JPS6144650B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a synthetic resin molded product having a unique color portion such as letters or patterns on a portion of its surface, and particularly to a method for manufacturing a synthetic resin molded product for a vehicle.

BACKGROUND OF THE INVENTION Some synthetic resin molded products such as center caps and wheel covers, which are automobile parts, have uniquely colored parts such as letters and patterns that are different in tone from the main body of the molded product on their surfaces. FIG. 1 is a perspective view showing a center cap as an example of such a molded product, where M is the molded product, 1 is the molded product body, and 2 is a different color portion.

Conventionally, as a method for producing such a molded article by injection molding, there has been a method in which a resin plate forming a different color portion is inserted into a mold and then injection molded. FIG. 2 is a vertical cross-sectional view of a mold showing such a method, in which 3 is a core mold, 4 is a cavity mold,
5 is a cavity space. In the conventional manufacturing method, a resin plate 6 of a different color is inserted into the cavity space 5, and the part to be left as a different color on the surface is clamped by the convex part 7 of the cavity mold 4, and the resin plate 6 of a different color is inserted into the cavity space 5.
A resin 8 is injected into the molded product body 1 to form the molded product body 1.

However, according to such a conventional manufacturing method, since the resin plate 6 is inserted and injection molded, the insertion process is laborious and cannot be automated, and as shown in FIG.
The injection resin 8 enters between the core mold 3 and the resin plate 6, deforms the resin plate 6, and pushes it up.
This caused problems such as exposing the deformed portion of the resin plate to the surface and making the parting line unclear.

This invention was made by focusing on such conventional problems, and involves injecting a first resin to fix the first resin molded part to the core mold, and then injecting a second resin. The aim is to solve the above problems.

In this invention, a core mold and a first cavity mold are clamped together, a first resin is injected, and a peripheral edge of the core mold is tapered from the surface side toward the bottom of the first cavity mold. A step of molding and fixing a resin molded part of the first resin molded part, and compressing a part of the first resin molded part with a convex part of a second cavity mold, and non-tapering the first resin molded part located around the said convex part. The core mold and the second cavity mold are clamped to form a cavity space between the shaped part and the tapered peripheral part and the second cavity mold, and a second resin having a different color tone is formed. Inject the second part, leaving the clamping pressure part
A method for manufacturing a synthetic resin molded article having a uniquely colored portion is characterized in that the method includes the step of forming a resin molded part.

The present invention will be explained below based on the drawings. 3 to 7 show an embodiment of the present invention,
3 is a vertical sectional view of the mold showing the molding state in the first step, FIG. 4 is a perspective view of the core mold after the first step molding, FIG. 5 is a perspective view of the first resin molding part, 6 is a cross-sectional view thereof, and FIGS. 7A to 7C are vertical sectional views of the mold showing the molding state in the second step, respectively.

The first step is to form a core mold 3 and a first cavity mold 4a.
and the first resin 8a is injected, and the first resin 8a is injected.
The resin molded part 9 is molded. In this case, core type 3
A fixing pin 10 having an engaging portion 10a is projected from the cavity space 5a, and the first resin molded portion 9 is molded and fixed to the tip of the core mold 3. This prevents peeling and falling off when the mold is opened. A cavity space 5a is formed in the peripheral edge of the first resin molded part 9 so as to form a tapered part 9a that slopes from the surface side toward the bottom. Inclination angle α of tapered portion 9a
should be approximately 10 to 50°.

As shown in FIG. 7, the core mold 3 with the first resin molded part 9 fixed thereon is processed in the second step as shown in FIG.
The mold is clamped with the second cavity mold 4b, and the part left as a different color part on the surface of the first resin molded part 9 is removed from the second cavity mold 4b.
The second resin 8b is injected into the cavity space 5b while being clamped by the convex portions 7b of the cavity mold 4b to form the second resin molded part, that is, the molded product main body 1. At this time, the first
A cavity space 5b is formed between the non-tapered part and the tapered part 9a of the resin molded part 9 and the second cavity mold 4b. FIG. 7A shows a state in which the mold is clamped, and FIG. 7B and C show states in which resin is being injected.

The resin 8b is transferred from the gate 11 to the first resin molded part 9.
The first resin molded part 9 is fixed to the core mold 3, passing over the non-tapered part located around the tapered part 9a and the convex part 7b on the peripheral edge of the cavity space 5b. Therefore, there is no floating or deformation. In particular, when the tapered part 9a is formed, the impact caused by the flowing resin is small and the flowing resin flows while holding down the first resin molded part 9, which further reduces the risk of deformation, and the resin flows easily and uniformly. molding is performed.

The molded product M molded in the above manner is opened,
It is extruded by the extrusion pin 12. In the completed molded product M, the first resin molded part 9 is exposed at the part pressed by the convex part 7b, and becomes a different color part 2.

