JPH08118426A - Hot-runner device - Google Patents

Abstract

PURPOSE: To eliminate the heat absorbed and released between a manifold and hot chips and make the fully independent temperature controlling of each hot chip possible by a method wherein a heat insulating plate is provided between the manifold and each hot chip. CONSTITUTION: The nozzle 1 of a molder can be moved to the directions indicated with the arrows so as to come into contact with a sprue bushing 2 at molding. The resin melted in the injection molding machine is poured through the nozzle 1 of the machine and passed through the resin passages of the sprue bushing 2 and of a manifold. In the manifold 4, heaters and temperature sensors are built so as to keep the resin under molten state at all times. The resin passed through the manifold 4 arrives a hot chip A7 or a hot chip B8. In the respective hot chips, heaters and temperature sensors are built similarly in the manifold 4. Further, each hot chip is prevented from being influenced by the temperature of the manifold 4 by means of a heat insulating plate 6. Thus, the temperature of each hot chip can be fully independently controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot runner device, and more particularly to a hot runner device for a multi-point gate or a multi-cavity injection molding die.

[0002]

2. Description of the Related Art Conventionally, hot runner systems have been used in plastic injection molding dies for the purpose of saving molding materials and improving productivity by eliminating runners.

FIG. 3 is a cross-sectional view showing an example of an injection mold using a conventional hot runner system. The hot runner system includes a manifold 2, a hot chip 4, and a heat insulating plate 5 shown in FIG. . This manifold 2
And the hot chip 4 has a built-in heater and a temperature sensor for adjusting the amount of heat, respectively.
The manifold 2 and the hot chip 4 have a mechanism for maintaining a target temperature. Further, the heat insulating plate 5 is attached to almost the entire upper and lower surfaces of the manifold 2, and the fixed side mounting plate 1 and the fixed side mold plate 3 are in contact with the heat insulating plate 5 with almost no gap. Accordingly, the fixed-side mold plate 3 is prevented from flexing during molding to eliminate the generation of burrs, and the heat is uniformly discharged from the manifold 2 to the fixed-side mounting plate 1 and the fixed-side mold plate 3, thereby preventing the occurrence of flow marks. doing. (For example, Japanese Patent Laid-Open No. 5-
No. 185471)

In the above-mentioned conventional hot runner device, although the fixed mold and the manifold are insulated, the temperature of the manifold and the hot tip can be adjusted separately. However, since the hot chip was completely in close contact with the manifold, the actual temperature of the hot chip was greatly affected by the manifold temperature, and it was difficult to provide a heating condition that caused a temperature difference between the two.

[0004] Therefore, although the temperature can be made uniform as a molding condition, there is a drawback that it is difficult to make a temperature difference between the hot chip and the hot chip in the case of a manifold and a multipoint gate.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate heat inflow and outflow between each hot chip and a manifold, and to carry out temperature control completely independently of each other. Therefore, the hot runner device of the present invention achieves the above object by using a heat insulating plate between the manifold and each hot chip.

[0006]

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention. In FIG. 1, the sprue bush 2 is screwed to the manifold 4, and the hot chips A 7 and B 8 are screwed to the manifold 4 via the heat insulating plate 6.

The sprue bush 2, the manifold 4, the heat insulating plate 6, the hot chip A 7, and the hot chip B 8, which have been screwed, are fitted into spaces fixed by the fixed molds A 3 and B 9, and are positioned by the positioning ring 13. Accurate positioning. In addition, the tips of the hot chips A7 and B8 are connected to a space provided between the fixed mold B9 and the movable mold 12 (the molded product A10 and the molded product B1 in FIG. 1).
Connected to 1).

Next, the operation of FIG. 1 will be described. The molding machine nozzle 1 is movable in the direction of the arrow in the figure, and contacts the sprue bush 2 during molding. The resin melted in the injection molding machine is injected from a molding machine nozzle 1 and passes through a resin flow path inside a sprue bush 2 and a manifold 4. The manifold 4 has a built-in heater and temperature sensor, Is always in a molten state. The resin that has passed through the manifold 4 reaches the hot chip A7 or the hot chip B8. Each hot chip has a built-in heater and a temperature sensor similarly to the manifold 4, and is further affected by the temperature of the manifold 4 by the heat insulating plate 6. Therefore, completely independent temperature control is performed.
Here, if a temperature difference of Δt ° C. is given between the temperature of the hot chip A7 and the temperature of the hot chip B8, a difference occurs in the viscosity of the resin passing through the hot chip A7 and the viscosity of the resin passing through the hot chip B8. A resistance difference occurs. Therefore, since the flow rate of the resin passing through the hot chip A7 and the flow rate of the resin passing through the hot chip B8 is different, even if the molded products A10 and B11 have different volumes or moldability, they can be almost simultaneously filled.

FIG. 2 is a sectional view showing another embodiment of the present invention.

In FIG. 2, the molded product A10 is a multi-point gate (FIG. 2).
Shows a case where the molding is performed by a two-point gate). Also in this case, it is possible to change the resin filling pattern by adjusting the flow rate of the resin supplied from each hot chip by giving a temperature difference between the hot chips A7 and B8.

[0012]

As described above, in the hot runner device according to the present invention, the heat insulating plate is provided between the manifold and each hot chip, and the temperature control of each hot chip is completely independent. As a result, it is possible to make a difference in temperature between each hot chip, so in a mold for molding two or more parts at the same time, even if there is a difference in the filling balance, the temperature of each hot chip is adjusted and the filling balance of each part is adjusted. Has the effect of improving the moldability.

[0013] In addition, by heating the hot chip of only a necessary part, there is an effect that only the part can be formed. Next, in a molded product having a multi-point gate, it is possible to change the filling pattern by giving a temperature difference to each hot chip, so that the position where the weld line is generated can be adjusted and the formability and the filling balance can be improved. There is an effect that the quality of a molded article can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 4 Manifold 6 Heat insulating plate 7 Hot tip A 8 Hot tip B

Claims (1)

[Claims] 1. A hot runner device having a multi-point gate for always keeping molten resin supplied from a molding machine nozzle in a molten state in a resin channel by a manifold having a heater and a temperature sensor built-in and hot chips. A hot runner device comprising a heat insulating plate between each of the hot chips and each hot chip.