JP3169310B2 - Mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die,
The present invention relates to a mold suitable for a hot runner type mold.

[0002]

2. Description of the Related Art Generally, a mold used for injection molding includes a fixed mold and a movable mold which are provided so as to be able to close and open the mold. The molding material in a molten state is press-fitted into the cavity formed by the method described above, and cooled while maintaining a predetermined pressure, whereby a molded product conforming to the shape of the cavity is formed.

In this case, the molding material is also located at the gate serving as the entrance to the cavity and the runner leading to the gate, and burrs conforming to those shapes are integrally formed with the molded product. Burr removal work is required.

On the other hand, as a molding die which eliminates the above-mentioned operation of removing burrs, a molding die of a hot runner system as shown in FIGS. 4 and 5 is known.

That is, this molding die is a hot runner type molding die of an internal heating type, and comprises a fixed side die 21 and a movable side die 27 which are provided so as to be able to close and open the mold.
A passage 24 for flowing the molding material is provided in the fixed mold 21.
Is mounted, a body 25 is located in a passage 24 of the manifold 23, and a tip 26 is mounted at a tip of the body 25.

Then, the fixed mold 21 and the movable mold 27 are clamped to form a runner 28, a gate 29 and a cavity 30 between the molds 21 and 27, and the manifold 23 is formed.
The molten molding material located in the passage 24 is injected from the injection port 22 of the fixed mold 21 through the space between the outer surface of the body 25 and the inner surface of the passage 24 and the runner 2.
By press-fitting into cavity 30 through 8 and gate 29 and cooling while maintaining a predetermined pressure, a molded product conforming to the shape of cavity 30 is formed.

In this case, by controlling the temperature of the chip 26 to be higher than or lower than the melting point of the molding material, the temperature of the chip 2 is reduced.
The molding material located in the passage 24, the runner 28, and the gate 29 in the vicinity of the flow path 6 is set in a flowing state or a non-flowing state to prevent burrs from being formed in portions corresponding to the runner 28 and the gate 29. I have.

On the other hand, when a material having a high melt viscosity (for example, PFA) is used as a molding material, it is necessary to prevent so-called drooling from occurring, so that the temperatures of the manifold 23, the body 25, and the chip 26 are reduced. It must be managed in a cycle as shown in FIG. That is, when drooling occurs, it bites into the contact surface between the two molds 21 and 27 to form burrs, which not only takes time and effort to remove the burrs, but also adds to the height dimension of the molded product. In addition, the finished dimensions of the molded product become unstable. Therefore, it is necessary to set the temperature of the chip 26 to a temperature equal to or lower than the melting point except at the time of injection, to make the molding material located in the passage 24 near the chip 26 non-flowable, and to prevent drooling from occurring.

However, even when the temperature of the chip 26 is set to a temperature equal to or lower than the melting point, the molding material located in the passage 24 near the chip 26 is different from the molding material in the molten state located in the passage 24 around the body 25. Since it receives heat, it is heated to a temperature higher than its melting point, which may cause drooling. To prevent this, it is conceivable to lower the temperature of the manifold 23 and the body 25. However, if the temperature is lowered, the viscosity of the molding material becomes high and the material becomes difficult to flow, thereby causing a short shot problem.

The present invention has been made to solve the above-mentioned problems of the prior art, and when drooling occurs, it is prevented from biting between the fixed mold and the movable mold. It is an object of the present invention to provide a molding die that can perform the molding.

[0011]

Means for Solving the Problems In order to solve the above problems, the present invention comprises a fixed side mold and a movable side mold which are provided so as to be able to close and open the mold. A runner, a gate, and a cavity are formed between the two dies, and a molding material is injected from an injection port of the fixed-side die through a passage of a manifold attached to the fixed-side die, and through the runner and the gate. In a molding die adapted to press-fit a molding material into the cavity to form a molded product conforming to the shape of the cavity, the runner is provided at a portion corresponding to the injection port on a contact surface of the movable mold. This means employs a means provided with a drooling absorption groove that leads to.

[0012]

According to the present invention, by adopting the above-mentioned means, when drooling occurs, it is absorbed in the drooling absorption groove. Therefore, the drooling does not bite between the fixed mold and the movable mold to form burrs, so that the work of removing burrs is not required, and the height of the molded product is affected by the burrs. It will not be received.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below. 1 and 2 show an embodiment of a molding die according to the present invention. FIG. 1 is an explanatory diagram showing a mold opening state, and FIG. 2 is an explanatory diagram showing a mold clamping state.

That is, the molding die shown in this embodiment is a hot runner type molding die of an internal heating system, which comprises a fixed mold 1 and a movable mold 7 which are provided so as to be able to close and open the mold. When the molds 1 and 7 are clamped, a runner 8, a gate 9 and a cavity 10 are formed between the molds 1 and 7 via a passage 4 provided in a manifold 3 mounted on the fixed mold 1. The molding material in a molten state is injected from the injection port 2 of the fixed mold 1, pressed into the cavity 10 via the runner 8 and the gate 9, and cooled while maintaining a predetermined pressure, thereby forming the shape of the cavity 10. Is formed so as to form a molded product conforming to the above.

