JP3336852B2 - Mold with gate mark shaping mechanism - 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 with a gate trace shaping mechanism which is optimal for treating unnecessary gate residues in resin injection molding and the like.

[0002]

2. Description of the Related Art There is a pinpoint gate method as a method for automatically separating a sprue, a runner and a molded product in a mold after completion of a molded product having a particularly small size in injection molding of a resin or the like.

[0003] In this method, a gate residue is generated on the molded product side at the time of separation, but the remaining amount varies depending on the gate diameter, the degree of use of the mold, and the like. Normally, assuming the remaining gate,
Although the shape of the molded article is devised by giving a drop or the like, a problem may occur in which the size exceeds a specified dimension due to restrictions on the size or shape.

Conventionally, in order to correct this problem, the dimensions of the gate portion of the molded product are measured to judge the quality, and the defective product is provided with a gate crushing step after the molding process to crush the gate by secondary processing. .

FIG. 5 is a cross-sectional view showing an example of such a molded product, and shows a drop amount b for preventing the gate remaining 31 and the reference surface 32 from protruding. The set dimensions are restricted by the fluidity, and if the remaining height a of the gate exceeds the drop amount b, the molded product becomes a functionally defective product.

[0006]

As described above, the conventional molding die has a problem that inspection and sorting are required, and a mechanism or apparatus for a post-processing step must be added.

SUMMARY OF THE INVENTION The present invention is intended to solve such a problem, and a gate mark shaping mechanism in which a gate is crushed in a mold, inspection and sorting is unnecessary, and a post-processing mechanism or apparatus is unnecessary and equipment cost is low. It is an object of the present invention to provide an attached molding die.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a molding die with a gate trace shaping mechanism according to the present invention is characterized in that after forming a hoop material conveyed at a constant interval, the gate remains of the molded product. Is pressed against the rest of the gate by pressing a shaping pin heated in the mold by the urging force of the spring and the mold clamping force to crush the gate by thermal compression.

According to the present invention, high-quality molded products can be obtained without the need for inspection and sorting of molded products, and equipment costs can be reduced without the need for a processing device in a post-process.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a cavity portion in which a cavity for molding a molded product by injection molding is formed at a predetermined position of a hoop material continuously supplied by intermittent conveyance. And a lower molding die provided with a guide portion for holding a molded product formed in the cavity portion and conveyed by one pitch at a predetermined position, and provided to face the upper portion so as to be paired with the lower molding die. The cavity is combined with the cavity of the lower molding die to form a cavity for molding the molded product, and the gate of the molded product held by the guide portion of the lower molding die is heated by being brought into contact with the cavity. In this way, it is configured as an upper mold provided with a shaping pin for shaping the gate mark, and has the effect of eliminating the need to shape the gate mark in a separate step.

According to a second aspect of the present invention, in the first aspect of the present invention, the heater for the shaping pin for shaping the gate mark is provided by a heater for heating the upper mold and the lower mold for molding the article to be molded. And has the effect of reducing the size of the device.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a guide hole is provided in the hoop material, and positioning is performed by the guide hole, so that processing accuracy is improved. Has an action.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the upper mold and the lower mold have a detachable unit structure. This has the effect of improving maintainability.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a molding die with a gate trace shaping mechanism in the embodiment, and FIGS. 2 to 4 are cross-sectional views for explaining the operation of crushing the remaining gate.

In FIG. 1 and FIG. 2, reference numeral 1 denotes a hoop material, which is a base body of a molded product made of a resin material or a metal material and provided with guide holes 15 for positioning and transfer at both ends, and is a carrier. . Reference numeral 8 denotes a lower molding die which forms the lower part of a molded molded product 12 formed by molding a thermoplastic resin material or the like, and is fixed to the upper surface of the lower die plate 2.

Numeral 7 denotes a molding upper mold which can move up and down in opposition to the molding lower mold 8 and forms an upper shape of the molded article 12. It is biased and movably mounted to provide spacing.

Reference numeral 4 denotes a crushing block, which is fixed to the right end of the upper mold 7 in the direction of travel of the hoop material 1,
A shaping pin 9 having a stopper 18 at the center is inserted through the spring 17 and is normally urged by the spring 17 so that the lower end of the shaping pin 9 projects from the lower surface of the crushing block 4 by a predetermined length. I have.

A heater 10 for heating the shaping pin 9 to a specified temperature is embedded in the crushing block 4.
Further, in order to prevent influences such as temperature setting on the mold body and stabilize the heating of the shaping pins 9, heat insulating plates 11 are attached to both side ends of the crushing block 4.

Reference numeral 3 denotes a pressing plate which is fixed to the right end of the upper die plate 6 at the upper part of the crushing block 4 and pushes the shaping pin 9 downward by moving the upper die plate 6 downward. Reference numeral 5 denotes a crushed receiving plate, which is fixed to the right end of the lower molding die 8 facing the crushing block 4 and on which the transferred molded product 12 is mounted and the remaining gate 19 of the molded product 12 is mounted. Performs a crushing operation to crush the molded product 1
3 is assumed.

