JPS62113521A - Powder resin molding device - Google Patents

Abstract

PURPOSE:To permit to reduce the ununiformity of the temperature of a mold and effect the cooling and heating of the mold quickly by a method wherein the mold is constituted of first metallic body, providing a molding surface having characteristics necessary for the molding of resin, and second metallic body, provided on the outer surface of the first metallic body and having a good heat conductivity. CONSTITUTION:A mold 1, contacting with powder resin and heating it to melt is, and an induction heating coil 2 for heating the mold 1 are provided. The mold 1 is consisting of a first metallic body 3, formed with a melting surface 3A, at least contacting with the powder resin and melting it, and second metallic body 4, provided on the outer surface of the first metallic body 3 and connected to the same. Here, the first metallic body 3 is preferable to be prominent in resistances to corrosion and wearing, mold releasing property of molded products and the like and nickel is the optimum from these points. On the other hand, the second metallic body 4 is preferable to be a metal having largest possible heat conductivity and copper, for example, is the optimum. When the induction heating of the mold 1 is effected by the induction heating coil 2 and the temperature thereof is increased to a predetermined temperature, the powder resin is sprayed on the inner surface 3A of the mold and is molten on the inner surface 3A. Thereafter, the mold 1 is cooled by water cooling by water spray or air cooling by blowing air or the like, then, the molten resin is cured and is released from the mold whereby the molded products of the resin may be manufactured.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an apparatus used for powder resin molding.

[Conventional technology]

Powder resin molding is currently known as a method for manufacturing instrument panels used in automobile parts.

In this powder resin molding, a nickel metal mold with a thickness of approximately 3.5 mol/m is used and a heat transfer pipe is welded to the outer surface.

By flowing high temperature oil into this heat transfer pipe, the mold is
The mold is heated to about 20°C, PVC resin powder (e.g. polyvinyl chloride) is sprinkled on the inner surface of the mold, the powder in contact with the inner surface of the mold is melted, and then the mold is cooled to harden the resin and molding is performed. Is going.

Nickel is used as the mold material here.

This is because it has advantages such as not rusting, good demoldability of molded products, and fine patterns that do not disappear.

[Problem that the invention seeks to solve]

However, in such conventional molds, the thermal conductivity of nickel that constitutes the mold is low, resulting in uneven temperature distribution.
For example, the part that is in contact with the heat medium pipes is heated to a high temperature, but the temperature of the part between the pipes is low, which causes a problem in that the thickness of the molded product is likely to be uneven. In addition, the heat transfer capacity of the mold is low, so heating is not possible.

It takes a long time to cool down, poor productivity, and when making molded products with irregular shapes, it is difficult to install a heating device, resulting in even more uneven temperature distribution and poor product quality. There were also problems.

The present invention has been made in view of such conventional problems.
An object of the present invention is to provide a powder resin molding apparatus that can reduce temperature unevenness in a mold and quickly perform heating and cooling.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention has been developed to provide a metal body with low thermal conductivity such as nickel that forms the inner surface of the mold, that is, the melting surface that melts in contact with the powdered resin, that is, the molding surface. The metal body 1, which has good thermal conductivity, such as copper, is provided by being bonded by thermal spraying, plating, lining, brazing, etc.

[Effect]

In the present invention, as described above, since a metal with good thermal conductivity is bonded to a metal with poor thermal conductivity, the overall heat conduction is improved and an even and stable temperature distribution can be obtained.

Enables rapid heating and cooling. Also, depending on the shape of the mold, there may be areas that are difficult to heat, which can lead to uneven temperatures, but in areas that are difficult to heat, we can increase the thickness of the metal body, which has good heat conductivity, or change the material.

More uniform heating becomes possible. For heating the mold, it is also possible to use piping through which a heat medium passes, as in the past.

Alternatively, high-speed heating such as heating by combustion gas or high-frequency induction heating may be used. When induction heating is used, rapid and uniform heating is possible, and further uniformity of the mold can be achieved by adjusting the distance between the induction heating coil and the outside surface of the mold, or by adjusting the winding spacing of the induction heating coil. heating is possible. Furthermore, it is also possible to bond a ferromagnetic metal piece or solid to parts of the mold that are difficult to heat or require a large amount of heat to increase the amount of heat generated and to achieve uniform heating.

〔Example〕

The present invention will be described in detail below with reference to the three drawings.