A body 5 is located in the passage 4 of the manifold 3, and a tip 6 is mounted on the tip of the body 5. By controlling the temperature of the tip 6, the inside of the passage 4 near the chip 6 is controlled. The molding material in the runner 8 and the gate 9 is kept in a flowing state or a non-flowing state.

On the contact surface of the movable mold 7 corresponding to the injection opening 2 of the fixed mold 1, a circular drooling groove 11 having a predetermined depth is provided.
1 communicates with the runner 8.

Reference numeral 12 denotes a cold slug communicating with the runner, 13 denotes an ejector pin, and 14 denotes a stripper plate for releasing a molded product.

Next, the operation of the above will be described. First, the fixed mold 1 and the movable mold 7 are clamped to form a runner 8, a gate 9 and a cavity 10 between the molds 1 and 7, and the molten state positioned in the passage 4 of the manifold 3 is formed. Is injected from the injection port 2 of the fixed mold 1 through the space between the outer surface of the body 5 and the inner surface of the passage 4, and is pressed into the cavity 10 through the runner 8 and the gate 9. By cooling while maintaining a predetermined pressure, a molded product conforming to the shape of the cavity 10 is formed.

In this case, if a material having a high melt viscosity, for example, PFA (melting point 310 ° C.) is used as the molding material, the manifold 3, the same as the conventional one is used to prevent drooling from occurring. It is necessary to manage the temperatures of the body 5 and the chip 6 in a cycle as shown in FIG. That is, it is necessary to set the temperature of the chip 6 to be equal to or lower than the melting point at times other than the time of injection, to make the molding material located in the passage 4 near the chip 6 non-flowable, and to prevent drooling from occurring.

In this case, even if the temperature of the chip 6 is set to be equal to or lower than the melting point, the molding material located in the passage 4 near the chip 6 is in the molten state located in the passage 4 around the body 5. , And is heated to above the melting point, causing drooling. However, according to this embodiment, since the circular drooling absorption groove 11 is provided on the contact surface of the movable mold 7 at the portion corresponding to the injection port 2 of the fixed mold 1, this drooling absorption groove is provided. The drooling generated in 11 will be absorbed.

Therefore, even if drooling occurs, it does not bite between the fixed die 1 and the movable die 7, and the bite becomes burrs, which takes time to remove. This does not affect the height dimension of the molded product.

[0022]

The present invention is constructed as described above, and is formed between the two dies at the time of clamping the two dies on the contact surface of the movable die at the portion corresponding to the injection port of the fixed die. By providing the drooling absorption groove leading to the runner, even if drooling occurs, it can be absorbed by the drooling absorption groove. Therefore, the drooling does not bite between the fixed-side mold and the movable-side mold, and the biting thing becomes a burr, which takes time to remove and adds to the height dimension of the molded product. As a result, the finished dimension of the molded product does not fall outside the predetermined range. As a result, it is possible to reduce the labor required for the molding operation, and to provide excellent effects such as providing a molded product having stable quality and finishing accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of a molding die according to the present invention, and is an explanatory diagram showing a mold opening state.

FIG. 2 is an explanatory diagram showing a mold clamping state of the one shown in FIG.

FIG. 3 is an explanatory diagram showing an example of temperature management for each cycle of the manifold, the body, and the chip shown in FIGS. 1 and 4;

FIG. 4 is a schematic diagram showing an example of a conventional molding die, and is an explanatory diagram showing a mold opening state.

FIG. 5 is an explanatory diagram showing a mold clamping state of the one shown in FIG. 4;

[Explanation of symbols]

 1, 21 fixed-side mold 2, 22 injection port 3, 23 manifold 4, 24 passage 5, 25 body 6, 26 tip 7, 27 movable mold 8, 28 …… Runner 9,29… Gate 10,30… Cavity 11… Druling absorption groove 12… Cold slug 13… Ejector pin 14… Stripper plate

Continuation of the front page (56) References JP-A-4-334421 (JP, A) JP-A-5-309699 (JP, A) JP-A-63-5510 (JP, A) JP-A-61-263720 (JP) JP-A-55-17569 (JP, A) JP-A-7-178773 (JP, A) JP-A 5-39925 (JP, U) JP-A-63-7509 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (1)

(57) [Claims] 1. A mold comprising a fixed mold (1) and a movable mold (7) which are provided so as to be able to clamp and open the mold.
At the time of the mold clamping of (7), a runner (8), a gate (9) and a cavity (10) are formed between the two molds (1) and (7), and a manifold (1) is mounted on the fixed mold (1). The molding material is injected from the injection port (2) of the fixed mold (1) through the passage (4) of (3), and the cavity (10) is injected through the runner (8) and the gate (9). The molding material is pressed into the cavity (1).
In a molding die adapted to form a molded product conforming to the shape of 0), a portion corresponding to the injection port (2) on a contact surface of the movable die (7) is provided on the runner (8). A mold having a drooling absorption groove (11) communicating therewith.