JP3247594B2 - Method of forming hard alumite coating on aluminum alloy injection mold and aluminum alloy injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a hard alumite film on an aluminum alloy injection mold and an aluminum alloy injection mold.

[0002]

2. Description of the Related Art In recent years, injection molding dies used for molding plastic molded products are made of aluminum alloy having good workability and thermal conductivity in order to reduce the cost of the mold and shorten the delivery time. A so-called aluminum mold using the same is being put to practical use. However, JIS-A7075, which has the highest mechanical strength, is inferior in strength and lower in durability compared to steel used in injection molding dies, especially for aluminum alloy materials, especially for slide cores and ejector pins. As described above, a surface that slides when a mold is used poses a problem in terms of wear resistance and galling resistance. Further, in the case of molding a resin mixed with glass fiber or the like, there arises a problem that the cavity surface of the mold is worn by the glass fiber.

[0003] To solve such a problem, for example, there is one described in Japanese Patent Publication No. 59-35770. This is 75S, 17S or 61
A plurality of aluminum alloy plates such as S are assembled by bolting, a cavity is cut in the inside to form a flow port on the upper surface, and the flow port and the cavity are connected by a through hole. A gate is formed at the connecting portion of the cavity and the oil reservoir through an oil reservoir, and the flow port, the through hole, the oil reservoir,
By subjecting the inner surfaces of the gate and cavity to hard alumite processing with a thickness of about 200 μm, the strength is improved, and the wear resistance and galling resistance are improved.

A major problem in forming the above-described hard alumite film is a dimensional change due to the film formation, and the dimensional change depends on the film thickness. This dimensional change is about ２〜 to ３ of the thickness of the hard anodized film, and becomes maximum 100 μm at the above-mentioned 200 μm thickness. Generally, in a mold for injection molding, there is a mating surface between mold parts, for example, a parting surface, a sliding surface, a press-cut surface, and the like. Therefore, a hard alumite film is formed on the mold part. In this case, it is necessary to process the mold parts smaller than the original dimensions in consideration of the dimensional change due to the formation of the hard alumite film.

At this time, the clearance between the mold parts before the formation of the hard alumite film is inevitably up to about 100 μm when the film is formed only on one mold part. In the case of forming, it is up to about 200 μm, and it is not possible to satisfy the clearance (up to about 20 μm) required between mold parts in performing plastic injection molding.

Therefore, in such a conventional method of forming a hard alumite film, there is a problem that it is not possible to perform preforming for confirming the shape and dimensions of a molded product before forming the hard alumite film. I have. In order to solve such a problem, the clearance between the metal parts before forming the hard alumite film is set to 20 μm or less, and the clearance between the mold parts after forming the film is reduced to 20 μm or less by machining after the formation of the hard alumite film. Although it is conceivable, in this case, the number of processing steps is increased, so that the manufacturing cost of the mold is increased, and the advantage of using an aluminum alloy material for the injection mold cannot be utilized.

[0007] In addition, a method described in Japanese Patent Publication No. 6-65483 can be considered. This is a mold in which a fixed side member and a movable side member that define a cavity are made of an aluminum alloy, and at least one type of sliding member selected from an ejector pin and a slide core is made of steel. The clearance between the sliding part of the fixed-side member and the movable-side member with which the sliding member slides and the sliding member is 20 μm or less, and a hard alumite film having a thickness of 10 μm or less is formed on the surfaces of the fixed-side member and the movable-side member. Is formed. For this reason, the dimensional condition that the clearance between the mold parts required for the mold is set to 20 μm or less can be sufficiently satisfied after the hard alumite film treatment.

[0008]

However, in such a conventional method of forming a hard alumite film, if the thickness of the fixed side member and the movable side member is as thin as 10 μm or less, the durability of the mold is reduced. Inadequate improvement in wear resistance, and sufficient wear resistance and galling resistance could not be obtained. The dimensional change due to the formation of such a hard alumite film is not limited to the sliding surface between the above-described mold parts, but is also a problem in a precision molded product having a dimensional tolerance of 10 μm or less, which is severe, in the cavity space. It needs to be resolved early.

