JPH0761670B2 - Mold surface heating device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an invention of a simple heating device capable of heating the surface of a mold to suppress the occurrence of defective products to a very small extent.

(Prior art and its problems) In conventional injection molding, there are a fixed mold and a movable mold, and the resin melted from the extruder on the fixed mold side enters the mold cavity during mold clamping of both molds. It was said that when the resin was injected and the resin was cured, the mold was opened and the molded product was taken out. In this case, the resin temperature (about 250 ° C) and the mold temperature (8
Since the difference between the temperature and the temperature of the mold is large, when a hot resin comes into contact with the surface of the cold mold, a thin skin is immediately generated on the surface. There was a drawback that fine wrinkles were generated on the surface along the flow of resin and the surface condition deteriorated, and as a result, the surface of the molded product had to be painted. This tendency is particularly large when a composite material of glass fiber or carbon fiber and resin is used.

(Object of the present invention) The present invention has been made in view of the drawbacks of the conventional example, and the object of the present invention is to clean the mold surface quickly, easily and easily at low cost, and to obtain the surface of the molded product. It is an object of the present invention to provide a mold surface heating device which is remarkably excellent in the improvement effect.

(Means for Solving the Problems) In order to achieve the above object, in the present invention; the halogen bulb (2) is provided in the storage window portion (5) of the frame member (4).
To place.

A coolant flow passage (6) is formed in the frame material (4).

The wiring material (7) of the halogen bulb (2) is arranged in the coolant flow passage (6).

The technical means called; is adopted.

(Operation) A heating device (3) having a halogen bulb (2) arranged in the mold opening of the die (1) is inserted between the dies (1), and the halogen bulb (2) is turned on to turn on the die (1). ) Heat the surface.

As a result, the surface temperature of the mold (1) rises to 110 ° C to 130 ° C.

After that, remove the heating device (3) from between the molds (1),
Close the mold (1).

After the mold is clamped, the molten resin is injected to mold the die, but the temperature difference between the hot molten resin and the surface of the die (1) becomes small, and wrinkles do not occur on the surface of the molded product.

Here, the heating device (3) is exposed to high temperature due to the heat generation of the halogen bulb (2) and the radiant heat of the mold (1), but the coolant flow passage (6) is formed in the frame material (4), and , The wiring material (7) of the halogen bulb (2) is the coolant flow path (6)
The wiring material (7) does not deteriorate because it is disposed inside.

(Examples) The present invention will be described below with reference to illustrated examples. 2 and 3 are a partially cutaway front view and a partially cutaway side view of a heating device (3) according to the present invention. (4) is a frame member (4) made of aluminum and having a hollow shape, and this hollow portion is a coolant flow passage (6). A storage window portion (5) is opened in the center of the frame member (4), and the straight tube halogen light bulbs (2) are arranged side by side on the outer surface side of the storage window portion (5). A halogen bulb (2) is installed in the coolant flow passage (6) in the frame material (4).
The wiring material (7) is provided and connected to the terminal (8) provided on the end surface of the frame material (4). Further, a cooling valve (9) is provided near the terminal (8), and a cooling tube (11) arranged so as to circulate in the coolant flow passage (6) is connected to the cooling valve (9). is there. Outside the halogen bulb (2) is a protective wire mesh (10)
Are arranged and bolted to the frame member (4).

In injection molding, there is a fixed mold (1a) and a movable mold (1b), and the resin melted from the extruder on the side of the fixed mold (1a) during mold clamping of both molds (1) is the mold (1). The mold is opened when the resin is injected into the cavity of the mold and the molded product is taken out. A pair of heating devices in which the halogen bulb (2) is arranged in the mold opening of the mold (1) ( 3) is inserted between the molds (1), the halogen bulb (2) is turned on, and the surface of the mold (1) is heated to about 110 to 130 ° C in a short time. After that, the heating device (3) is pulled out from between the molds (1), the molds are quickly clamped, and the molten resin (about 250 ° C.) is injected from the extruder into the cavity of the molds (1). However, since the difference between the resin temperature and the surface temperature of the mold (1) is relatively small, the resin surface in the fluid state does not have a thin skin, and the resin cures when the fluid state is stopped, and glass fiber or carbon A molded product having an extremely smooth surface state can be obtained even with a material such as a composite material of fiber and resin, which is easily wrinkled on the surface.

(Effect of the present invention) As described above, the present invention inserts a heating device in which a halogen bulb is arranged in the mold opening between molds to heat the surface of the mold, and then the heating device is installed. Since it is extracted from between molds and clamped before molding, the difference between the resin temperature and the mold surface temperature is much smaller than before, and the molten state immediately after being injected into the mold. There is no such thing as a thin skin being immediately generated even if the resin of the above comes into contact with the mold surface, and as a result, an extremely smooth surface is obtained without wrinkling or shrinkage of the surface of the molded product. There is an advantage that you don't need any finishing paint. In addition, the heating rate of the mold surface is extremely fast because it is heated by a halogen bulb, and it does not cause deterioration of the working environment, and at the same time, it does not require large-scale equipment such as induction heating and the equipment cost is also high. It has the advantage of being extremely inexpensive.

Further, since the wiring material of the halogen bulb is arranged in the coolant flow passage, even if the entire apparatus is exposed to high temperature, the wiring material is kept at a relatively low temperature and is not deteriorated.

[Brief description of drawings]

 FIG. 1 ... Front view for explaining the usage state of the present invention FIG. 2 ... Front view of a heating device used in the present invention in a partially cutaway view FIG. 3 ... Side view of partially cutaway view in FIG. 2 (1). Mold, (1a) …… Fixed mold (1b) …… Movable mold, (2) …… Halogen bulb (3) …… Heating device, (4) …… Frame material (5) …… Storage window, (6) …… Coolant flow passage (7) …… Wiring material, (8) …… Terminal (9) …… Cooling valve, (10) …… Protective wire mesh

Claims (1)

[Claims] 1. A heating device, in which a halogen bulb is arranged during mold opening, is inserted between the molds to heat the surface of the molds, after which the heating device is pulled out from between the molds and the molds are clamped. After heating the mold surface, it is a mold surface heating device.Halogen bulbs are placed inside the window of the frame material, a coolant flow passage is formed in the frame material, and the wiring material of the halogen bulb is circulated through the coolant. A mold surface heating device characterized by being arranged in a passage.