Barrel plating device

Abstract

A barrel plating device includes a cylindrical drum which is immersed in a plating solution in a horizontal state and configured for containing objects to be plated; a support member for rotatably supporting the drum; a drive mechanism for rotatably drive the drum; and a conductive member in a shape of bar which is disposed coaxially with the drum and integrally rotate with the drum.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects, other advantages and further features of the present invention will become more apparent by describing in detail illustrative, non-limiting embodiments thereof with reference to the accompanying drawings.

FIG. 1 is a perspective view of a configuration diagram of a barrel plating device according to one embodiment of the present invention.

FIG. 2 is an elevational view of a configuration diagram of a barrel plating device according to one embodiment of the present invention.

FIG. 3 is an exploded perspective view of a drum of a barrel plating device according to one embodiment of the present invention.

FIG. 4 illustrates tapered portions formed in a drum of a barrel plating device according to one embodiment of the present invention. FIG. 4A is a sectional view of the drum taken along a line X-X in FIG. 3. FIG. 4B is a sectional view of the drum taken along a line Y-Y in FIG. 3.

FIG. 5 is a partial cross sectional view of the barrel plating device illustrating configurations of a drum, a center bar and an electrode shielding part.

FIG. 6 is an exploded perspective view of an electrode shielding part of a barrel plating device according to one embodiment of the present invention.

FIGS. 7A-C are partial perspective views illustrating methods for attaching and fixing a support member to a drum of a barrel plating device according to one embodiment of the present invention.

FIG. 8 is a view showing a state of an inside of a drum during an operation of a barrel plating device according to one embodiment of the present invention.

FIG. 9 is an elevational view showing a configuration of a conventional barrel plating device.

FIG. 10 is a view showing a state of an inside of a drum during an operation of a conventional barrel plating device.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Embodiments of the present invention will be described in detail below with reference to the drawings.

(Barrel Plating Device 1)

A barrel plating device 1 according to the present invention is a device for plating small objects, such as small parts, and as shown in FIGS. 1 and 2, is mainly formed of: a drum 2 configured for holding objects to be plated therein; a center bar 3 arranged in the drum 2 coaxially with the drum 2 (see FIG. 2); an electrode shielding part 4 configured for protecting an electrically connected part between a shaft bar 26B and an electrode 41 from a plating solution, to which shaft bar 26B the center bar 3 is connected; a driving mechanism 5 configured for rotatably driving the drum 2 about a center of an axle thereof; and a support member 6 configured for rotatably supporting the drum 2.

Also referring to FIG. 8, when the barrel plating device 1 is operated, it is immersed in a plating solution L contained in a plating bath 11 in which a positive electrode (not shown) is disposed. The drum 2 is rotatably supported by a lower part of the support member 6. One end (i.e. a gear 28) of the drum 2 is connected to the drive mechanism 5, and a rotation of a motor 50 disposed at an upper part of the support member 6 is transmitted to the drum 2 through the drive mechanism 5 (including gears 51-53). The other end (i.e. the shaft bar 26B) of the drum 2 is inserted in (a liquid-proof part 43 of) the electrode shielding part 4 configured for holding the electrode 41 to be connected to a negative pole of a power supply (not shown), and is electrically connected to the electrode 41. In the drum 2, the center bar 3 is disposed (see FIG. 2), and objects P to be plated are introduced.

Each component of the barrel plating device 1 will be described in detail below.

(Drum 2)

The drum 2 is a cylindrical container configured for holding objects to be plated. In this embodiment, the drum 2 is mainly formed of: a drum body 20 including side walls 23 made of acrylic resin arranged as a hexagonal cylinder and end parts 22,22 at both ends of the side walls 23; and drum lids 21A,21B each removably attached to the respective end parts 22,22. The drum 2 is rotatably supported by the lower part of the support member 6 (see FIGS. 1 and 2).

Though in the present invention, the drum body 20 is (or the side walls 23 are arranged) in a shape of a hexagonal cylinder, the shape may be other polygonal cylinder, such as an octagonal cylinder, or a circular cylinder.

