JP2015030897A - Surface treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treatment apparatus which enables a surface treatment with high accuracy and efficiency even when a to-be-treated surface is an inner wall of a bottomed hole which varies in inside diameter between the opening to the bottom part.SOLUTION: An electrolytic treatment apparatus 10 (surface treatment apparatus) is provided with an electrode 16 to be inserted into a bottomed hole 12 so as to surface-treat the inner wall of the bottomed hole 12 which varies in inside diameter from the opening to the bottom part. The electrode 16 is a tubular body extending along the bottomed hole 12 and changes in outside diameter in the longitudinal direction according to the inside diameter of the bottomed hole 12. A feed passage for an electrolytic treatment solution is formed between the outer wall of the electrode 16 and the inner wall of the bottomed hole, and a recovery passage for the electrolytic solution may be formed inside the electrode 16.

Description

  The present invention relates to a surface treatment apparatus for performing a surface treatment on an inner wall of a bottomed hole.

  Surface treatment equipment that has an electrode facing the conductive surface to be processed (counter electrode), and applies surface treatment such as electroplating or electrodeposition coating to the surface to be processed by energizing with an electrolytic treatment solution interposed between both electrodes It has been known. As a to-be-processed surface, as shown to patent document 1, the inner wall etc. of the cooling channel (bottomed hole) formed in the metal mold | die for casting are mentioned, for example.

  In this case, surface treatment is performed by inserting an electrode into the cooling passage. It is preferable that the surface to be treated is subjected to surface treatment substantially uniformly throughout. For example, when electroplating or the like is performed as the surface treatment, a plating film having a substantially uniform thickness is preferably formed on the surface to be processed.

  Note that a surface treatment apparatus that performs a process involving electrolysis such as electroplating is also referred to as an “electrolytic treatment apparatus”.

JP 2009-72798 A

  The cooling passage may have a different inner diameter between the opening and the bottom. In this case, the surface to be treated by the surface treatment apparatus has a complicated shape such as a tapered shape or an uneven shape. In such a processed surface having a complicated shape, the current distribution tends to be non-uniform due to variations in the distance between the electrodes and the concentration of current at the tip of the convex portion. As a result, there is a concern that the surface treatment becomes non-uniform between the high current density portion and the low current density portion. That is, in the above electrolytic treatment apparatus, a substantially uniform surface treatment is performed on the entire surface to be treated having a complicated shape such as an inner wall of a bottomed hole having a different inner diameter from the opening to the bottom. There is a concern that it will be difficult.

  It can be considered that it is effective to use a technique such as electroless plating or immersion etching that does not require energization for the surface to be processed having a complicated shape as described above. However, these methods have disadvantages such as a long time for the surface treatment and difficulty in forming a coating such as zinc or chromium (in other words, there are restrictions on the material of the coating that can be formed). is there.

  The present invention has been made to solve the above-described problem. Even when the inner wall of a bottomed hole having a different inner diameter from the opening to the bottom is used as the surface to be processed, the electric power can be obtained with high accuracy and high efficiency. An object of the present invention is to provide a surface treatment apparatus capable of performing a surface treatment.

In order to achieve the above-mentioned object, the present invention inserts an electrode into a bottomed hole having a different inner diameter from the opening to the bottom, and circulates the treatment liquid, thereby A surface treatment apparatus for performing a surface treatment on an inner wall,
The electrode is a tubular body extending along the depth direction of the bottomed hole, and the outer diameter of the electrode varies depending on the inner diameter of the bottomed hole. And

  The surface treatment apparatus according to the present invention includes tubular electrodes having different outer diameters in the longitudinal direction according to the inner diameter of the bottomed hole. Thus, the distance between the inner wall of the bottomed hole (also referred to as the surface to be processed) and the electrode can be easily adjusted. As a result, it is possible to suppress a difference in current density from occurring on the surface to be processed, so that a substantially uniform surface treatment can be performed on the surface to be processed.

  Moreover, in this surface treatment apparatus, electrical surface treatment is performed by generating a potential difference by energizing between the electrode and the surface to be treated (counter electrode). Therefore, the surface treatment can be performed efficiently in a short time compared to the case where the surface treatment is performed only by a chemical reaction such as electroless plating or immersion etching.

  In addition, for example, when electroplating is performed as the surface treatment, unlike a method such as electroless plating, it is easy to form a plating film such as zinc or chromium. That is, the choice of materials that can be used for the surface treatment can be expanded.

  In the surface treatment apparatus, a supply path for the treatment liquid is formed between an inner wall of the bottomed hole and an outer wall of the electrode inserted into the bottomed hole, and the treatment liquid is collected inside the electrode. A path is preferably formed. In this case, the feeding pressure of the processing liquid to the inside of the bottomed hole can be increased satisfactorily, and the processing liquid can be circulated efficiently in the bottomed hole. As a result, the surface treatment can be performed on the surface to be processed with higher efficiency and higher accuracy.

  In the surface treatment apparatus, the electrode includes a plurality of hollow tubes having different outer diameters, and a small-diameter tube having a small outer diameter is inserted into a large-diameter tube having a large outer diameter among the hollow tubes. It is preferable. In this case, the outer diameter of the electrode can be easily adjusted by preparing a plurality of hollow tubes having different outer diameters according to the inner diameter of the bottomed hole.