Therefore, the inventions according to the first to fifth aspects of the present invention enable the formation of a hard alumite film without depending on the dimensional change due to the formation of the hard alumite film and the thickness of the hard alumite film. It is an object of the present invention to provide a method for forming a hard alumite film of an aluminum alloy injection molding die which can reduce a dimensional change of the hard alumite film when forming the alumite film.

According to a sixth aspect of the present invention, there is provided an injection molding made of an aluminum alloy having high durability, which is capable of improving the wear resistance and galling resistance of a sliding portion of an ejector pin of a mold component made of an aluminum alloy. The purpose is to provide a mold. The invention according to claim 7 can improve the wear resistance and galling resistance of the slide core sliding portion of the mold component made of an aluminum alloy,
An object of the present invention is to provide a highly durable aluminum alloy injection mold.

[0011] The invention according to claim 8 can improve the wear resistance and galling resistance of the parting surface of a mold component made of an aluminum alloy, and is a highly durable aluminum alloy injection mold. It is intended to provide. The invention according to claim 9 is to improve the wear resistance in the cavity space of the mold component made of an aluminum alloy, for example, when molding a resin mixed with glass fiber or the like, by using this glass fiber. An object of the present invention is to provide a highly durable aluminum alloy injection mold capable of preventing the cavity defining surface from being worn.

An object of the present invention is to provide an aluminum alloy injection molding die which can be preformed for confirming the shape and dimensions of a molded product before forming a hard alumite film. And

[0013]

According to the first aspect of the present invention,
In order to solve the above-mentioned problems, an injection molding mold is provided in which at least one or more of mold components defining a cavity is made of an aluminum alloy material, and a mold component made of the aluminum alloy material is provided. In the method of forming a hard alumite film on a substrate, the formed film thickness of the hard alumite film is defined by a limit film thickness, and the dimensional change of the alumite film with respect to the initial formation surface of a mold component made of an aluminum alloy material is measured. Is controlled independently of the processing film thickness.

In this case, it is possible to form a hard anodized film without making the dimensional change due to the formation of the hard anodized film depend on the thickness of the alumite film. Can be reduced. According to a second aspect of the present invention, in order to solve the above problem, in the first aspect of the present invention, the critical film thickness is defined by at least a type, a concentration and a temperature of an electrolytic solution, and a current density and a voltage. It is characterized by:

In this case, the thickness of the hard alumite film can be set to an arbitrary value. In order to solve the above-mentioned problem, the invention according to claim 3 is characterized in that the amount of dimensional change due to the formation of the hard alumite film is controlled by the processing time after the formation of the critical thickness of the hard alumite film.

In this case, the dimensional change due to the hard anodized film after the formation of the critical film thickness can be controlled independently and freely from the film thickness of the hard anodized film. According to a fourth aspect of the present invention, in order to solve the above-mentioned problems, in the first aspect of the present invention, the thickness of the hard alumite film is set to several tens to several hundreds μm. Features.

In this case, it is possible to perform a surface treatment capable of dramatically improving the wear resistance and galling resistance of the mold component made of the aluminum alloy material. According to a fifth aspect of the present invention, in order to solve the above-mentioned problem, in the first or the third aspect of the present invention, the processing time after the formation of the limit thickness of the hard alumite coating is arbitrarily set, whereby the gold is removed. The dimensional change of the hard alumite film with respect to the initial formation surface of the mold component is set within a range of ± 1 μm.

In this case, taking into account the dimensional change when the hard alumite film is formed, it is possible to eliminate the need to pre-process the mold components to be smaller than the original size, and to provide the hard alumite film. It is possible to eliminate the need for additional processing such as cutting after the formation of the mold, and to greatly improve the workability of the manufacturing operation of the injection mold. In order to solve the above-mentioned problems, the invention according to claim 6 is based on claim 1.
5. An aluminum alloy injection molding die having a hard anodized film formed by the method of any one of claims 1 to 5, wherein an ejector pin is slid on one of the die component parts made of the aluminum alloy material. A moving sliding part is formed, and the hard alumite film is formed on the sliding part.

