JP2012097290A - Surface treatment method and surface treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treatment method and a surface treatment apparatus in which at the same time when process parts are agitated uniformly within a treatment container, a treatment liquid is made to flow efficiently, and thereby variation of a plated film thickness can be inhibited, and plating unevenness, and poor adhesion can be solved.SOLUTION: The surface treatment method and the surface treatment apparatus comprise as follows. Two or more process parts 3 are held in a treatment container 1 which has an opening 2 at the upper part, and in which a curved surface is formed toward the opening 2 from a proximity of an inner surface bottom center thereof, a desired treatment liquid is injected from an injection tip arranged toward a bottom center proximity of an inner surface of the treatment container 1 from the opening 2, the treatment liquid hits the bottom center of the treatment container 1, then the process parts 3 are flowed and stirred by a liquid current which circulates toward the opening 2 along the curved surface, and the process parts 3 are made to contact with a cathode electrode prepared in an inside of the treatment container 1, and are performed with electrolytic treatment with an anode electrode arranged at a proximity of the opening 2.

Description

  The present invention relates to a surface treatment technique used for performing surface treatment such as electrodeposition coating or metal plating on the surface of a machine part or an electronic part.

A surface treatment such as metal plating may be applied to the surface of an electronic component used in an electronic device or the like for the purpose of improving electrical characteristics and durability. In particular, with respect to chip resistors and capacitors, quality requirements for electronic components are increasing as performance is improved and size is reduced. In particular, high quality is required for the surface treatment that greatly affects the mountability, electrical characteristics, and corrosion resistance.
2. Description of the Related Art Conventionally, a so-called barrel plating method in which a component to be processed such as an electronic component is placed in a plating treatment barrel and electrolytic plating is performed while rotating in a plating solution has been widely used. In this case, there is an advantage that a large amount of articles can be plated at a time.

  However, the product cannot be sufficiently agitated inside the barrel, resulting in variations in the plating film thickness, the size of the product itself is reduced, and it enters into a minute gap inside the barrel and stagnates. In addition, there is a chronic problem that the plating film thickness of the part becomes thin.

  Moreover, it is set as the structure which forms the mesh-shaped opening of the grade which does not fall to the to-be-processed part in the outer peripheral part of a barrel, and replaces the plating solution inside and outside a barrel. However, as the size of the part to be processed itself decreases, the mesh-shaped gap must be reduced, which is disadvantageous for replacement of the plating solution inside and outside the barrel. When barrel plating is performed for a long time in this state, the metal ion concentration of the plating solution staying in the barrel is lowered, which has a problem of adversely affecting the plating efficiency and the deposition state.

  As described above, when plating electronic parts using the barrel plating method, the efficiency of plating is poor due to uneven stirring of the parts to be processed put into the barrel and insufficient replacement of the plating solution. Have problems such as becoming. In the surface treatment industry, various efforts have been made to solve these problems. For example, Patent Document 1 proposes a method in which a part to be plated and a current-carrying medium are accommodated in a container provided with an electrode for a cathode and plating is performed while giving a rotational motion to the container as shown below. .

  FIG. 4 shows an example of a conventional plating method. A predetermined motion is given to the container 101, and the cathode component 102 and the current-carrying medium 103 in the container 101 are repeatedly subjected to a forward flow that flows in one direction and a reverse flow that flows in the reverse direction while repeating the cathode flow. Plating is performed by energizing the working electrode 104.

  In addition, a step of temporarily stopping the rotation of the container 101 is provided between the forward rotational motion and the reverse rotational motion of the container 101. After the rotational motion of the container 101 is temporarily stopped, a reverse rotational motion is given to the container 101 while the component 102 and the energizing medium 103 are flowing by the rotational motion of the container 101 before the stop.

  Further, the movement in which the trajectory of the container 101 moves in a substantially circular shape is repeatedly given in one direction and the opposite direction, whereby the forward flow and the reverse flow are applied to the component 102 and the energizing medium 103. Repeat this step. Thus, the component to be plated 102 and the energization medium are effectively stirred, and the component to be plated 102 is uniformly plated.

JP 2005-146396 A Japanese Utility Model Publication No. 5-19360 JP-A-6-173092 JP-A-11-238704 JP 11-312654 A Japanese Patent Laid-Open No. 2002-30696 JP 2009-185334 A

However, a part 102 to be plated placed in a large amount in the container 101 is cyclically switched between the part 102 to be plated near the cathode electrode 104 and the part 102 to be plated near the surface only by flowing in the forward and reverse directions. It is difficult to perform uniform stirring. Furthermore, the plating solution flows relatively near the surface of the component to be plated 102, but the vicinity of the cathode electrode 104 is covered with the component to be plated 102, so that the plating solution does not flow sufficiently. There is a fear.
As described above, the fact that the part to be plated 102 cannot be sufficiently stirred in the container 101 and the difference in the flow of the plating solution depending on the part in the container 101 is due to variations in the plating film thickness on the part to be plated 102 and plating. There is a risk of unevenness and poor adhesion. Especially in electronic parts, there is a possibility of adversely affecting the electrical characteristics of the product.

