JPH0111449Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold having a liquid flow path for cooling or heating a cavity.

For example, in a plastic mold with a cavity formed by electroforming, a copper or stainless steel pipe, etc., is closely placed along the back side of the cavity to shorten the molding cycle.
Cooling water or hot oil for heating is passed through the pipe. Such a cavity is usually used after being fixed to a formwork and then lined by filling the back side of the cavity with a filler such as zinc alloy or epoxy resin. However, in such a conventional structure, the filler has a considerable heat capacity, so it takes time to heat and cool the cavity, and the heat dissipates from the outer surface of the filler during heating, which requires a lot of energy and time. There is.

The present invention was developed in view of the above circumstances, and its purpose is to reduce heat radiation to the back side of the cavity as much as possible, shorten heating time, and reduce cooling time at the same time. The object of the present invention is to provide a mold that can shorten the molding cycle and reduce energy loss.

An embodiment in which the present invention is applied to a mold for urethane foaming will be described below with reference to FIGS. 1 to 3. Reference numeral 1 denotes a cavity formed by nickel electroforming, and a flange portion 3 oriented outward is integrally formed at the opening edge of a molded portion 2 of this cavity by nickel electroforming. Reference numeral 4 denotes a copper pipe serving as a liquid flow path that curves in a meandering manner along the back side of the cavity 1, and is temporarily attached to the back side of the cavity 1 in a tight state by, for example, brazing. 5
is a copper electroformed layer formed by electroforming on the back side of the cavity 1 and the front surface of the copper pipe 4 after temporarily attaching the copper pipe 4, and this is in close contact with the cavity 1 and the copper pipe 4. Needless to say, it has been formed. 6 is a reinforcing frame fixed to the back side of the cavity 1 in a grid pattern by welding; 7 is a rectangular outer frame fixed to the flange portion 3 and the reinforcing frame 6 by welding; The end surface opposite to the cavity 1 is closed by an end plate 8 that is liquid-tightly fixed to the outer frame 7 by welding or the like, and the outer frame 7 and the end plate 8 cooperate with the back side of the cavity 1 to The formwork 9 forms two spaces. Therefore, the inside of the formwork 9 has eight hollow chambers 10 partitioned by the reinforcing frame 6. Reference numeral 11 denotes a communication hole as a communication portion bored in the reinforcing frame 6 so as to communicate the hollow chambers 10 with each other;
12 and 13 are inflow holes and outflow holes provided in the outer frame 7. Thus, with the above configuration, the mold 14
This mold 14 is used as an upper mold, for example, and a lower mold corresponding to the upper mold is formed in the same manner as described above (not shown), and these molds form a set of urethane foam moldings. Configure the type.

Now, when the mold for urethane foaming configured as described above is attached to a molding machine to mold a molded object, hot oil is poured into the copper pipe 4 from one open end as shown by arrow A. The cavity 1 is heated by letting the hot oil flow in and discharging the hot oil from the other open end. During this heating, there is no liquid in each hollow chamber 10, and the hollow chamber 10 forms an insulating air layer on the back side of the cavity 1, thereby preventing heat radiation to the back side of the cavity 1 as much as possible. Then, when the temperature of the cavity 1 is raised to a predetermined temperature, a resin material is supplied into the cavity 1. Next, all the hot oil in the copper pipe 4 is drained, and instead, cooling water is supplied from one open end of the copper pipe 4 as shown by arrow A, and is discharged from the other open end to open the cavity 1. At the same time, cooling water is supplied from the inflow hole 12 into the formwork 9 as shown by arrow B, and is discharged from the outflow hole 13. Thus, the cooling water entering one hollow chamber 10 in the formwork 9 from the inlet 12 flows through the communication hole 1.
1 to the adjacent hollow chambers 10, and is finally discharged from the outlet 13. However, as the cooling water vigorously passes through the communication holes 11, each hollow chamber 1
The cooling water is turned upside down and circulated inside the cavity 1, thereby effectively cooling the cavity 1 from the back side. That is, the cavity 1 is cooled by both the cooling water flowing through the copper pipe 4 and the cooling water flowing through each hollow chamber 10 in the formwork 9, and the temperature rapidly decreases.
The molded product inside the cavity 1 is cooled. After the molded product in the cavity 1 has been cooled to the mold release temperature, the mold is opened to take out the molded product, and the above-mentioned operations are repeated to produce the molded product.