In this case, the abrasion resistance and galling resistance of the sliding portion of the ejector pin of the mold component made of the aluminum alloy material can be sufficiently ensured, and the durability of the mold for injection molding is greatly improved. Can be improved. According to a seventh aspect of the present invention, there is provided an aluminum alloy injection molding mold having a hard alumite film formed by the method according to any one of the first to fifth aspects. A mold component made of the aluminum alloy material has at least a first mold component made of a slide core and a second mold component having a sliding portion on which the slide core slides; The hard alumite film is formed on a sliding portion of a slide core of a two-die component.

In this case, the wear resistance and galling resistance of the slide core sliding portion of the first and second mold components made of an aluminum alloy material can be sufficiently ensured,
The durability of the injection mold can be greatly improved. According to an eighth aspect of the present invention, there is provided an aluminum alloy injection mold having a hard alumite film formed thereon by the method of any one of the first to fifth aspects. A hard alumite film is formed on a parting surface of a mold component made of the aluminum alloy material.

[0021] In this case, the wear resistance and galling resistance of the parting surface of the mold component made of the aluminum alloy material can be sufficiently ensured, and the durability of the injection mold can be greatly improved. Can be. According to a ninth aspect of the present invention, there is provided an aluminum alloy injection mold having a hard alumite film formed by the hard alumite film forming method according to any one of the first to fifth aspects. A hard alumite film is formed on the cavity defining surface of the mold component made of the aluminum alloy material.

In this case, in order to improve the abrasion resistance in the cavity space of the mold component made of an aluminum alloy, for example, when molding a resin mixed with glass fiber or the like, the cavity is formed by the glass fiber. Wear of the formed surface can be prevented, and the injection mold for aluminum alloy can be greatly improved.

According to a tenth aspect of the present invention, in order to solve the above-mentioned problems, in the invention according to any one of the sixth to ninth aspects,
The clearance between the sliding portion and the ejector pin before the formation of the hard alumite film, the clearance between the first mold component and the second mold component, or the clearance between the parting surface or the cavity defining surface. It is characterized by being set to 20 μm or less.

In this case, since the same injection molding can be performed before and after the formation of the hard alumite film, it is possible to perform preforming for confirming the shape and dimensions of the molded article before forming the hard alumite film.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments. 1 to 6 are views showing a first embodiment of a method for forming a hard alumite film on an aluminum alloy injection molding die and an aluminum alloy injection molding die according to the present invention. This corresponds to the invention described in any one of Items 8 to 10.

First, the basic principle of the present invention will be described with reference to FIGS. In FIG. 1, 1 is an aluminum alloy,
2 is a hard alumite film, 3 is an aluminum alloy surface before forming a hard alumite film (initial formation surface), 4
Is the limit thickness of the hard anodized film, and 5 is the dimensional change of the alumite film with respect to the surface 4 of the aluminum mold due to the formation of the hard anodized film.

FIG. 2 is a diagram showing the relationship between the processing time and the thickness of the hard alumite film when the processing conditions are changed, and shows three patterns of processing conditions A, B, and C, respectively. As shown in FIG. 2, the thickness of the hard alumite coating increases with the processing time. In other words, when the film thickness formed on the aluminum alloy is soluble in the electrolytic solution, a part of the film thickness of the formed hard alumite film dissolves to form pores in the film, from which current flows and the film grows. However, as the film grows, the electrical resistance increases and the growth rate of the film decreases.

When the growth rate of the film and the rate of melting into the solution become equal, the thickness of the film becomes constant at an arbitrary film thickness (limit film thickness) determined by the upper limit of the processing. The film thickness does not change (see “Surface treatment of aluminum”, published by Uchida Lao Tsuruho Co., Ltd.). The critical film thickness is defined by the type, concentration, and temperature of the electrolytic solution, and processing conditions such as current density and voltage. By changing these processing conditions, A to A in FIG.
It changes as shown in C. That is, the thickness of the hard alumite film can be controlled by arbitrarily setting the processing conditions and performing the processing up to the limit film thickness.