  In the surface treatment apparatus, the small-diameter pipe is inserted into the large-diameter pipe while being electrically insulated from the large-diameter pipe, and the small-diameter pipe and the large-diameter pipe have different sizes. A current is preferably supplied. In this case, different sizes of current can be supplied to the small-diameter pipe and large-diameter pipe depending on the shape of the bottomed hole, so that the difference in current density on the surface to be processed is effectively suppressed. it can. This makes it possible to perform surface treatment with higher accuracy on the surface to be processed.

  Further, in the surface treatment apparatus, it is preferable that the insertion lengths of the large diameter tube and the small diameter tube with respect to the bottomed hole are adjustable. In this case, since the insertion length of the electrode can be easily adjusted in accordance with the depth of the portion having a different inner diameter, the versatility of the surface treatment apparatus is improved. That is, it is possible to perform surface treatment with high accuracy and efficiency for a plurality of bottomed holes having different depths at portions having different inner diameters.

  According to the present invention, the distance between the inner wall and the electrode can be easily adjusted even with a bottomed hole having a different inner diameter between the opening and the bottom. Thereby, when energization is performed between the inner wall of the bottomed hole and the electrode, it is possible to suppress a difference in current density from occurring on the inner wall of the bottomed hole. As a result, the surface treatment can be performed on the surface to be processed with high accuracy.

  In addition, since it is possible to perform an electrical surface treatment, the surface treatment is efficiently performed in a short time compared to the case where the surface treatment is performed only by a chemical reaction such as electroless plating or immersion etching. be able to.

  Furthermore, since it is possible to form a coating such as zinc or chromium, which is difficult to form when surface treatment is performed only by the above chemical reaction, there are choices of materials that can be used for surface treatment. Can be spread.

It is a principal part schematic block diagram of the electrolytic treatment apparatus (surface treatment apparatus) which concerns on embodiment of this invention, and the bottomed hole which performs the surface treatment of an inner wall with this electrolytic treatment apparatus. It is a schematic sectional drawing of the process liquid supply part of the electrolytic processing apparatus shown in FIG. It is a schematic sectional drawing which shows the relationship between the front-end | tip part and bottomed hole of the large diameter pipe and small diameter pipe of the electrolytic processing apparatus shown in FIG. It is a schematic sectional drawing of the process liquid discharge part of the electrolytic treatment apparatus shown in FIG. It is a schematic sectional drawing of the process liquid collection | recovery part of the electrolytic processing apparatus shown in FIG. It is a graph which shows the relationship between the distance (mm) from opening, and the thickness (plating thickness) (micrometer) of a plating film at the time of performing an electroplating process on the inner wall of the bottomed hole shown in FIG. The relationship between the distance from the opening (mm) and the thickness of the plating film (plating thickness) (μm) when electroplating the inner wall of a straight hole with a uniform inner diameter between the opening and the bottom It is a graph which shows.

  Hereinafter, preferred embodiments of the surface treatment apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  The surface treatment apparatus according to the present invention can be applied to a surface to be treated such as electroplating, electrolytic etching, electrolytic degreasing, electrodeposition coating, anodizing, cathodic oxidation, electrolytic polishing, or pre-treatment or post-treatment thereof. In particular, the present invention can be suitably applied when surface treatment is performed.

  In the present embodiment, an electrolytic treatment apparatus that performs electroplating will be described as an example of the surface treatment apparatus. In the following, “left” and “right” refer to the left and right in the drawings, respectively.

  As shown in FIG. 1, the electrolytic treatment apparatus 10 according to the present embodiment is for performing electroplating on the inner wall (surface to be treated) of the bottomed hole 12, for example, a plated film made of a zinc alloy ( (Not shown). In addition, the plating film which consists of zinc alloys can be formed using the electrolytic processing liquid prepared by mixing zinc chloride, nickel chloride, ammonium chloride, etc. However, the plating film that can be formed on the inner wall by the electrolytic treatment apparatus 10 is not limited to the zinc alloy, and may be formed from a material that can be deposited on the inner wall by electroplating. As an example of the substance, a simple substance or an alloy such as zinc, chromium, gold, silver, copper, and tin can be given.

  Here, the bottomed hole 12 is a cooling passage formed in the casting mold 14 and supplied with a coolant for cooling the casting mold 14, and has an inner diameter between the opening and the bottom. Is different. That is, the bottomed hole 12 includes a large diameter portion 12a formed on the opening side and a small diameter portion 12b formed on the bottom side and having an inner diameter smaller than the large diameter portion 12a.

  The casting mold 14 is formed of, for example, an alloy steel material, and is cooled by supplying water or the like as a coolant into the bottomed hole 12. At this time, if the refrigerant directly contacts the inner wall of the bottomed hole 12, heat shrinkage, corrosion, or the like starting from the inner wall may occur, and the casting mold 14 may be easily deteriorated. Accordingly, a plating film is formed on the inner wall of the bottomed hole 12 by the electrolytic treatment apparatus 10 in order to avoid direct contact between the refrigerant and the inner wall. Thereby, the durability of the casting mold 14 can be improved.

  First, the overall configuration of the electrolytic treatment apparatus 10 will be described with reference to the schematic configuration diagram of FIG. The electrolytic processing apparatus 10 includes an electrode 16, a processing liquid supply unit 18, a processing liquid discharge unit 20, a processing liquid recovery unit 22, and a flexible tube 24.