  Therefore, in the present invention, the processing component is uniformly stirred in the processing container with respect to the processing component, and at the same time, the processing liquid is efficiently flowed to suppress plating film thickness variation, plating unevenness, and poor adhesion. A surface treatment method and a surface treatment apparatus that can be solved are provided.

  According to a plating apparatus according to the present invention, comprising: a processing container for storing an object to be plated; and a supply pipe having an injection port for supplying a processing liquid for plating processing to the processing container. In the plating method, an opening is formed at the top of the processing container, a curved surface is formed from the bottom to the opening in the processing container, a first electrode is provided along the curved surface, and the processing The treatment liquid is ejected from an injection port arranged toward the bottom from the opening of the container, and after the treatment liquid hits the bottom of the treatment container, the treatment liquid is directed toward the opening along the curved surface. The processing object is fluidly stirred by the circulating liquid flow so that the processing object comes into contact with the first electrode, the second electrode is immersed in the processing liquid added to the processing container, and the first electrode 1 electrode and the first And performing electrolytic process by energizing of the electrode. Further, the center axis of the injection port is dynamically moved relatively in a predetermined range in the horizontal direction with respect to the center axis of the opening of the processing container.

  A plating apparatus according to the present invention is a processing container for storing an object to be plated, wherein an opening is formed at the top of the processing container, and the opening is formed from the bottom in the processing container. The processing container having a curved surface toward the part; a first electrode provided along the curved surface; and an injection port for supplying a processing solution for plating to the processing container. A supply pipe whose mouth is arranged from the opening to the bottom of the processing container, a second electrode that is not in contact with the first electrode, and the processing liquid ejected from the ejection port After hitting the bottom of the processing container, the processing object is fluidly stirred by the liquid flow circulating toward the opening along the curved surface, and the processing object is brought into contact with the first electrode. The treatment liquid ejected from the ejection port An adjustment unit that adjusts the flow rate or flow pressure, characterized in that it comprises a second electrode in contact with the process liquid added to the processing vessel, and a power supply unit for energizing said first electrode. Further, the second electrode is provided in the supply pipe or is separated from the supply pipe. The edge of the opening has a predetermined thickness or is bent toward the inside of the processing container.

  According to the surface treatment method of the present invention, it is possible to uniformly agitate the parts to be processed that have been put into the processing container by the circulating flow in the processing container that is generated by jetting the processing liquid. Thereby, uniform agitation can be performed between the component to be processed near the cathode and the component to be processed near the surface. Furthermore, since the processing solution is always in a circulating flow state in the processing container, the flow of the plating solution does not deteriorate near the cathode as in the prior art.

  Thus, according to the surface treatment method of the present invention, the parts to be treated can be sufficiently stirred in the processing container, and there is no difference in the flow of the processing liquid depending on the site in the processing container. Thus, it is possible to obtain a plating method capable of suppressing the unevenness of the plating film thickness and performing good plating without causing uneven plating and poor adhesion.

An example of the external appearance structure of the plating processing apparatus which concerns on this embodiment is shown. An example of the plating processing method which concerns on this embodiment is shown. It is a figure for demonstrating the modification of this embodiment. An example of the conventional plating method is shown.

  FIG. 1 shows an example of an external configuration of a plating apparatus according to this embodiment. FIG. 2 shows an example of the plating method according to the present embodiment. Below, the plating apparatus 20 which concerns on this embodiment is demonstrated, referring FIG. 1, FIG. 2 (A).

  The plating apparatus 20 includes a processing container 1, an opening 2, a component 3 to be processed, a drain 4, a cathode electrode 5, a plating tank 6, a transport means 7, a reserve tank 8, a processing liquid 9, an injection port 10, an anode electrode 11, It has a pump 12, a vertical part 13, a folding part 14, a supply pipe 15, and a power supply part 16.

  The processing container 1 is made of an electrically insulating material such as vinyl chloride, polypropylene, polyethylene, or fluororesin, and is made of a material that can withstand surface treatment chemicals. The processing container 1 is formed by using an injection resin molding process, a cutting process, a vacuum molding process, or the like so as to have a desired hollow structure.