FIG. 3 is a diagram showing the relationship between the processing time and the dimensional change due to the formation of the hard alumite film when the processing conditions are changed, and shows three patterns of the processing conditions A, B and C, respectively. As shown in FIG. 3, the dimensional change due to the formation of the hard alumite film increases in the positive direction at the beginning of the treatment and shows a maximum value at an arbitrary treatment time, as described in the above-mentioned literature. , And then increase in the negative direction when the processing is further continued. The dimensional change in the region increasing in the positive direction is generally known to be 1/2 to 1/3, and is determined by the type of the aluminum alloy. Further, it is known that the point where the dimensional change reaches the maximum value corresponds to the point where the above-mentioned limit film thickness is reached.

This phenomenon will be described in detail with reference to FIG. In the initial stage of the process of forming the hard alumite film 2 on the aluminum alloy 1, a film having a thickness depending on the processing time progresses from the state of FIG. 1 (a). The dimensional change increases in the positive direction, and the state shown in FIG.

After that, even if the treatment is further advanced, the thickness of the hard alumite film 2 does not change while maintaining the limit film thickness, and only the dimensional change due to the formation of the hard alumite film 2 decreases.
At an arbitrary processing time, as shown in FIG. 1 (c), there is a point where the dimensional change is 0, that is, the dimension after the hard alumite treatment matches the dimension of the aluminum alloy 1 before the hard alumite treatment.

Thereafter, when the treatment is further advanced, the dimensional change due to the formation of the hard alumite film 2 increases in the negative direction.
As shown in (d), the dimensions after the hard alumite treatment are smaller than the dimensions of the aluminum alloy 1 before the hard alumite treatment. That is, by controlling the processing time after the hard alumite film 2 is formed to the limit film thickness, the dimensional change of the hard alumite film 2 with respect to the initial formation surface of the aluminum mold 1 is independent of the processed film thickness of the alumite film 2. The dimensions after the formation of the hard alumite coating 2 can be set as appropriate. In particular, by setting the treatment time, the dimensions after the formation of the hard alumite coating 2 can be made equal to the dimensions of the aluminum alloy 1 before the formation of the hard alumite coating 2.

As described above, it is possible to form a hard alumite film whose dimensional change due to the formation of the hard alumite film does not depend on the thickness of the hard alumite film. Next, an embodiment of the present invention will be described with reference to FIG.
This will be described based on Nos. 6 to 6. In FIGS. 4 and 5, reference numeral 11 denotes a movable side insert piece which is slidably provided on a fixed side mold plate which constitutes a part of an injection molding die, and which is slidably provided on a movable side mold plate (not shown). This is a fixed side piece that defines a cavity on the parting surface, and the fixed side piece 11 is made of an aluminum alloy material.

A cylindrical sliding portion 11a is formed on the inner peripheral portion of the fixed side insertion piece 11, and a steel ejector pin 12 is slidably inserted in the sliding portion 11a in the direction of the arrow. The ejector pin 12 has a function of extruding a resin molded product housed in a known cavity. Reference numeral 13
Is a hard alumite film formed on the sliding portion 11a.

Next, a method of forming a hard alumite film on the sliding portion 11a will be described. First, as the processing conditions of the hard alumite film formed 6 reaches the limit thickness in the processing time t ₁ (a), the process of such conditions dimensional change due Hard anodized becomes 0 in the processing time t ₂ I do. That is, by performing the processing until the hard anodized film reaches the limit film thickness at the processing time t ₁ shown in FIG. 6A, the hard anodized film becomes T as shown in FIG.
Defined in

The film thickness T here is determined by the type, concentration and temperature of the electrolytic solution, current density and voltage, and can be set to an arbitrary value by manipulating these processing conditions. Can be. In the present embodiment, the thickness T of the hard alumite film 13 is set to be several tens to several hundreds μm. In this case, for example, the type of the electrolytic solution is oxalic acid, and the concentration is oxalic acid. It is specified that the temperature is 40 g / liter, the temperature is 40 ° C., and the current density is 200 A / m ² .