Reference numeral 14 denotes a molded article which has been transferred to the next process position and has been crushed. Reference numeral 16 denotes a parting line, and reference numeral 7a denotes an upper cavity portion having a tip 7b of a resin injection gate (pinpoint gate).

Next, the operation will be described. First, FIG. 1 shows a state in which the crushing process of the remaining gate 19 and the molding process are completed, and the molded product 14, the crushed molded product 13, and the molded product 12 are set at predetermined positions of the hoop material 1.
The upper mold 7 has risen and returned to its original position.

Next, as shown in FIG. 2, the hoop material 1 is transported at regular intervals in the direction of the arrow (the transport mechanism is not shown), and the molded product 12 is crushed and mounted on a predetermined position of the receiving plate 5. .
The molding base of the new hoop material 1 is set in the lower molding die 8 facing the cavity 7a of the upper molding die 7.

Next, as shown in FIG. 3, the upper mold plate 6 and the forming upper mold 7 are lowered while maintaining the interval by the bias of the spring 20 (the drive mechanism is not shown), and the hoop material is removed. The lower mold 8 is brought into close contact with, ie, clamped through, the mold. Subsequently, a resin material is injected under pressure from the front end 7b of a pinpoint gate (not shown) and heated under pressure to form a molded article 12.

At the same time, the lower end of the shaping pin 9 which is projected from the parting line 16 and heated by the spring 17 abuts on the upper end of the gate remainder 19, and the mold clamping force and the spring 17
To gradually heat and compress the remaining gate. At this time, the shaping pin 9 is pushed back upward by overcoming the urging force, i.e., the pressing force of the spring 17 due to the crushing resistance of the remaining gate 19, and the upper end of the shaping pin 9 protrudes from the upper crushing block 4 and the upper surface of the upper molding die 7. At the same time, the formed molded product 12 is accurately and stably set and held on the crushed receiving plate 5.

Next, as shown in FIG.
By compressing the spring 20 and lowering it.
Presses the upper end of the shaping pin 9 to lower it, so that the lower end of the shaping pin 9 heats and presses the remaining gate 19 to a length determined by the set dimension of the shaping pin 9 (corresponding to the dimension a shown in FIG. 5). Processing is performed to complete the crushed molded product 13.

Then, the upper mold plate 6 and the molding upper mold 7 are raised and returned to the original positions, thereby completing one process. Thereafter, by repeating the above-described operation, a molded product is continuously formed, and the crushing of the gate is simultaneously performed in the mold.

The upper plate 6 and the upper mold 7 are not movably separated by the spring 20 depending on the shape, size or molding speed of the molded product. The upper die 7 may be integrated.

Further, the heater 10 may be used also as a heating mechanism (not shown) used for the upper molding die 7 and the lower molding die 8 without being separately buried and installed. A book may be used, and an oil or an air damper may be used instead of the spring 17.

[0029]

As described above, according to the present invention, it is possible to reduce the impact, stabilize the molded product, and to squeeze the remaining gate with smoothness and high precision simultaneously with the molding in the mold. And the number of steps can be reduced, and the effect of reducing equipment costs and improving productivity can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a molding die with a gate trace shaping mechanism according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating an operation of crushing the remaining gate.

FIG. 3 is a sectional view illustrating an operation of crushing the remaining gate.

FIG. 4 is a cross-sectional view illustrating an operation of crushing the remaining gate.

FIG. 5 is a sectional view showing an example of a molded product.

[Explanation of symbols]

 Reference Signs List 1 hoop material 2 lower mold plate 3 push plate 4 crushing block 5 crush receiving plate 6 upper mold plate 7 molding upper mold 7a cavity 7b tip 8 molding lower mold 9 shaping pin 10 heater 11 heat insulating plate 12 molded molded product 13 crushed Molded product 14 Molded product 15 Guide hole 16 Parting line 17 Spring 18 Stopper 19 Gate remaining 20 Spring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-189150 (JP, A) JP-A-63-109026 (JP, A) JP-A-1-267014 (JP, A) JP-A-55-189150 61438 (JP, A) JP-A-58-175643 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (4)

(57) [Claims] 1. A cavity formed with a cavity for molding a molded product by injection molding at a predetermined position of a hoop material continuously supplied by intermittent transportation, and a cavity formed by the cavity and transported by one pitch. And a lower mold provided with a guide portion for holding the molded product at a predetermined position, and provided opposite to the upper portion so as to form a pair with the lower mold and combined with the cavity of the lower mold to cover the molded product. A molding part provided with a cavity part having a cavity for molding the molded article, and a shaping pin for shaping the gate mark by heating by contacting and heating the gate part of the molded article held by the guide part of the lower molding die. Molding die with gate mark shaping mechanism. 2. The gate trace shaping mechanism according to claim 1, wherein the heater for shaping pins for shaping the gate trace is used in common with the heaters for the upper and lower molds for molding the molded article. With molding die. 3. The molding die with a gate trace shaping mechanism according to claim 1, wherein a guide hole is provided in the hoop material, and positioning is performed by the guide hole. 4. The mold according to claim 1, wherein the upper mold and the lower mold have a detachable unit structure.