JPH09141715A - Injection mold apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold apparatus reduced in wt., having sufficient strength and excellent in temp. control efficiency. SOLUTION: A cavity part 17 is formed in at least one of a fixed mold 11 and a movable mold 12 so as to permit a temp. control fluid L to flow and a cylinder device 24 operated in synchronous relation to the injection cylinder device 34 of an injection apparatus 30 is arranged to the temp. control circuit of the temp. control fluid L to apply pressure to the temp. control fluid L in synchronous relation to the injection apparatus at a time of the injection of a resin material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold device for injection molding.

[0002]

2. Description of the Related Art When a metal mold for injection molding is made of iron, the weight of a large product is as heavy as 10 to 50 tons, and heavy equipment such as a crane is used when it is transported or attached to an injection molding machine. It was necessary and costly and there was a problem in workability. Therefore, in recent years, the weight of the mold has been reduced as much as possible by using a light metal such as aluminum or aluminum casting as the material of the mold or thinning the mold.

However, even if the mold weight is reduced, the cavity surface must not be distorted by the resin pressure in the cavity during injection molding. Depending on the molded product, it is necessary to make the mold larger, and a mold that is lightweight and has sufficient strength is required. On the other hand, if the mold is made large, it takes a lot of time and energy to heat and cool the mold. Therefore, in order to improve the molding cycle of such a large product and reduce the manufacturing cost, the temperature control efficiency of the mold should be improved. It was essential to raise.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above problems, and it is an object of the present invention to provide an injection molding die which is lightweight, has sufficient strength, and is excellent in temperature control efficiency. It is what

[0005]

That is, the present invention provides:
A cavity is formed inside at least one of the fixed-side die and the movable-side die, and the cavity is configured to allow the temperature control fluid to flow therethrough, and the temperature control fluid is injected into the temperature control circuit. A cylinder device that operates in synchronism with an injection cylinder device of the apparatus is arranged to apply pressure to the temperature control fluid in synchronism with the injection device when injecting a resin material. Pertain to.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing an example of an injection molding apparatus having an injection molding die apparatus of the present invention, FIG.
Is an enlarged cross-sectional view of the mold part, and FIG. 3 is a cross-sectional view showing an example of the cavity.

4 to 6 show an example of injection molding using this mold apparatus. FIG. 4 is a schematic circuit diagram showing the temperature control state of the mold, and FIG. 5 shows the injection molding state. Circuit diagram, FIG. 6 is a circuit diagram showing a mold cooling state after molding.

First, FIGS. 1 and 2 show an injection molding apparatus having an injection molding die apparatus 10 of the present invention. The injection molding device includes a mold device 10 and an injection device 30.

The mold device 10 is composed of a pair of a fixed mold 11 and a movable mold 12, and a molded product cavity 28 is formed therein by closing the mold. The fixed mold 11 is attached to a fixed platen 14 via a fixed die mounting plate 13. Similarly, the movable die 12 is also attached to the movable plate 16 via the movable die mounting plate 15. A drive device (not shown) is provided on the movable platen 16, and the movable side mold 12 is moved forward and backward with respect to the fixed side mold 11 to open and close the mold. Depending on the shape of the molded product, a middle mold or the like may be placed between the fixed mold 11 and the movable mold 12.

The fixed mold 11 or the movable mold 12
A cavity 17 is formed inside at least one of the molds. The cavity 17 is provided to reduce the weight of the mold by making the mold thin (thickness stealing), and is formed on the entire back side of the mold surface forming the molded product cavity 28, as understood from FIG. . In this embodiment, the hollow portion 17
Is provided on both the fixed-side mold 11 and the movable-side mold 12.

The hollow portion 17 is a portion for not only reducing the weight of the die but also for adjusting the temperature of the die 10 by allowing the fluid L adjusted to a predetermined temperature to flow inside. , And has an inlet 18 and an outlet 19 for the fluid L. The inlet 18 and the outlet 19 are the temperature control circuit 2
Connected to 0. The temperature adjusting circuit 20 adjusts the temperature of the mold 10 by adjusting the temperature of the fluid L to a predetermined temperature and circulating and circulating the fluid L in the cavity 17 of the mold through the inlet 18 and the outlet 19. And a fluid supply unit 21, a fluid discharge unit 22, and a temperature control unit 23 including a known heater, cooler, and the like.