  The electrode 16 is a tube formed of, for example, platinum-coated titanium or the like, and a tip protruding from the processing liquid supply unit 18 is inserted into the bottomed hole 12. The electrode 16 includes a large-diameter tube 16a having an outer diameter smaller than the inner diameter of the large-diameter portion 12a of the bottomed hole 12, and a small-diameter tube 16b having an outer diameter smaller than the inner diameter of the large-diameter tube 16a. .

  The large-diameter pipe 16 a has a distal end side inserted into the large-diameter portion 12 a of the bottomed hole 12 and a rear end side connected to the processing liquid discharge unit 20. The small diameter pipe 16b is inserted into the large diameter pipe 16a while being electrically insulated from the large diameter pipe 16a. Further, the distal end side of the small diameter tube 16 b protrudes outward from the distal end of the large diameter tube 16 a and is inserted into the small diameter portion 12 b of the bottomed hole 12. The rear end side of the small diameter pipe 16b is connected to the processing liquid recovery unit 22.

  The flexible tube 24 is a flexible tube and can be formed of resin, rubber, metal, or the like. The processing liquid recovery unit 22 and the processing liquid discharge unit 20 are connected via the flexible tube 24.

  The electrolytic treatment apparatus 10 further includes a treatment liquid supply unit (not shown), a treatment liquid tank, and an external power source. The processing liquid supply means supplies the electrolytic processing liquid into the bottomed hole 12 via the processing liquid supply unit 18. The treatment liquid tank stores the electrolytic treatment liquid discharged through the treatment liquid discharge unit 20. The external power supply supplies a current to the electrode 16 and causes a potential difference between the electrode 16 and the inner wall of the bottomed hole 12. At this time, as will be described later, the external power supply can supply different currents to the large diameter tube 16a and the small diameter tube 16b.

  Next, a specific configuration of the processing liquid supply unit 18 will be described with reference to the schematic cross-sectional view of FIG. The processing liquid supply unit 18 includes a main body member 26 that is detachably attached to the bottomed hole 12, and a first mail connector 28 that fixes the electrode 16 to the main body member 26.

  In the main body member 26, a tubular insertion portion 30 inserted into the bottomed hole 12 and a processing liquid supply pipe 32 connected to the processing liquid supply means are formed so as to protrude. The outer diameter of the insertion portion 30 is formed to be equal to or slightly smaller than the inner diameter in the vicinity of the opening of the bottomed hole 12 (large diameter portion 12a). By fitting the insertion portion 30 into the bottomed hole 12, the main body member 26 can be detachably attached to the bottomed hole 12.

  An annular groove 33 is formed in the main body member 26, and a seal member 34 is attached to the annular groove 33. The seal member 34 provides a seal between the casting mold 14 and the main body member 26.

  The body member 26 is formed with an electrode insertion hole 36 that penetrates the inside of the body member 26. By inserting the insertion portion 30 into the bottomed hole 12 as described above, the bottomed hole 12 and the electrode insertion hole 36 are communicated with each other. The electrode insertion hole 36 is a through hole having an inner diameter larger than the outer diameter of the large diameter tube 16a, and the electrode 16 (the large diameter tube 16a and the small diameter tube 16b) is inserted through the inside. Further, as will be described later, the first mail connector 28 is attached to the left end portion of the electrode insertion hole 36. Thereby, the relative position of the large diameter tube 16a with respect to the electrode insertion hole 36 is fixed, and the space between the outer wall of the large diameter tube 16a and the inner wall of the electrode insertion hole 36 is sealed.

  The electrode insertion hole 36 communicates with the inside of the processing liquid supply pipe 32 inside the main body member 26. Therefore, the electrolytic treatment liquid supplied from the treatment liquid supply means via the treatment liquid supply pipe 32 passes through the space between the outer wall of the large diameter pipe 16 a and the inner wall of the electrode insertion hole 36, and has the bottomed hole 12. Supplied in.

  That is, a supply path for the electrolytic treatment liquid is formed between the outer wall of the large diameter tube 16 a and the inner walls of the electrode insertion hole 36 and the bottomed hole 12. Hereinafter, for convenience of explanation, a supply path between the outer wall of the large-diameter pipe 16a and the inner wall of the electrode insertion hole 36, a supply path between the outer wall of the large-diameter pipe 16a and the inner wall of the large-diameter portion 12a, and a small-diameter pipe The supply path between the outer wall of 16b and the inner wall of the small-diameter portion 12b will be referred to as “first supply path”, “second supply path”, and “third supply path”, respectively, and reference numerals 37a, 37b and 37c.

  The first mail connector 28 includes a connector main body 38 and a fastening member 40, and an electrode 16 (a large diameter tube 16a and a small diameter tube 16b) is inserted therein. A male screw 42 is formed on the outer peripheral surface on one end side of the connector main body 38, and the male screw 42 is screwed into the electrode insertion hole 36, whereby the connector main body 38 is connected to the main body member 26. At the same time, it is possible to seal between the inner wall at the left end of the electrode insertion hole 36 and the outer wall of the large diameter tube 16a.

  A male screw 44 is formed on the outer peripheral surface of the left end of the connector main body 38. When the male screw 44 is screwed with a female screw 46 formed on the inner peripheral surface of the fastening member 40, a fastening force is applied to the large-diameter tube 16 a of the electrode 16 in the first mail connector 28. . That is, after adjusting the insertion length of the large-diameter pipe 16 a in the depth direction of the bottomed hole 12, the tightening force is applied by the tightening member 40. As a result, the large-diameter pipe 16a is positioned with the insertion length adjusted.