  The inner surface of the processing container 1 forms a smooth curved surface in an R shape from the bottom center to the upper opening 2, and the end of the curved surface forms the contour of the opening 2. As a result, the internal space of the processing container 1 has a shape such as a sphere or an ellipsoid. Further, a plurality of drains 4 smaller than the outer dimensions of the component 3 to be processed are provided near the center of the bottom of the processing container 1.

  Inside the processing vessel 1, a cathode electrode 5 is provided along the curved surface of the inner wall of the processing vessel 1. It is desirable that the cathode electrode 5 has a shape with a contact efficiency as high as possible with respect to the component 3 to be processed and a shape that does not hinder the flow of the component 3 to be processed. In the present embodiment, as an example, the metal wire as the cathode electrode 5 is processed into an R shape, attached along the curved surface of the inner wall of the processing vessel 1, and connected to a rectifier (not shown). However, the present invention is not limited to this.

  The structure of the processing container 1 is not limited to the above description, and may be any shape as long as the part to be processed 3 can easily flow inside the processing container 1. Further, the shape of the curved surface, the size of the drain 4, or the shape, material, or internal volume of the processing container 1 may be determined in accordance with the shape of the component 3 to be processed.

  When it is not necessary to consider that the plating film is deposited on the cathode electrode 5 such as an electrolytic cleaning process that does not deposit the plating film, the processing container 1 is formed of a conductive material, and the inner surface of the processing container 1 itself is formed. It can also be a cathode electrode. Thereby, it has the effect that the contact efficiency of the to-be-processed component 3 and a cathode electrode improves.

  Inside the plating tank 6 is provided a transport means 7 for transporting to each processing step in accordance with the traveling direction of the plating process. In this embodiment, it is set as the structure which conveys the processing container 1 to each processing process using a conveyor belt. A reserve tank 8 is provided below the plating tank 6. The reserve tank 8 stores necessary processing liquid 9.

  Further, a supply pipe 15 for supplying the processing liquid 9 into the processing container 1 is disposed in the plating tank 6. At the tip of the supply pipe 15, there is an injection port 10 for injecting and supplying the processing liquid 9 guided by the supply pipe. The supply pipe 15 is provided so as to be movable up and down so that the height of the injection port 10 can be adjusted with respect to the opening 2 of the processing container 1.

  An anode electrode 11 is attached to the peripheral portion of the supply pipe 15 around the injection port 10. In accordance with the vertical movement of the injection port 10, the anode electrode 11 also moves up and down in the same manner. Accordingly, the processing liquid 9 can be supplied by inserting and removing the injection port 10 and the anode electrode 11 into the processing container 1 without hindering the conveyance of the processing container 1 in the traveling direction. In addition, although the disk shape was used for the shape of the anode electrode 11 in this embodiment, it is not limited to this, Any shape may be sufficient.

  As shown in FIG. 2A, the cathode electrode 5 and the anode electrode 11 are connected to a power supply unit 16, and a direct current flows from the power supply unit 16 to the processing liquid in the processing container 1. Yes. Thereby, electrolytic treatment can be performed.

  Next, an example of the plating method according to the present embodiment will be described. A large number of parts to be processed 3 are placed inside the processing container 1. In addition, a stirring medium, a current-carrying auxiliary medium, and the like are mixed and introduced into the processing container 1 in accordance with the shape and quantity of the component 3 to be processed.

  Originally, it is general to perform pretreatment such as cleaning, polishing, or activating the material surface before the step of depositing a plating film. Furthermore, after the plating process, a cleaning process for washing away chemicals, a process for drying a component to be processed, and the like are provided. However, this time, only the plating film deposition process will be described, and the processes before and after that will be omitted.

  First, the processing container 1 is transported through the processing means by the transport means 7 and transported to the plating tank 6 (FIG. 2A). An injection port 10 provided so as to be movable up and down by an up-and-down mechanism (not shown) is inserted into the opening 2 of the processing vessel 1 that has been temporarily stopped, and at the same time, the anode electrode 11 is also disposed near the opening 2.

  Next, the processing liquid 9 (plating liquid) stored in the reserve tank 8 is pumped up by the pump 12 and injected into the processing container 1 from the injection port 10. The sprayed processing liquid 9 forms a liquid flow that rises along a curved surface after hitting the vicinity of the center of the bottom inside the processing container 1. The processing liquid 9 that has formed the liquid flow further flows to the center of the bottom by the processing liquid 9 continuously supplied from the injection port 10, thereby forming a circulating flow state. In synchronism with the processing liquid 9 that circulates and flows in this way, all the parts to be processed 3 are uniformly stirred. The part to be processed 3 is in contact with the cathode electrode 5 during the circulation flow, and is plated by the anode electrode 11 disposed on the upper part (FIG. 2B).