The fluid L flowing in the temperature control circuit 20 includes
A liquid whose temperature can be adjusted, such as water, oil or steam, is used. These fluids L are continuously, intermittently, or constantly supplied from the fluid supply unit 21. Then, the temperature is adjusted to a predetermined temperature by the temperature adjusting unit 23, and circulates and circulates in the cavity 17 of the mold and the temperature adjusting circuit 20,
The molds 11 and 12 are heated or cooled. The temperature of the fluid L can be appropriately determined according to the set temperature of the mold. Reference numerals A, B, C, and D in the figure denote switching valves.

As described above, in the mold device 10, at least the back side of the mold surface of the cavity 28 is thinned by the cavity 17 inside the molds 11 and 12. According to this structure, it is possible to make the weight much lighter than that of the conventional mold, and not only the mounting, replacement or transfer of the mold can be made more efficient, but also the mold can be easily enlarged. It will be possible.

Since the temperature control fluid L adjusted to a predetermined temperature is circulated in the cavity 17 through the temperature control circuit 20, the temperature control such as the temperature raising and cooling of the mold is extremely efficient. You can do it well. In particular, in the case of a large mold that requires a large amount of time and energy for the temperature control, by using the mold of the present invention, not only the molding cycle can be significantly shortened and the productivity can be improved, but also the energy It is extremely economical both in terms of cost and cost.

The fluid L flowing in the cavity 17
In order to improve the temperature control efficiency of the mold by
It is preferable to make the contact time between the inner wall and the fluid L as long as possible. FIG. 3 shows an example. A large number of projecting walls 17B, 17B, ... Are formed on the inner wall of the hollow portion 17A, and the fluid L is injected from the introduction port 18A and the discharge port 19A.
The contact area between the inner wall of the hollow portion 17A and the fluid L until the fluid is discharged is made as large as possible to extend the contact time.

By the way, if the cavity 17 is provided and the die is made thin, as described above, the cavity surface may not withstand the resin pressure at the time of molding and may be distorted. Therefore,
In the structure of the present invention, pressure is applied through the temperature control fluid L, and the mold 1 is thinned by the cavity 17.
Configured to protect 1,12. That is, in the temperature control circuit 20 through which the fluid L flows, a cylinder device 24 that pressurizes the liquid L is arranged. The cylinder device 24 is connected to the injection cylinder device 34 of the injection device 30 via a pressurizing circuit 26 as shown in the figure, and is operated in synchronization with the injection cylinder device 34 by a common drive unit 25. Is configured to.

As can be seen from the figure, the pressure increasing portions 24a and 34a of the two cylinder devices 24 and 34 and the pressure reducing portions 24b and 34b of the two cylinder devices 24 and 34 are connected by a pressurizing circuit 26, respectively. When the injection cylinder device 34 injects the resin material P, a predetermined pressure is applied by the cylinder device 24 to the fluid L filling and flowing in the cavity 17. As a result, resin pressure is applied to the mold cavity surface, and at the same time, the back surface of the cavity is pressed by the fluid L to prevent the molds 11 and 12 from being distorted by the resin pressure. The pressure applied to the fluid L by the cylinder device 24 is preferably balanced with the pressure of the resin material P in the cavity 28 at the time of injection. According to this structure, since the back surface side of the mold is pressurized and held by the fluid L, the strength of the mold is improved, and the thickness of the mold can be made thinner than that of a conventional mold having a thin wall. .

As shown in FIG. 1, the injection device 30 for injecting the resin material is operated by the injection cylinder device 34 to inject a predetermined amount of the resin material P into the cavity 28 of the mold device 10. A known structure can be used as the injection device 30, and thus detailed description thereof will be omitted. Reference numeral 31 is a heating cylinder,
32 is a screw and 33 is a nozzle.

Next, a method of manufacturing an injection-molded article using the mold apparatus of the present invention will be described with reference to FIGS. Note that, in order to clarify the operation of the present invention, illustrations of known mold structures such as a fixed platen and a movable platen are omitted. First, prior to molding, the mold 10 is heated to a predetermined molding temperature. As shown in FIG. 4, the temperature of the fluid L is raised to a predetermined temperature by the temperature adjusting section 23 of the temperature adjusting circuit 20.
Distribute it inside. The fluid L reaches the cavity 17 in the mold via the inlets 18 provided in the fixed mold 11 and the movable mold 12. The fluid L raises the temperature of the mold cavity surface while filling the cavity 17 and flowing out from the discharge port 19. The temperature control circuit 20 opens the valve C of the valve A of the fluid supply unit 21, the valve B of the fluid discharge unit 22, and the valve D of the temperature control unit 23 until the mold 10 is heated to a predetermined molding temperature. Is closed to allow a certain amount of the temperature-controlled fluid L to circulate in the temperature control circuit 20.

