JPH10202698A - Injection molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase heat conductivity and provide high corrosion resistance by applying the surface treatment using an alloy of nickel and tungsten on the outer face of a core main body composed of copper alloy. SOLUTION: One small core 21 is formed by inserting a base of a core main body 211 composed of copper alloy into a recessed section 213 of a core ring 212, installing the core ring 212 by using a ball 14 and curing the outer face except an end hitting recessed face 215 of a small core 21 with a film 216. The other small core 22 is formed by mounting a base of the core main body 221 composed of a copper alloy or a core ring 222 in a similar manner for the above-said small core 21 and coating the outer face except an end heating protruded face 225 of the small core 22 with a film 226 formed of the nickel and tungsten alloy by plating. The high heat conductivity and high corrosion resistance can be provided and the fear of generating of corrosion on the outer face of the cores is eliminated by the arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal mold for injection molding, and is particularly suitable for use in molding pipe joints and the like made of hard vinyl chloride resin.

[0002]

2. Description of the Related Art Conventionally, in the injection molding of pipe joints and the like made of hard vinyl chloride resin, there has been a problem that a corrosive gas such as hydrogen chloride gas is generated and corrodes a cavity surface of an injection mold.

In order to solve such a problem, conventionally, as shown in FIG. 7, an injection molding die (core) (a)
For example, a stainless steel having excellent corrosion resistance is used as the material of the mold, or as shown in FIG.
Applying a hard chrome plating layer (b) on the surface of (a),
Or by applying electroless nickel plating, or
For example, as described in Japanese Patent Application Laid-Open No. 5-261765, it is known to apply a surface treatment such as a ceramic coating to a portion where the corrosion resistance or the like of an injection mold is to be improved. .

[0004]

However, as described above, the use of stainless steel having excellent corrosion resistance as the material of the injection mold is not only expensive, but also required for machining. There are drawbacks in that it is troublesome and costly, and that it takes a long time to cool the injection mold because of its low thermal conductivity.

In the means for applying hard chromium plating or electroless nickel plating, countless minute holes are generated on the surface, and a corrosive gas enters through these minute holes and corrodes from the inside of the plating layer to form a plating layer. There is a disadvantage that the layer floats or peels off.

[0006] Further, in order to improve the corrosion resistance and the like, surface treatment such as ceramic coating requires high-temperature treatment, and dimensional changes are apt to occur in the injection mold due to the high-temperature treatment. There were drawbacks.

The present invention has been made in view of such problems in the conventional injection mold, and an object thereof is to solve the problems in the conventional injection mold. Another object of the present invention is to provide an injection mold having a low mold material cost and a low machining cost, a high thermal conductivity, and excellent corrosion resistance.

[0008]

In order to achieve the above-mentioned object, according to the injection molding die of the present invention, the outer surface of a core body made of a copper alloy is subjected to a surface treatment with an alloy of nickel and tungsten. By doing so, high corrosion resistance is imparted.

According to a second aspect of the present invention, there is provided the injection mold of the first aspect, wherein carbon steel is used instead of the copper alloy in the injection mold of the first aspect.

In the injection molding die according to the present invention, the core is composed of a plurality of small cores. An injection molding die to be formed, wherein the main body of the small core is made of a copper alloy, and the abutment surface is made of a highly durable steel material.

According to a fourth aspect of the present invention, in the injection mold of the third aspect, a reinforcing core material made of a highly durable steel material is provided in the small core body. It is characterized by the following.

In the injection molding die according to the present invention, since the outer surface of the core body is subjected to a surface treatment using an alloy of nickel and tungsten, high corrosion resistance is imparted. Even if corrosive gas such as hydrogen chloride gas is generated, there is no possibility that the outer surface of the core is corroded.

Since the core body is made of a copper alloy, its thermal conductivity is 0.25 to 0.3 cal / cm.sec..degree. C., which is excellent in thermal conductivity and requires only a short cooling time.

Further, in the injection mold according to the present invention, since carbon steel is used instead of the copper alloy,
Stainless steel (thermal conductivity = 0.04 to 0.05 cal /
cm · sec · ° C), its thermal conductivity is 0.1c
al / cm · sec · ° C., excellent thermal conductivity, and short cooling time.

Further, in the injection mold according to the present invention, since the main body of the small core is made of a copper alloy, the heat conductivity is excellent and the cooling time is short. In addition, since the abutment surface is made of a highly durable steel material, even if the body of the small core is made of a copper alloy, there is no danger of being damaged by the abutment between the small cores, and it can be used for a long time.

In the injection molding die according to the present invention, since the reinforcing core member made of a highly durable steel material is provided in the small core body, the small core body is made of a copper alloy. Even so, the entire core is prevented from being deformed due to abutment between the small cores, and can be used for a long time.

[0017]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing an example of the injection mold of the present invention, and FIG. 2 is a partially cutaway front view showing a main part of the injection mold of the present invention shown in FIG. In FIG. 1, reference numeral 1 denotes a movable mold for the injection mold of the present invention, and 2 denotes a movable mold 1.
The core 2 is composed of two small cores 21 and 22.

