JP2948329B2 - Manufacturing method of molding die - 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 of manufacturing a molding die having a temperature adjusting circuit necessary for adjusting the temperature of the molding die such as cooling and heating during resin molding. .

[0002]

2. Description of the Related Art A mold made of a nickel shell is manufactured by an electroforming method. Conventionally, in the case of a nickel electroformed mold, a copper pipe or a stainless steel pipe is arranged along the nickel shell mold on the back surface of a nickel shell mold having a thickness of 2 to 3 mm manufactured by a nickel electroforming method, and welding or welding is performed. Temporarily fix the pipe to the back of the nickel shell with brazing. After that, heat-resistant epoxy resin or the like was poured around the pipe, and the pipe was fixed to the back of the mold to form a cooling circuit.

[0003] However, this method requires many man-hours and skill in processing a pipe, and there is a limitation that a circuit cross-section can be designed only with a round cross-section of the pipe. In addition, since the pipe is fixed to the back surface of the shell and the periphery of the pipe is covered with a material having poor thermal conductivity such as epoxy resin, the heat efficiency is deteriorated and the thickness of the nickel shell is 2 to 3 mm at most. There were drawbacks such as insufficient strength as a mold.

[0004] Further, in a mold made by cutting a general machining method using a steel-based material or the like, or in a mold made by casting using a method such as a precision casting method, a mold corresponding to the product shape is formed. Drilling is performed linearly at a position several tens of mm away from the surface, and the linear holes are used as a cooling circuit.

[0005] However, at this time, drilling can only be performed at a position within the mold several tens mm from the molding surface, and in general, only linear holes having a circular cross section have been formed. Also, because of the drilling, the distance from the molding surface to the hole could not be equalized. For these reasons, the cooling and heating efficiency of the mold is poor, and it takes time to control the temperature of the mold, which hinders the improvement of the productivity of the molded product.
That is, when the surface and the inside of the mold are heated by the heat of the molding resin injected or injected into the mold, in order to quickly lower the temperature of the mold to room temperature for the next molding, the above temperature is required. The adjustment circuit had its limits.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the number of steps for arranging a circuit when forming a temperature adjusting circuit between a first nickel shell and a second nickel shell. The aim is to shorten the manufacturing period of the mold and reduce the production cost.The cross-sectional shape of the circuit is not limited to a circular shape, but can be any shape according to the purpose of use of the mold and the product shape of the mold. The object of the present invention is to enable the most rational circuit design suitable for the purpose of use of the mold by making it possible to manufacture the circuit and freely setting the sectional dimensions of the circuit.

[0007]

According to the present invention, there is provided a step of forming a first nickel shell on a resin mandrel or a metal master model by a chemical vapor deposition method; the surface of the first nickel shell is made of a low melting point alloy. A step of adhering and fixing the elongate body; forming a second nickel shell by a chemical vapor deposition method along the surface of the first nickel shell and the surface of the elongate body; Covering the first nickel shell with a resin mandrel or a metal master model; and heating the elongated body to a temperature equal to or higher than the melting point of the low melting point alloy. Melts and drains the melt from the first nickel shell and the second nickel shell,
Accordingly, the present invention relates to a method for manufacturing a forming circuit, in which a temperature adjusting circuit is formed between the first nickel shell and the second nickel shell.

[0008]

FIG. 1 is a sectional view showing a plastic molding die which can be produced by the present invention.

In the molding die 13 shown in FIG. 1, between the first nickel shell 2 and the second nickel shell 4,
For example, an elongated space 16 having a substantially quadrangular cross section is provided, and this space is used as a temperature adjustment circuit 16. That is, the temperature adjustment circuit 16 is formed as a gap between the first nickel shell 2 and the second nickel shell 4, and the periphery of the temperature adjustment circuit 16 is the first nickel shell 2 and the second nickel shell 2. It is surrounded by two nickel shells 4.

Next, a method of manufacturing such a molding die will be described step by step. First, the first and second nickel shells 2 and 4 are formed by a so-called chemical vapor deposition method (Chemical vapor deposition method), unlike the conventional electroforming method.

Specifically, a nickel compound, for example, nickel carbonyl, is formed using nickel as a raw material, and nickel is deposited on a model maintained at an appropriate temperature in an airtight chamber to form a nickel shell. For example, a chemical vapor deposition apparatus as schematically shown in FIG. 2 is used.

That is, in FIG. 2, first, a nickel compound such as nickel carbonyl Ni (CO) ₄ is vaporized and sent from the supply system 24 into the hermetic chamber 21 together with the carrier gas as shown by an arrow A. In the hermetic chamber 21, a resin mandrel or a metal master model 22 having a surface shape corresponding to a predetermined product shape is installed, and sealing is performed by an insulating barrier 23. For example, when Ni (CO) ₄ is heated to 200 ° C., it decomposes into nickel and carbon monoxide gas, and nickel is deposited on the mandrel or the master model 22 to form a nickel deposited film (nickel shell) 26 on its surface. The interior of the airtight chamber 21 is replaced with an inert gas in advance, and a heating medium is blown from the back of the mandrel or the master model 22 as indicated by an arrow B, so that the surface of the mandrel or the master model 22 is heated to, for example, 200 ° C. Raise the temperature to Note that FIG.
Among them, 25 is a gas recovery system.

