JP2008291283A - Plating method and electrode unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating method in which a plurality of fine pores are subjected altogether to highly uniform plating, with respect to a structure having the plurality of the fine pores arranged in a fixed form. <P>SOLUTION: For batch electroplating the inner surfaces of the plurality of the fine pores of the structure to be plated on which a plurality of the fine pores are arranged in the fixed form, an electrode unit 11 on which bar-like electrodes 12 are projected by the number equal to that of the fine pores corresponding to the arrangement of the fine pores from a planar-formed frame part 13 is used to batch-electroplate each of bar-shaped electrodes of the electrode unit in a state of being inserted into the fine pore to be plated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plating process, and more particularly, to a plating process suitable for selective electrolytic plating of the inner peripheral surface of a pore in a structure provided with a large number of pores.

  Synthetic resin pellets are generally produced by extruding a raw thermoplastic resin into a linear shape to form pellets. Specifically, using a synthetic resin granulation die in which nozzle pores each having a nozzle portion formed at the tip thereof are provided in a predetermined arrangement, for example, several tens to thousands, a number of fine nozzles are provided. This is a method of forming a pellet by extruding the raw material resin into a linear shape and cutting it in water using the nozzle portion in the hole as a nozzle (for example, Patent Documents 1 to 4).

  In such a synthetic resin pellet manufacturing method, the nozzle of the synthetic resin granulation die (or the synthetic resin granulation die) is corroded by an oxidizing gas such as chlorine gas generated from the raw resin, or at a high pressure. It is subject to wear by the extruded resin. Therefore, the nozzle is desired to have high corrosion resistance and wear resistance. In addition, since it is preferable for the stability and efficiency of pellet production that the frictional resistance during extrusion of the raw resin is as small as possible, it is also desirable for the nozzle to have a low frictional resistance.

  In order to fully satisfy the characteristics required for such nozzles, plating with high corrosion resistance and wear resistance, such as hard chrome plating, and a low friction coefficient is applied to the inner peripheral surface of the nozzle or nozzle pore. It is best to apply.

  As a technique for performing plating on the inner peripheral surface of a pore such as a nozzle pore, a method of performing electrolytic plating with a rod-shaped electrode inserted in the pore to be plated is known (for example, Patent Documents). 5, 6).

  In principle, it is possible to apply plating to nozzles or pores for nozzles of synthetic resin granulation dies by using such conventional techniques. However, it is common for synthetic resin granulation dies to have hundreds to thousands of nozzle pores, and each of such a large number of nozzle pores has a conventional rod electrode method. Plating is practically impossible, and even if it can be done, it is practically impossible to ensure uniformity in the plating state of each nozzle pore.

JP-A-8-323743 JP 2004-299314 A JP 2003-220606 A JP 2006-168235 A Japanese Patent Laid-Open No. 10-310896 JP 2006-111958 A

  As described above, with respect to the synthetic resin granulation die, it is desired to plate the nozzle or the nozzle pore, but the conventional plating technique cannot respond to it. The present invention is made in the background of such a conventional situation, and a structure such as a synthetic resin granulation die, that is, a pore such as a nozzle pore in a synthetic resin granulation die is predetermined. An object of the present invention is to provide a plating method that enables a plurality of pores to be subjected to uniform plating on a plurality of pores and to provide an electrode unit used in such a plating method. Is an issue.

  In the present invention, in order to solve the above-described problem, a structure in which a plurality of pores are formed in a predetermined arrangement is a plating process target, and the inner peripheral surface of each of the plurality of pores in the plating process target structure is collectively The electrode unit is formed by projecting a rod-shaped electrode corresponding to the number of the pores corresponding to the arrangement of the pores from a frame portion formed in a planar shape. The collective plating process is performed in a state in which each of the rod-shaped electrodes of the electrode unit is inserted into each of the pores of the plating target structure corresponding to the arrangement.

  As described above, in the plating method of the present invention, the electrode unit formed by protruding the rod-shaped electrode from the frame portion formed in a planar shape corresponding to the number of the pores corresponding to the arrangement of the pores in the structure to be plated. Is used. Such an electrode unit is a rod-shaped electrode for each pore while adjusting the protruding state for each pore in accordance with the actual pore state (arrangement, pore depth, etc.) in the structure to be plated. Can be arranged. For this reason, by inserting each rod-shaped electrode of the electrode unit into each of the plurality of pores in the structure to be plated at once, a highly uniform electric field distribution is collectively collected inside each pore. Therefore, it is possible to plate each pore in a batch with high uniformity.

