JP2003170433A - Electroforming mold for molding plastic product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroforming mold made hard to generate damage by the stress due to the heating and cooling at the time of molding of a plastic product, having high durability and capable of being made inexpensive by dispensing with a complicated structure. <P>SOLUTION: The electroforming mold 10 for molding the plastic product comprises a product molding part 13 having a product molding surface 11 formed to the inner surface thereof, and a mold attaching part 17 having the wall 14 extended from the end 12 of the product molding part 13. A deformable part 15 bent into a bellows shape is provided to all of or a part of the wall 14 of the mold attaching part 17 and the extension, and contraction deformation due to the heating and cooling of the electroforming mold 10 at the time of slush molding is enabled by the extension and contraction caused by the bellows shape in the deformable part 15 and the deformation of the wall 14 in the inward and outward directions thereof, not only to prevent the damage of the electroforming mold due to the obstruction of extension and contraction deformation but also to enhance the durability thereof. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroforming mold for molding plastic products, and more particularly to an electroforming mold for powder slush molding having a crack prevention measure.

[0002]

2. Description of the Related Art A powder slush molding method is known as a method for molding a film-shaped plastic product. In this powder slush molding method, as shown in FIG. 3, a product molding side portion 23 having a product molding surface 21 of the product shape on the inside and a wall portion extending from an end 23a of the product molding side portion 23 (generally, Is also referred to as a skirt.) A mold 20 including a mold attachment side portion 25 having a
The molding die 20 is heated to a high temperature usually exceeding 200 ° C., and the bucket 31 containing the plastic powder P is stored.
And is rotated together with the bucket 31. The rotation causes the plastic powder P in the bucket 31 to adhere to the product molding surface 21 of the molding die 20 to a required thickness, and the adhered plastic powder is heated by the heat of the product molding surface 21 to form a gel. Then, after cooling and curing to form a plastic film on which the surface shape of the product is transferred, the film is peeled off from the product molding surface 21 to obtain a desired film-shaped plastic product.

An electroforming mold is often used as the molding die 20 for the plastic product. The electroforming mold was obtained by immersing an electroforming master mold called a mandrel in an electrolytic solution containing a metal salt to deposit a metal salt on the master mold surface by electrolysis, and peeling the deposited metal layer from the master mold. And has an inner surface, on which the irregularities on the surface of the mother die are copied, as a product molding surface.

The electric mold for powder slush molding is expanded and deformed by heating during powder slush molding, and contracted and deformed by cooling. But,
As mentioned above, the electroforming mold for powder slush molding is
Since the mold mounting side part 25 is fixed to the powder slush molding device including the bucket 31 and the rotating device, expansion and contraction deformation is hindered, strain stress concentrates on the weak part of the electroforming mold, and damage occurs during repeated powder slush molding. There is a problem that is likely to occur. In particular, since the product molding side portion 23 is heated to a higher temperature more intensively than the mold mounting side portion 25, the product molding side portion 23 is greatly expanded and contracted and is often formed into a complicated uneven shape corresponding to the shape of the product coating. There is a portion that is weaker in strength than the other portions, and is liable to be damaged due to the inhibition of the elastic deformation.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above points, and is less likely to be damaged by stress due to heating and cooling during molding of plastic products.
It is an object of the present invention to provide an electroforming mold which has high durability and is inexpensive without making a complicated structure.

[0006]

According to a first aspect of the present invention, there is provided a mold attachment side having a product molding side portion having a product molding surface formed on an inner surface thereof and a wall portion extending from an end of the product molding side portion. In an electric mold for molding a plastic product consisting of a part, on the entire circumference or part of the wall part of the mold mounting side part,
It is characterized in that a deformable portion bent in a bellows shape is provided.

According to a second aspect of the present invention, in the first aspect, both the product molding side portion and the mold mounting side portion are formed by electroforming.

A third aspect of the present invention is characterized in that, in the first aspect, a product forming side portion that is electroformed and a die mounting side portion that is not formed by electroforming are joined.