When a nickel shell is manufactured by such a method, unlike the conventional electroforming method, the formation speed of the nickel shell can be increased, and the nickel shell can be uniformly formed in all portions or gaps having a complicated shape. Further, both the first and second nickel shells can be formed to have an arbitrary thickness.

In order to produce a molding die as shown in FIG. 1, the procedure shown in FIGS. 3 (a) to 3 (d) is followed. First, a metal master model 11 (or, for example, a mandrel made of heat-resistant epoxy resin) is prepared. Then, the metal master model 11
The first nickel shell 2 having an appropriate thickness is formed on the surface of the substrate by a chemical vapor deposition method.

Next, an elongated body having a substantially quadrangular cross section made of a low melting point alloy composed of Sn, Pb, Sb, Zn or the like is prepared, and as shown in FIG. 15 is brought into close contact with the first nickel shell 2 and fixed with a low melting point alloy or a heat resistant adhesive. When arranging this elongated body 15,
It follows a planar shape and layout in which cooling and heating of the molding die can be performed most efficiently. The cross-sectional dimension of the elongated body 15 is not limited to the cross-sectional shape shown in FIG. 3 (a) as long as the heating and cooling of the mold can be performed most efficiently.

At the stage of FIG. 3 (a), the surfaces of the first nickel shell 2 and the elongated body 15 are sandblasted, cleaned by pickling, and the first nickel shell 2 and the second nickel shell 2 are cleaned. 4 and the long body 15 are preferable in order to strengthen mutual adhesion.

Next, as shown in FIG. 3B, a second nickel shell 4 is formed along the surface of the first nickel shell 2 and the surface of the elongated body 15 by a chemical vapor deposition method. The periphery of the body 15 is covered by the first nickel shell 2 and the second nickel shell 4.

Next, as shown in FIG. 3 (c), the first nickel shell 2 is released from the metal master model 11. Then, the entire mold was placed in an oven, and the elongated body 15 was heated and melted to a temperature equal to or higher than the melting point of the low melting point alloy constituting the elongated body, and the melt was subjected to a first melting process. It flows out of the nickel shell 2 and the second nickel shell 4, thereby forming an elongated space between the first nickel shell 2 and the second nickel shell 4, as shown in FIG. I do. This space functions as the temperature adjusting circuit 16. Thus, a molding die 33 having a configuration similar to that of the molding die 13 of FIG. 1 is obtained.

According to such a molding die and a method of manufacturing the same, the shape of the first nickel shell 2, that is, the predetermined product shape, is immediately passed through the first nickel shell 2 which is a chemical vapor deposition film. Since the temperature adjustment circuit 16 can be arranged,
When molding using a mold, the cooling and heating efficiency of the mold can be greatly improved, and thus the productivity in the molding process is greatly improved.

Further, the number of steps for arranging the temperature adjusting circuit can be reduced, and the time and cost for manufacturing the mold can be greatly reduced. Furthermore, since the cross-sectional shape and cross-sectional dimension of the temperature adjusting circuit can be arbitrarily changed, a rational circuit design suitable for the purpose of use of the mold can be performed.

Also, unlike the conventional electroforming method, the sum of the thickness of the first nickel shell 2 and the thickness of the second nickel shell 4 can be made 10 mm or more by the chemical vapor deposition method. In this case, the strength of the molding dies 13 and 33 is much higher than in the case of electroforming, so that blow molding and injection molding are also possible.

In the above, it is preferable that the thickness of the first nickel shell 2 be 1 mm or more and 20 mm or less. In order to deposit the nickel shell on the entire surface of the mandrel or the master model, a deposition thickness of 1 mm or more is required. Also, when the thickness of the first nickel shell 2 exceeds 20 mm,
The distance between the temperature adjustment circuit 16 and the surface of the molding die increases, and the thermal efficiency deteriorates.

The melting point of the low melting point alloy forming the elongated body 15 is preferably 210 ° C. or higher. If the temperature is lower than 210 ° C., the low melting point alloy is melted by the heating temperature (about 200 ° C.) when forming the second nickel shell 4. However, finally, at the stage of FIG.
The lower the temperature, the better the workability is, and the thermal distortion of the nickel shell can be avoided.
Therefore, this temperature is preferably as low as possible above 210.degree. C., but in practice, if it is below 500.degree. The following can be exemplified as such a low melting point alloy. Pb (327 ° C), Sn (232 ° C) 96.5% Sn-3.5% Ag (221 ° C) 80% Pb-17.5% Cd-2.5% Sb (236 ° C) Zn-5% Al (382 ° C) 87% Pb- 13% Sb (247 ° C) (): melting point.

It is preferable that the thickness of the second nickel shell 4 be 1 mm or more and 10 mm or less. The thickness of the shell 4 needs to be 1 mm or more in order to completely cover the elongated body 15 and firmly fix it, and from the viewpoint of heat transfer efficiency. However, it is sufficient if the thickness of the second nickel shell 4 is at most 10 mm, and this is not necessary.