FIG. 8 is a vertical cross-sectional view showing the manufacturing apparatus in a closed state, and FIG. 9 is a vertical cross-sectional view showing the mold in an open state. The core molds 3a and 3b are rotary plates 13
A first cavity mold 4a and a second cavity mold 4b are disposed on base plates 14a and 14b provided on both sides of the base plate 17, and a first cavity mold 4a and a second cavity mold 4b are provided on mold mounting plates 15 and 16, respectively. ,18
It is located in 19, 20 are guide pins, 2
1 and 22 are injection nozzles. The mold mounting plate 16 is fixed, and the mold mounting plate 15 and the rotating plate 1
3 is movable in directions A, B, C, and D, respectively, and FIG. 9 shows a state in which the molds are moved in directions A and C and the mold is opened. Further, the rotary plate 13 is configured to rotate half a rotation in the E direction when the mold is opened.

The method for manufacturing molded product M in the above apparatus is as follows.
As shown in the figure, the first resin 8a is injected from the injection nozzle 21 with the mold clamped, and the cavity space 5a is filled with the first resin 8a.
The first resin molded part 9 is molded and fixed to the core mold 3a, and in the core mold 3b, a part of the first resin molded part 9 is pressed between the convex parts 7b, and the injection nozzle 22 is pressed.
The second resin 8b is injected from the cavity space 5.
The molded product main body 1 is molded in step b. Then, as shown in FIG. 9, the mold is opened and the molded product M is taken out using the extrusion pin 12, and the rotary plate 13 is turned half a turn, the mold is clamped again, and the above operation is repeated to produce the molded product M. .

In addition, in the above description, the first resin molded part 9
The fixing method is not limited to the above method, and the tapered portion 9a at the peripheral edge may be curved. 1st
The resin 8a and the second resin 8b are preferably compatible, and the resin components may be the same as long as the colors are different. Molded product body 1 and unique color part 2
can be molded into any shape, and the mold can be changed accordingly. Furthermore, the present invention is applicable not only to center caps but also to the manufacture of synthetic resin molded products for other vehicles.

As explained above, according to this invention,
The configuration is such that the first resin is injected and the first resin molded part is fixed to the core mold, and then the second resin is injected, which eliminates the need for conventional inserts such as resin plates, and automates molding. Moreover, it is possible to prevent deformation of the first resin molded part, and to produce a synthetic resin molded product having a uniform and unique appearance with an excellent appearance. 1st
By forming a tapered part in the first resin molded part, the risk of deformation of the first resin molded part is further reduced, which allows sufficient injection pressure, and the resin flows quickly and uniformly, resulting in a better appearance. An excellent molded product can be obtained, and the effect of reducing the occurrence of sink marks can be obtained.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the center cap, Figure 2 is a perspective view showing the center cap.
The figure is a vertical sectional view of a mold showing a conventional manufacturing method, and FIGS. 3 to 7 show an embodiment of the present invention.
3 is a vertical sectional view of the mold showing the molding state in the first step, FIG. 4 is a perspective view of the core mold after the first step molding, FIG. 5 is a perspective view of the first resin molding part, 6 is a cross-sectional view thereof, FIGS. 7 A to C are vertical sectional views of the mold showing the molding state in the second step, respectively, FIG. 8 is a vertical sectional view showing the mold clamping state of the manufacturing equipment, and FIG. 9 FIG. 2 is a vertical cross-sectional view showing the mold in an open state. In each figure, the same reference numerals indicate the same or equivalent parts, M is the molded product, 1 is the molded product body, 2 is a different color part, 3, 3a, 3b are the core mold, 4a is the first cavity mold, 4b is the first cavity mold. 2 cavity type, 5,5
a, 5b are cavity spaces, 7, 7b are convex parts, 8
a is the first resin, 8b is the second resin, 9 is the first resin molded part, 10 is the fixing pin, 12 is the extrusion pin,
13 is a rotating plate, 15 and 16 are mold mounting plates, 21,
22 is an injection nozzle.

Claims (1)

[Claims] 1. Clamping the core mold and the first cavity mold, injecting the first resin, and forming a peripheral edge tapered from the surface side toward the bottom on the tip surface of the core mold. a step of molding and fixing the first resin molded part, and compressing a part of the first resin molded part with a convex part of a second cavity mold, and forming a first resin mold located around the convex part. The core mold and the second cavity mold are clamped so as to form a cavity space between the non-tapered part and the tapered peripheral part of the part and the second cavity mold, and the mold has different color tones. Second
A method for manufacturing a synthetic resin molded article having a different color portion, the method comprising: injecting the resin and forming a second resin molded portion leaving the pinched portion. 2. A method for producing a synthetic resin molded product having a different color portion as set forth in claim 1, wherein the first resin molded portion is fixed by a fixing pin formed in a core shape. 3. A method for producing a synthetic resin molded product having a different color portion as claimed in claim 1 or 2, wherein the core mold is rotated and clamped with the first and second cavity molds in sequence.