

Primary anode means are provided at opposite sides of the tank 2. Each primary anode means comprises a primary anode bar 70 and a basket 71 for containing anodic material. The basket 71 is releasably hung by means of hooks 72 from the anode bar 70 so that the basket 71 is below the level of electroplating solution in the tank.

The primary anode means includes a hoist connection for ease of removal of the basket from the electroplating tank to replenish the anodic material.

Referring now to Fig. 21 in the electroplating system according to the invention there are two electroplating tanks 80, 81 and an interconnector in the form of a pipe 85 fitted with a valve 86 to control the flow of electroplating solution between the tanks to achieve a substantially uniform electroplating solution in each tank.

The inlets from the electroplating tanks 80, 81 to the pipe 85 are located at a position between a quarter and a half, most preferably approximately one third of the height of the electroplating solution in the tank. It has been found that this position is optimum to maintain uniformity of the electroplating solution in the tanks 80, 81.

The electroplating system of the invention also includes an electroplating solution conditioning system including a heat exchanger 90 for heating and/or cooling the solution to achieve a target temperature of from 20 to 24°C in the electroplating tank. The conditioning system includes an electroplating solution temperature sensor 92, heating means in the form of a heating element 93 for heating the electroplating solution in the tank, and control means 94 for activating the heating means if the temperature falls below a target temperature.

Cooling means for cooling the electroplating solution is in this case provided by the heat exchanger 90 which has a cooling fluid inlet with a solenoid valve 95 which is responsive to the control means 94 for closing off the cooling liquid supply if the temperature of the electroplating solution falls below a target temperature.

Electroplating solution from the tanks 80, 81 overflows over weirs 97 through delivery pipes 98 to an intermediate tank 99. From the tank 99 the solution is pumped by a pump 100 through a filter 101 to the heat exchanger 90.

The invention provides an electroplating jig which is highly efficient in use because a plurality of different articles are quickly and easily accommodated. The particular arrangement of the anode connection and the dropping of the secondary anode support bar in use, below the level of electroplating solution in the electroplating tank ensures that the electroplating process is optimised and that the secondary anodes have a prolonged useful life. Further, the dropping of the anode baskets and their case of replenishment also aids optimisation of the electroplating process.

The provision of two interlinked electroplating tanks greatly increases production efficiency without sacrificing the quality of the electroplating. The electroplating conditioning system also greatly enhances production efficiency and product quality.

The invention is not limited to the embodiments hereinbefore described which may be varied in construction and detail.

Claims (5)

1. An electroplating system having a plurality of separate stations for performing operations associated with electroplating and a hoist for moving an electroplating jig from one location to another, the system including at least two electroplating tanks and an interconnector for interconnecting electroplating solution in the tanks to achieve a substantially uniform electroplating solution in the tanks, each tank having an anodic contact and a cathodic contact at least at one end of the tank for electrically contacting an anode of the jig and a cathode of the jig respectively.

2. An electroplating system as claimed in claim 1 wherein the electroplating tank has an anodic contact and a cathodic contact at opposite ends of the tank, each for electrically contacting the secondary anode and the cathode of the jig, preferably the electroplating tank includes primary anode means on opposite sides of the tank, the primary anode means comprising a primary anode bar and a basket for containing anodic material, the basket being releasably hung from the primary anode bar below the level of the electroplating solution in the tank, preferably the primary anode means includes a hoist connection means for removal of the basket from the electroplating tank to replenish the anodic material.

3. An electroplating system as claimed in claim 1 or 2 wherein the interconnector comprises a pipe means between the tanks, the pipe means being fitted with a valve means to control the flow of electroplating solution between the tanks, preferably the inlets from the electroplating tanks to the pipe means are located at a position between a quarter and a half of the height of the electroplating solution in the tank, prefearbly the inlets from the electroplating tanks to the pipe means are located at a position approximately one third of the height of the electroplating solution in the tank.

4. An electroplating system as claimed in any preceding claim including an 5 electroplating solution conditioning system having heat exchanger means for heating and/or cooling the solution to achieve a target temperature of from 20 to 24°C in the electroplating tank, preferably the conditioning system includes an electroplating solution temperature sensor, heating means for heating the electroplating solution, and control means for 10 activating the heating means to heat the electroplating solution if the temperature falls below a target temperature, preferably the cooling means comprises a heat exchanger through which the electroplating solution is passed, the heat exchanger having a cooling fluid inlet and a valve means responsive to a control means for closing off the cooling fluid supply if the 15 temperature of the electroplating solution falls below a target temperature.

5. Electroplated articles whenever electroplated using an electroplating system as claimed in any preceding claim.