JPH02155708A - Manufacture of resin product - Google Patents

Abstract

PURPOSE:To form integrally a resin product of sophisticated shape by combining a metal piece with a bottom force to form cavity sections of sophisticated shape, rolling a thermoplastic resin sheet out of said mold, manufacturing a resin product wrapping the metal piece in and melting and removing the metal piece by heat treatment. CONSTITUTION:A metal piece C is fitted in a part of a bottom force 2 to form inner cavities 4 folded sophisticatedly inwards. The metal piece C is made of alloy of low melting metal. A heat softened thermoplastic resin sheet 5 is placed on the upper surface formed with the bottom force 2 and the metal piece C. When a top force cavity section 3 is in contact with the resin sheet 5 and pressure is applied continuously, the resin sheet 5 is rolled and flows into a side section space formed by a top force 1 and the bottom force 2 wrapping the metal piece C in. A resin product W wrapping in the metal piece C thus released is put in to an oil bath 7 to accelerate heat exchange between oil O and the metal piece C and also discharges a dissolved low melting point metal S out of the resin product W.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method suitable for manufacturing resin products of complex shapes from thermoplastic resin sheets.

(Prior Art and Problems) A method of manufacturing resin products by heating and softening a thermoplastic resin sheet and rolling-molding it using a mold is attracting attention because of its high productivity.

However, the above method cannot manufacture products with complex shapes (for example, shapes with large undercuts, complicated bends, or shapes with hollow parts, etc.) using only one unit, so multiple parts must be manufactured separately. These parts are then glued or welded to obtain a finished product.

For this reason, when manufacturing a resin product with a complicated shape, a plurality of mold devices are required, as well as work for gluing or welding the parts, which has caused many problems such as the need for skill in this work.

(Purpose) The present invention was made in view of the above problems, and provides a method suitable for manufacturing a resin product having a complicated shape by integrally forming a resin sheet.

(Means for solving the problem of space order) The present invention allows a metal piece made of a low-melting point metal to fit into the surface part of the lower mold in a manner that allows it to be cut out. A process of defining a complex-shaped cavity with a metal piece, and a thermoplastic resin sheet of a predetermined thickness that is cut into a predetermined shape and softened by heating on the upper surface of the mold formed by the lower mold and the metal piece. a step of placing an upper mold having an upper mold cavity portion relatively to the lower mold into which the metal piece is fitted, and the placed thermoplastic resin sheet; A step of molding a resin product that is rolled to extend into the complex-shaped cavity and enclose the metal piece, and a step of molding the resin product that encloses the metal piece after opening the upper mold and the lower mold. a step of taking out the product from the mold; a step of heat-treating the resin product enclosing the metal piece to melt and remove the metal piece;
It is characterized by consisting of the following.

(Function) By adopting the above solution, the present invention
It is possible to manufacture resin products with complex shapes by integrally cutting them out from resin sheets.

(Example) Embodiments of the present invention will be described in detail below based on the drawings.

In the state shown in Fig. 1, the upper mold (1) and the lower mold (2) are arranged vertically facing each other, and both molds (1) and (2) are supplied with hot water from a temperature controller (not shown). 30℃~6 by circulation
The temperature is controlled to 0°C.

Further, the upper mold (1) is formed with an upper mold cavity (3) into which a lower mold protrusion formed by the lower mold (2) and a metal piece (C) to be described later can be inserted. .

In this state, the metal piece (C) (
The metal piece (C) is made of 50% bismuth. The upper and lower molds (1) and (2) are made of a low melting point metal alloy of 25% lead and 25% tin, with a melting point of 93°C.
is heated to the same temperature (30° to 60°C).

In this state, the lower mold (2) and metal piece CC') (
A thermoplastic resin sheet (5) (polypropylene in the example) that has been cut to a predetermined thickness and shape and softened by heating in consideration of the capacity and deformed shape of the final product is placed on the upper surface of the mold formed by C). Sur.

The thermoplastic resin (5) was heated to 190 to 22 in the infrared heater.
It is heated to 0°C. For this reason, the temperature of the metal piece (C') is raised, but the metal piece (0) has a larger heat capacity and thermal conductivity than the resin sheet (5), and in addition, the metal piece (0) has a larger heat capacity and thermal conductivity than the resin sheet (5), and in addition, the metal piece (0) has a higher heat capacity and thermal conductivity than the resin sheet (5). Since the resin sheet (5) is required, there is no problem of the resin sheet (5) being melted and losing its shape.

