JPH0551621U - Injection mold - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To provide an injection molding die in which the gas venting space 7 can always be formed accurately and easily and which has a long life. [Structure] At least one of the cavity mold 2 and the core mold 3 has a fitting recess at a desired position on its parting surface, and abuts against the corresponding surface of the other mold at the time of closing, and the parting surface of both molds Pressure receiving plates 4 and 5 that form a predetermined degassing space 7 therebetween are detachably fitted and fixed in the fitting concave portion so as to project from the parting surface in the other mold direction by a predetermined thickness. did.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an injection molding die.

[0002]

[Prior Art]

 The injection mold is provided with gas grooves having a depth of about 0.2 mm at the parting surface where the cavity mold and the core mold come into contact with each other until reaching the outside of the mold. When closed, the gas generated in the cavity during molding is discharged to the outside of the mold through the degassing space formed along the parting line by this gas groove, so that there is no cavity and a precise molded product is obtained. ing.

[0003]

[Problems to be solved by the device]

 By the way, conventionally, the gas groove is formed by cutting a desired portion of the parting surface, but since the cutting is done by hand, even if it is a skilled worker, the processing accuracy is high. There are variations. Therefore, the groove depth may be insufficient and gas may not be sufficiently discharged, or the groove depth may be too deep and the resin may enter the gas groove and remain as burrs on the molded product.

Further, even if the gas groove is accurately formed, when the cavity mold and the core mold are closed, a strong pressure is applied to the parting surface, so that the parting surface is worn out after long-term use. As a result, the gas groove disappears, and the maintenance work of polishing the parting surface and forming the gas groove again must be performed, but as mentioned above, it is not a maintenance work that even a skilled worker can easily do. The workability was poor.

Moreover, if the parting surface is excessively polished, the molded product will be affected, and there is a problem that the life of the mold is short. In view of such circumstances, an object of the present invention is to provide an injection molding die which can always form a degassing space accurately and easily and has a long life.

[0006]

[Means for Solving the Problems]

 In order to achieve such an object, the injection mold according to the present invention has at least one of a cavity mold and a core mold having a fitting recess at a desired position on its parting surface, and at the time of closing the mold. The pressure receiving plate, which comes into contact with the corresponding surface of the other mold to form a predetermined degassing space between the parting surfaces of both molds, is fitted so that it protrudes from the parting surface toward the other mold by a predetermined thickness. The structure is such that it is detachably fitted and fixed in the recess.

In the above structure, the pressure receiving plate may be provided in either one of the cavity type and the core type, or may be provided so as to face both types. Further, the projection thickness of the pressure receiving plate is not particularly limited, but it is preferable to set the thickness so that the gap between the degassing spaces can be formed to about 0.2 mm at the time of closing. The material of the pressure receiving plate may be the same as that of the cavity type and the core type, and when provided in only one type, it is preferable to use a material slightly softer than the corresponding surface of the other type.

[0008]

[Action]

 According to the above configuration, when the pressure receiving plate is provided only on one of the molds, when the cavity mold and the core mold are closed, the pressure receiving plate comes into contact with the parting surface of the other mold and the pressure receiving plate is applied between the parting surfaces of both molds. A degassing space with a gap width approximately the same as the protruding thickness of the plate is uniformly formed.

Therefore, if the cavity is filled with the resin, the gas generated in the cavity is discharged to the outside through the degassing space, so that a molded product can be obtained accurately. In addition, the pressure plate wears out after long-term use, but the worn pressure plate was released by releasing the fixing means such as the set bolt to release the fitting, and was accurately formed by machining. A new pressure plate can be fitted into the mating recess to again create the desired venting space.

[0010]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the drawings showing an embodiment thereof. As shown in FIG. 1, the mold 1 is provided with a cavity mold 2 and a core mold 3, and a plastic bucket is molded as a molded product 9. As shown in FIG. 2, the cavity mold 2 has three fitting recesses 22 (only one of which is shown in FIG. 2) 22 formed on the parting surface 21, and as shown in FIG. As shown in FIG. 4, the three pressure receiving plates 4 are fitted to the respective 22, and the upper end surface of the pressure receiving plate 4 is adjusted so as to protrude by 0.1 mm from the parting surface 21 and fixed by the set bolts 6, 6, and 6. ing.