  As shown in FIG. 2, in the electrode 16, a spacer 48 is provided between the large-diameter pipe 16a and the small-diameter pipe 16b at the portion to which the above-described tightening force is applied to prevent mutual contact. Also good. As will be described later, the space between the large diameter pipe 16a and the small diameter pipe 16b serves as a first recovery path 49 for recovering the electrolytic treatment liquid. For this reason, the spacer 48 is provided with a through-hole or the like along the flow direction (the extending direction of the first recovery path 49) so as not to hinder the flow of the electrolytic treatment solution.

  Next, a specific configuration on the distal end side of the large diameter tube 16a and the small diameter tube 16b inserted into the bottomed hole 12 will be described with reference to the schematic cross-sectional view of FIG.

  An insulating cap 50 is attached to the tip of the large diameter tube 16a. This prevents contact between the electrode 16 and the inner wall of the bottomed hole 12 and contact between the large diameter tube 16a and the small diameter tube 16b.

  The insulating cap 50 is formed in a tubular shape from a material having insulation and chemical resistance such as silicone rubber and fluororesin. The inner diameter of the insulating cap 50 is formed larger than the outer diameter of the small-diameter pipe 16b, and the small-diameter pipe 16b is inserted into the insulating cap 50.

  Specifically, the insulating cap 50 is formed by integrally forming a cylindrical insertion portion 52 fitted into the large diameter tube 16a and a cap portion 54 having an outer diameter substantially equal to the outer diameter of the large diameter tube 16a. Yes. The insertion portion 52 has an outer diameter that is the same as or slightly smaller than the inner diameter of the large-diameter tube 16a, and is fitted inside the large-diameter tube 16a.

  The cap portion 54 is formed in a shape corresponding to the shapes of the large diameter portion 12a and the small diameter portion 12b of the bottomed hole 12 and the boundary portion, and an arcuate curved surface is formed at the tip. Thereby, contact between the inner wall of the bottomed hole 12 and the electrode 16 can be effectively prevented.

  On the side wall of the cap portion 54, a through hole 56 that penetrates the side wall and communicates with the insulating cap 50 is provided. That is, the through hole 56 communicates with the space between the outer wall of the small diameter tube 16 b and the inner wall of the insulating cap 50.

  Further, a seal member 58 is interposed between the inner wall on the tip side of the through hole 56 of the cap portion 54 and the outer wall of the small-diameter pipe 16b to seal the cap portion 54. As a result, the electrolytic treatment liquid flowing through the second supply path 37b (between the inner wall of the large-diameter portion 12a and the outer wall of the large-diameter pipe 16a) passes through the through-hole 56 and the inner wall of the insulating cap 50 and the small-diameter pipe 16b. Between the first and second outer walls, that is, in the second collection path 59 which is the inside of the small diameter pipe 16b. Further, the electrolytic treatment liquid flows through the first recovery path 49 formed between the large diameter pipe 16a and the small diameter pipe 16b.

  As shown in FIG. 3, an O-ring 60 is provided between the insulating cap 50 and the large diameter pipe 16a. The O-ring 60 functions as a cushion when the insulating cap 50 is attached.

  In the bottomed hole 12, the distal end side of the small diameter tube 16b extends outside from the distal end of the large diameter tube 16a via the insulating cap 50 as described above, and is disposed inside the small diameter portion 12b. . The third supply path 37c is formed between the outer wall of the small diameter tube 16b and the inner wall of the small diameter portion 12b. In the third supply path 37c, the electrolytic treatment liquid that has been branched without flowing from the second supply path 37b into the through hole 56 flows.

  In addition, the electrolytic treatment liquid that has flowed to the bottom of the bottomed hole 12 (the bottom of the small diameter portion 12b) can flow from the tip of the small diameter tube 16b to the inside of the small diameter tube 16b. That is, an electrolytic treatment liquid recovery path 61 is formed inside the small diameter pipe 16b.

  Next, a specific configuration of the processing liquid discharge unit 20 will be described with reference to the schematic cross-sectional view of FIG. The processing liquid discharger 20 includes a main body member 62, a second mail connector 64, a third mail connector 66, and a fourth mail connector 68.

  A treatment liquid discharge pipe 70 connected to the treatment liquid tank protrudes from the main body member 62. Further, a merge pipe 72 is formed to protrude from the side wall of the processing liquid discharge pipe 70. The main body member 62 is formed with a small diameter pipe insertion hole 74 that penetrates the inside of the main body member 62 and through which the small diameter pipe 16b is inserted. The small diameter pipe insertion hole 74 communicates with the inside of the processing liquid discharge pipe 70. Further, the inside of the processing liquid discharge pipe 70 is also communicated with the inside of the junction pipe 72.

  The rear end portion of the large diameter tube 16a is connected to the small diameter tube insertion hole 74 via the second mail connector 64, and one end portion of the flexible tube 24 is connected to the junction tube 72 via the fourth mail connector 68. Is connected.