  The stirring state of the part to be processed 3 can be managed by adjusting the strength of the circulating flow with the adjusting unit. Examples of the adjusting unit include a pump 12, a valve that adjusts the flow rate or flow pressure, or a regulator that adjusts the flow rate or flow pressure. For example, the strength of the circulating flow can be arbitrarily changed by adjusting the flow rate of the processing liquid 9 supplied from the pump 12 with a valve or the like. Therefore, the adjustment unit may be adjusted so as to obtain an optimum circulating flow state in consideration of the shape of the part to be processed 3 and the quantity to be charged.

  Furthermore, the method of supplying the treatment liquid 9 is not limited to continuous supply, and the supply and stop of the treatment liquid 9 may be intermittently performed to repeat stirring and rest. According to this, the effect that the contact efficiency of the to-be-processed component 3 and the cathode electrode 5 improves is acquired.

  When the plating process is completed, the supply of the processing liquid 9 to the processing container 1 is stopped. The processing liquid 9 staying in the processing container 1 is discharged by the dead weight of the processing liquid 9 from the drain 4 provided in the lower part (FIG. 2C).

  Although the processing liquid 9 is discharged little by little from the drain 4 during supply, the processing liquid 9 is filled with no problem in the processing container 1 because the supply amount is larger. If the supply of the treatment liquid 9 is stopped, the treatment liquid 9 is discharged to the end by the drain 4. It is desirable to form the drain 4 with such a size that the part 3 to be processed does not fall off or bite. Further, when it is desired to quickly discharge the processing liquid 9 or when it is desired to increase the replacement of the processing liquid 9 during the plating process, the effect can be obtained by forming a large number of drains 4. At the same time as the processing liquid 9 is discharged, the injection port 10 and the anode electrode 11 rise. Then, the processing container 1 is transported to the next step by the operation of the transport means 7 (FIG. 2D).

  Thus, according to the present embodiment, the component 3 to be processed put into the processing container 1 can be uniformly agitated by the circulating flow generated by the injection of the processing liquid 9. Thereby, the to-be-processed part 3 vicinity of the cathode electrode 5 and the to-be-processed part 3 vicinity of the surface which were difficult with the prior art can be stirred uniformly. Furthermore, since the processing liquid 9 is always in a circulating flow state in the processing container 1, the flow of the processing liquid 9 in the vicinity of the cathode electrode 5 does not become insufficient unlike the prior art.

  According to the surface treatment method of the present embodiment, the component 3 to be treated can be sufficiently stirred in the processing container 1, and there is no difference in the flow of the processing liquid 9 depending on the portion in the processing container 1. Therefore, variation in the plating film thickness between the parts to be processed can be suppressed, and good plating can be performed without causing uneven plating and poor adhesion.

  In the present embodiment, the anode electrode 11 is provided on the periphery of the injection port 10, but the present invention is not limited to this, and the anode electrode 11 may be provided on the side surface of the supply pipe away from the injection port 10. Further, the anode electrode 11 and the injection port 10 may be separated. For example, the injection port 10 is submerged in a deep position of the processing liquid added to the processing container 1 to inject the processing liquid from the injection port 10 and the anode electrode 11 is immersed in the processing liquid in the vicinity of the opening 2 to perform electrolytic treatment. May be performed.

  Next, a modification of this embodiment will be described. FIG. 3 is a diagram for explaining a modification of the present embodiment. As shown in FIG. 3A, a vertical portion 13 having a predetermined height may be provided along the periphery of the opening 2 provided in the upper portion of the processing container 1. According to this, even when the component 3 to be processed is flowed in the liquid stream to be discharged around the opening 2, it is blocked by the vertical portion 13 and prevents the component 3 to flow out. be able to.

  Further, as shown in FIG. 3B, a folded portion 14 may be provided in the inner direction along the periphery of the opening 2 provided in the upper portion of the processing container 1. According to this, similarly to the above, even if the part to be processed 3 is caused to flow in the liquid flow to be discharged around the opening 2, it is returned to the normal circulation flow by the folding portion 14. The outflow of the component 3 to be processed can be prevented. The shape of the folded portion 14 is not particularly limited as long as it is a shape that does not hinder the flow or momentum of the circulating flow, such as a curved shape with a smooth R shape, and the like.