FIG. 1 is a cross-sectional view of an embodiment of the present invention, and FIG. 2 is a schematic perspective view of the whole. The powder resin molding apparatus of the present invention includes a mold 1 that contacts and heats powder resin to melt it; The mold 1
It has an induction heating coil 2 that is provided on the opposite side of the mold 1 and heats the mold 1. The mold 1 includes at least a first metal body 3 forming a melting surface 3A that contacts and melts powdered resin, and a second metal body 4 bonded to the outer surface of the first metal body 3. As mentioned above, the first metal body 3 forms the melting surface for melting the powdered resin, that is, the molding surface, so it is desirable that it has excellent corrosion resistance, abrasion resistance, demoldability of molded products, etc.
From these points of view, nickel is preferred. On the other hand, the second metal body 4 is provided to prevent a large temperature distribution from occurring if only the first metal body 3 is used, and is preferably made of a metal having as high thermal conductivity as possible, such as copper. The second metal body 4 is formed by coating or thermal spraying.

Lining, raw material, etc. are possible, but there are other options as well.

Alternatively, the second metal body 4 may be made as a separate mold in advance and then joined to the first metal body 3. in this case,
It is preferable to inject brazing material between the first metal body 3 and the second metal body 4 to ensure reliable heat transfer between the two.

The thickness of the second metal body 4 does not need to be constant over the entire mold; it may be thicker in areas that are difficult to heat or require a large amount of heat (for example, the protrusion 3a) than in other areas. It's okay. In this way, the amount of heat transfer can be increased, so that the heating temperature can be made uniform. Also.

A similar effect can be obtained by partially using a material with better thermal conductivity instead of increasing the thickness.

The induction heating coil 2 is placed on the outer surface of the mold 1.

It is arranged to inductively heat a desired position of the mold l.

This coil 2 is determined by the clearance with the mold or.

Since the amount of heat generated changes depending on the distance between the windings, the clearance and the distance between the windings are set so that the temperature difference generated in the mold 1 is within an allowable range. That is, in places where a large amount of heating heat is required, the clearance or the winding spacing can be made small, and in other places the temperature can be made uniform.

Note that by bonding and providing a ferromagnetic metal piece or solid to a necessary portion of the outer surface of the mold, it is also possible to increase the amount of heat generated by the induced current and to equalize the temperature.

The induction heating coil 2 is connected to a power source 5.

In the powder resin molding apparatus with the above structure, the induction heating coil J2
When the mold 1 is induction heated and the temperature rises to a predetermined temperature,
Resin powder is sprinkled on the inner surface 3A, and the powdered resin is melted on the inner surface 3A. After that, when the mold l is cooled by water cooling by water spray or air cooling by air blowing, the molten resin hardens, and then the mold is demolded.
A molded article is manufactured.

By the way, when heating a mold by induction heating, if the thermal conductivity of the mold is low, uniform heating is difficult.

It is difficult to design an induction heating coil (clearance to the mold, spacing between windings, etc.) to ensure uniform heating. Figure 3 shows the material of the mold 1 and the induction heating coil 2.
It is a figure which shows the result of measuring the temperature distribution of a metal mold|die by arrangement|positioning. In Fig. 3, the mold l has the same shape as that in Fig. 1, and is made of aluminum stainless steel.

+bl copper and (C) a composite material of stainless steel and copper are prepared, and the clearance from the mold and the winding interval are increased as the induction heating coil 2 goes up as shown in the figure.

We conducted a temperature rise test using this mold and coil.

Figure 3 shows fat, (bl, (0 curve obtained from the temperature curve shown as C1) (al is the stainless steel mold 1 curve fbl is the copper mold 1 curve (C1 is the stainless steel and copper composite mold) As is clear from this experimental result, if the thermal conductivity of the mold is low, such as stainless steel, the mold temperature will be uneven. However, by joining a material with good thermal conductivity to stainless steel, which has a low thermal conductivity, the unevenness of the mold temperature has been improved.For this reason, the design of the induction heating coil has been improved. This makes it possible to achieve uniform heating using an induction heating coil with a relatively simple structure.

In addition, although induction heating is used to heat the mold in the above embodiment, it is not limited to this, and any other heating method may be used. However, if the induction heating of the illustrated embodiment is used, Compared to heating using a normal heating medium, this method has the advantage of shortening the temperature raising and cooling times. That is, when using heat medium heating, there is a limit to the heating temperature of the heat medium.

Although the heating time cannot be shortened sufficiently, induction heating allows for rapid temperature rise by adjusting the output, and in the case of cooling, when using a heat medium, it tends to take time to replace the oil. 9 In the case of induction heating, cooling can be done quickly by simply spraying water, and the cooling rate can be shortened.