Subsequently, while the temperature of the mold is being raised by the fluid L or after the temperature is completed, the fixed side mold 11 and the movable side mold 12 are closed. When the mold temperature reaches the set value, the valve C of the temperature control circuit 20 is closed and the fluid L
Stop circulation. Thereafter, the molds 11 and 12 are further clamped, and as shown in FIG. 5, a predetermined amount of the resin material P is injected from the injection device 30 into the molded product cavity 28. At that time, the cylinder unit 24 of the pressurizing circuit 26 is driven by the drive unit 25 so that the injection cylinder unit 34 of the injection unit 30 is driven.
And the fluid L in the temperature control circuit 20 is pressurized simultaneously with the injection of the resin material P from the injection device 30.
Since the valves A, B and C for opening the temperature control circuit 20 are all closed, the fluid L in the pressurized circuit presses the inner wall of the mold cavity 17. As described above, the amount of pressurization of the inner wall of the cavity 17 by the fluid L is measured by the pressure gauge 2
9 and the like so as to balance and pressurize the resin pressure injected from the injection device 30.
The die made thin by 7 is held so as not to be distorted by the resin pressure. The temperature control fluid of the temperature control unit 23 is circulated by opening the circulation valve D.

After the injection of the resin material P is completed, the mold is cooled. As shown in FIG. 6, the valve A of the fluid supply unit 21 and the valve B of the fluid discharge unit 22 of the temperature control circuit 20 are opened, and the cooling fluid L is continuously passed from the fluid supply unit 21. To cool the mold.

When the mold is sufficiently cooled after a predetermined cooling time, the valve A of the fluid supply unit 21 is closed to finish cooling the mold. Then, as shown in FIG. 4, the mold 1
1 and 12 are opened and the molded product is taken out from the cavity 28. Then, in the case of continuously producing the molded product, as described with reference to FIG.
Is circulated to raise the temperature of the mold to a predetermined temperature.

[0023]

As shown and described above, according to the injection molding die apparatus of the present invention, it is possible to make the die much lighter than the conventional one. Therefore, the workability at the time of manufacturing a molded product is extremely excellent, and even if the mold becomes large, equipment such as a crane is unnecessary. Moreover, since the temperature of the mold can be controlled extremely efficiently, the molding cycle can be shortened and the productivity can be improved.
Therefore, especially when the mold is large, such as in the manufacture of large-sized molded products, it is difficult to reduce the cost because the equipment cost and energy cost for temperature adjustment are bulky. By using it, it is possible to significantly reduce the cost required for manufacturing a molded product and perform economical molding. In addition, by disposing a cylinder device that synchronizes with the injection cylinder device, the temperature control fluid is pressurized and the mold cavity surface is held from the back side in synchronization with the injection device when the resin material is injected, so the mold is made even thinner. In addition, it is possible to impart a die strength that sufficiently withstands the resin pressure of the resin material.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an example of an injection molding device having an injection molding die device of the present invention.

FIG. 2 is an enlarged cross-sectional view of the die part.

FIG. 3 is a cross-sectional view showing an example of a hollow portion.

FIG. 4 is a schematic circuit diagram showing a temperature control state of a mold.

FIG. 5 is a schematic circuit diagram showing an injection molding state.

FIG. 6 is a schematic circuit diagram showing a cooling state of a mold.

[Explanation of symbols]

 10 Mold Device 11 Fixed Side Mold 12 Movable Side Mold 17 Cavity 20 Temperature Control Circuit 21 Fluid Supply 22 Fluid Exhaust 23 Temperature Control 24 Cylinder 26 Pressure Circuit 30 Injection Cylinder 34 Injection Cylinder L Fluid

Claims (1)

[Claims] 1. A cavity is formed inside at least one of a fixed-side mold and a movable-side mold, and the temperature-regulating fluid is made to flow through the cavity. An injection characterized in that a cylinder device that operates in synchronization with the injection cylinder device of the injection device is arranged in the temperature control circuit, and pressure is applied to the temperature adjustment fluid in synchronization with the injection device when the resin material is injected. Molding equipment for molding.