In the end part 22 of the drum body 20, a sample inlet 22a in a shape of a circle is formed. The sample inlet 22a is used before and after plating, i.e., for putting the objects P to be plated in the drum 2, and for removing plated objects P from the drum 2. Examples of the objects P to be plated include: electronic parts, such as IC chip, resistor and condenser; minute machine parts made of ceramic, glass fiber, resin or the like; and fine powder.

Though in the present embodiment, the sample inlet 22a is in a shape of a circle, it may be in a shape of a polygon. There is no limitation with respect to a size (or an opening diameter) of the sample inlet 22a.

In the side wall 23 of the drum body 20, at least one side wall opening 23a is formed, and a perforated lid 24 made of acrylic resin having at least one liquid passing part 24a that allows the plating solution L to pass is removably attached to the side wall 23 with screws 24b made of polyether ether ketone (PEEK), in such a manner that the liquid passing part 24a covers the side wall opening 23a.

The liquid passing part 24a may be in a form of a mesh, a set of slits or a set of pores, or combinations thereof. There is no limitation with respect to a size of the liquid passing part 24a, i.e., a size of the mesh, a width of the slit or a diameter of the pore or the like, as long as the liquid passing part 24a allows the plating solution L to pass through and holds the objects P to be plated in the drum 2. In the present embodiment, the liquid passing part 24a is in a form of a mesh.

Since the perforated lid 24 is exchangeable with other perforated lid 24 having the liquid passing part 24a with a mesh (or the like) of different size, the same drum 2 is applicable to objects to be plated (such as small parts) having different size. Therefore, as compared with the conventional drum 102 (see FIG. 9) having the liquid passing part 124a directly formed in the side wall 123, workability is enhanced in the drum 2 of the present embodiment, and thus the drum 2 of the present invention is cost-effective.

The drum lid 21A is mainly formed of: a lid part 25A made of acrylic resin removably attached to the end part 22 of the drum body 20; a shaft bar 26A made of Teflon™ connected to the lid part 25A and served as a rotational shaft of the drum 2; a slide shaft bearing 27A made of Teflon™ and supported by the support member 6 which will be explained below, in which slide shaft bearing the shaft bar 26A is inserted; and the gear 28 made of polymethylpentene (TPX)™ with which the shaft bar 26A is connected and the drive mechanism 5 is coupled (see FIG. 2). It should be noted that the shaft bar 26A may be made of resin other than Teflon™, or may be made of stainless steel coated with insulation film, such as Teflon™ coating.

The drum lid 21B is mainly formed of: a lid part 25B made of acrylic resin removably attached to the end part 22 of the drum body 20; a shaft bar 26B made of stainless steel connected to the center bar 3 and served as a rotational shaft of the drum 2; and a slide shaft bearing 27B made of Teflon™ and supported by the support member 6 which will be explained below, in which slide shaft bearing the shaft bar 26B is inserted. In an end of the shaft bar 26B on an inner side of the drum 2, a fitting hole 29 for fitting the center bar 3, which will be described below, is formed. A portion of the shaft bar 26B which is to be brought into direct contact with the plating solution L is covered with an insulation film, such as Teflon™ coating (not shown).

The center bar 3 which will be described below and the shaft bar 26B in the present embodiment correspond to “conductive member”.

On an inner face of the lid part 25B, a plurality of grooves G is formed, each of which is smaller than a size of the object P to be plated. With this configuration, as compared with the lid part without grooves, objects P to be plated does not tend to attach to the inner face of the lid part 25B, and thus a formation of the plating film on the surface of the objects becomes excellent, leading to improvement of quality. At the same time, removal of the plated objects P is facilitated to thereby improve workability.