  However, when the number of pores in the structure to be plated increases, that is, when the number of rod-shaped electrodes in the electrode unit increases, rod-shaped electrodes that have insufficient correspondence with the pores may occur. And since the correspondence of a pore and a rod-shaped electrode is inadequate, the rod-shaped electrode may contact the inner peripheral surface of a pore and may cause the situation which becomes an electrical short circuit. If such an electrical short-circuit condition is incurred, energization for plating while leaving it untouched may damage the pores in the electrical short-circuit condition or affect the plating condition of other pores. Or even damage the structure to be plated. For this reason, when the rod-shaped electrode comes into contact with the inner peripheral surface of the pore and is brought into an electrical short circuit state, it is required to be able to quickly eliminate the state.

  Therefore, in the present invention, in the plating method as described above, the rod-shaped electrode of the electrode unit is energized through the frame portion, and the rod-shaped electrode is in contact with the inner peripheral surface of the pore. In the case where an electrical short-circuit condition occurs, a bonding material that melts due to the heat generated by the electrical short-circuit condition, preferably soldered to the frame section by fixing to the frame section, is projected from the frame section. Yes.

  By doing so, the joint fixing part functions as a fuse, and the fuse function can quickly eliminate the electrical short-circuit state between the pore and the rod-shaped electrode, and thus the electrical connection between the pore and the rod-shaped electrode. It is possible to effectively avoid a situation in which a short circuit has an adverse effect.

  In the plating method as described above, the pores of the structure to be plated have a small diameter portion on one end side and a large size on the other end side, such as nozzle pores in a synthetic resin granulation die. There may be a two-stage structure having a diameter portion. For such two-stage pores, the distance between the small-diameter portion and the large-diameter portion is different between the rod-shaped electrodes of the electrode unit. For this reason, for example, when plating is performed under voltage conditions that match the small-diameter portion. In the large diameter portion, it is difficult to avoid a state where almost no plating metal is deposited.

  Therefore, in the present invention, in the plating method as described above, when the pore has a small diameter portion on the front end side and a large diameter portion on the rear end side, the batch plating process is performed in two stages. The plating process in the second stage is performed in a state where the rod-shaped electrode is inserted into the pores to the extent that the tip does not reach the small-diameter portion. It is preferable to carry out in a state in which it is inserted into the pores until it penetrates through.

  The plating method as described above is particularly suitable for plating the nozzle of the synthetic resin granulation die. Therefore, in the present invention, a synthetic resin granulation die is particularly preferable as an application target of the above plating method.

  Further, in the present invention, in order to solve the above-described problem, a structure in which a plurality of pores are formed in a predetermined arrangement is a plating target, and the inner peripheral surface of each of the plurality of pores in the plating target structure. About the electrode unit used for performing the plating process by electrolytic plating collectively, the frame part formed in a planar shape using a conductive linear body, and the frame part by joining and fixing to the frame part A rod-shaped electrode is provided so as to protrude corresponding to the number of the pores corresponding to the array of the pores, and each of the rod-shaped electrodes is inserted into each of the pores of the structure to be plated corresponding to the array. In this state, the batch plating process can be performed.

  Such an electrode unit makes it possible to collectively perform plating in a highly uniform state on each of the plurality of pores in the structure to be plated for the same reason as described above.

  For the electrode unit as described above, the frame portion is formed of a conductive material so that the rod-shaped electrode can be energized through the frame portion, and the rod-shaped electrode is an inner peripheral surface of the pore. In the case where an electrical short-circuit state is caused by contact with the electrode, the bonding material that melts due to heat generated by the electrical short-circuit state, preferably solder, is used to fix the joint of the rod-shaped electrode to the frame portion. It is preferable to do so. This is for the same reason as described above.

  According to the present invention as described above, with respect to a structure having a plurality of pores in a predetermined arrangement, it is possible to collectively apply plating with high uniformity to the plurality of pores. Therefore, by using the plating method according to the present invention, for example, it is possible to perform highly uniform plating on the nozzle pores of a synthetic resin granulation die, which has been difficult in the past, thereby improving the production environment of synthetic resin pellets. It becomes possible to make it.

