JPS59202829A - Mold for injection molding synthetic resin product - Google Patents

Abstract

PURPOSE:To obtain the flat surface of a mold, controlling the contractive force at the solidification of molten lining metal, and preventing the strain of an electroformed nickel plating layer, by casting the core metal provided in suspended state on the upper surface of the electroformed nickel plating layer in the molten lining metal. CONSTITUTION:The lining metal 7 having relatively low melting temperature such as copper or copper alloy is poured by casting on the whole surface of the outer periphery 6 of the nickel plating layer 5 electroformed on the surface of the portion 4 to be electroformed of a core steel rod 3. The blow-holes and shrinkage cavities generated at the solidification of the molten lining metal 7, are crushed by the push metal 9 applied on the upper surface 8 of molten metal, and the lining metal 7 is stuck by casting to the electroformed nickel plating layer 5 surely. The strain of the electroformed nickel plating layer 5 caused by the contraction at the solidification of the molten lining metal is controlled by the core metal 10 having higher melting temperature than the lining metal such as carbon steel cast in the molten lining metal. While the core metal 10 is formed into a flat body, said core metal 10 is provided in suspended state by a wire 13, apart from the upper surface 11 of the electroformed nickel plating layer 5 with a suitable small distance 12 such that the lining molten metal can flow therethrough.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for controlling distortion in an electroformed nickel plating layer due to shrinkage during solidification of molten lining metal when manufacturing injection molds for synthetic resin products. Copper, copper alloy, etc. are applied to the entire outer periphery of the nickel plating layer that is electroformed on the surface of the cast part of the core steel rod, which is formed by molding and polishing into an outer shape that corresponds to the inner shape of the target synthetic resin product. When the molten metal of the graded metal with a low melting temperature is cast on the lining, the gases, bubbles, cavities, etc. that live when the molten metal of the lining metal solidifies are removed after the molten metal of the lining metal is cast. 9. Regarding an injection mold for a synthetic resin product, in which the lining metal and the electroformed nickel plating layer are firmly bonded by molding by being immediately crushed by a pusher applied to the upper surface of the mold, the molten metal of the lining metal is crushed. Distortion of the electroformed nickel plating layer due to shrinkage during solidification is controlled by a core metal having a higher melting temperature than the backing metal such as carbon steel cast into the molten metal of the backing metal, In one embodiment, the core metal is configured as a flat body, and the flat core metal is placed on the upper surface of the electroformed nickel plating layer with an appropriately small gap in which the molten metal of the backing metal can flow.
It is suspended in the air using wire.

Conventionally, as an injection mold for synthetic resin products, the entire outer periphery of the nickel-plated jaw is electroformed on the surface of the electroformed part of the core steel rod, which is formed by molding and polishing to an outer shape that corresponds to the inner shape of the synthetic resin product. To,! It is known that a molten backing metal having a relatively low melting temperature, such as a copper alloy or a copper alloy, is cast onto the backing.

In this conventional structure, when the molten metal of the lining metal is cast and deposited on the entire outer periphery of the electroformed nickel plating layer, gas, bubbles, cavities, etc. are generated in the molten metal of the lining metal. As a result, the backing metal material is poor quality and not strong enough, and the product is forced to have a reduced resistance to high-pressure synthetic resin injection molding.

In order to prevent this, immediately after the molten lining metal is cast, the molten metal for the lining is crushed with a pusher placed on its top surface to eliminate the gas, bubbles, and cavities that occur when the molten metal for the lining solidifies. A solid casting bond between a metal and an electroformed nickel plating layer has been developed as an injection mold for a synthetic resin product in a prior patent application No. 1977-17.

In this prior patent application, during the process of solidifying the molten metal of the lining metal, the molten metal of the lining metal contracts, and the shrinkage force causes distortion in the electroformed nickel plating layer. become.