Though in the present embodiment, the grooves G are arranged as concentric circles with the center bar 3 (or the shaft bar 26B) as a center, there is no limitation with respect to the arrangement of the grooves G, as long as a plurality of the grooves G each smaller than the objects P to be plated is formed. For example, the arrangement of the grooves G may be in a shape of diamond cut (or pineapple cut) or grid. In addition, there is no limitation with respect to a cross sectional shape of the groove G, and the cross section may be, for example, in a V-shape. With respect to an area (or range) of the inner face of the lid part 25B in which the grooves G are formed, there is no limitation as long as the area is large enough to cover the sample inlet 22a when the lid part 25B is attached to the drum body 20. In other words, the grooves G are formed in at least a part of an inner face of the lid part 25B exposed to an internal space of the drum 2 when the lid part 25B is attached to the drum body 20.

Likewise, the lid part 25A also has the grooves G (not shown).

As shown in FIG. 4A, in the drum 2, a tapered portion Ti is formed from the side walls 23 to the sample inlet 22a. As shown in FIGS. 4A and 4B, a tapered portion T2 is formed on a circumference of the side wall opening 23a, from inside to outside. With this configuration, the drum 2 has less acute corners inside thereof, as compared with the conventional drums without tapered portions. Therefore, scratches on the surface of the plated objects P that may otherwise be caused by contact or collision with the corners can be reduced. In addition, due to the tapered portions T1,T2, the inner face of the drum 2 becomes smooth and therefore, the objects P to be plated are not caught by the inner face of the drum 2. As a result, formation of a plating film on the surface of the objects becomes excellent and quality is improved, and at the same time, the plated objects P can be easily removed, to thereby improve workability.

(Center Bar 3)

The center bar 3 is a member made of, for example, brass or copper, which serves as a negative electrode of the barrel plating device 1. As shown in FIG. 3, the center bar 3 is mainly formed of: an electrode part 31 to be disposed in the drum 2; and a fitting part 32 for removably attaching the center bar 3 to the fitting hole 29 of the shaft bar 26B. At least the electrode part 31 is disposed inside the drum 2, and arranged coaxially with the drum 2.

A male thread part (thread ridge) is provided on the fitting part 32 and a female thread part is provided in the fitting hole 29 formed in the end of the shaft bar 26B on the inner side of the drum 2. By engaging the male thread part with the female thread part as shown in FIG. 5, the center bar 3 and the shaft bar 26B are connected.

Optionally, the connection of the center bar 3 and the shaft bar 26B is reinforced by pressingly fastening from a lateral side of the fitting part 32 with a center-bar-fixing screw 29a made of PEEK resin.

By connecting the center bar 3 and the drum 2 (shaft bar 26B) as a single piece in a manner described above, the drum 2 and the center bar 3 can integrally rotate. Therefore, a gap is not formed between the center bar 3 and the objects P to be plated in the drum, which prevents a generation of a high-current-density part. As a result, there is prevented an occurrence of burnt deposit in a plating film formed on a surface of the plated object.

Since the center bar 3 and the drum 2 (shaft bar 26B) are removably attached, replacement of the center bar 3 is facilitated, not only when an unserviceable center bar 3 is replaced with a new one, but also when a center bar 3 is replaced with a center bar 3 made of a material compatible with a material of the objects P to be plated or a composition of the plating solution L. Therefore, the same drum 2 can be used for different objects to be plated or plating solutions, regardless of the material of the objects, or the composition of the plating solution, which contribute to excellent cost performance.

(Electrode Shielding Part 4)

The electrode shielding part 4 is configured for protecting an electrically connected part to between the shaft bar 26B to which the center bar 3 is connected and the electrode 41, from the plating solution L. As shown in FIGS. 5 and 6, the electrode shielding part 4 is mainly formed of: the electrode 41 electrically connected to the center bar 3 through the shaft bar 26B; a housing 42 configured for holding the electrode 41 and the shaft bar 26B inserted therein; and the liquid-proof part 43 for preventing the plating solution L from entering the housing 42. The electrode shielding part 4 is attached to a side face (on a shaft bar 26B-side) of the support member 6 (see FIGS. 1 and 2).

The electrode 41 is mainly formed of: an electrode bar 41a; a conductor 41b electrically connected to the shaft bar 26B; and a conductive elastic member 41c electrically connecting the electrode bar 41a with the conductor 41b and biasing the conductor 41b to the shaft bar 26B.