  Each of the second mail connector 64, the third mail connector 66, and the fourth mail connector 68 is basically configured in the same manner as the first mail connector 28 described above. That is, the second mail connector 64 has a connector main body 76 and a fastening member 78. A step 80 having a height substantially equal to the wall thickness of the large diameter tube 16a is formed inside the connector main body 76, and the rear end of the large diameter tube 16a is in contact with the step 80. As a result, the large-diameter pipe 16a is positioned with respect to the connector main body 76.

  Further, the male screw 82 formed on the outer peripheral surface of the left end of the connector main body 76 is screwed into the small diameter tube insertion hole 74, so that the connector main body 76 is connected to the main body member 62. On the other hand, the male screw 84 formed on the outer peripheral surface of the right end of the connector main body 76 and the female screw 86 of the fastening member 78 are screwed together, so that the large-diameter pipe 16a inserted into the second mail connector 64 is inserted. A tightening force is applied to. Thereby, the small diameter pipe insertion hole 74 of the main body member 62 and the inside of the large diameter pipe 16a communicate with each other while being sealed from the outside. Therefore, the electrolytic treatment liquid that has flowed through the first recovery path 49 flows through the second mail connector 64 into the small diameter pipe insertion hole 74 and is sent into the treatment liquid discharge pipe 70.

  In the electrode 16, a spacer similar to the spacer 48 (see FIG. 2) may be provided between the large-diameter tube 16a and the small-diameter tube 16b where the above-described tightening force is applied. .

  The third mail connector 66 has a connector body 88 and a fastening member 90. The third mail connector 66 is attached to the main body member 62 by screwing the connector main body 88 into the small diameter pipe insertion hole 74. Further, the tightening force is applied to the small-diameter pipe 16b by screwing the tightening member 90 and the connector main body 88 together. That is, after adjusting the insertion length of the small-diameter pipe 16b into the bottomed hole 12, the insertion length of the small-diameter pipe 16b into the bottomed hole 12 is adjusted by applying the above-described tightening force by the fastening member 90. It is free. Further, the small-diameter pipe 16 b can be fixed to the main body member 62 in a state where the space between the outer wall of the small-diameter pipe 16 b and the inner wall of the small-diameter pipe insertion hole 74 is sealed.

  The fourth mail connector 68 has a connector main body 92 and a fastening member 94. The fourth mail connector 68 is attached to the main body member 62 by screwing the connector main body 92 into the junction pipe 72. A step 96 having a height substantially equal to the wall thickness of the flexible tube 24 is formed in the connector main body 92. The flexible tube 24 is fixed to the connector main body 92 by contacting one end of the flexible tube 24 with the stepped portion 96.

  That is, the inside of the flexible tube 24 and the junction pipe 72 are connected via the fourth mail connector 68 while being sealed from the outside. As a result, as described later, the electrolytic treatment liquid that has circulated through the flexible tube 24 circulates in the junction pipe 72 through the fourth mail connector 68 and is sent into the treatment liquid discharge pipe 70.

  Next, a specific configuration of the processing liquid recovery unit 22 will be described with reference to the schematic cross-sectional view of FIG. The treatment liquid recovery unit 22 includes a so-called elbow-type main body member 98, a fifth mail connector 100, and a sixth mail connector 102.

  A recovery hole 104 is formed through the body member 98. A rear end portion of the small-diameter pipe 16 b is connected to the right end side of the recovery hole 104 via the fifth mail connector 100. Further, the left end portion of the flexible tube 24 is connected to the lower end side of the recovery hole 104 via the sixth mail connector 102.

  Accordingly, the electrolytic treatment liquid that has flowed through the inside of the small diameter pipe 16 b (second recovery path 59) flows through the recovery hole 104 through the fifth mail connector 100, and then passes through the sixth mail connector 102 to the flexible tube 24. Circulate inside.

  In the above configuration, the main body members 26, 62, 98 and the first to sixth mail connectors 28, 64, 66, 68, 100, 102 are made of a material having insulating properties and chemical resistance, such as a fluororesin. Can be formed from

  The electrolytic treatment apparatus 10 according to the present embodiment is basically configured as described above. Next, the function and effect will be described in relation to the operation of the electrolytic treatment apparatus 10.

  First, the large-diameter pipe 16a is protruded from the insertion section 30 of the processing liquid supply unit 18 so that the large-diameter pipe 16a is disposed in the large-diameter section 12a. A tightening force is applied by the first mail connector 28 and the second mail connector 64. As a result, the large-diameter pipe 16 a is fixed to the processing liquid supply unit 18 and the processing liquid discharge unit 20.

  In addition, the small-diameter pipe 16b inserted through the large-diameter pipe 16a is also protruded by a predetermined length from the tip of the large-diameter pipe 16a so as to be disposed in the small-diameter portion 12b. In this state, the small diameter pipe 16b is fixed to the processing liquid discharge section 20 and the processing liquid collection section 22 by applying a tightening force by the third mail connector 66 and the fifth mail connector 100 to the small diameter pipe 16b.

  In addition, with adjustment of the insertion length of the large-diameter pipe 16a and the small-diameter pipe 16b into the bottomed hole 12 as described above, each of the processing liquid supply unit 18, the processing liquid discharge unit 20, and the processing liquid collection unit 22 is adjusted. The distance between changes. The length of the flexible tube 24 may be set according to the maximum separation distance between the processing liquid discharge unit 20 and the processing liquid recovery unit 22. Since the flexible tube 24 has flexibility, the flexible tube 24 maintains a state of being connected to the processing liquid discharge unit 20 and the processing liquid recovery unit 22 while being tensioned or relaxed within the range of the maximum separation distance. Accordingly, the electrolytic treatment liquid can be circulated between the treatment liquid discharge unit 20 and the treatment liquid collection unit 22 via the flexible tube 24.