When the processing is performed up to the processing time t ₂ after the formation of the limit thickness, the dimensional change due to the formation of the limit thickness of the hard alumite film 13 becomes 0 while the limit thickness of the hard alumite film 13 is maintained. The dimension of the fixed-side insert piece 11 can be made equal to the dimensional change before the formation of the hard alumite film 13. As described above, in the present embodiment, the aluminum alloy fixed side insert 11 into which the ejector pin 12 is inserted is inserted.
When the hard alumite film 13 is formed on the sliding portion 11a of the base member, the formed film thickness of the hard alumite film 13 is defined by the limit film thickness, and the dimensional change of the alumite film 13 with respect to the initial formation surface of the fixed side piece 11 is determined. Since the treatment thickness of the alumite film 13 is controlled independently, the dimensional change due to the formation of the hard alumite film 13 can be formed without depending on the thickness of the alumite film 13. When forming a thick hard alumite film, the dimensional change of the hard alumite film 13 can be reduced.

Since the critical film thickness of the hard alumite film 13 is defined by the type, concentration and temperature of the electrolytic solution and the current density and voltage, the film thickness of the hard alumite film 13 can be set to an arbitrary value. It can be specified. Also, the dimensional change due to the formation of the hard anodized film 13 is
Since the processing time (t ₂ −t ₁ ) after the formation of the critical thickness of the hard anodized film 13 is controlled, the dimensional change due to the hard anodized film 13 after the formation of the critical thickness is reduced. The thickness can be controlled independently and freely.

Further, since the thickness of the hard alumite film 13 is set to several tens to several hundreds μm, the wear resistance and the galling resistance of the sliding portion 11a of the fixed input piece 11 can be drastically improved. Thus, the durability of the injection mold can be greatly improved. The dimensional change due to the formation of the hard alumite film 13 is particularly problematic when forming a thick hard alumite film having a thickness of several tens to several hundreds μm. Also, by arbitrarily setting the processing time after the formation of the critical film thickness of the hard anodized film 13, the dimensional change amount of the hard anodized film 13 with respect to the initial formation surface of the fixed side input piece 11 can be made zero. In consideration of the dimensional change when the hard alumite film 13 is formed, it is possible to eliminate the need to previously work to fix the fixed side insertion piece 11 smaller than the original size, and to form the hard alumite film 13 It is possible to eliminate the need for additional processing such as cutting later, and it is possible to greatly improve the workability of the manufacturing operation of the injection mold. In particular,
Hard anodized film for initial formation surface of fixed side insert piece 11
By setting the dimensional change of 13 in the range of ± 1 μm, such an effect can be easily obtained.

Since the dimensional change can be reduced to zero, the clearance Tc1 between the sliding portion 11 and the ejector pin 12 before and after the injection molding can be set to 20 μm or less, and the same as before and after the formation of the hard alumite film 13. Injection molding can be performed. As a result, before forming the hard alumite film 13, preforming for confirming the shape and dimensions of the molded product can be performed.

In the present embodiment, the movable-side receiving piece 11 provided on the fixed-side mold plate is made of an aluminum alloy material. However, the movable-side receiving piece may be made of an aluminum alloy material. In addition, the fixed-side template and the movable-side template may be made of an aluminum alloy material. 7 and 8
1 is a diagram showing a second embodiment of a method for forming a hard alumite film of an aluminum alloy injection mold according to the present invention and an aluminum alloy injection mold;
The invention corresponds to the invention described in any one of the fifth and seventh aspects.

First, the configuration will be described. In FIGS. 7 and 8, reference numeral 21 denotes a fixed side mold plate which constitutes a part of the injection mold and is slidably provided on the movable side mold plate (not shown) together with a movable side insertion piece. This is a fixed-side receiving piece (a second mold component) that defines a cavity on the parting surface, and the fixed-side receiving piece 21 is made of an aluminum alloy material.