  Further, as shown in FIG. 3C, the processing liquid 9 may be ejected while moving the central axis of the ejection port 10 within the range of φA while the processing container 1 is stationary. According to this, there is a case where a positional deviation occurs between the central axis of the injection port 10 and the central axis of the processing container 1 due to apparatus factors (for example, processing container processing accuracy, conveyance accuracy, trouble due to aging, etc.). Even so, the central axis of the injection port 10 is moved within the range of φA. As a result, uniform agitation of the component to be processed 3 can be obtained without causing flow unevenness due to the uneven flow of liquid.

  Further, as shown in FIG. 3D, the processing liquid 9 may be sprayed while moving the central axis of the processing container 1 within the range of φB in a state where the injection port 10 is fixed. According to this, even if a positional deviation occurs between the central axis of the injection port 10 and the central axis of the processing container 1 due to apparatus factors as described above, the central axis of the processing container 1 is within the range of φB. Can exercise. Thereby, the to-be-processed part 3 can be stirred uniformly, without producing the fluid stirring nonuniformity by the deviation of a liquid flow.

  The movement pattern of the processing container 1 or the injection port 10 is the best pattern depending on the flow rate and flow velocity of the liquid flow to be jetted, or the shape of the component to be treated, such as rotational movement, reciprocating movement, and combined movement thereof. Should be selected. Further, if the present invention is used, in the final cleaning step or the like, the parts to be processed 3 can be efficiently stirred and cleaned by supplying cleaning water or the like into the processing container 1. Further, in the draining and drying process, the compressed air or heated air is sent while the opening 2 is sealed, and the water adhering to the component 3 to be processed can be forcibly discharged from the drain 4 to drain the water. .

  As described above, the surface treatment method of the present invention is not limited to the plating treatment, but includes the basics within the scope of the present invention from chemical cleaning, electrolytic cleaning, chemical polishing, electrolytic polishing, and electrodeposition coating. Configuration can be utilized.

In the surface treatment method of the present invention, the component to be treated can be sufficiently stirred in the treatment container. In addition, variation in the plating film thickness between the parts to be processed can be suppressed without causing a difference in the flow of the processing liquid depending on the site in the processing container. Moreover, it can utilize as a plating method when it is necessary to perform favorable plating which does not generate | occur | produce plating unevenness and adhesive failure.
The present invention is not limited to the above-described embodiment, and various configurations or embodiments can be taken without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Processing container 2 Opening part 3 To-be-processed part 4 Drain 5 Cathode electrode 6 Plating tank 7 Conveyance means 8 Reserve tank 9 Treatment liquid 10 Injection port 11 Anode electrode 12 Pump 13 Vertical part 14 Folding part 15 Supply pipe 16 Power supply part 20 Plating process apparatus

Claims (5)

A surface treatment method using a surface treatment apparatus comprising: a treatment container for storing an object to be surface-treated; and a supply pipe having an injection port for supplying a treatment liquid for surface treatment to the treatment container. And
An opening is formed at the top of the processing vessel, a curved surface is formed from the bottom toward the opening in the processing vessel, and a first electrode is provided along the curved surface,
Injecting the processing liquid from an injection port arranged toward the bottom from the opening of the processing container,
After the treatment liquid hits the bottom portion of the treatment container, the treatment object is flow-stirred by a liquid flow that circulates toward the opening along the curved surface, and the treatment object is applied to the first electrode. Make contact
Immersing the second electrode in the treatment liquid added to the treatment vessel;
Electrolytic treatment is performed by energizing the first electrode and the second electrode. A surface treatment method, comprising: The surface treatment method according to claim 1, wherein the central axis of the injection port is dynamically moved relatively in a predetermined range in the horizontal direction with respect to the central axis of the opening of the processing container. . A processing container for storing an object to be surface-treated, wherein an opening is formed in an upper part of the processing container, and a curved surface is formed from the bottom toward the opening in the processing container. A processing vessel;
A first electrode provided along the curved surface;
A supply pipe for supplying a processing solution for surface treatment to the processing container, the supply port being arranged from the opening of the processing container toward the bottom;
A second electrode not in contact with the first electrode;
After the treatment liquid ejected from the ejection port hits the bottom of the treatment container, the object to be treated is fluidly stirred by a liquid flow that circulates toward the opening along the curved surface. An adjustment unit that adjusts the flow rate or flow pressure of the processing liquid ejected from the ejection port so that the workpiece is brought into contact with one electrode;
A power supply for energizing the second electrode in contact with the processing liquid added to the processing container, and the first electrode;
A surface treatment apparatus comprising: The surface treatment apparatus according to claim 3, wherein the second electrode is provided in the supply pipe or is separated from the supply pipe. The surface treatment apparatus according to claim 3, wherein the edge of the opening has a predetermined thickness or is bent toward the inside of the processing container.