〔Effect of the invention〕

As described above, the present invention provides a mold used for molding powdered resin, which includes a first metal body that provides a molding surface with characteristics necessary for resin molding, and a second metal body that is provided on the outer surface and has good heat conduction. It has the demoldability and corrosion resistance required for molds.

The overall thermal conductivity can be increased without sacrificing wear resistance etc., which not only enables uniform heating and improves quality, but also reduces the time required for heating and cooling, increasing productivity. It has the effect of being able to improve the Furthermore, the apparatus of the present invention can be applied not only to melt molding of powdered resin, but also to heat molding of other metals, nonmetallic materials, and the like.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is a perspective view schematically showing the entire embodiment, and Fig. 3 is a diagram showing the results of temperature rise tests using molds made of various materials. be. ! -Mold 2-Induction heating coil 3-First metal body 3A-Book melting surface 4-Second metal body Patent applicant Daiichi Koshuha Kogyo Co., Ltd. Agent Patent attorney Kyo Matsu Sansho 1 Figure Onsen Figure 3 Procedural amendment July 12, 1988 Michibu Uga, Commissioner of the Patent Office 16 Indication of the case 1985 Patent Application No. 252674 2 Name of the invention Powder resin molding device 3 Person making the amendment Relationship to the case Patent Applicant address: 1-13-10 Tsukiji, Chuo-ku, Tokyo Name
Daiichi Koshuha Kogyo Co., Ltd. (Representative) Kosei Hirata 4, Agent ■1) 6 6. Number of inventions increased by amendment 0+1) The scope of claims will be amended as shown in the attached sheet. (2) “Thickness of the body” on page 4, line 20 of the specification
----" is corrected to "change the thickness and material of the body." (3) `` from line 14 to line 20 on page 6 of the specification.
A second metal body can be obtained. ” is corrected as follows. ``The thickness of the second metal body 4 does not need to be constant over the entire mold, and may be applied to areas that are difficult to heat or areas that require a large amount of heat (for example, the protrusion 3a).Ferromagnetic Alternatively, a material with better thermal conductivity may be partially used.'' 2. Claims (1) A mold that heats and melts powdered resin by contacting it. ,
The first metal body forms a melting surface that contacts and melts at least the powdered resin, and the first metal body is connected to the outer surface of the first metal body. A powder resin molding apparatus comprising: a second metal body having a higher thermal conductivity than the first metal body. (2) The powder resin molding apparatus according to claim 1, wherein the first metal body and the second metal body are joined by injecting a brazing material between the two. (3) In order to adjust the heating temperature of the first metal body, the thickness and material of the second metal body are made to vary depending on the location, according to claim 1 or 2. powder resin molding equipment. (4) The device for heating the mold comprises an induction heating coil provided on the outer surface of the mold. Powder resin molding equipment. (5) The powder according to claim 4, wherein the distance between the induction heating coil and the mold is varied depending on the location in order to adjust the heating temperature of the first metal body. Resin molding equipment. (6) In order to adjust the heating temperature of the first metal body, the distance between the windings of the induction heating coil is varied depending on the location, according to claim 4 or 5. powder resin molding equipment. (7) In order to adjust the heating temperature of the first metal body, a ferromagnetic metal piece or solid is bonded to a required portion of the outer surface of the mold near the heating induction coil. The powder dressing molding apparatus according to any one of Items 4 to 6 as described in Item 1. ”

Claims (7)

[Claims] (1) A first metal body comprising a mold that contacts powdered resin and heats it to melt it, and a device that heats the mold, the mold forming at least a melting surface that contacts and melts the powdered resin; , and a second metal body having a higher thermal conductivity than the first metal body, the second metal body being bonded to the outer surface of the powder resin molding apparatus. (2) The powder resin molding apparatus according to claim 1, wherein the first metal body and the second metal body are joined by injecting a brazing material between them. (3) In order to adjust the heating temperature of the first metal body, the thickness and material of the second metal body are made to vary depending on the location, according to claim 1 or 2. powder resin molding equipment. (4) The device for heating the mold comprises an induction heating coil provided on the outer surface of the mold. Powder resin molding equipment. (5) The powder according to claim 4, wherein the distance between the induction heating coil and the mold is varied depending on the location in order to adjust the heating temperature of the first metal body. Resin molding equipment. (6) In order to adjust the heating temperature of the first metal body, the distance between the windings of the induction heating coil is varied depending on the location, according to claim 4 or 5. powder resin molding equipment. (7) In order to adjust the heating temperature of the first metal body, a ferromagnetic metal piece or solid is bonded to a required portion of the outer surface of the mold near the heating induction coil. The powder molding device according to any one of items 4 to 6.