A sliding portion 21a on which a sliding portion 22a of a slide core (second mold component) 22 made of an aluminum alloy material slides is provided on the fixed side insertion piece 21, and this sliding portion is provided. A hard alumite film 23 is formed on 21a and 22a. When the slide core 23 is provided on the movable-side insert, the movable-side plate, or the fixed-side plate, a hard alumite film 23 is formed on a sliding portion between these members and the slide core.

Next, the operation will be described. First, FIG.
It is assumed that the processing time t ₁ shown in FIG. 6B reaches the limit thickness T at the processing time t ₁ , and the dimensional change due to the hard alumite processing becomes 0 at the processing time t ₂ . Next, the film thickness T of the hard alumite film 23 is regulated as shown in FIG. 8B by performing the processing until the hard alumite film 23 reaches the limit film thickness at the processing time t ₁ shown in FIG. Is done. The film thickness T here is determined by the type, concentration and temperature of the electrolyte, current density and voltage, and can be set to any value by manipulating these processing conditions.

After that, when the processing is performed until the processing time t ₂ shown in FIG. 6B, the hard alumite coating 23 is maintained while the hard alumite coating 23 maintains the limit thickness as shown in FIG. 8B.
23 No dimensional change due to formation, hard alumite coating
The dimensions of the fixed side insertion piece 21 and the slide core 22 after the formation of the 23 can be made equal to the dimensional changes before the formation of the hard alumite film 23.

As described above, even in this embodiment, the sliding portion 21
When the hard alumite film 23 is formed on the a and 22a, the formed film thickness of the hard alumite film 23 is defined by the limit film thickness, and the dimensional change of the alumite film 23 with respect to the initial formation surface of the fixed side insertion piece 21 and the slide core 22. Since the amount was controlled independently of the treatment film thickness of the alumite film 23, the dimensional change due to the formation of the hard alumite film 23 can be formed without depending on the thickness of the alumite film 23, and the hard alumite film 23 can be formed. In particular, when forming a thick hard alumite film, the dimensional change of the hard alumite film 23 can be reduced.

Since the dimensional change due to the formation of the hard alumite film 23 is controlled by the processing time (t ₂ -t ₁ ) after the formation of the limit film thickness of the hard alumite film 23, The dimensional change caused by the formed hard anodized film 23 can be controlled independently and freely from the thickness of the hard anodized film 23. In addition, hard anodized film 23
Since the thickness of the film is set to several tens to several hundreds of μm, the wear resistance and galling resistance of the sliding portions 21a and 22a of the fixed side insertion piece 21 and the slide core 22 can be dramatically improved, The durability of the injection mold can be greatly improved.

Further, by arbitrarily setting the processing time after the formation of the critical thickness of the hard anodized film 23, the dimensional change of the hard anodized film 23 with respect to the initial formation surface of the fixed side insertion piece 21 and the slide core 22 can be reduced. Since it can be set to 0, the work of processing the fixed side insertion piece 21 and the slide core 22 beforehand to be smaller than the original dimensions in consideration of the dimensional change when the hard alumite film 23 is formed is unnecessary. In addition to this, additional processing such as cutting after the formation of the hard alumite film 23 can be eliminated, and the workability of the manufacturing operation of the injection mold can be greatly improved. More specifically, such an effect can be easily obtained by setting the dimensional change of the hard alumite film 23 with respect to the initial formation surface of the fixed side insertion piece 21 and the slide core 22 in a range of ± 1 μm.

Since the dimensional change can be reduced to zero, the clearance Tc2 between the sliding portions 21a and 22a before and after the injection molding can be set to 20 μm or less, and the same before and after the formation of the hard alumite film 23. Injection molding can be performed. As a result, preforming for confirming the shape and dimensions of the molded article can be performed before the formation of the hard alumite film 23.

In the present embodiment, the hard alumite film 23 is formed on both the fixed side insertion piece 21 and the sliding portions 21a and 22a of the slide core 22.
23 may be formed on only one of the fixed side insertion piece 21 and the slide core 22. Further, in the present embodiment, the hard alumite film 23 is applied to the sliding portions 21a and 22a of the fixed-side insert piece 21 and the slide core 22, but is not limited to this, and may be applied to any aluminum alloy material sliding portion. It goes without saying that it can be applied.