  Then, after attaching the insulating cap 50 to the tip of the large diameter tube 16a, the electrode 16 is inserted into the bottomed hole 12 and the insertion portion 30 is fitted in the vicinity of the opening of the bottomed hole 12 as shown in FIG. Combine.

  Next, an electrolytic treatment liquid is supplied from the treatment liquid supply means to the treatment liquid supply pipe 32. Here, the flow path of the electrolytic treatment liquid will be specifically described with reference to FIGS.

  As shown in FIG. 2, the electrolytic treatment liquid supplied from the treatment liquid supply pipe 32 is supplied into the bottomed hole 12 through the first supply path 37a. Thereby, as shown in FIG. 3, the electrolytic treatment liquid can be circulated through the second supply path 37b.

  A part of the electrolytic treatment liquid that has flowed up to the tip of the large-diameter pipe 16 a flows through the first recovery path 49 through the through hole 56. On the other hand, the remainder of the electrolytic treatment liquid that has not circulated in the through hole 56 circulates in the third supply path 37c. And the electrolytic treatment liquid which distribute | circulated to the bottom part of the bottomed hole 12 distribute | circulates from the front-end | tip of the small diameter pipe | tube 16b to the inside of this small diameter pipe | tube 16b. That is, the electrolytic treatment liquid that has finished flowing through the third supply path 37 c flows into the second recovery path 59 in the electrode 16.

  As shown in FIG. 4, the electrolytic processing liquid flowing through the first recovery path 49 flows into the processing liquid discharge pipe 70 through the small diameter pipe insertion hole 74 in the processing liquid discharge section 20. As a result, the electrolytic treatment liquid is discharged from the treatment liquid discharge pipe 70 to the treatment liquid tank.

  On the other hand, the electrolytic treatment liquid flowing through the second collection path 59 in the small diameter pipe 16b flows into the flexible tube 24 through the collection hole 104 in the treatment liquid collection unit 22, as shown in FIG. As a result, as shown in FIG. 4, it flows through the merging pipe 72 of the processing liquid discharge section 20 via the flexible tube 24, and in the processing liquid discharge pipe 70, the electrolytic treatment from the small-diameter pipe insertion hole 74. Combined with the liquid, it is discharged to the processing liquid tank.

  As described above, an electric current is supplied to the electrode 16 by the external power supply while the electrolytic treatment liquid is circulated between the inner wall of the bottomed hole 12 and the outer wall of the electrode 16. At this time, by setting the outer diameters of the large diameter pipe 16a and the small diameter pipe 16b, the distances of the large diameter pipe 16a and the small diameter section 12b with respect to the inner walls of the large diameter section 12a and the small diameter section 12b can be easily adjusted. be able to. Moreover, the magnitude | size of the electric current supplied to the large diameter pipe | tube 16a and the small diameter pipe | tube 16b can be adjusted separately, respectively.

  For this reason, it can suppress effectively that the difference of a current density arises between the inner walls of the large diameter part 12a and the small diameter part 12b. As a result, it is possible to form a plating film having a substantially uniform thickness on the inner wall of the bottomed hole 12. Therefore, the plating film can be formed with high accuracy and high efficiency even on the inner wall of the complicated shape of the bottomed hole 12 including the large diameter portion 12a and the small diameter portion 12b.

  Further, as described above, the second supply path 37b and the third supply path 37c of the electrolytic treatment liquid are formed between the inner wall of the bottomed hole 12 and the outer walls of the large diameter pipe 16a and the small diameter pipe 16b, and the large diameter pipe A first recovery path 49 and a second recovery path 59 for the electrolytic treatment liquid are formed inside 16a and the small diameter pipe 16b, respectively. Thereby, the feeding pressure of the electrolytic treatment liquid to the inside of the bottomed hole 12 can be increased satisfactorily, and the electrolytic treatment liquid can be efficiently circulated in the bottomed hole 12. As a result, it is possible to form a plating film on the inner wall of the bottomed hole 12 with high efficiency and high accuracy.

  In addition, this invention is not specifically limited to above-described embodiment, Of course, a various deformation | transformation is possible in the range which does not deviate from the summary.

  For example, in the above-described embodiment, the bottomed hole 12 includes the large diameter portion 12a and the small diameter portion 12b, and the electrode 16 includes an outer diameter large diameter tube 16a and an outer diameter corresponding to the inner diameter of the large diameter portion 12a and the small diameter portion 12b. The small diameter pipe 16b is used. However, it is not particularly limited to this, and the bottomed hole may be composed of three or more inner diameter portions having different sizes. In this case, the outer diameter of the electrode can be easily adjusted by configuring the electrode from a plurality of hollow tubes corresponding to the number of inner diameter portions of the bottomed hole. Accordingly, as described above, it is possible to perform surface treatment with high accuracy and high efficiency on the inner wall of the bottomed hole.

  Further, the electrode is not limited to a plurality of hollow tubes, and may be composed of one hollow tube whose outer diameter changes in the longitudinal direction according to the inner diameter of the bottomed hole. it can.