A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, the properties of the metal in the product molding side portion and the mold mounting side portion are different from each other.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, at least one of the product forming side portion and the die mounting side portion is annealed.

The invention of claim 6 is characterized in that, in claim 5, the annealing temperature is from the temperature of the modification point of the electroformed metal of -200 ° C to the temperature of the modification point + 50 ° C.

According to a seventh aspect of the present invention, there is provided a plastic product comprising a product molding side portion having a product molding surface formed on an inner surface thereof and a mold mounting side portion having a wall portion extending from an end of the product molding side portion. In the molding electroforming mold, the properties of the metal at the product molding side and the mold mounting side are different from each other.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a schematic cut end face of a plastic product molding electric mold 10 according to an embodiment of the present invention. The illustrated electroforming mold 10 is a molding die used for publicly known powder slush molding of a plastic skin for an instrument panel of an automobile, and a product molding side portion 1
3 and a mold mounting side portion 17, which is mounted on a powder slush molding machine such as a bucket as described in the section of the prior art.

The product molding side portion 13 is formed of a metal such as nickel deposited on the surface of the mother die by known electroforming, and is formed according to the desired coated plastic product (in this example, plastic skin for instrument panel). It has a product molding surface 11 having different shapes and dimensions inside. Of course, the electroforming mold 10 of the present invention is not limited to a mold for molding a plastic skin for an instrument panel, but may be a mold for various coated plastic products, and in that case, it is an object. The shape and size of the product molding surface 11 are set according to the coated plastic product. In addition, the product molding side portion 13 may be provided with heating means for the product molding surface 11 on the outer surface (back surface) thereof. Examples of the heating means include a heat medium pipe for circulating a heat medium such as water or oil.

The mold mounting side portion 17 is formed by electroforming similarly to the product forming side portion 13 or, unlike the product forming side portion 13, is not formed by electroforming and is subjected to normal sheet metal working or cutting. It is formed of a metal such as nickel and is formed by, for example, and is joined to the product forming side portion 13 by welding or the like. Mold mounting side part 1 of this example
Reference numeral 7 includes a wall portion 14 and a mounting flange portion 16. The wall portion 14 is a portion commonly referred to as a skirt portion, and extends from the end 12 of the product molding side portion 13 so as to surround the entire circumference of the end 12.

A deformable portion 15 bent in a bellows shape is formed on the wall portion 14. This bellows-shaped deformable part 1
5 is preferably provided all around the wall portion 14, but if it is difficult to provide all around the wall portion 14 due to the shape of the wall portion 14, etc., it is provided at a part of the wall portion 14 (including a plurality of locations). Good. Further, it is preferable that the bellows concave groove 15a or the top portion 15b between the concave grooves 15a is substantially parallel to the end 12 of the product molding side portion 13. Further, the number of the bellows concave grooves 15a, the size of the concave grooves 15a, etc. are determined by the electroforming mold 10.
It is appropriately determined according to the size of the.

According to the known powder slush molding method, the electroforming mold 10 having the above-mentioned structure is manufactured by powder slush molding, in which the product molding side portion 13 is mainly heated, and the powder is composed of the bucket 41 containing the plastic powder and the rotating device. It is attached to the slush molding apparatus via the attachment flange portion 16 and cooled after rotation. At this time, since there is a deformable portion 15 bent in a bellows shape on the wall portion 14 of the die mounting side portion 17, heat is generated in the product forming side portion 13 which is heated to a particularly high temperature by heating and cooling of the electroforming mold 10. Even if expansion and contraction due to the deformation occurs, the deformable portion 15 deforms in accordance with the expansion and contraction of the product molding side portion 13 in the expansion and contraction A due to the bellows shape and in the wall part inward and outward direction B, so that it is fixedly attached to the powder slush molding device. The product molding side portion 13 can be expanded and contracted without being hindered by the side of the mounting flange 16 that is prevented from being deformed. Therefore, the product molding side portion 13
The strain stress due to the expansion and contraction inhibition is less likely to occur, and breakage is less likely to occur in a weakened portion.