In each of the above embodiments, the hard alumite film is coated with the sliding portion 12a of the ejector pin 12 or the slide core.
The sliding part 21a, 22a of the 22 is formed, but is not limited to this, a hard alumite film is formed on the parting surface of a mold component made of an aluminum alloy material in the same manner as in each of the above embodiments. Is also good. By doing so, the wear resistance and galling resistance of the parting surface of the mold component can be sufficiently ensured, and the durability of the injection mold can be greatly improved.

Further, a hard alumite film may be formed on the cavity defining surface of a mold component made of an aluminum alloy material. By doing so, the wear resistance in the cavity space of the mold component made of an aluminum alloy is improved, and, for example, when molding a resin mixed with glass fiber or the like, the cavity image is formed by the glass fiber. Wear of the formed surface can be prevented, and in particular, when a hard anodized film having a thickness of several tens μm to several hundreds of μm is formed, remarkable wear resistance can be obtained.

In addition, since the dimensional change due to the formation of the hard alumite film can be reduced to 0, it is possible to obtain a molded product having the same dimensions and shape before and after the formation of the hard alumite film, and to have a strict tolerance with a dimensional tolerance of 10 μm or less. It can respond to the molding of products.

[0054]

According to the first aspect of the present invention, a hard alumite film can be formed without making the dimensional change due to the formation of the hard alumite film depend on the thickness of the alumite film. During the formation, the dimensional change of the hard alumite film can be reduced.

According to the second aspect of the present invention, the thickness of the hard alumite film can be set to an arbitrary value. According to the third aspect of the present invention, the dimensional change due to the hard alumite film after the formation of the critical film thickness can be controlled independently and freely from the film thickness of the hard alumite film.

According to the fourth aspect of the present invention, it is possible to perform a surface treatment capable of dramatically improving the wear resistance and galling resistance of a mold component made of an aluminum alloy material. According to the invention as set forth in claim 5, it is possible to eliminate the need to previously process the mold component parts to be smaller than the original dimensions in consideration of the dimensional change when the hard alumite film is formed. This eliminates the need for additional processing such as cutting after the formation of the hard alumite film, thereby greatly improving the workability of the manufacturing operation of the injection mold.

According to the sixth aspect of the invention, it is possible to sufficiently secure the wear resistance and galling resistance of the sliding portion of the ejector pin of the metal mold component made of the aluminum alloy material, and the metal for the injection molding. The durability of the mold can be greatly improved. According to the seventh aspect of the invention, it is possible to sufficiently secure the wear resistance and the galling resistance of the sliding portion of the slide core of the first and second mold components made of an aluminum alloy material, and it is possible to perform the injection molding. The durability of the mold can be greatly improved.

According to the eighth aspect of the present invention, it is possible to sufficiently secure the wear resistance and galling resistance of the parting surface of the mold component made of the aluminum alloy material.
The durability of the injection mold can be greatly improved. According to the ninth aspect of the present invention, in order to improve the abrasion resistance in the cavity space of the mold component made of an aluminum alloy, for example, when molding a resin mixed with glass fiber or the like, this glass is used. Wear of the cavity defining surface due to the fibers can be prevented, and the durability of the injection mold can be greatly improved.

According to the tenth aspect of the present invention, the same injection molding can be performed before and after the formation of the hard alumite coating, so that the preliminary molding for confirming the shape and dimensions of the molded article before the formation of the hard alumite coating is performed. Molding can be performed.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of an aluminum alloy injection mold for achieving a method for forming a hard alumite film of an aluminum alloy injection mold according to the present invention;
It is a figure explaining the basic principle for forming the hard alumite film.

FIG. 2 is a diagram showing the relationship between the processing time and the thickness of a hard alumite film when the processing conditions are changed.

FIG. 3 is a diagram showing a relationship between a processing time when a processing condition is changed and a dimensional change due to formation of a hard alumite film.

FIG. 4A is a side sectional view of a mold component of the first embodiment, and FIG. 4B is a sectional view taken along the line AA in FIG.