In the small core 21, as shown in FIG. 2, the base of a core body 211 made of a copper alloy is inserted into a recess 213 of a stainless steel core ring 212, and the core ring 212 is bolted by a bolt 214. On the outer surface of the small core 21 except for the abutting concave surface 215,
The coating 216 of the nickel-tungsten alloy is covered by plating.

In the other small core 22, as shown in FIG. 2, the base of a core body 221 made of a copper alloy has a base ring 2 made of stainless steel in the same manner as one small core 21.
The outer surface of the small core 22 except for the abutment convex surface 225 is coated with a coating 226 made of a nickel-tungsten alloy by plating.

As shown in FIG. 1, both small cores 21, 2
The two core rings 212 and 222 are slide plates 217 and 2
27, the slide plates 217 and 227 are provided so as to be able to reciprocate along guides 218 and 228 as indicated by arrows.

When the movable die 1 and the fixed die (not shown) are closed, as shown in FIGS. 1 and 2, the concave end surface 215 of the small core 21 and the convex surface 225 of the small core 22 are abutted. The coating 216 of the small core 21 and the coating 226 of the small core 22
A cavity 4 is formed between the outer mold 3 and the outer mold 3 of the movable mold 1 and a fixed outer mold (not shown).

FIG. 3 is a partially cutaway front view showing a main part of another example of the injection mold of the present invention. In the core 2a of the injection molding die of the present invention shown in FIG.
221 is made of carbon steel, and instead of attaching separate core rings 212 and 222 to the bases of the core bodies 211 and 221 as in the core 2 of the injection molding die of the present invention shown in FIGS. 12a and 22a are provided integrally.

The core 2 of the injection mold of the present invention shown in FIG.
Other points of a are the same as the core 2 of the injection molding die of the present invention shown in FIGS. 1 and 2, and the same reference numerals as those of the core 2 of the injection molding die of the present invention shown in FIGS. The description will be omitted by attaching.

FIG. 4 is a partially cutaway front view showing an essential part of still another different example of the injection mold of the present invention. In the core 2b of the injection molding die of the present invention shown in FIG.
As shown in the mold for injection molding of the present invention shown in FIG.
The concave surface 215 and the convex surface 225
The stainless steel thin plates 2151 and 2251 are attached with stainless steel bolts 2152 to form the abutting concave surface 215 and the abutting convex surface 225 of stainless steel. The cooling bush 2112 is inserted and the cooling bush 21 is inserted.
12, a cooling water passage 2113 is provided.

FIG. 4 shows the core 2 of the injection mold according to the present invention.
The other points of b are the same as those of the core 2 of the injection mold of the present invention shown in FIGS. 1 and 2, and the same reference numerals as those of the core 2 of the injection mold of the present invention shown in FIGS. The description will be omitted by attaching. Although illustration is omitted, FIGS.
Are coated with the same coatings 216 and 226.

The core 2 of the injection mold of the present invention shown in FIG.
b, the tip abutment concave surface 215 and the tip abutment convex surface 22
5 is made of stainless steel, there is no danger of being deformed and damaged by the abutment between the abutting concave surface 215 and the abutting convex surface 225, and the abutment between the abutting concave surface 215 and the abutting convex surface 225. In some cases, both surfaces are close to each other, and there is no problem that burrs are generated, and it can be used for a long time.

In the core 2b of the injection mold of the present invention shown in FIG.
Since the cooling bush 2112 made of stainless steel is inserted and reinforced in 1, there is no possibility that the entire core body 211 is deformed, and the core body 211 can be used for a long time.

FIG. 5 is a partially cutaway front view showing a main part of still another different example of the injection mold of the present invention. In the core 2c of the injection molding die of the present invention shown in FIG. 5, the stainless steel thin plates 2151 and 2251 are attached with the stainless steel bolts 2152 like the core 2b of the injection molding die of the present invention shown in FIG. Instead, stainless steel sheet 2
151, 2251, a plurality of convex portions 2153, 2
The stainless steel thin plates 2151 and 2251 are attached by inserting and fitting 253 into concave portions 2154 and 2254 formed in the concave end surface 215 and the convex end surface 225.

The core 2 of the injection mold of the present invention shown in FIG.
The other points of c are the same as those of the core 2b of the injection molding die of the present invention shown in FIG. 4, and are described by attaching the same reference numerals as those of the core 2b of the injection molding die of the present invention shown in FIG. Is omitted. In addition, similarly to FIG.
226 are coated.

FIG. 6 is a partially cutaway front view showing the main part of still another example of the injection mold according to the present invention. In the core 2d of the injection molding die of the present invention shown in FIG. 6, like the core 2b of the injection molding die of the present invention shown in FIG. 4, the stainless steel thin plates 2151 and 2251 and the stainless steel cooling bush 2112 are formed. Instead, the stainless steel thin plates 2151, 2251 and the stainless steel cooling bush 2112 are integrated, and the rear end of the stainless steel cooling bush 2112 is attached to the core body 211 by the mounting plate 2114 and the bolt 2115. It is attached.