The electrode bar 41a is made of, for example, brass or copper, and electrically connected to a negative pole of the power supply, which energizes the center bar 3 through the elastic member 41c, the conductor 41b and the shaft bar 26B.

The conductor 41b is electrically connected to the shaft bar 26B, and energized while slidably moving. Examples of the conductor 41b include carbon brush. Carbon brush, which is a block-shaped mass mainly formed of graphite, is suitable for a member electrically connected and energized while slidably moving, since it hardly rusts but is still highly conductive like metal, and slippery with low friction.

The elastic member 41c is, for example, a conductive coil spring, which connects the electrode bar 41a with the conductor 41b, and biases the conductor 41b to the shaft bar 26B to such a degree that the rotation of the shaft bar 26B (or the drum 2) is not hindered.

It should be noted that, the electrode bar 41a may be directly (and electrically) connected to the shaft bar 26B and energized while slidably moving, as long as the rotation of the shaft bar 26B (or the drum 2) is not hindered.

Referring to FIG. 6, the housing 42 is made of acrylic resin, which is mainly formed of: an electrode insertion hole 42a into which the electrode 41 is inserted from an upper end thereof; a mounting recess 42b formed in one side face of a lower portion of the housing 42, to which the liquid-proof part 43 (which will be described below) is attached; and a shaft bar-insertion hole 42c formed in the mounting recess 42b, into which the shaft bar 26B is inserted. The housing 42 is attached to the support member 6 with mounting members 44,45.

As shown in FIG. 6, the liquid-proof part 43 is mainly formed of: a liquid-proof sealing 43a for preventing the plating solution L from entering the housing 42; a fixing plate 43b made of acrylic resin, in which a through-hole 43c for an insertion of the shaft bar 26B is formed; and screws 43d made of PEEK resin, for fixing the fixing plate 43b to the mounting recess 42b of the housing 42.

When the liquid-proof part 43 is mounted on the housing 42, the through-hole 43c of the fixing plate 43b, the liquid-proof sealing 43a and the shaft bar-insertion hole 42c are communicatively aligned in line. When the shaft bar 26B is inserted, the plating solution L is prevented from entering the housing 42 due to the liquid-proof sealing 43a.

With this configuration of the electrode shielding part 4, the plating solution L is prevented from entering the housing 42, even though the drum 2 (or the shaft bar 26B) is rotating. Therefore, an electrically connected part between the shaft bar 26B to which the center bar 3 is connected and the electrode 41 (or the conductor 41b) is prevented from being brought into contact with the plating solution L. As a result, defective rotation of the drum 2 (or the shaft bar 26B), which may be caused due to a formation of plating film on the above-mentioned electrically connected part, can be prevented.

Since a plating film is not formed on the above-mentioned electrically connected part or the electrode 41, the plating solution L is not wasted, and at the same time, the shaft bar 26B and the electrode 41 can be repeatedly used, leading to excellent cost performance.

(Drive Mechanism 5)

The drive mechanism 5 serves as a power supply and is configured for transmitting a driving force to rotate the drum 2. As shown in FIG. 2, the drive mechanism 5 is mainly formed of: the motor 50 having a driving shaft 50a; the gear 51 made of TPX™ resin, which is attached to a driving shaft 50a; the gear 52 made of TPX™ resin, which engages with the gear 51; and the gear 53 made of TPX™ resin, which engages with the gear 52. The motor 50 is disposed at the upper part of the support member 6, and the gears 51, 52 and 53 are attached to a side face (on a shaft bar 26A-side) of the support member 6.

With this drive mechanism 5, when the motor 50 is driven, a rotation of the driving shaft 50a of the motor is transmitted to the gear 52 through the gear 51 to thereby rotate the gear 52. The rotation of the gear 52 is then transmitted to the gear 53 to thereby rotate the gear 53, which in turn is transmitted to the gear 28 engaging with the gear 53, to thereby rotate the gear 28. Accordingly, the drum 2 connected to the gear 28 through the shaft bar 26A, as well as the center bar 3 connected to the drum 2 (the shaft bar 26B), can be rotated about the center of the axle thereof.