  In the above embodiment, the large diameter pipe 16a and the small diameter with respect to the bottomed hole 12 are mainly driven by the tightening force of the first mail connector 28, the second mail connector 64, the third mail connector 66, and the fifth mail connector 100. The insertion length of the tube 16b is adjustable. However, the insertion length adjusting means is not limited to a mail connector, and for example, a Wilson seal or the like that can fix the relative positions of the large-diameter pipe 16a and the small-diameter pipe 16b with respect to the bottomed hole 12 can be used. Also in this case, the distance between the inner wall of the bottomed hole 12 and the electrode 16 can be easily adjusted according to the shape of the bottomed hole 12, and the bottomed hole 12 having various shapes can be adjusted. Surface treatment can be performed with high accuracy and efficiency on the inner wall.

  Further, in the above-described embodiment, the surface treatment is performed in the cooling passage provided in the casting mold 14 by the electrolytic treatment apparatus 10, but the present invention is not particularly limited thereto. If it is the inner wall of the bottomed hole formed in the substance which has electroconductivity, it is possible to surface-treat with high precision and high efficiency similarly to the above.

  Electrolytic plating was performed on the inner wall of the cooling passage (bottomed hole) 12 provided in the casting mold 14 formed of steel by the electrolytic treatment apparatus 10 to form a zinc alloy plating film. The bottomed hole 12 includes a large-diameter portion 12a having an inner diameter of 16 mm and a small-diameter portion 12b having an inner diameter of 6 mm. The depth from the opening of the bottomed hole 12 to the bottom is 250 mm, of which the depth of the large diameter portion 12a is 150 mm and the depth of the small diameter portion 12b is 100 mm. The large-diameter pipe 16a and the small-diameter pipe 16b constituting the electrode 16 are both a tube body made of titanium coated with platinum, the outer diameter of the large-diameter pipe 16a inserted into the large-diameter portion 12a is 12 mm, and the small-diameter portion The outer diameter of the small diameter tube 16b inserted into 12b was 4 mm.

  First, the large-diameter pipe 16a is projected from the insertion part 30 of the processing liquid supply part 18 with a length corresponding to the length of the large-diameter part 12a, and the small-diameter pipe 16b is protruded from the tip of the large-diameter pipe 16a. It protrudes with a length corresponding to the length of the small diameter portion 12b. And as above-mentioned, after attaching the insulating cap 50 to the front-end | tip of the large diameter pipe | tube 16a, the electrode 16 is inserted in the bottomed hole 12, and the electrode 16 with respect to the metal mold | die 14 for casting, the process liquid supply part 18, The relative positions of the processing liquid discharge unit 20 and the processing liquid recovery unit 22 are fixed.

  Next, a degreasing cleaning liquid (water-soluble alkaline cleaning agent) is supplied from the processing liquid supply pipe 32, and the degreasing cleaning liquid is supplied to the first to third supply paths 37 a to 37 c, the first recovery path 49, and the second recovery path 59. Circulate. Thereby, the degreasing process is performed on the inner wall of the bottomed hole 12. Note that this degreasing treatment can also be performed by electrolytic degreasing (cathodic electrolysis or anodic electrolysis) by supplying current to the electrode 16 from an external power source.

  After the degreasing process, compressed air is introduced from the processing liquid supply pipe 32 and the degreasing cleaning liquid is discharged from the bottomed hole 12 and the electrode 16. Further, water and compressed air are alternately supplied from the treatment liquid supply pipe 32 to wash the inside of the bottomed hole 12 and the electrode 16 with water.

  Next, an etching liquid (10 wt% hydrochloric acid aqueous solution or 10 wt% sulfuric acid aqueous solution) is supplied from the treatment liquid supply pipe 32, and the first to third supply paths 37 a to 37 c and the first recovery path 49, The etching solution is circulated through the second recovery path 59. Thereby, the etching process is performed on the inner wall of the bottomed hole 12. This etching process can also be performed by electrolytic etching (anodic electrolysis) by supplying a current to the electrode 16 from an external power source.

  After the etching process, the etching solution is discharged with compressed air and washed with water and compressed air in the same manner as the above degreasing process.

  Next, the smut removing liquid is supplied from the processing liquid supply pipe 32, and the smut removing liquid is circulated through the first to third supply paths 37a to 37c, the first recovery path 49, and the second recovery path 59. The smut removing liquid can be prepared by mixing sodium hydroxide at a rate of 100 g / L, ethylenediaminetetraacetic acid (EDTA) at a rate of 30 g / L, and sodium citrate at a rate of 20 g / L. As a result, the smut removal process is performed on the inner wall of the bottomed hole 12. Note that this smut removal treatment can also be performed by electrolytic treatment (cathodic electrolysis or anodic electrolysis) by supplying current to the electrode 16 from an external power source.

  After the smut removing process, the smut removing liquid is discharged with compressed air and washed with water and compressed air in the same manner as the above degreasing process.

  Next, an electrolytic treatment liquid at 35 ° C. is supplied from the treatment liquid supply pipe 32 at a flow rate of 5 L / min. The electrolytic treatment solution was mixed at a ratio of 50 g / L of zinc chloride, 60 g / L of nickel chloride, 200 g / L of ammonium chloride, and 30 g / L of the primary gloss material, and the pH was adjusted to 5.8. While circulating the electrolytic treatment solution through the first to third supply paths 37a to 37c, the first recovery path 49, and the second recovery path 59, an electric current is supplied to the electrode 16 so that the inner wall of the bottomed hole 12 is electrically connected. Plating is performed.

