JPH0235039B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvements in plating technology for injection molded synthetic resin products, and relates to a novel technique for electroplating the surface of injection molded products such as plastic resin cores. This relates to a method of plating injection molded products.

[Conventional technology]

Conventionally, when obtaining a plated product 2 in which the surface of a hollow cylindrical core formed by injection molding of plastic is plated as shown in FIG. 3, the core is first coated as shown in FIG. The molded body 51 is injection molded in a frame arrangement in which the axes thereof are parallel to each other. This is because the cavity of the injection mold needs to be arranged in this manner in order to take in and out the core rod for forming the hollow portion of each molded body 51. Next, with each molded body 51 separated and independent from the gate portion 53 of the runner 52, a screw 54 is machined on the bottom of the molded body 51, and the screw 54 is
The plating hanging jig 55 is supported on each hanging branch 56 end of the plating hanging jig 55 shown in FIG.
The molded bodies 51 are supported in parallel on the extension of the axis of the rotating support shaft 57 of No. I had obtained a plated item 2 that had been plated.

[Problem that the invention seeks to solve]

However, as mentioned above, when the molded body 51 is made of a synthetic resin material such as plastic and is non-conductive, chemical plating is performed as a pretreatment for electroplating. This pretreatment and electroplating
Generally, it is carried out through many steps and liquid types, and each step requires thorough cleaning of the previous step.
In the conventional method, the screw 5 between the molded body 51 and the hanging branch 56
The preliquid remains in the gap between parts 4 and 4, which causes poor plating, and also causes problems such as poor contact between the screws 54 and the electrical current not flowing through the molded body 51 and electroplating not being performed. Ta. Further, the conventional method has problems such as requiring processing of screws 54 for attaching the molded body 51 to the plating hanging jig 55, and requiring labor for attachment and detachment.

The present invention was made for the purpose of eliminating the above-mentioned problems, and aims to provide a method of plating injection molded products without increasing the number of steps, and to improve the quality of the plated product. .

[Means for solving problems]

In the method for plating injection molded products of the present invention, a runner for arranging a large number of injection molded products in blocks is used as a hanging jig for plating, and electroplating is performed. In other words, the hollow molding has a runner main rod having a rotating support shaft on the rotational axis at one end, and a piece arrangement located at the tip of a runner branch rod extending from the runner main rod, the axis of which intersects with the runner main rod. After pre-treating the injection molded product, in which the body and the locking protrusion extending from the runner main rod in a direction corresponding to the runner branch rod and having a hook-shaped end at the tip thereof, are integrally injection molded, to make it conductive. The runner branch is bent to change the posture of the molded body to a position concentric with the rotation support shaft, and the changed posture is maintained by being locked to the locking protrusion, and the rotation support shaft is rotationally driven. The agitation plating process is performed while the molded body is rotated in an electroplating bath.

[Effect]

The present invention is characterized by the plating process of the above-mentioned molded product, the arrangement of a large number of injection molded bodies with respect to the runner, and the change in the posture of the molded bodies after molding. The present invention was achieved by positioning each molded body coaxially with the pivot shaft by hooking the molded bodies onto a locking protrusion formed at the same time as the runner main rod. In other words, when applying electroplating, it is very important to always position the body to be plated at the same distance from the anode and rotate it in the liquid to remove uneven plating, and to ensure that the molded body stabilizes the cathode. However, in the above method, each molded body remains a single piece until it is separated from the runner after plating, so problems such as poor current conduction do not occur, and each molded body It is molded in a piece arrangement until the axis intersects with the runner main rod, but by bending the runner branch rod and engaging each molded body with the locking protrusion, each molded body is placed at the center of rotation. Because the bodies become parallel,
Uniform plating can be achieved. Therefore, by cutting at the end and appropriately selecting the gate position where the non-plated portion appears, the plating finishing process of the injection molded product can be extremely simplified.

〔Example〕

The method of plating injection molded products will be explained below with reference to the drawings. Figures 1 and 2 show electroplating applied to the surface of a hollow cylindrical core molded body 1 of plastic. An example of obtaining a plated product 2 as shown in FIG. 3 is shown.

