JPS60122125A - Multicolor forming method of synthetic resin - Google Patents

Abstract

PURPOSE:To elevate the productivity with a shorter cycle time by a method wherein after the injection molding of a seal piece, molding components are injection molded simultaneously or separately on both sides thereof to be integrated with the seal piece and secure the separation between the components. CONSTITUTION:A resin injection molded into cavities of dies 11 and 12 with an injection cylinder 4 is poured into a die cavity via a hot runner 12a of a fixed die 12 to form two seal pieces 15, for instance, having a necessary as well as sufficient dimensions on the mobile die 13. Thereafter, injection cylinders 4 and 6 for injecting resins in different colors are abutted against respective pushpulls of the fixed die 13 and, for example, an injection molding is performed into the die cavities simultaneously. Thus, a colored resin molding integrated with the seal piece 15 is formed. Poor separation can be effectively prevented simply by arranging accuracies of both the dies 12 and 13 for the molding part of the seal piece 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a multicolor molding method for synthetic resin, which produces color-coded resin moldings by multiple injection moldings.

(Conventional technology) For example, large car bumpers, aprons, etc.

A conventional method for molding mold parts in multiple colors is exemplified in FIG.

This method is carried out by using a common movable mold 1 that is reciprocated in the vertical direction, and two fixed molds 2 and 3 that are arranged above the movable mold 1 and driven in the horizontal direction. According to this method, first, a specific color is injected into a mold cavity formed by a common movable mold 1 and one fixed mold 2 by using an injection cylinder as shown in FIG. The molded body component part 5 subjected to the above steps is injection molded, and then,
As shown in ) in FIG. 1, the movable mold 1 is lowered and the mold is opened with the molded body component 5 placed thereon, and the mold is opened.
The fixed molds 2 and 8 are moved horizontally to bring the other fixed mold a to a position directly above the movable mold 1, and the movable mold 1 is raised to form a mold cavity between it and the fixed mold 3,
Furthermore, as shown in FIG. 1(C), another injection cylinder 6 is used to inject into the mold cavity a molded body component 7 having a color different from that of the molded body configuration +t+S 5 described above. Then, by fusing and solidifying the component part 7 with the component part 5, color-coded resin molded bodies are manufactured.

However, in such a conventional technique, after the molded body component part 5 is molded using the fixed mold 2, the molded body 11I component part 7 is injection molded using another fixed mold 8 to form the image component part. 5 and 7 are directly joined, and due to the machining dimensions of the double-sided fixed mold, there will be variations in the mold contact with the single moving mold, so there will be a slight difference between the other fixed mold and the cut molded body component. If a gap occurs, the next resin will be inserted due to the injection pressure, resulting in poor cutting between the image component parts 5 and 7, which requires no correction.In other words, the color of the image component parts 5 and 7 will change Jlj had a major problem in that it was not possible to clearly divide it into straight lines and other shapes that required a lift. Especially the first one? body structure 1η1 (if the volume or area per mold is large, another solid size j1
There was a problem in that improving the self-t+1 degree between the mold and the initial molded body component was a very difficult task and required a large number of man-hours. Moreover, the image composition parts 5 and 7
Generally, both have a relatively large volume, so even if any of them is molded first, there is a problem that the injection and cooling times in the first molding process will be considerably long, resulting in poor productivity. there were.

(Objective of the Invention) The present invention has been made by focusing on the above-mentioned problems of the prior art, and aims to ensure the separation between the constituent parts of the molded body, shorten the cycle time, and increase productivity. The present invention provides a multicolor molding method for synthetic resins that can be used.

(Structure of the Invention) The multi-color molding method for synthetic resin of the present invention is particularly characterized in that after at least one seal piece is injection molded, constituent parts of the molded body are injection molded on both sides of the seal piece, either simultaneously or separately. It consists of integrating them with a sealing piece.

According to this multicolor molding method for synthetic resin, each molded body component is reliably separated by a relatively small-volume seal piece just contained in the mold cavity when molding the molded body component, so that multiple molded body components are reliably separated. The desired separation of the molded body components is achieved. In addition, by first injection molding a relatively small-volume seal piece, multiple molded body components can be molded simultaneously in the subsequent process. By shortening it, cycle time can be shortened and productivity can be increased.

(Example) The present invention will be explained below based on illustrated examples.

FIG. 2 is a sectional view showing an embodiment of the present invention.

In the figure, 11 indicates a common movable type, and 12.18 indicates a fixed type that is integrally connected in the horizontal direction.1 In this example, the common movable type 11 is vertically connected, and the fixed type 12.1.13 is horizontal. It is driven reciprocatingly in each direction.

The fixed mold 12 here has a mold recess of −(i) for a relatively small-volume seal piece, and the fixed mold 18
The mold has a depression whose contour corresponds to the shape of the resin molded body.

Further, in the figure, 14 indicates a split mold of the fixed mold 12 and 18 that engages with the A-bar hang portion 11a of the movable mold 11, and these divided molds 14 are attached to the tip of a rod 14a extending from the ejector plate. There is. The split mold 14 is moved diagonally by the operation of the rod 14a, and the rod 1
By retreating 4a, the movable mold 11, fixed mold and split mold 1 are separated.
4 is fixed, and the advancing of the rod 14a upon ejection causes separation of both molds and release of the molded product.

In carrying out the present invention using such a mold, first, as shown in FIG. 2(a), the fixed mold 12 is clamped to the movable mold 11, and the injection cylinder is inserted into the mold cavities of both molds. Injection molding is performed according to step 4. Through this injection molding, the resin is made with or without the desired color.
As shown in FIG. 8(a), this example is injected into the mold cavity through the hot runner 12a of the fixed mold 12 and solidified there, so that it is placed on the movable mold 11 with necessary and sufficient dimensions. Then, two seal pieces 15 are formed.