At this time, the magnitudes of the current supplied to the large diameter tube 16a and the current supplied to the small diameter tube 16b are adjusted so that the current density of the large diameter portion 12a and the small diameter portion 12b is 10 A / dm ² . Thus, a plating film was formed at a rate of 2.7 μm / min, and electroplating was performed until the thickness of the plating film became approximately 20 μm.

  After the plating film made of nickel-zinc alloy is formed on the inner wall of the bottomed hole 12 by electroplating, the smut removing liquid is discharged with compressed air and washed with water and compressed air in the same manner as after the degreasing process. And do.

  Next, chromate liquid (trade name “680 chromate liquid” manufactured by SurTec) is supplied from the treatment liquid supply pipe 32, and the first to third supply paths 37 a to 37 c, the first recovery path 49, and the second recovery path are supplied. The chromate solution is circulated through the passage 59. Thus, chromate treatment is performed, and a chromate film is deposited on the plating film. Thereafter, similarly to the above-described degreasing treatment, the chromate solution is discharged with compressed air and washed with water and compressed air. As a result, a chromate film is formed on the nickel-zinc plating film covering the inner wall of the bottomed hole 12. As a result, the corrosion resistance of the inner wall of the bottomed hole 12 is further improved.

  After performing the above processing, the thickness of the obtained plated film was measured at predetermined intervals between the opening of the bottomed hole 12 and the bottom. The result is shown in FIG. For comparison, electroplating was performed on the inner wall of the straight hole formed in the casting mold 14 and having the same inner diameter from the opening to the bottom under the same conditions as described above. The plated film thus formed was used as a comparative example, and the thickness of the plated film of the comparative example was also measured at predetermined intervals from the opening to the bottom. The result is shown in FIG. In addition, the thickness of the plating film was measured by observing a cross section of the casting mold 14 used as a measurement sample along the longitudinal direction of the bottomed hole 12 with a scanning electron microscope (SEM).

  From FIG. 6 and FIG. 7, it is possible to form a plating film having a substantially uniform thickness over the entire inner wall of the bottomed hole 12 by performing electroplating using the electrolytic treatment apparatus 10. I understood. Moreover, the average thickness of this plating film was 20.1 micrometers, and the average thickness of the plating film of the comparative example was 20.4 micrometers. That is, the same accuracy as the case where the plating film is formed on the inner wall of the straight hole having the uniform inner diameter, even on the inner wall of the bottomed hole 12 having a different inner diameter from the opening to the bottom. It was found that a plating film can be formed at a high speed.

DESCRIPTION OF SYMBOLS 10 ... Electrolytic processing apparatus 12 ... Bottom hole 12a ... Large diameter part 12b ... Small diameter part 14 ... Mold for casting 16 ... Electrode 16a ... Large diameter pipe 16b ... Small diameter pipe 18 ... Treatment liquid supply part 20 ... Treatment liquid discharge part 22 ... Processing liquid recovery part 24 ... Flexible tubes 26, 62, 98 ... Main body member 28 ... First mail connectors 30, 52 ... Insertion part 32 ... Processing liquid supply pipes 34, 58 ... Seal member 36 ... Electrode insertion holes 37a to 37c ... First to third supply passages 38, 76, 88, 92 ... connector main bodies 40, 78, 90, 94 ... fastening members 42, 44, 82, 84 ... male screws 46, 86 ... female screws 48 ... spacers 49 ... first DESCRIPTION OF SYMBOLS 1 Recovery path 50 ... Insulation cap 54 ... Cap part 56 ... Through-hole 59 ... 2nd recovery path 60 ... O-ring 64 ... 2nd mail connector 66 ... 3rd mail connector 68 ... 4th mail connector 70 ... Treatment liquid supply Feed pipe 72 ... Merge pipe 74 ... Small diameter pipe insertion hole 80, 96 ... Step portion 100 ... Fifth mail connector 102 ... Sixth mail connector 104 ... Recovery hole

Claims (5)

A surface treatment apparatus for performing surface treatment on the inner wall of the bottomed hole by inserting an electrode into the bottomed hole having a different inner diameter between the opening and the bottom and allowing the treatment liquid to flow therethrough,
The electrode is a tubular body extending along the depth direction of the bottomed hole, and the outer diameter of the electrode varies depending on the inner diameter of the bottomed hole. Surface treatment equipment.   2. The surface treatment apparatus according to claim 1, wherein a supply path of the treatment liquid is formed between an inner wall of the bottomed hole and an outer wall of the electrode inserted into the bottomed hole, and A surface treatment apparatus, wherein a treatment liquid recovery path is formed.   3. The surface treatment apparatus according to claim 1, wherein the electrode includes a plurality of hollow tubes having different outer diameters, and an outer diameter of the hollow tube is larger than a large diameter tube. A surface treatment apparatus in which a small small-diameter pipe is inserted.   4. The surface treatment apparatus according to claim 3, wherein the small diameter tube is inserted into the large diameter tube in a state of being electrically insulated from the large diameter tube, and the small diameter tube and the large diameter tube are different in size. A surface treatment apparatus characterized by being supplied with a current.   5. The surface treatment apparatus according to claim 3, wherein insertion lengths of the large diameter pipe and the small diameter pipe with respect to the bottomed hole are adjustable.

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