The product molding side portion 1 of the electroforming mold 10
3 and the mold mounting side portion 17 have the following properties of metal.
Different from each other, the product molding side portion 13
More preferably, it is suitable for the die mounting side portion 17. In particular, when the product molding side portion 13 and the mold mounting side portion 17 are integrated by joining as described above, the product molding side portion 13 and the mold mounting side portion 17 are formed.
Each metal can be decided independently. For example,
The product molding side portion 13 is made to have little expansion and contraction due to temperature change and is excellent in dimensional stability, while the mold mounting side portion 17 is made to have high strength even at high temperature.

As a method of making the properties of the metal forming the product molding side portion 13 and the mold mounting side portion 17 different and improving, the same temperature can be applied to the product molding side portion 13 and the mold mounting side portion 17. The product forming side part 13 and the die mounting side part 17 with different annealing temperatures, or the product forming side part 13
It is possible to anneal at least one of the mold attachment side portion and not to anneal the other. For example, the product forming side portion 13 and the die mounting side portion 17 are electroformed, and then the same annealing temperature or different annealing temperatures are used for annealing, or only one of them is annealed.

The annealing temperature is a temperature at which the electroformed metal greatly changes its physical properties, that is, the temperature of the so-called modification point-200.degree.
It is preferable to correct the influence of hydrogen in the electroformed metal within the range of the temperature of the modification point + 50 ° C. For example, in the case of nickel formed by electroforming from a nickel sulfamate bath or a nickel chloride bath, the tensile strength, yield strength and elongation change greatly at 450 ° C.
C is the temperature of the denaturation point, and the preferable temperature range is 250 ° C to 500 ° C.

As a specific method for changing the properties of the metal depending on the annealing temperature, in the case of nickel formed by electroforming from the nickel sulfamate bath or the nickel chloride bath, the annealing temperature is set to the product forming side. 250 ° C to 400 ° C for the metal (nickel) of the part 13
On the other hand, the metal (nickel) of the mold mounting side portion 17 may be set to 250 ° C. to 500 ° C., respectively.

In the present invention, the product molding side portion 1 is provided.
3 and the die mounting side portion 17 were annealed at the same temperature (including the case of the same temperature within the temperature of the modification point −200 ° C. to the temperature of the modification point + 50 ° C.) to improve the properties of the metal. It does not exclude, but includes it.

FIG. 2 shows a schematic cut end face of an electric mold 10A for molding a plastic product according to another embodiment of the present invention. The electric mold 10A shown in the figure is for powder slush molding similarly to the electric mold 10 of FIG. 1, and has a structure in which the product molding side portion 13A and the mold mounting side portion 17A are joined and integrated.

The product molding side portion 13A is formed by electroforming and has a product molding surface 11A inside. On the other hand, the mold mounting side portion 17A is formed by electroforming, or formed by metal such as nickel formed by ordinary sheet metal working or cutting without electroforming. It is composed of a wall portion 14A and a mounting flange portion 16A. The wall portion 14A is a portion commonly referred to as a skirt portion, and is formed from the end 12A of the product molding side portion 13A to the end 12A.
A is extended so as to surround the entire circumference.

Further, in this embodiment, the product molding side portion 13A and the mold mounting side portion 17A are different from each other in metal property. For example, the product molding side portion 13A is made to have little expansion and contraction due to temperature change and has excellent dimensional stability, while the mold mounting side portion 17A is made to have high strength even at high temperature. The method and contents for changing the properties of the metal are the same as described in the embodiment of FIG. That is, the product forming side portion 13A and the die mounting side portion 17A are annealed at the same temperature, the annealing temperature is made different between the product forming side portion 13A and the die mounting side portion 17A, or the product forming side portion. At least one of 13A and the die mounting side portion 17A is annealed, and the other is not annealed. The annealing temperature is, as described above, the temperature of the modification point of the electroformed metal −200 ° C. to the temperature of the modification point + 50 ° C.
Is preferred. When the metal forming the electroforming mold 10A is nickel, the product molding side portion 13A
Metal (nickel) on the other hand and the metal (nickel) on the die mounting side portion 17 are annealed at the same temperature within 250 ° C to 450 ° C, or 250 ° C for the metal (nickel) on the product molding side portion 13A. Annealed at ~ 400 ° C, while the metal (nickel) of the die mounting side part 17
As for the above, annealing at 250 ° C. to 500 ° C. may be mentioned.