The core 2 of the injection mold of the present invention shown in FIG.
Other points of d are the same as those of the core 2b of the injection molding die of the present invention shown in FIG. 4, and are described by attaching the same reference numerals as those of the core 2b of the injection molding die of the present invention shown in FIG. Is omitted. In addition, similarly to FIG.
226 are coated.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A nickel-tungsten alloy coating 216 and a coating 226 of the core 2 of the injection mold of the present invention shown in FIGS. At 15 μm, a corrosion test was performed by the hydrochloric acid method, and the dissolved weight ratio was measured. The results are shown in Table 1.

[0033]

COMPARATIVE EXAMPLE 1 A 10 μm-thick nickel coating by nickel plating was applied to the core 2 shown in FIGS. 1 and 2 in place of the nickel-tungsten alloy coatings 216 and 226 shown in FIGS. And the dissolved weight ratio were measured, and the results are shown in Table 1.

[0034]

Comparative Example 2 Instead of the nickel film having a thickness of 10 μm in Comparative Example 1, a multilayer chromium film having a thickness of 5 μm was formed by multilayer chromium plating, and the same corrosion test as in the example was performed.
The dissolved weight ratio was measured, and the results are shown in Table 1.

[0035]

Comparative Example 3 Instead of the nickel film having a thickness of 10 μm of Comparative Example 1, a chromium plating film having a thickness of 5 μm was formed by chromium plating, and the same corrosion test as in the example was performed. The results are shown in Table 1.

[0036]

Comparative Example 4 As shown in FIG. 7, using a stainless steel core, a corrosion test similar to that of the example was performed, and the weight ratio of the melt was measured. The results are shown in Table 1.

[0037]

[Table 1]

[Evaluation] As shown in Table 1, in Example 1, the dissolution weight ratio was the minimum as compared with Comparative Examples 1 to 4, and it was found that it was resistant to corrosion.

Although the embodiment of the present invention has been described with reference to the drawings, the specific configuration of the present invention is not limited to this embodiment, and the design change within a range not departing from the gist of the present invention. The present invention is also included in the present invention.

[0040]

According to the injection molding die of the present invention, since the outer surface of the core body is given a high corrosion resistance by being subjected to a surface treatment with an alloy of nickel and tungsten. Even if corrosive gas such as hydrogen gas is generated, there is no possibility that the outer surface of the core is corroded.

Since the core body is made of a copper alloy, it has a thermal conductivity of 0.25 to 0.3 cal / cm · sec · ° C., is excellent in thermal conductivity, and requires a short cooling time.

In addition, in the injection molding die of the present invention, carbon steel is used instead of the copper alloy.
Stainless steel (thermal conductivity = 0.04 to 0.05 cal /
cm · sec · ° C), its thermal conductivity is 0.1c
al / cm · sec · ° C., excellent thermal conductivity, and short cooling time.

Further, in the injection molding die according to the third aspect of the present invention, since the main body of the small core is made of a copper alloy, the heat conductivity is excellent and the cooling time is short. In addition, since the abutment surface is made of a highly durable steel material, even if the body of the small core is made of a copper alloy, there is no danger of being damaged by the abutment between the small cores, and it can be used for a long time.

In the injection molding die according to the present invention, since the reinforcing core member made of a highly durable steel material is provided in the small core body, the small core body is made of a copper alloy. Even so, the entire core is prevented from being deformed due to abutment between the small cores, and can be used for a long time.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of an injection mold according to the present invention.

FIG. 2 is a partially cutaway front view showing a main part of the injection mold of the present invention shown in FIG.

FIG. 3 is a partially cutaway front view showing another example of the injection mold of the present invention.

FIG. 4 is a partially cutaway front view showing still another different example of the injection mold according to the present invention.

FIG. 5 is a partially cutaway front view showing still another example of the injection mold according to the present invention.

FIG. 6 is a partially cutaway front view showing another example of still another injection mold according to the present invention.

FIG. 7 is a partially cutaway front view showing an example of a conventional injection mold.

FIG. 8 is a partially cutaway front view showing another example of the conventional injection mold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moving type 2 Core 21, 22 Small core 211, 221 Core body 212, 222 Core ring 215 Tip abutment concave surface 225 Tip abutment convex surface 216, 226 Coating

Claims (4)

[Claims] 1. A mold for injection molding, wherein a high corrosion resistance is imparted by performing a surface treatment with an alloy of nickel and tungsten on an outer surface of a core body made of a copper alloy. 2. The injection mold according to claim 1, wherein carbon steel is used in place of the copper alloy. 3. An injection molding die, wherein a core comprises a plurality of small cores, and abutment surfaces of the plurality of small cores abut against each other when the mold is closed to form a core. 3. The injection molding die according to claim 1, wherein the main body is made of a copper alloy, and the abutment surface is made of a highly durable steel material. 4. The injection molding die according to claim 3, wherein a reinforcing core member made of a highly durable steel material is provided in the small core body.