Due to the mold structure of the core molded body 1, which has a core rod for forming the cylindrical hole 1a, the molded body 1 is attached to the tip of a runner branch rod 4 that branches off from the runner main rod 3 and extends.
The runner is integrally formed with the runner main rod 3 intersecting the runner main rod 3 via the gate portion 5. The runner main rod 3 extends in a direction parallel to the center axis C of the rotation support shaft 6 formed continuously at the end thereof, and has one locking protrusion protrudingly provided corresponding to each runner branch rod 4. When the middle part 4a of the runner branch 4 is bent and supported so as to lock the cylindrical hole 1a of the core molded body 1 to the hook-shaped end 7a of the locking projection 7, the core molded body The central axis of the rotary support shaft 6 coincides with the central axis C of the rotation support shaft 6 (see FIG. 1).

When the surface of the molded core 1 is to be plated, as shown in FIG. At the same time, the core molded body 1 is moved to the locking protrusion 7 so that the core molded body 1 does not shift from the concentric position due to the elastic restoring force of the bent runner branch rod 4. It is in a locked state. In this state, the rotating shaft 6 is attached to a moving rack (not shown) of the plating processing equipment, and after being subjected to a number of conductive pretreatment processes such as a chemical plating processing tank and a cleaning processing tank, it is placed in an electroplating tank. Perform plating treatment. In this electroplating tank, the plating process is performed while rotating the entire body around the rotation support shaft 6, and each core molded body 1 rotates around the central axis C, and the peripheral surface maintains a uniform distance from the anode. It becomes like this.

During the electroplating process, since the core molded body 1 is integrated with the runner main rod 3 and the runner branch rod 4, the conductive pretreatment process ensures that each core molded body 1 is electrically connected to the runner main rod 3. The cathode is polarized via the pivot shaft 6.

After the plating process is completed through the above steps, the rotating support shaft 6 is removed from the movable rack after washing and drying, and the gate portion 5 is cut to obtain the plated product 2.
Since no plating is applied to the cut surface of the plated product 2 cut at the gate portion 5, it is desirable to design the mold in consideration of the position of the gate portion 5 so that the plating does not appear on the surface side of the molded product. .

〔Effect of the invention〕

As described above, in the method for plating injection molded products of the present invention, each plating process is performed while the injection molded product remains integrated with the runner, and the runner is used as a plating hanging jig, so there is no joint and the front Not only is it easy to clean during the process, but the conductivity is reliable, so chemical plating and electroplating can be applied well, improving the quality of the product. Moreover, the present invention changes the posture of the molded product integrally with the runner to a position coaxial with the rotational support shaft, holds the changed posture by a locking protrusion, and performs electroplating while rotating the molded product through the runner. Therefore, even though the molded body is hollow and cannot be arranged concentrically with each other in the mold, it can be easily plated without the need for a hanging jig for plating. It is possible to perform good plating by holding it in the core position. Therefore, it is possible to omit pre-processing for attaching and detaching the molded article to and from the plating hanging jig, and it is possible to improve productivity. The effect is extremely large.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of the frame arrangement of a synthetic resin molded body for carrying out the present invention, FIG. 2 is a front view showing a plating treatment mode of the same synthetic resin molded body, and FIG.
The figure is a perspective view showing an example of the product, Figure 4 is a front view of a synthetic resin molded product showing a conventional piece arrangement, and Figure 5 is a front view of the same molded product attached to a plating hanging jig. be. 1... Core molded body, 2... Core, 3... Runner main rod, 4... Runner branch rod, 5... Gate part,
6... Rotating support shaft, 7... Locking protrusion, C... Center shaft.

Claims (1)

[Claims] 1. A hollow molding having a runner main rod having a rotating support shaft on the rotational axis at one end, and a piece arrangement located at the tip of a runner branch rod extending from the runner main rod, the axis of which intersects with the runner main rod. After pre-treating the injection molded product, in which the body and the locking protrusion extending from the runner main rod in a direction corresponding to the runner branch rod and having a hook-shaped end at the tip thereof, are integrally injection molded, to make it conductive. The runner branch is bent to change the posture of the molded body to a position concentric with the rotation support shaft, and the changed posture is maintained by being locked to the locking protrusion, and the rotation support shaft is rotationally driven. 1. A method of plating an injection molded product, characterized in that stirring plating is performed while the molded body is rotated in an electroplating tank while being connected to the molded body.