JPH0235458Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a molding die used for molding synthetic resin products, and more specifically, the present invention relates to a molding die that is composed of a plurality of split molds that facilitates removal of burrs that occur at the mating part of the molded product. Regarding usage types.

Generally, two or three or more split molds are used to mold synthetic resin products. Showing the cross section of the product during molding, 10,
11 is the upper mold and lower mold of the mold, a is the mold matching part, 1
2 is a synthetic resin product. When the synthetic resin product is, for example, polyurethane foam, the raw material to be produced is a foamable liquid, and during molding, the liquid raw material flows out into the mold matching area a, and foams and hardens in this mold matching area, forming burrs. easy. In particular, when using foamable raw materials, the foaming pressure during molding tends to cause gaps in the mold matching area, and to prevent the formation of underfill areas in the product, a small gap is provided in the mold matching area to prevent cavities from forming. In many cases, it is necessary to prevent air pockets from forming inside the mold, and it is an unavoidable fact that burrs are formed at the part where the molds fit together. Therefore, it is necessary to remove this burr after molding.

FIG. 2 shows the removal of burrs from a synthetic resin product.
The burr is removed with a sharp cutting tool 13 such as a knife, but since this burr is foamed and hardened in a small gap between the molds, the burr and burr base are smaller than other parts. The surrounding area has a low foaming ratio and high density, which means it is hard, and the burr cannot be removed without applying considerable force.
In order to remove the burr from the base, it is desirable to use a knife or the like in contact with the surface of the synthetic resin product where the burr base is present.
Since it is difficult to apply force to the knife, etc., and the work efficiency is not good, it is necessary to use the knife at an angle, that is, diagonally to the surface of the product. Since the burr hits the surface, the burr cannot be completely removed from the base, and the burr cut portion protrudes.

FIG. 3 shows the state after the burrs have been removed, and is a partial sectional view of the synthetic resin product cut along the cutting line--line in FIG. 2.

As described above, since some of the burrs remain on the surface of the synthetic resin product, it is necessary to use a thick skin that can hide the protrusions of the burrs, or to use a larger skin.

The present invention has been made in consideration of these points, and provides a molding die consisting of two or more split molds that facilitates removal of burrs on synthetic resin products that occur at the mold mating part. It is something.

The present invention will be explained below using the accompanying drawings.

FIG. 4 shows a perspective cross-sectional view of an embodiment of a mold according to the present invention. The molding mold consists of two halves, an upper mold 20 and a lower mold 21, which do not have an elastic material for sealing in the mold mating part, and one of the mold parts, in this example, the upper mold 20, has a mold part in the mold mating part. A flange 20a is provided that projects into the cavity, and a step is formed between the flange 20a and the mold matching portion of the lower mold 21.

FIG. 5 shows a perspective cross-sectional view of a synthetic resin product molded using this molding die. It has a recessed portion 22b formed therein.

FIG. 6 shows a burr 22a of this synthetic resin product 22.
This explains the removal of the. The burr 22a is cut off with a sharp cutting tool 23 such as a knife, but at this time, the tip of the knife 23 can be inserted into the recess 22b.
Even if the blade is applied to the base of the burr and used obliquely to the product surface, the tip of the knife or the like will not hit the product surface, and the burr can be removed from the base.

FIG. 7 shows a partial cross-sectional view of the end portion of the synthetic resin product 22 after the burr has been removed, and 22c is the removed portion of the burr base.

8 to 10 are partial cross-sectional views of molds of other embodiments, 30, 31, 40, 41, 50, 5
1 indicates a split mold, and 30a, 41a, and 51a indicate a brim. In addition, in any of the molds, there is no sealing elastic material in the mold matching portion.

Molding molds are not limited to those consisting of two split molds, but also those consisting of three or more split molds, which have the same structure as this explanation and are used for molding synthetic resin products, and will be explained again. It's out of nowhere. Further, the material of the molding die is a commonly used material such as resin, metal, electroforming, etc.

As described above, the molding mold according to the present invention has a structure in which one mold mating part of the split mold has a collar that protrudes into the cavity, and there is a step between it and the other mold mating part. Synthetic resin products that are molded using a molding mold have a recessed part formed by the brim of the molding mold at the base of the burr formed in the mold matching part, and a cutting tool such as a knife is inserted into this recessed part. Since burrs can be removed by inserting the tip, even if a knife or the like is used diagonally by applying it to the base of the burr, the burr can be removed without the tip of the knife hitting the surface of the synthetic resin product. It has the advantage that a knife or the like can be used at an angle that makes it easy to apply force, and hard burrs can be completely removed from the base.

[Brief explanation of the drawing]

1 to 3 illustrate conventional molding molds,
Figure 1 is a cross-sectional view of the mold and synthetic resin product during molding, Figure 2 is a perspective view illustrating burr removal from the synthetic resin product, and Figure 3 is a cross-sectional view taken along the cutting line - line in Figure 2. 4 to 7 illustrate the mold according to the present invention, FIG. 4 is a perspective sectional view of one embodiment of the mold, and FIG. 5 shows the mold shown in FIG. 4. FIG. 6 is a perspective view illustrating burr removal from the synthetic resin product; FIG. 7 is a partial sectional view of the end of the synthetic resin product after burr removal; FIG. 8 to FIG. 10 are partial sectional views of a molding die of another embodiment. 20... Upper mold, 21... Lower mold, 20a... Brim, 22... Synthetic resin product, 22a... Burr, 2
3... Cutting tool, 30, 31, 40, 41, 50,
51...Split mold, 30a, 41a, 51a...Brim.

Claims (1)

[Scope of utility model registration request] In a mold for molding a molded product that is made up of two or more split molds and makes it easier to remove generated burrs after molding, one mating part of the split molds that are combined with each other is made to protrude into the cavity to create a collar. 1. A molding mold characterized in that a step is formed between the mating part and the other mating part.