  Hereinafter, modes for carrying out the present invention will be described. FIG. 1 shows a simplified configuration of a synthetic resin granulation die, which is a structure to be plated by a plating method according to an embodiment. FIG. The partial cross-sectional structure is shown in FIG. The synthetic resin granulation die 1 is formed in a disc shape as a whole, and has a mounting portion 2 and a nozzle array portion 3, and a synthetic resin structure not shown in the figure is connected through a bolt hole 4 provided in the mounting portion 2. It is designed to be attached to the grain device.

  The nozzle array portion 3 is formed in an annular shape, and a large number of nozzle pores 5 are provided therein. The nozzle pore 5 is provided with a nozzle portion 6 functioning as a nozzle for extruding the raw material resin in a linear shape on the front end side, and an introduction portion 7 for guiding the raw material resin to the nozzle portion 6 on the rear end side. It has a provided structure. That is, the nozzle pore 5 has a two-stage structure including a nozzle portion 6 which is a small diameter portion having a diameter of about 2 mm and an introduction portion 7 which is a large diameter portion having a diameter of about 5 mm, for example. The nozzle pores 5 are provided in the nozzle array portion 3 in a predetermined array. In the case of the example in the figure, the nozzle pores 5 have an arrangement pattern in which a plurality of nozzle pores 5 are provided in each of a plurality of concentric arrangement circles 8 (8a, 8b, 8c). Note that FIG. 1 is simplified, and the array circles 8 and the nozzle pores 5 are actually provided in a higher density state than the state shown in the figure.

  In FIG. 2, the external appearance structure of the electrode unit by one Embodiment is simplified and shown. The electrode unit 11 has a configuration corresponding to the synthetic resin granulation die 1 of FIG. That is, the rod-shaped electrode 12 is projected from the frame portion 13 at a right angle so as to correspond to the arrangement of a large number of nozzle pores 5 in the synthetic resin granulation die 1. Yes.

  The frame portion 13 includes a base body 14 formed in a disc shape and disposed in the center, a plurality of radiation frames 15 projecting radially from the peripheral surface of the base body 14, and a plurality of circular frames assembled to the radiation frame 15. 16 (16a, 16b, 16c) is formed in a planar shape. The frame portion 13 has a function of evenly energizing each of the large number of rod-shaped electrodes 12, and a main portion related to the energizing function of the frame portion 13 is formed by the radiation frame 15 and the circular frame 16. Therefore, both the radiation frame 15 and the circular frame 16 are formed by using a linear body having a high conductivity such as a general wire material. Further, as in the example of the figure, circular frames 16a, 16b, and 16c are formed so as to correspond to the array circles 8a, 8b, and 8c of the nozzle pores 5.

  The rod-shaped electrode 12 is formed by using the same linear body as the radiation frame 15 and the circular frame 16, and as shown in FIG. 3, the base portion thereof has a frame portion 13, more specifically, a circular frame of the frame portion 13. 16 is provided so as to protrude from the frame portion 13 by being joined and fixed to the joint 16. The joint 17 of the rod-shaped electrode 12 is formed of a specific joining material. The specific bonding material is a state in which the electrode unit 11 is set on the synthetic resin granulation die 1 in the later-described plating process, and the rod-shaped electrode 12 is formed on the inner peripheral surface of the nozzle pore 5. It is a material that melts due to heat generated by an electrical short circuit when an electrical short circuit is caused by contact. As such a bonding material, for example, a solder that melts at about 150 to 200 ° C. is preferably used.

  The electrode unit 11 as described above has a protruding rod electrode 12 corresponding to each nozzle pore 5 in accordance with the actual state of the nozzle pore 5 in the synthetic resin granulation die 1 which is a structure to be plated. It is manufactured by adjusting the installation state (projection angle, length, bending condition, etc.). More specifically, in the production work of the electrode unit 11, first, the frame portion 13 formed with the configuration corresponding to the arrangement of the nozzle pores 5 in the synthetic resin granulation die 1 as described above is made of synthetic resin. It is set as the state appropriately positioned with respect to the grain die 1. Then, in this state, the projecting operation of the rod-shaped electrode 12, that is, adjusting the projecting state while passing the linear body material for the rod-shaped electrode 12 through the nozzle pore 5 for every 51 nozzle pores, The operation of forming the rod-like electrode 12 and forming the joint portion 17 at the base end portion of the rod-like electrode 12 and joining and fixing the rod-like electrode 12 to the frame portion 13 is repeated for the number of nozzle pores 5 in the synthetic resin granulation die 1. The electrode unit 11 manufactured in this way is inserted by inserting each of the rod-like electrodes 12 into the corresponding nozzle pores 5 as described later during the plating process (see FIG. 5). In addition, a highly uniform electric field distribution can be collectively formed for each of the nozzle pores 5. Therefore, by using the electrode unit 11, it is possible to collectively plate the nozzle pores 5 of the synthetic resin granulation die 1 in a highly uniform state.