In the present embodiment, the gears made of polymethylpentene (TPX™) are illustrated. However, the gears may be made of other materials with chemical resistance (resistance to the plating solution), such as polypropylene (PP) resin. Though in the present embodiment, the rotation of the motor 50 is transmitted to the drum 2 through the gears 51, 52, 53 and 28, there is no limitation as long as the rotation of the motor 50 is transmitted to the drum 2. For example, the rotation may be transmitted to the drum 2 through a belt or the like which is made of materials with chemical resistance.

(Support Member 6)

The support member 6 is made of acrylic resin, which serves as a chassis of the barrel plating device 1 and configured for supporting the drum 2, the electrode shielding part 4 and the drive mechanism 5 (see FIGS. 1 and 2). In the support member 6, as shown in FIG. 7, guide grooves 61 are formed for slidably receiving and supporting the slide shaft bearings 27A, 27B in which the shaft bars 26A, 26B are inserted, respectively.

To the support member 6, the electrode shielding part 4 and a fixing member 62, both serve as fixing means, are attached in order to prevent the slide shaft bearings 27A, 27B in which the shaft bars 26A, 26B are inserted, from detaching from the respective guide grooves 61, during the operation of the barrel plating device 1 (the rotation of the drum 2).

The guide groove 61 is configured in such a manner that the drum 6 is removably attached to the support member 6 by slidably moving the slide shaft bearings 27A, 27B in which the shaft bars 26A, 26B are inserted, respectively (see FIG. 7B). With this configuration, the drum 2 is easily removed, and thus a replacement of the drum and introduction and removal of objects are facilitated to thereby improve workability.

In addition, during the operation of the barrel plating device 1 (the rotation of the drum 2), the shaft bar 26B is rotatably fixed by insertion into the liquid-proof part 43 of the electrode shielding part 4 supported on the side face of the support member 6, as shown in FIGS. 1 and 2, while the shaft bar 26A is rotatably fixed by the fixing member 62, as shown in FIGS. 1 and 7C.

As shown in FIGS. 7B and 7C, the fixing member 62 made of acrylic resin is configured for fixing the shaft bar 26A through the slide shaft bearing 27A, so that the shaft bar 26A does not come off of the support member 6 (guide groove 61) during the rotation of the drum 2.

It should be noted that, when the fixing member 62 is fixing the shaft bar 26A through the slide shaft bearing 27A, the fixing member 62 is fastened to the support member 6 with, for example, a screw made of PEEK resin (not shown).

With this configuration, the shaft bars 26A, 26B together with the slide shaft bearings 27A, 27B, are prevented from coming off of the support member 6 (guide groove 61) during the rotation of the drum 2. As a result, the drum 2 is stably rotated without coming off of a use position during the operation of the plating device 1 (during a rotation of the drum 2).

In the present embodiment, the slide shaft bearings 27A, 27B in which the shaft bars 26A, 26B are inserted, respectively, are slidably moved or fixed by the fixing member 62 and the like. However, the shaft bars 26A, 26B may be directly moved in the guide grooves 61, or directly fixed to the support member 6, without a presence of the slide shaft bearings 27A, 27B, as long as the drum 2 is rotatably supported. In this case, the shaft bar 26A is directly and rotatably fixed by the fixing member 62.

The components of the barrel plating device 1 have been described in detail. In the present embodiment, the drum 2 (including the drum body 20, the lid parts 25A, 25B and the like), the electrode shielding part 4 (including the housing 42, the fixing plate 43b and the like), the support member 6 and the fixing member 62 are made of acrylic resin. However, other resins may be used as long as they have chemical resistance and heat resistance, and the same level of hardness as that of acrylic resin.

