JPS5917614Y2 - plastic mold - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a plastic mold.

2. Description of the Related Art Conventionally, plastic molding molds are known in which an injection port for pouring a plastic material into a mold groove is provided in the upper part of the mold.

However, in such molds, air bubbles are generated due to air mixed in when plastic material is injected into the mold groove from the injection port provided at the top of the mold, or due to internal shrinkage or retention of moisture or air afterwards. .

Even if the bubbles are removed, the bubbles remaining in the lower part of the mold do not escape, resulting in the formation of cavities inside the mold.

Furthermore, in plastic molding, test pieces are generally collected for product quality control.

Traditionally, test pieces have been used to measure the performance and characteristics of plastic molded products, such as chemical resistance and mechanical strength.
After molding, the injection port was cut out and used.

However, in addition to plasticizers and stabilizers, fillers such as carbon and silica are mixed into plastic materials for reinforcement and cost reduction.

Therefore, due to the sedimentation of the filler, the mixing ratio of the filler differs between the inside and outside of the molded metal, the upper and lower parts, especially at the injection port, and the strength etc. between the test piece and each part of the molded metal differs, resulting in the measurement results being different. It lacked reliability.

The present invention was made in order to eliminate such conventional drawbacks, and aims to provide a plastic molding die that can obtain high-quality molding metals and accurately grasp the characteristics of the molding metals. purpose.

In order to achieve such an object, the present invention provides a plastic molding die that is provided with an injection port at the top of the mold for pouring plastic material into the mold groove, with one end of the mold having a height that is approximately the same as the injection port. Now, a bubble escape hole is formed which is open to the outside and whose other end communicates with the mold groove near the vertically intermediate portion of the mold groove, so that at least a portion thereof becomes a mold for the test piece.

As a result, air bubbles generated in the lower part of the mold are discharged to the outside of the mold through the air bubble escape hole.

In addition, a test piece having the same characteristics as the molded metal is placed at the bottom of the bubble escape hole.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view showing one (female) mold for producing a cap-shaped plastic molded product, and FIG. 2 is a sectional view taken along line A-0-A' in FIG. 1.

A cap-shaped mold groove 5 is formed inside one (female) mold 2, and the other (male) mold 1 has a mold groove 5 formed in the mold 2 as shown by the imaginary line in FIG. It has a shape that corresponds to

These two molds 1 and 2 are 11 molds 1 and 2, respectively.
The bolts are integrally connected by passing bolts through a plurality of bolt grooves 3 provided around the periphery of the bolts and tightening the bolts with the bolts 1 that form a pair with the bolts.

Note that an annular backing 4 is fitted into the surface of the mold 1 that comes into contact with the mold 2, so that the mold groove 5 can be sealed.

On the other hand, as shown in FIG.
An injection port 6 for pouring plastic material into the mold groove 5
It is formed in communication with the

The mold 2 also includes a plurality of protrusions 7 that protrude into the mold groove 5.
is provided.

These protrusions 7 are for forming a hole for attaching a molded metal.

Further, on both sides of the mold groove 5, adjacent to the mold groove 5, one end opens to the outside of the mold 1°2 at almost the same height as the injection port 6, and the other end opens in the vertical direction of the mold groove 5. A bubble escape hole 8 communicating with the mold groove 5 is formed near the middle part of the mold.

The diameter of the bubble escape hole 8 is approximately 5 mm, for example, and the length of the portion 9 from which the test piece is obtained is 130 mm or less and the diameter is 10 mm, or a rectangular cross section of 5 mm x IO mm is used. None, provided at a position closest to the mold groove 5 and separated by about 7 mm.

Next, a process of obtaining a molded metal using a plastic molding mold having such a configuration will be explained.

First, a liquid plastic material containing a filler and the like is injected into the mold groove 5 through the injection port 6 .

As a result, the plastic material descends within the mold groove 5,
It gradually accumulates from the bottom of the mold groove 5.

At this time, the remaining air in the lower part of the mold groove 5 escapes to the outside of the molds 1 and 2 through the bubble escape hole 8.

In addition, bubbles generated on the inner surface of the mold groove 5 and around the protrusion 7 due to heat shrinkage of the plastic material, retention of moisture, air, etc., are transferred to the molds 1 and 2 through the injection port 6 as the plastic material increases. It is discharged to the outside.

Here, the air bubbles in the upper part of the mold groove 5 are easily discharged to the outside from the injection port 6 as described above, but the air bubbles generated or remaining in the lower part cannot rise to the injection port 6. It is discharged to the outside of the molds 1 and 2 through the escape hole 8.

Then, the plastic material is filled up to the vicinity of the injection port 6, and after the injection is completed, residual air is bubbled out by a well-known defoaming operation.

In addition, the viscosity of the plastic material decreases due to the temperature rise (of the mold) during the subsequent curing process, and the air bubbles slightly remaining in the mold groove 5 also rise and flow out through the injection port 6 and the air bubble escape hole 8. released.

On the other hand, since the cross-sectional area of the groove is small and long, a small amount of air bubbles in the part 9 from which the test piece is obtained may remain without being completely removed, but the air bubbles gather above the part 9 from which the test piece is obtained. Therefore, it is possible to obtain a test piece of about 110 mm at the bottom excluding that part and use it as a measurement sample, so that such minute air bubbles do not have an adverse effect on the sample and the molded metal.

As described above, according to the plastic mold of the present invention, one end opens to the outside at almost the same height as the injection port, and the other end opens near the middle part of the mold groove in the vertical direction. Since air bubble escape holes are formed in the mold that communicate with the grooves, air bubbles generated during molding can be completely discharged from the mold grooves, and high-quality molded metal can be obtained without forming cavities in the molded metal. Can be done.

Moreover, what is molded in the bubble escape hole is the molding metal and homogeneity within the mold groove.

Therefore, by using the molded metal in the bubble escape hole as a test piece, it is possible to accurately grasp the chemical properties such as mechanical strength and chemical resistance, as well as the electrical and physical properties of the molded product. This has effects such as enabling good quality control.

[Brief explanation of drawings]

FIG. 1 is a front view showing one mold in an embodiment of the plastic molding mold of the present invention, and FIG. 2 is a sectional view taken along the line A-0-A' in FIG.

Claims (1)

[Scope of utility model registration request] Plastic molding molds 1 and 2 are provided with an injection port 6 at the top of the molds 1 and 2 for pouring plastic material into a mold groove 5.
In the molds 1 and 2, one end opens to the outside at almost the same height as the injection port 6, and the other end communicates with the mold groove 5 near the middle part in the vertical direction of the mold groove 5. A plastic molding die characterized in that at least a portion thereof is formed with a bubble escape hole 8 that serves as a mold for a test piece.