  Hereinafter, a plating process applied to the nozzle pores 5 of the synthetic resin granulation die 1 of FIG. 1 using the electrode unit 11 of FIG. 2 will be described. As shown in the flow in FIG. 4, the plating process includes each of steps 101 to 109.

  First, as step 101, pretreatment is performed on the synthetic resin granulation die 1 which is a structure to be plated. In the pretreatment of step 101, the nozzle pores 5 of the synthetic resin granulation die 1 are inspected with a dedicated scope or polished with a dedicated polishing tool.

  In step 102, the pretreatment-processed synthetic resin granulation die 1 is washed by pickling or the like. This cleaning process is usually performed by immersing the synthetic resin granulation die 1 in a cleaning tank filled with a cleaning solution.

  In step 103 to step 107, a substantial plating process is performed, and the plating process is performed in two stages. In step 103, the synthetic resin granulation die 1 is placed in a plating tank. Specifically, as schematically shown in FIG. 5, a synthetic resin granulation die 1 is installed in a plating tank 22 filled with a plating solution 21.

  In step 104, the electrode unit 11 for the first stage plating is set. The set of electrode units 11 for the first stage plating is such that the rod-shaped electrodes 12 of the electrode units 11 reach the corresponding nozzle pores 5 and the tip of the rod-shaped electrode 12 reaches just before the nozzle portion 6. The insertion is performed (FIG. 5A).

  In step 105, energization is performed with the synthetic resin granulation die 1 connected to the cathode and the electrode unit 11 connected to the anode, and the plated metal (for example, hard chrome) is fed to the inner peripheral surface of the introduction portion 7 of the nozzle pore 5. To form a plating layer 23 (FIG. 7) having a predetermined thickness. At this time, the plating solution 21 is circulated through the nozzle pores 5 by stirring with a stirring means (not shown).

  When the processing of step 105 is finished, in step 106, the electrode unit 11 for the second stage plating is set. In the set of electrode units 11 for the second stage plating, the insertion depth of the rod-shaped electrode 12 with respect to the nozzle pore 5 is changed, and the rod-shaped electrode 12 is inserted until the tip penetrates the nozzle portion 6 (FIG. 5). (B)).

  In step 107, plating metal is deposited on the inner peripheral surface of the nozzle portion 6 of the nozzle pore 5 by energization in the same manner as in step 105 to form a plating layer 24 (FIG. 6) having a predetermined thickness. Note that the energization in step 107 is performed under a voltage condition that matches the inner diameter of the nozzle portion 6 which is a small diameter portion. For this reason, in step 107, the plating metal is mainly deposited only on the nozzle portion 6, and the plating metal is hardly deposited on the introduction portion 7 which is the large diameter portion.

  Here, the electrode unit 11 has a large number of rod-shaped electrodes 12. Therefore, for example, when hitting something in the above-described setting or the like, the projecting angle differs from the initial state as shown in FIG. 6, that is, there is a corresponding relationship with the corresponding nozzle pore 5. The rod-shaped electrode 12x which becomes inadequate is produced, and this rod-shaped electrode 12x may contact the inner peripheral surface of the pore 5 for nozzles, and may cause the situation where it becomes an electrical short circuit. And when such an electrical short circuit state is caused, the junction part 17 functions as a fuse. That is, since the joint portion 17 is formed of a material that melts due to heat generated by an electrical short circuit as described above, when an electrical short circuit occurs between the rod-shaped electrode 12x and the nozzle pore 5, the electrical short circuit is performed. The rod-shaped electrode 12x is separated from the frame portion 13 by being melted by the heat generated by the above, and thereby the energization of the rod-shaped electrode 12x is released, thereby eliminating the electrical short-circuit state between the nozzle pore 5 and the rod-shaped electrode 12. Therefore, it is possible to effectively avoid a situation in which the electrical short circuit between the nozzle pore 5 and the rod-shaped electrode 12 has an adverse effect. The nozzle pores 5 that are electrically short-circuited with the rod-shaped electrode 12 are dealt with by separately performing plating or the like.

