JP2575675B2 - Method for producing styrofoam molding die - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a mold used for foam molding of a synthetic resin such as styrene foam.

[Prior art] Conventionally, for forming porous synthetic resin products such as styrofoam, steam is used in which pre-foamed raw material beads are supplied into a cavity of a mold, and steam is supplied to a chamber partitioned by the mold to heat and foam. The chest method is generally adopted, and this mold is made into a male mold and a female mold, and is used by being fixed to a frame box, respectively.

Then, as shown in FIG. 1 (I), a molding die is first made from a design drawing, and a cavity is formed by casting using the wooden mold, and then deburring the inner peripheral surface of the cavity. After the surface treatment described above, a mold was obtained.

[Problems to be solved by the invention]

However, due to the large number of processing steps, it takes a long time from ordering to shipping, and the production cost is extremely high due to the production of wooden molds and cast products.
mm or less, it takes foam molding time, that is, it takes time for heating and cooling, the amount of steam used for heating increases, and there is unevenness on the back of the mold, and moisture adheres after cooling. Since the amount is large and the drying time is long, the molding cycle is long in the foam molding operation, and there is a problem that the productivity cannot be increased due to heat loss and loss time.

The present invention provides a metal mold suitable for styrofoam molding, which can easily eliminate these conventional disadvantages, significantly reduce the cost of mold production, and improve productivity and cost by shortening the foam molding time. It is an object to provide a method for manufacturing a mold.

[Means for solving the problem]

In order to achieve the above object, in the present invention, from the surface of the aluminum alloy, magnesium alloy, or zinc alloy block to the thickness direction thereof, a recess having a thickness of 6 to 8 mm forming a cavity for synthetic resin foam molding or The convex portion is boring-cut with an NC processing machine, and the outer peripheral surface of the block is cut out along with the concave portion or the convex portion so as to have the same thickness to form a mold. Is attached to the front opening flange of the frame to form a chamber.

〔Example〕

To explain the embodiment of the method of the present invention, as shown in FIG. 1, the outer, inner and outer periphery of the light alloy block 1 is cut into the shape of a die product directly from a design drawing by a high-speed processing machine such as an NC processing machine. This is a molding die 3 which is subjected to cutting and has a concave portion or a convex portion capable of forming a cavity 2 suitable for molding a synthetic resin foam. In this case cut form blocks 1 of light alloy material to the shape and the cavity dimensions 2 adapted to blueprint the concave or convex portion in the thickness direction from the surface 1 ₁ of the aluminum alloy, the recesses or protrusions In addition, the outer peripheral surface is cut out so as to have the same thickness, thereby forming a mold 3. Reference numeral 3a denotes a cut-out portion that protrudes from an upper peripheral portion of the mold 3 in a horizontal outward direction in a flange shape.

Note that the block 1 is a block formed by drawing from a plate-like body, which is formed by boring a concave or convex portion with an NC processing machine, and is made of an aluminum alloy, a magnesium alloy, or a zinc alloy. The outer peripheral surface of the block is cut into uneven portions having a thickness of 6 to 8 mm forming the cavity 2 using a light alloy selected from one type.

The cut-out portion 3a of the mold 3 is attached to the front opening of the frame boxes 4, 4 facing each other as shown in FIG. In the state where the, 5 is formed, the bead-like foamed material of styrofoam is foamed to form a synthetic resin foam.

Since the shaving portion 3a is formed in the mold 3, when it is attached to the front opening of the frame box 4, the frame box 4
The mold 3 can be easily attached to the front opening flange of the mold. The mold 3 is provided with a number of small holes (not shown) for ventilation as necessary, and a part of the air is discharged from the cavity 2 by the suction effect of the vacuum mechanism, and the inside of the mold 3 is semi-depressurized. A series of molding cycles of a drying step of evaporating the moisture of the molded body after passing through a preheating step of replacing residual air in the mold with steam and a foaming and fusion step by secondary foaming are facilitated.

In other words, heating to give a dry molded product → water cooling, and then the inside of the mold is evacuated (-600 mmHg to -700 mmHg) to evaporate the water in the mold and simultaneously dry the inside of the mold and the product. It is.

In the drawing, 6 is a fluid supply pipe for steam or the like, 7 is a discharge pipe for drain or the like, and 8 is a raw material supply pipe for a foam material such as a raw material bead.

Incidentally, the cavity 2 is surface 1 ₁ so that the product surface to the block 1 is built in blueprint street machining machined, there is no uneven as the outer surface is processed into a predetermined thickness by machining out the back surface scuff The mold 3 is as described above.

〔The invention's effect〕

As described above, according to the present invention, from the surface of the aluminum alloy, magnesium alloy, or zinc alloy block to the thickness direction, a concave or convex portion having a thickness of 6 to 8 mm forming a synthetic resin foam molding cavity is formed. Boring is performed by an NC processing machine, and the outer peripheral surface of the block is cut out so as to have the same thickness along the concave or convex portions to form a mold. Since the chamber is formed by attaching it to the front opening flange of the body, complicated processes such as wooden mold processing, casting processing, and surface processing that were conventionally required are omitted, and the man-hour process from order receipt to shipping Is significantly reduced, and the production cost can be significantly reduced. In addition, the material of the mold can be stabilized with a light alloy, and the thickness of the mold
8mm thinner compared to conventional castings to obtain good heat transfer effect, greatly reduce foaming time, reduce steam usage and shorten heating / cooling time Becomes In addition, the mold has less irregularities on the back side of the mold and a smaller amount of water adhering after cooling than a cast product, so that the drying time in vacuum molding can be shortened and the molding cycle can be significantly improved. Further, since the frame box constituting the chamber also has an open front surface, the manufacturing process is easy. Further, a mold capable of producing an efficient foam molded product can be obtained. Furthermore, since the cut portion is formed in the mold, there is a remarkable effect that the mold can be easily attached to the front opening flange portion of the frame box when attached to the frame box.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention, and FIG. 1 is an explanatory view of a processing step, wherein I shows a conventional method and II shows a method of the present invention. 2 is a perspective view of a semifinished mold, FIG. 3 is a longitudinal sectional view thereof, FIG. 4 is a perspective view of a completed mold, and FIG. 5 is a longitudinal sectional view of a used state. 1 ... light alloy block, 2 ... cavity, 3 ... molding die, 3a ... cut-out part, 4 ... frame box, 5 ... chamber, 6 ... fluid supply pipe, 7 ... discharge Tube 8, material feed tube.

Claims (1)

(57) [Claims] 1. A wall thickness of 6 to form a synthetic resin foam molding cavity from the surface of an aluminum alloy, magnesium alloy, or zinc alloy block to its thickness direction.
An 8 mm concave or convex portion is bored with an NC processing machine, and the outer peripheral surface of the block is cut out along the concave or convex portion so as to have the same thickness to form a mold. A method for producing a styrofoam molding die, characterized in that a chamber is formed by attaching a face-cut portion to a front flange portion of a frame box.