FIG. 5 is a view showing a state in which a hard alumite film is formed on a mold component of the first embodiment.

6A is a diagram showing a relationship between a processing time and a thickness of a hard alumite film, and FIG. 6B is a diagram showing a relationship between a processing time and a dimensional change due to formation of a hard alumite film.

FIG. 7 is a view showing a second embodiment of the aluminum alloy injection molding die for achieving the method for forming a hard alumite film of the aluminum alloy injection molding die according to the present invention;
(A) is a perspective view of the mold component, and (b) is an enlarged view of a portion B in FIG.

FIG. 8 is a view showing a state in which a hard alumite film is formed on a mold component of the second embodiment.

[Description of Signs] 11 Fixed-side insert (mold component) 11a Sliding part 12 Ejector pin 13, 23 Hard anodized film 21 Fixed-side insert (die component, second mold component) 21a, 22a Sliding part 22 Slide core (mold component, first mold component)

──────────────────────────────────────────────────の Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B29C 45/26-45/38 B29C 33/38 C25D 11/02-11/04

Claims (10)

(57) [Claims] An injection molding mold is provided in which at least one of the mold components defining a cavity is made of an aluminum alloy material, and a hard anodized mold component is made of the aluminum alloy material. In the method for forming a film, the film thickness of the hard alumite film is defined by a limit film thickness, and a dimensional change amount of the alumite film with respect to an initial formation surface of a mold component made of an aluminum alloy material is determined by treating the alumite film with a film. A method for forming a hard alumite film on an aluminum alloy injection mold, wherein the method is controlled independently of the thickness. 2. The aluminum alloy injection molding die according to claim 1, wherein the critical film thickness is defined by at least the type, concentration and temperature of the electrolytic solution, and the current density and voltage. Hard alumite film forming method. 3. The aluminum alloy injection molding according to claim 1, wherein the amount of dimensional change due to the formation of the hard alumite coating is controlled by the processing time after the formation of the critical thickness of the hard alumite coating. Method of forming a hard alumite coating on a metal mold. 4. A method according to claim 1, wherein said hard alumite film has a thickness of several tens to several hundreds of micrometers.
A method for forming a hard alumite film on an aluminum alloy injection mold according to any one of the above. 5. The dimensional change of the hard anodized film with respect to the initial forming surface of the mold component is set within a range of ± 1 μm by arbitrarily setting a processing time after the formation of the critical film thickness of the hard anodized film. 4. A method for forming a hard alumite film on an aluminum alloy injection mold according to claim 1 or 3, wherein the method is set. 6. An aluminum alloy injection molding mold having a hard alumite film formed by the method of forming a hard alumite film according to any one of claims 1 to 5, wherein the mold component is made of the aluminum alloy material. A sliding part on which an ejector pin slides is formed, and the hard alumite film is formed on the sliding part. 7. An aluminum alloy injection molding mold having a hard alumite film formed by the method of forming a hard alumite film according to any one of claims 1 to 5, wherein the mold component is made of the aluminum alloy material. Has at least a first mold component comprising a slide core and a second mold component having a sliding portion on which the slide core slides,
An injection mold made of an aluminum alloy, wherein the hard alumite film is formed on a slide portion of a slide core of the first and second mold components. 8. An aluminum alloy injection molding die having a hard alumite coating formed by the method of forming a hard alumite coating according to claim 1, wherein the die is made of the aluminum alloy material. An aluminum alloy injection molding mold, characterized in that a hard alumite film is formed on the parting surface. 9. An aluminum alloy injection molding mold having a hard alumite film formed by the method of forming a hard alumite film according to any one of claims 1 to 5, wherein the mold component is made of the aluminum alloy material. An aluminum alloy injection mold, characterized in that a hard alumite film is formed on the cavity defining surface. 10. The clearance between the sliding portion and the ejector pin before the formation of the hard alumite film, the clearance between the first mold component and the second mold component, or the parting surface or cavity image. The aluminum alloy injection mold according to any one of claims 6 to 9, wherein the clearance of the formed surface is set to 20 µm or less.