[0026]

As described and shown in the above, claims 1 to
According to the invention of 5, the deformable portion bent in a bellows shape is provided on the entire circumference or a part of the wall portion of the die mounting side portion.
Even if the product molding side portion expands and contracts due to heating, it is difficult to prevent expansion and contraction deformation of the product molding side part by fixing the mold attachment side part to the molding device, and the electric mold is damaged by the stress due to the expansion and contraction inhibition. Can be prevented and durability can be improved. In particular, in the electroforming mold used for powder slush molding, the product molding side part is heated to a very high temperature and then cooled,
Since the product molding side portion is significantly expanded and contracted by heating and cooling, the effect of preventing damage and improving the durability by the deformable portion bent in a bellows shape becomes very remarkable. Further, the structure of the electroforming mold is not complicated, and the cost increase can be suppressed.

Further, according to the fifth and sixth aspects of the invention, the effect of preventing damage and the durability of the electroforming mold can be further enhanced by combining with the annealing process.

Further, according to the invention of claim 7, since the properties of the metal in the product molding side and the mold mounting side are different from each other, expansion and contraction due to temperature change is small and dimensional stability is excellent. In addition, it becomes possible to obtain high strength even at high temperatures, and it becomes possible to prevent damage to the electroforming mold.

[Brief description of drawings]

FIG. 1 is a schematic cut end view of an electroforming mold according to an embodiment of the present invention.

FIG. 2 is a schematic cut end view of an electroforming mold according to an embodiment of the present invention.

FIG. 3 is a schematic cut end view showing an example of a conventional molding die in combination with a powder slush molding bucket.

[Explanation of symbols]

10 Electric molds for molding plastic products 11 Product molding surface 12 Product molding side edge 13 Product molding side 14 wall 15 Deformable part bent in a bellows shape 16 Mounting flange 17 type mounting side part

Claims (7)

[Claims] 1. An electric mold for molding a plastic product, comprising a product molding side portion having a product molding surface formed on an inner surface thereof, and a mold mounting side portion having a wall portion extending from an end of the product molding side portion. An electroforming mold for molding plastic products, characterized in that a deformable portion bent in a bellows shape is provided on the entire circumference or a part of the wall portion of the die mounting side portion. 2. The electroforming mold for plastic product molding according to claim 1, wherein both the product molding side portion and the mold mounting side portion are formed by electroforming. 3. The electroforming mold for plastic product molding according to claim 1, wherein an electroformed product forming side portion and a mold mounting side portion not formed by electroforming are joined. 4. The electric mold for molding a plastic product according to claim 1, wherein the properties of the metal in the product molding side and the mold mounting side are different from each other. 5. The plastic product molding according to any one of claims 1 to 4, wherein at least one of the product molding side portion and the mold mounting side portion is annealed. Electroforming mold. 6. The annealing temperature is the temperature of the modification point of the electroformed metal −2.
The electroforming mold for molding a plastic product according to claim 5, wherein the temperature is 00 ° C to the temperature of the modification point + 50 ° C. 7. An electric mold for molding a plastic product, comprising: a product molding side portion having a product molding surface formed on an inner surface thereof; and a mold mounting side portion having a wall portion extending from an end of the product molding side portion. An electric mold for molding a plastic product, characterized in that the properties of the metal on the product molding side and the mold mounting side are different from each other.