According to the above configuration, since the hollow chamber 10 forms a heat insulating air layer when the cavity 1 is heated, the temperature of the cavity 1 is rapidly increased when hot oil is supplied into the copper pipe 4. That is, since there is no filler material equivalent to the conventional structure, the thermal energy possessed by the hot oil in the copper pipe 4 is exclusively used for heating the cavity 1, which is relatively thin and has a small heat capacity, and is also used to heat the cavity 1, which is relatively thin and has a small heat capacity. Since the heat radiation to the hollow chamber 10 is reduced as much as possible by the insulating air layer formed in the hollow chamber 10, the cavity 1 is heated to a predetermined temperature in a short time, and when cooling, the inside of the copper pipe 4 and the hollow chamber 10 are heated. Since the cooling water is allowed to flow through both the hollow chambers 10 and the plurality of hollow chambers 10 through the communication holes 11, heat exchange between the cavity 1 and the cooling water is performed extremely efficiently. 1 can be cooled in a short time. Therefore, the time required for heating and cooling the cavity 1 can be shortened, the molding cycle can be shortened, and energy loss due to heat radiation can also be reduced.

In the above embodiments, the present invention has been described as being applied to a mold for foaming urethane, but it can be widely applied to molds for molding other synthetic resins such as thermosetting resins, hot press molds, and the like.

Further, in the above embodiment, the cavity 1 was formed by electroforming, but it may be formed relatively thinly by casting, sheet metal, synthetic resin, etc. If it is formed from synthetic resin, the back side of the cavity 1 The copper electroformed layer 5 may be formed after conducting conductive processing on the copper layer.

Furthermore, in the above embodiment, the flow path was formed by attaching the copper pipe 4 to the back side of the cavity 1, but as shown in FIG. Use material 14 in cavity 1 instead of copper pipe 4.
The copper electroformed layer 5' is deposited on the back side of the filler 14 by brazing or other appropriate means, and then the cavity 1 is heated to a temperature higher than the melting point of the filler 14 to melt and remove the filler 14. The liquid flow path 15 may be formed by this.

In this case, the shape of the filler 14 is flat compared to the copper pipe 4 (see the two-dot chain line in FIG. 4), and is shaped so that it faces the inner surface of the cavity 1 over a wide area, thereby improving heating and cooling efficiency. It is possible. and,
In the above case, the removal of the filler 14 is selected as appropriate depending on the material, such as using an aluminum alloy for the filler 14 and chemically dissolving the filler 14 with an alkaline solution after forming the copper electroformed layer 5'. can do.

As is clear from the above description, the present invention reduces heat radiation to the back side of the cavity as much as possible, shortens heating time, and also reduces cooling time, thereby shortening the molding cycle and A mold that can reduce energy loss can be provided.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention, with Figure 1 being a longitudinal sectional view, Figure 2 being a sectional view taken along the - line in Figure 1, and Figure 3 being an exploded perspective view. , FIG. 4 is a partial cross-sectional view showing another embodiment of the present invention. In the drawing, 1 is a cavity, 2 is a molding part, 4 is a copper pipe (liquid flow path), 6 is a reinforcing frame, 7 is an outer frame, 8 is an end plate, 9 is a formwork, 10 is a hollow chamber, 11 is a communication 14 is a filling material, 15 is a liquid flow path, and 5' is a copper electroformed layer.

Claims (1)

[Claims for Utility Model Registration] 1. A cavity having a molded part, a liquid flow path provided on the back side of the cavity through which a liquid for heating or cooling the cavity flows, and the cavity being installed on one side. a formwork that cooperates with the back side of the cavity to form one space, and a formwork that is disposed inside this formwork so that one end is in contact with the back side of the cavity to form a plurality of hollow chambers. a reinforcing frame which is partitioned into sections and which reinforces the cavity under the load acting on the cavity during molding, and in which the plurality of hollow chambers act as an insulating air layer when the cavity is heated; a plurality of communicating portions arranged to communicate with each other so that liquid supplied into the mold frame during cooling of the cavity flows through the plurality of hollow chambers. 2. The mold according to claim 1, wherein the cavity is formed by electroforming.