The sum of the thickness of the first nickel shell 2 and the thickness of the second nickel shell 4 is preferably 2 to 30 mm. If it is less than 2 mm, the strength required for a molding die cannot be obtained. On the other hand, if it exceeds 30 mm, it takes a long time to form a nickel shell during chemical vapor deposition, and it becomes difficult to shorten the delivery time.

Hereinafter, an example in which a blow molding die is actually manufactured will be described. (Example: Example of FIG. 3) First, a metal master model 11 made of pre-hardened steel for a mold is used.
Was prepared. The part to be parted of the molding die was also reflected in the metal master model 11. The dimensions of the metal master model 11 were 300 mm × 200 mm. Oils and fats, stains, and the like adhering to the surface of the metal master model were washed with an organic solvent. Further, the metal master model 11 was heated in an oven at 220 ° C. to 250 ° C. to remove minute deposits such as cutting oil.

Next, the metal master model 11 was set in a chemical vapor deposition apparatus, and the first nickel shell 2 was formed as described above. The thickness of the first nickel shell 2 was 5 mm, the deposition rate of nickel was 2.5 mm / 10 hours, and the deposition time was 12 hours.

A low melting point alloy (melting point: 24% by weight of Pb: 87% by weight, Sb: 13% by weight) having a square cross section of 9 mm × 9 mm.
7 ° C.), and these long bodies 15 are closely adhered to the entire first nickel shell 2 at a pitch of 20 mm and soldered to the shell 2 by Sn. Fixed.

Next, a second nickel shell 4 was formed by chemical vapor deposition (thickness: 5 mm). Next, the metal master model 11 is taken out of the chemical vapor deposition apparatus, and the nickel shells 2 and 4 are heated to about 100 ° C.
The metal master model 11 and the first nickel shell 2 were separated by utilizing the difference in thermal expansion between 11 and nickel.

Thereafter, the entire nickel shell was heated to 300 ° C. to elute the rectangular rod-shaped elongated body 15 made of a low melting point alloy, thereby obtaining a molding die.

The time required to form the first and second nickel shell layers was 12 and 24 hours, respectively.

(Comparative Example) On the other hand, as a comparative example, an attempt was made to produce a first 3 mm thick nickel shell layer by nickel electroforming using the same master model. It took 20 days to do so. In this case, the thickness of the nickel shell was also uneven. In particular, the amount of nickel deposited in the concave portions is small, and conversely, a large amount of nickel is deposited in the convex portions.
During electroforming, it was necessary to manually remove a large amount of the deposited portion.

The molding die and the method of manufacturing the same according to the present invention
The present invention can be applied to molds for injection molding, blow molding, RIM molding, powder slush molding, FRP molding and the like, and to a method for producing the same.

[0034]

According to the molding die and the method of manufacturing the same according to the present invention, since the first and second nickel shells are formed by the chemical vapor deposition method, the shell manufacturing speed is high, and It is also easy to increase the strength of the molding die by increasing the thickness.

Further, since the temperature adjusting circuit can be provided in the molding die by the relatively simple procedure as described above, the number of steps for arranging the temperature adjusting circuit can be reduced, and the production of the die can be reduced. Time and cost can be greatly reduced.

Further, the layout of the temperature adjusting circuit in the molding die can be determined simply by adhering and fixing a long body made of a low melting point alloy prepared in advance to the first nickel shell. Since the cross-sectional shape and cross-sectional dimension of the circuit for use can be determined in advance at the stage of the elongated body, a rational circuit design suitable for the purpose of use of the molding die can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a molding die manufactured by the present invention.

FIG. 2 is a schematic view showing an apparatus used for forming a nickel shell by a chemical vapor deposition method.

FIGS. 3 (a), (b), (c) and (d) are cross-sectional views showing respective manufacturing steps when manufacturing a molding die according to the manufacturing method of the present invention.

[Explanation of symbols]

2 First Nickel Shell 4 Second Nickel Shell 11 Metal Master Model 13, 33 ... Molding Mold 15 Long Body Made of Low Melting Point Alloy 16 Temperature Control Circuit (Leaching of Long Body 15 (Space formed in nickel shell) 22 Resin mandrel or metal master model 26 Nickel deposited film (nickel shell) A Flow of gas containing nickel compound B Flow of heating medium

Claims (1)

(57) [Claims] 1. A step of forming a first nickel shell on a resin mandrel or a metal master model by chemical vapor deposition; adhering a long body made of a low melting point alloy to the surface of the first nickel shell. Fixing, forming a second nickel shell by a chemical vapor deposition method along the surface of the first nickel shell and the surface of the elongated body, the periphery of the elongated body of the first nickel A step of covering the shell with the second nickel shell; a step of releasing the first nickel shell from the resin mandrel or the metal master model; and The mixture is heated to a temperature and melted, and the molten material flows out of the first nickel shell and the second nickel shell, whereby the first nickel shell and the Forming a temperature adjusting circuit between the secondary nickel shell mold manufacturing method of.