Here, preferably, as in the illustrated example, the seal piece 15
A lip 15a that slightly enters the movable mold is provided at the movable mold 1, and this lip 15a allows the sealing piece 15 to move into the movable mold 1 when the mold is opened.
Effectively prevents departure from 1.

Next, as shown in FIG. 2(b), the mold is opened based on the downward movement of the movable mold 11, and the fixed mold 12.1
8 is moved horizontally, and a fixed mold 18 having a mold recess having a contour corresponding to the shape of the resin molded body and exactly enclosing one seal piece 15 is clamped to the movable mold 11.

Thereafter, as shown in FIG. 2(0), the injection cylinders 4 and 6, which inject resins of different colors, are brought into contact with the respective spur units of the fixed mold 18, and from them, for example, gold is simultaneously produced. Perform injection molding into the mold cavity. During this molding, both molds 11 and 18 are
As shown in the figure, since the seal pieces 15 are opposed to each other in the thickness direction, the resin from one injection cylinder 4 is transferred between the two seal pieces, and the resin from the injection cylinder 6 is transferred between each seal piece 1.
6 to the outside and solidified, the molded body component part 1 (1°1
7 are brought respectively, and color-coded resin molded bodies are produced as a whole.

In addition, according to this example, since the seal piece 15 and the molded body component part 16 are injection molded from the same injection cylinder 4, a resin molded body that is divided into two colors is produced. Molded body component part 1 (1
, 17 colors can of course be selected as required.

According to such a multicolor molding method, by sandwiching the seal piece 15 having a small contact area with the mold in the thickness direction between the molds 11 and 111, the resin injected into both sides of the seal piece 15 (7) is This ensures that the seal piece 15
Since the resin does not flow beyond this point, there is extremely little risk of rejecting the product due to poor cutting.

Regarding the relative angle of 11 degrees between the double-sided molds 12 and 113, only a small-sized mold recess for the seal piece 15 is formed in the fixed mold 12, so the accuracy of the double-sided mold 12 and 18 is based on the seal piece molding part. In particular, simply by aligning the edges, it is possible to sufficiently effectively prevent the occurrence of poor termination.

In addition, in this multicolor molding method, the seal piece 15 of relatively small volume is formed by the first injection JJ (depending on the shape), and a plurality of +ilz shaped body constituent parts 10° 17 are simultaneously formed by the next injection molding. Compared to the prior art in which each component part of the molded body is sequentially injection molded, the time required for the first injection molding can be significantly shortened and the cycle time can be shortened.

By the way, if we look at this in the case of manufacturing a resin molded article of about 2 to 3 kg using a 1500-inch injection molding machine, the time required for the first injection molding is 4.1 seconds, which was about 88 seconds with the conventional technology.
In this invention, the injection molding time (from the start of injection to the end of cooling) can be reduced to about 12 seconds, which is a time reduction of about 15% in the entire molding cycle. Incidentally, the 4-1 molding time of No. 2 No. 11 is almost the same for both.

Furthermore, here, since the volume of the seal piece 1fi is small and its heat capacity is also small, it is sufficiently melted by the heated resin injected to both sides thereof, and as a result, the seal piece 15 and the molded body constituent parts 10, 17 are melted sufficiently. A bond with sufficient strength is provided. In addition, since the internal temperature of the small-volume seal piece 16 is considerably increased by injecting heated resin into both sides thereof, there is a risk that this will cause large thermal deformation to the resin molded body during injection molding of the molded body component. There is no.

FIG. 4 is a sectional view showing an example of changing the shape of the seal piece,
A runner 15b is integrally formed on the side of the seal piece 15 in order to eliminate the possibility that the resin may not flow sufficiently within the mold cavity due to the small volume of the seal piece. According to this example, in addition to reducing the number of gates and providing sufficient flow of the resin to the seal piece 15 having a desired shape, the joint area with at least one molded body component is increased by 7Jl. Further improvement in strength can be brought about.

The present invention has been explained above based on the illustrated example, but the fixed and movable molds are arranged horizontally, the injection molding of a plurality of molded body components is performed sequentially, and the molded body is formed into two molded bodies in the illustrated example. The number of constituent parts can be three or more, and the number of seal pieces can also be increased or decreased as required.

(Effects of the Invention) Therefore, according to the present invention, after injection molding at least one seal piece, the molded body constituent parts are injection molded on both sides of the seal piece simultaneously or separately. By converting them into seal pieces and parts, it is possible to reliably see the color of each molding (+Gl h'tr part) with a simple mold configuration, and it also shortens the cycle time of JIJ and increases productivity. This has the remarkable effect of increasing the

[Brief explanation of the drawing]

FIG. 1 is a molding process diagram showing a conventional example; FIG. 2 is a molding process diagram showing an embodiment of the present invention; FIG. The figure is an enlarged cross-sectional view showing an example of a change in the shape of the seal piece. 11...Movable type 12.13...Fixed type 14...
Split type 15... Seal piece 15a... Lip 15h
...Runners 16, 17... Molded body constituent parts Fig. 1 Fig. 2 [1 Fig. 3 (a) 1 -] 4N

Claims (1)

[Scope of Claims] L: When producing a color-coded resin molded body by multiple injection moldings, the step of injection molding at least a seal piece (15) and both sides of one seal piece (15). to the molded body component (16,1
7) respectively by injection molding and sealing pieces (15).
A multi-color molding method for synthetic resin that combines the process of integrating the