On the other hand, the invention of this application further improves this prior patent application, and when manufacturing injection molds for synthetic resin products, electroforming nickel plating is performed by shrinkage of the molten metal of the backing metal during solidification. According to the invention of this application, the distortion of the i@nickel plating layer due to contraction during solidification of the molten metal of the backing metal is controlled. Surface metal such as carbon steel cast inside the molten metal is also controlled by a core metal with a high melting temperature, so the weight and specific gravity of the core metal is greater than the molten metal of the backing metal, so it is difficult to Even when the molten metal of the lining metal is poured into the outer circumferential surface of the cast nickel plating layer, the position of the molten metal does not move, and when the casting is completed at that position and the desired appearance is cast, the pusher is moved to the top. Because the core metal is cast into the molten lining metal, the shrinkage force when the molten lining metal solidifies is controlled, and its distortion can be significantly suppressed. This is extremely useful because distortion of the electroformed nickel plating layer can be prevented and a flat surface can be obtained.

The invention of this application will now be described with reference to the drawings.

Fig. 1 shows a longitudinal sectional view of one embodiment of the injection mold (1) for synthetic resin products of the invention of this application, and Fig. 3 shows a longitudinal sectional view of another embodiment. The figure shows an explanatory longitudinal cross-sectional view of the manufacturing method, and as shown in the longitudinal cross-sectional view of Fig. 2, the synthetic resin product is molded and polished into an outer shape (2) corresponding to the inner shape of the product. The entire outer periphery of the nickel plating layer (5) electroformed on the surface of the electroformed part (4) of the core steel rod (3) is coated with a lining metal of relatively low melting temperature such as copper or copper alloy. +71 molten metal is cast on the lining, and gas, bubbles, cavities, etc. generated when the molten lining metal (7) solidifies, immediately after the molten metal lining (7) is cast. Push metal (9) placed tightly on the top surface
The lining metal and the electroformed nickel plating layer (5) are firmly bonded by being crushed by the nickel plating layer (5), and the electroformed nickel plating layer (5) is not distorted due to shrinkage during solidification of the molten metal of the lining metal. The lining metal such as carbon steel cast into the molten metal of the lining metal is also controlled by the core metal a value, which has a high melting temperature, and the core metal Ql is configured as a flat body. At the same time, the upper surface 9 of the electroformed nickel plating layer (5) is provided with a suitable surface so that the molten metal of the lining metal can flow.

In the drawing, +14 (ri) indicates the pressing force of the pusher.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the invention of this application, FIG. 2 is a longitudinal sectional view illustrating its manufacture, and FIG. 3 is a longitudinal sectional view of another embodiment. In the figures, the same reference numerals indicate the same or equivalent parts, and (1
) is the injection mold of the invention of this application, (2) is the outer shape corresponding to the inner shape of the synthetic resin product, (3j is the core steel rod, (4
) is the electroformed part, (5) is the nickel plating layer, the blank is the entire outer periphery, (7) is the lining metal, and the helmet is the lining metal (7)
The upper surface of the molten metal, +91 ii is the pusher, αG is the core metal, ri is the upper surface of the nickel plating layer (5), αzl′i is the small gap, the wire is the wire, and G41 is the pressing force of the pusher 191. Inventor: Miki K.
Hikodai/Hikodai 3

Claims (2)

[Claims] (1) A core steel rod made by molding and polishing into an outer shape corresponding to the inner shape of the synthetic resin product is coated on the entire outer periphery of a nickel plating layer electroformed on the surface of the cast part. When the molten lining metal with a relatively low melting temperature, such as , the lining metal and the electroformed nickel plating layer are firmly bonded by being crushed by a presser applied to the upper surface of the nickel plating layer. The distortion of the cast nickel plating layer is
An injection mold for a synthetic resin product, characterized in that the mold is controlled by a core metal whose melting temperature is higher than that of the lining metal such as carbon steel, which is cast into the molten metal of the lining metal. (2) The core metal is configured as a flat body, and the flat core metal is attached to the upper surface of the electroformed nickel plating layer with an appropriately small gap in which the molten metal of the backing metal can flow. An injection mold for a synthetic resin product according to claim 1, which is provided in a suspended shape.