Next, an outline of the operation of the barrel plating device 1 will be explained (see FIGS. 1 and 2, as appropriate)

First, the center bar 3 is connected to the shaft bar 26B, and objects P to be plated (not shown) are put in the drum 2. The volume of the objects P put in the drum 2 is adjusted so that the objects P and the center bar 3 are electrically connected when the drum 2 is in a horizontal state, and that the objects P are satisfactorily stirred when the drum 2 is being rotated. The volume is preferably a half of the total volume of the drum 2, as shown in FIG. 8, for example.

Next, while maintaining the drum 2 in a horizontal state, the slide shaft bearings 27A, 27B in which the shaft bars 26A, 26B are inserted, respectively, are slidably moved in the guide grooves 61 (see FIGS. 7A-7C), so that the drum 2 is rotatably supported by the support member 6. Subsequently, the gear 28 connected to the shaft bar 26A of the drum 2 is engaged with the gear 53 of the drive mechanism 5, to thereby connect the drum 2 with the drive mechanism 5. The fixing member 62 is attached to thereby rotatably fix the shaft bar 26A through the slide shaft bearing 27A. In addition, the shaft bar 26B of the drum 2 is inserted in the liquid-proof part 43 of the electrode shielding part 4, to thereby electrically connect the shaft bar 26B with the electrode 41, and at the same time, to rotatably fix the shaft bar 26B.

The barrel plating device 1 having the above-described configuration is placed in the plating bath 11 (not shown) storing the plating solution L, in such a manner that the entire drum 2 (or at least the objects P to be plated and the center bar 3) is immersed in the plating solution L. Then, the motor 50 of the drive mechanism 5 is driven, and the rotation of the motor 50 is transmitted to the drum 2 through the gears 51, 52, 53 and 28, to thereby rotate the drum 2. The positive electrode (not shown) disposed in the plating bath 11 and the center bar 3 (negative electrode) are electrically connected, to thereby form a plating film on a surface of the object P.

According to the barrel plating device 1 of the present embodiment having the above-mentioned configuration, the drum 2 and the center bar 3 integrally rotate while maintaining electrical connection between the center bar 3 and the electrode 41. Therefore, as shown in FIG. 8, gap is not formed between the center bar 3 and the objects P to be plated in the drum 2, which prevents a generation of high-current-density part. As a result, there is prevented an occurrence of burnt deposit in a plating film formed on a surface of the plated object P.

The configuration and the outline of the operation of the barrel plating device 1 have been described. However, the present invention should not be limited to the above-described embodiments. Specific configuration may be modified within the scope of the present invention without deviating from the spirit of the present invention. For example, in the above-mentioned embodiment, the center bar 3 and the shaft bar 26B as separate components are assembled and used as a single conductive member. However, the center bar 3 and the shaft bar 26B may be integrally formed into a single component as a conductive member.

Claims

1. A barrel plating device comprising: a cylindrical drum for containing objects to be plated and being immersed in a plating solution in a horizontal state;a support member for rotatably supporting the drum;a drive mechanism for rotatably driving the drum; anda conductive member in a shape of a bar which is disposed coaxially with the drum and integrally rotates with the drum.

2. The barrel plating device according to claim 1, further comprising an electrode shielding part comprising: an electrode electrically connected to the conductive member;a housing for holding the electrode, in which an end part of the conductive member is inserted; anda liquid-proof part for preventing the plating solution from entering the housing.

3. The barrel plating device according to claim 2, wherein the electrode comprises: an electrode bar;a conductor electrically connected to the conductive member; andan elastic member for connecting the electrode bar with the conductor, and biases the conductor to the conductive member.

4. The barrel plating device according to claim 1, wherein the drum is removably attached to the support member.

5. The barrel plating device according to claim 1, wherein the drum has tapered portions formed in internal faces thereof.

6. The barrel plating device according to claim 1, wherein the drum has lid parts on both ends, and at least a part of an inner face of the lid part exposed to an internal space of the drum has a plurality of grooves formed thereon.

7. The barrel plating device according to claim 1, wherein the drum has rotational shafts on both ends, the shaft being rotatably supported by fixing means provided on the support member.