JPH0121778Y2 - - Google Patents

Description

[Detailed description of the invention] Technical field The present invention relates to a mold for injection molding ornaments, and in particular to injection molding for molding ornaments that have an uneven pattern on the back surface, such as a disc-shaped ornament that is attached to the center of an automobile wheel cover. This relates to the improvement of molds.

BACKGROUND TECHNOLOGY In general, an ornament 1 (see Figures 1 and 2) made of a synthetic resin and molded by injection molding into a disk shape, such as the one attached to a wheel cover, is distinguished by forming patterns such as predetermined characters and symbols on the front or back surface for identification and decoration. Efforts are being made to improve gender.
The pattern is made by injection molding the ornament from transparent or colored transparent synthetic resin so that the front surface 10 of the ornament 1 is smooth and the back surface 11 is partially formed with recesses 12, 12'.
A colored paint 13 or the like is applied to the bottom surface of 2' so that it can be seen through from the surface side.

By the way, the mold for molding this type of ornament 1 (see FIG. 3) is made up of a cavity mold 2 and a core mold 3, and the core mold 3 is formed with unevenness 30. When resin is injected from the gate G to this mold, the unevenness 3 of the core mold 3
0, the resin flow is disturbed and separates in the cavity space, and when the filling is completed, they merge again and peck each other, resulting in a weld line W on the surface and inside of the ornament 1, which has the disadvantage of significantly impairing the decorativeness. (Refer to Figure 4) This weld line becomes a fatal defect if the surface of the ornament is not painted.In order to prevent this weld line from occurring, the applicant first removed the weld line. It was proposed that a resin pool should be provided in the area where resin is generated to form an ear 14, and this ear should be removed after molding (Japanese Patent Laid-Open Publication No.
57-185130). However, according to this method, ear 1
There remains some complication of having to cut out the weld line W after the fact, and the occurrence of the weld line W is greatly affected by the position of the gate where the resin is injected, so it takes several times to specify the position where the resin reservoir is to be placed. The reality is that you have to take a trial shot.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide an injection molding die that can mold an ornament without creating a weld line by simple adjustment without providing a resin reservoir or the like.

That is, in the injection molding mold according to the present invention, in the main body of the mold for injection molding a disc-shaped ornament having a concavo-convex pattern, the entire surface of one side of the cavity space is formed with the shaped surface of the concavo-convex pattern as the top surface. Assemble the mold part to
The entire mold part is rotated and adjusted according to the flow of resin injected from the side into the cavity space from the gate of the mold, so that the position of the shaped surface of the mold part can be adjusted within the cavity space. It is made up of.

Embodiment The following description will be made with reference to FIGS. 5 to 8.

As shown in FIG. 5, this injection molding mold is equipped with a cavity mold 2 and a core mold 3, and the core mold 3 is a mold part that forms one entire surface of the cavity space 4 with a shaped surface having an uneven pattern as the top surface. 31 and a main body part 32 surrounding the mold part. The mold part 31 is formed into a conical column shape close to a cylinder, and a support plate 33 is attached behind the main body part 32 by bolts 3.
It is integrated with the main body body part 32 by tightening and fixing it with 4. Therefore, since the mold part 31 has a perfect circular outer shape, the rotation can be adjusted within the main body part 32 by removing the support plate 33. Moreover, instead of this mold part 31, a mold part 35 can be formed so as to fit into a perfect circular recess formed in the main body part 32, as shown in FIG. It is disc-shaped, and the mold section 35 can be removed by pushing it up through a hole 36 provided in the main body section 32 with a rod or the like, and then adjusted for rotation.

In addition, in these molds, a gate G for injecting resin from the side into the cavity space 4 is provided in the main body part 32, and the mold parts 31 and 35 are connected to the main body part 3.
It is provided so as to be rotatable as a whole so as to adjust the positional relationship of the shaped surface 30 having the uneven pattern with respect to the gate G of No. 2.

With the injection molding mold configured in this way, the occurrence of weld lines is checked when a trial shot is made by injecting resin from gate G at the position where the unevenness is indicated by the solid line as shown in Fig. 7. If found, mold part 3
The optimal position can be found by rotating and adjusting the rotation of the weld lines 1 and 35 to the positions indicated by the broken lines, performing a trial shot again, and checking the occurrence of weld lines in this order. Once the optimum position has been determined, the mold parts 31 and 35 are securely fixed to the main body part 32, and can be used as is as a mold for mass production.

In the above-mentioned embodiments, the mold part of the core mold is made rotatable, but conversely, depending on the shape of the ornament, a mold part that can be rotated can be provided in both the cavity mold and the core mold. You can do it like this. In addition, when molding multiple ornaments at the same time with one mold, please use the 8th mold.
As shown in the figure, the position can be adjusted by individually rotating and adjusting the mold parts 31 and 35 with respect to the gate G which is branched and continuous from the runner R.

Effects of the Invention As described above, according to the injection molding mold according to the present invention, the mold part is rotatably installed as a whole inside the mold body, so that the shaped surface with the uneven pattern can be shaped according to the flow of the resin. to adjust the position.
By adjusting the rotation of the mold part, you can easily find the optimal position where the weld line is least likely to occur, and there is no need to perform extensive machining on the mold to change the position of the gate. Furthermore, since the mold part is removable, repair of the mold is easy.

[Brief explanation of the drawing]

1 and 2 are a plan view and a side sectional view showing an example of an ornament, FIG. 3 is a side sectional view of a conventional injection molding mold, and FIG. 4 is a perspective view of an ornament molded with the same mold. FIG. 5 is a side sectional view of the injection molding mold according to the present invention;
FIG. 6 is a side sectional view of an injection molding die according to another embodiment, FIG. 7 is a plan view thereof, and FIG. 8 is a perspective view of an injection molding die according to still another embodiment. 1... Ornament, G... Gate, 30...
Shaped surface with uneven pattern, 31, 35...Mold part, 4
...Cavity space.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) Molding that forms one entire surface of a cavity space with the uneven patterned surface as the top surface in the main body of a mold for injection molding a disc-shaped ornament having an uneven pattern. The mold section is assembled, and the shaping surface of the mold section is positioned within the cavity space by adjusting the rotation of the entire mold section according to the flow of resin injected from the side into the cavity space from the gate of the mold. An injection molding mold characterized by being adjustable. (2) The injection molding mold according to claim 1, wherein the molding part is formed in the shape of a plate that can be freely fitted into the main body of the mold. (3) The injection molding mold according to claim 1, wherein a plurality of the mold parts are provided so that their positions can be adjusted individually for each gate branching from one runner.