As shown in FIG. 4, the core die 3 also has three pressure receiving plates 5 at the positions corresponding to the pressure receiving plates 4 of the cavity die 2 in the same manner as the cavity die 2 with the upper end surface of the cavity die 3 being the upper surface of the cavity die 3. It is fitted and fixed in the fitting recess of the parting surface 31 by protruding 0.1 mm from the parting surface 31. In addition, in FIG. 1 and FIG. 3, 11 is a gate.

The mold 1 is configured as described above. As shown in FIG. 4, when the cavity mold 2 and the core mold 3 are closed, the pressure receiving plate 4 and the pressure receiving plate 5 come into close contact with each other, A degassing space 7 having a gap width of 0.2 mm is accurately formed between the parting surface 21 of the cavity mold 2 and the parting surface 31 of the core mold 3 over the entire circumference of the mold. In FIG. 4, the gap width of the gas vent space 7 is emphasized for the sake of clarity of the invention. However, in order to prevent burrs from being caused by the resin flowing into the gas vent space 7 from the cavity 8. Actually, the gap width is narrower.

Therefore, as shown in FIG. 1, when resin is filled into the cavity 8 from the gate 11, the gas generated in the cavity 8 is discharged to the outside of the mold through the degassing space 7, and the inside of the cavity 8 is discharged. Therefore, it is possible to obtain a precise molded product 9 having no voids. Further, since the degassing space 7 has a predetermined gap width accurately, burrs are not generated.

Moreover, in the mold 1, when the pressure receiving plate 4 (5) is worn out for a long period of time, the set bolts 6, 6, 6 are unfastened and the worn pressure receiving plate 4 (5) and the machine are preliminarily used. The degassing space 7 can be accurately formed again by simply replacing it with the spare pressure receiving plate 4 (5) that has been accurately made by the manufacturing process. No need for manual processing such as forming gas grooves, and anyone can easily perform maintenance work.

Further, since the parting surfaces 21 and 31 of the cavity mold 2 and the core mold 3 do not come into contact with each other when they are closed, there is no wear and the life of the mold is improved. The injection molding die according to the present invention is not limited to the above embodiment. For example, in the above embodiment, both facing pressure receiving plates are projected by the same size, but it is also possible to project only one of them.

[0016]

[Effect of the device]

 Since the injection molding die according to the present invention is constructed as described above, the degassing space is accurately formed by fitting and fixing the pressure receiving plate accurately formed by the mechanical manufacturing in the fitting recess. Therefore, it is possible to always obtain a precision molded product without burrs.

Moreover, since the degassing space having a constant gap can be easily formed only by exchanging the pressure receiving plate, and the skill of the work is not required, anyone can easily perform the maintenance work. Also, even if it is used for a long period of time, the pressure receiving plate only wears, the damage to the mold body is small, and the life of the mold is short.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which a core mold and a cavity mold of an injection molding mold according to the present invention are closed and a cavity is filled with a resin.

FIG. 2 is a cross-sectional view showing the cavity type pressure receiving plate portion in an exploded manner.

FIG. 3 is a front view of the cavity mold facing the inside of the mold.

FIG. 4 is an enlarged cross-sectional view showing a degassing space portion of FIG.

[Explanation of symbols]

 1 mold 2 cavity type 3 core type 4 pressure receiving plate 5 pressure receiving plate 7 degassing space 21 cavity type parting surface 22 fitting recess 31 core type parting surface

Claims (1)

[Scope of utility model registration request] 1. At least one of a cavity mold and a core mold has a fitting concave portion at a desired position on its parting surface, and abuts against a corresponding surface of the other mold at the time of closing so that the parting surface of both molds. An injection characterized in that a pressure receiving plate that forms a predetermined degassing space is detachably fitted and fixed in the fitting recess so as to protrude from the parting surface in the other mold direction by a predetermined thickness. Mold for molding.