  Through step 107, the plating layer 23 and the plating layer 24 are formed in each of the introduction portion 7 and the nozzle portion 6 of the nozzle pore 5 as shown in FIG. In the subsequent step 108, a finish inspection is performed in which the state of the plating layer 23 and the plating layer 24 of the nozzle pore 5 is inspected with a dedicated scope. If the finish inspection is acceptable, finally, as step 109, a finish polishing process is performed with a dedicated polishing tool, and the process ends.

  As mentioned above, although the form for implementing this invention was demonstrated, these are only typical examples, This invention can be implemented with various forms in the range which does not deviate from the meaning. For example, in the above-described embodiment, the nozzle pores to be plated consisted of a small diameter part having a diameter of about 2 mm and a large diameter part having a diameter of about 5 mm. The pores that can be formed are not limited to such sizes. Generally speaking, the pores targeted by the plating method of the present invention are the holes provided in the plating target structure with a sufficiently small diameter compared to the size of the plating target structure in which the plating method is provided. Can be defined. In the above embodiment, the structure to be plated is a synthetic resin granulation die. However, the structure is not limited to this, and a structure having a plurality of pores that require plating in an array. If so, the plating method of the present invention can be widely applied.

It is a figure which simplifies and shows the structure of the synthetic resin granulation die | dye made into plating object by the plating method by one Embodiment. It is a figure which simplifies and shows the external appearance structure of the electrode unit by one Embodiment. It is a figure which expands and shows the principal part of the electrode unit of FIG. It is a figure which shows the flow of the process in the plating method by one Embodiment. It is a figure which shows typically the state of a plating process. It is a figure which shows typically the state which a rod-shaped electrode contacts the pore for nozzles, and causes an electrical short circuit. It is a figure which shows typically the state of the pore for nozzles in which the plating layer was formed.

Explanation of symbols

1 Synthetic resin granulation dies (structure)
5 Nozzle pores (pores)
6 Nozzle part (small diameter part)
7 Introduction part (large diameter part)
11 Electrode unit 12 Rod electrode 13 Frame part 17 Joint part

Claims (8)

A plating method in which a structure in which a plurality of pores are formed in a predetermined arrangement is to be plated, and an inner peripheral surface of each of the plurality of pores in the structure to be plated is subjected to a plating process collectively by electrolytic plating Because
An electrode unit formed by projecting rod electrodes corresponding to the number of the pores from the planarly formed frame portion in correspondence with the arrangement of the pores is used, and each of the rod electrodes of the electrode unit is arranged in the array. The plating method is characterized in that the batch plating process is performed in a state of being inserted into each of the pores of the corresponding plating target structure.   When the rod-shaped electrode of the electrode unit is energized through the frame portion, and the rod-shaped electrode is brought into contact with the inner peripheral surface of the pore, an electrical short-circuit state occurs, A plating method characterized by protruding from the frame portion by bonding and fixing to the frame portion using a bonding material that melts due to heat generated by the electrical short circuit state.   The plating method according to claim 2, wherein solder is used as the bonding material.   When the pore has a small-diameter portion on one end side and a large-diameter portion on the other end side, the batch plating process is performed in two stages. Performed in a state in which the tip is inserted into the pore to the extent that it does not reach the small-diameter portion, the second-stage plating treatment is a state in which the rod-like electrode is inserted into the pore until the tip penetrates the small-diameter portion The plating method according to any one of claims 1 to 3, wherein the plating method is performed in step (1).   The plating method according to claim 1, wherein the structure to be plated is a synthetic resin granulation die. A structure in which a plurality of pores are formed in a predetermined arrangement is to be plated, and the inner peripheral surface of each of the plurality of pores in the structure to be plated is subjected to a plating process by electrolytic plating collectively. An electrode unit used,
A frame portion formed in a planar shape, and a rod-like electrode protruding from the frame portion by the number of the pores corresponding to the arrangement of the pores by bonding and fixing to the frame portion, An electrode unit characterized in that the batch plating process can be performed by inserting each rod-shaped electrode into each of the pores of the structure to be plated corresponding to the arrangement.   By forming the frame portion with a conductive material, the rod-shaped electrode can be energized through the frame portion, and the rod-shaped electrode is connected to the frame portion by the rod-shaped electrode. 7. The bonding material according to claim 6, wherein when an electrical short circuit is caused by contact with the inner peripheral surface of the hole, the bonding material is melted by heat generated by the electrical short circuit. Electrode unit.   The electrode unit according to claim 6, wherein solder is used as the bonding material.

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