In this state, quickly clamp the upper mold (1) against the lower mold (2) in the direction of the arrow (Fig. 3). When the sheet (5) is contacted and pressurized, the resin sheet (5) is rolled and rolled between the upper mold (1) and the lower mold (2) containing the metal piece (0) as shown in Fig. 4. When the fluid flows into the side space (part of the cavity) and is further pressurized, it flows to the tip of the internal cavity (4), resulting in the state shown in FIG. 5.

The molding pressure at this time was about 150%, and the mold was opened after about 40 seconds of curing time in the state shown in Figure 5, and the metal pieces (C) (C) were held in as shown in Figure 6. Take out the resin product (g).

The resin product (B) containing the metal pieces (C) and (C) taken out in this way is placed in an oil bath (7) in which oil (0) is heated to 110°C using a temperature 111 regulator (6).・During this time, change the position of the resin product (5) in the oil bath (7) to exchange heat between the oil (0) and the metal pieces (C). At the same time, the discharge of the melted low melting point metal (8) from the resin product (car) is promoted.

The oil (0) in the oil bath (7) is preferably ethylene glycol, but silicone oil, mineral oil, vegetable oil, etc. can also be used.

After the metal pieces (C) are thus melted and separated from the resin product (6), the resin product (5) is lifted from the oil bath (7) and cleaned as shown in FIG. In other words, water is sprayed from the cleaning nozzle (9) in the cleaning chamber (8) and the oil (O) adheres in the oil bath (7).
(ethylene glycol) is washed away.

In addition, when using other oils, it is preferable to use water or warm water to which a surfactant has been added.

Thereafter, the resin product (b) is drained and dried to obtain a product.

In the example, the upper mold (1) is concave, and the lower mold (2) is
Although the upper and lower molds are convex, the same effect can be obtained even if the upper and lower molds are turned upside down (the metal pieces are set in the lower mold).

(Effects) As is clear from the above description, the present invention combines metal pieces made of a low-melting point metal into a lower mold to define a complex-shaped cavity, and uses this mold to form a thermoplastic resin sheet. By rolling a resin product that envelops metal pieces, the metal pieces are melted and removed from the resin product through heat treatment, making it possible to manufacture resin products with complex shapes in single units. It has many benefits, such as not requiring any skill in the process and reducing manufacturing costs.

[Brief explanation of the drawing]

The figures are explanatory diagrams showing the implementation process of the present invention, in which Figure 1 is a sectional view of the upper and lower molds, Figure 2 is a sectional view of the upper and lower molds with metal pieces attached, and Figure 3 is the initial stage of mold closing. Figure 4 is a cross-sectional view showing the state immediately before the mold closes, Figure 5 is a cross-sectional view showing the state at the end of mold closing, and Figure 6 shows the oil bath and metal piece holding resin product. FIG. 7 is a cross-sectional view showing the cleaning state of the resin product. (1) Double mold (2): Lower mold (5): Thermoplastic resin sheet (7) Two Oil bath (C):
Metal piece (0) Nioil (6): Resin product Answer 1 Diagram 2 Police map Vine 6 Figure lol

Claims (1)

[Claims] A metal piece made of a low-melting point metal is fitted onto the surface of the lower mold so that it can be cut out, thereby defining a complex-shaped cavity by the partial surface of the lower mold and the metal piece. In the process, on the upper surface of the mold formed by the lower mold and the metal piece,
A step of placing a thermoplastic resin sheet of a predetermined thickness that has been cut into a predetermined shape and softened by heating, and placing an upper mold having an upper mold cavity relative to the lower mold into which a metal piece is fitted. rolling the thermoplastic resin sheet that has been fitted and mounted so as to extend into the complex-shaped cavity, thereby molding a resin product that envelops a metal core; After opening the upper mold and the lower mold, a step of removing the resin product enclosing the metal piece from the mold, and a step of heat-treating the resin product enclosing the metal piece to melt and remove the metal piece. A method for manufacturing a resin product consisting of