JPH0462019A - Bicolor molding method for cassette half - Google Patents

Abstract

PURPOSE:To more increase the number of moldings in one cycle by filling a primary injection material into the frame molding space of a cavity via the first direct gate, and filling a secondary injection material into the window molding space of a cavity via the second direct gate. CONSTITUTION:First, at the same time of clamping commencement, the tip surface of a core mold body 19 is brought into contact with the carved surface of the stationary mold plate 10. In this state, a primary injection material passed through the first conduit 29 is filled in the frame molding space 37 of a cavity whereby a frame 2 is molded. Next, when the piston rod 22 of a hydraulic cylinder 21 is made retreat therefrom, the core mold body 19 returns and becomes approximately the same as the carved surface of a movable mold plate 13 and, between the tip surface and the carved surface, a window molding space 38 is formed. In this form, after a secondary injection material B passed through the second conduit 30 is filled into the window molding space 38, the gate of the second nozzle 36 is closed by the second torpedo 40, whereby an audio half cassette 4 is bicolor-molded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is characterized by sequentially filling a cavity defined between a male mold and a female mold facing each other with a primary injection material and a secondary injection material. This invention relates to a two-color molding method for a cassette γ-tower 7 for molding an audio cassette half or the like.

U. Prior Art, U. Conventional Art. A conventional audio cassette half as shown in FIG.
It is well known to mold the audio cassette half 4, which includes a transparent window 3 formed in the center of the frame 2, by a two-color molding method. In this two-color molding method, a cavity forming the overall shape of the audio cassette half 4 is defined between the female mold and the male mold, and a primary injection passage is provided in the frame molding space corresponding to the head corresponding part I of this cavity. A side gate is formed, and a direct gate of a secondary injection passage is connected to the JlI molding space of the cavity, and a core that closes the window molding space of the cavity is formed in the male mold. is provided so that it can be moved in and out by a hydraulic cylinder, and during molding, the core is first advanced to close the window molding space, and then primary injection is performed into the frame molding space through the primary injection passage and the side gate. Fill the material, then operate the hydraulic cylinder to move the core back, fill the window molding space of the cavity that was previously closed with the secondary injection material through the secondary injection path and direct gate, and then fill the female mold. The male mold was opened, and the audio cassette half, which was a two-color molded product made of different resins, was taken out along with the runner, and then the runner was cut out or broken off.

In addition, 5 in FIG. 5 is a molded symbol forming part to indicate the A side or the B side of the tape.

[Problems to be Solved by the Invention] Generally, the projected area of a molded product that can be molded with an injection molding machine with a fixed mold clamping capacity is (projected area) x
(In-mold resin pressure): The upper limit is determined by the mold clamping force, and if (projected area) x (in-mold resin pressure) exceeds the mold clamping capacity of the molding machine, the pressure between the female and male molds will increase. When the split surfaces open, resin enters the gap created between the split surfaces, causing cracks in the molded product, resulting in product defects.

In the prior art, the frame portion 2 was filled with the primary injection material through the side gate and molded.
Not only the audio cassette half 4 but also the runner is molded, and the projected area is increased by the runner, and as a result, the female mold and the male mold have a cavity consisting of a frame molding space and a window molding space. There was a problem in that it was not possible to arrange a large number of such devices, resulting in low productivity. Furthermore, in the prior art, when the runner is cut off or broken off after molding, chips are generated, and the chips adhere to the audio cassette half, reducing the commercial value.

The present invention solves the above-mentioned conventional problems, and provides a two-color molding method for cassette halves that can increase the number of half cassettes molded per cycle using a set of female and male molds and increase the commercial value. The purpose is to provide.

[Means for Solving the Problems] In order to achieve the above object, the two-color molding method for a cassette half of the present invention includes filling the primary injection material into the molding space of the cavity frame via a first direct gate, The secondary injection material is filled into the window forming portion of the cavity via the second direct gate.

[Function] In the two-color molding method of the present invention, the window molding space and the window molding space of the cavity are filled with primary and secondary injection materials through the first and second direct gates, respectively. By doing so, it is possible to eliminate runners and form a larger number of cavities into female and male molds, thereby improving productivity.

[Example] Hereinafter, an example of the present invention will be specifically described using FIGS. 1 to 4.

1 and 2 show an example of a mold apparatus for carrying out the two-color molding method of the present invention. In these figures, reference numeral 10 denotes a fixed mold plate which is a female mold, and this fixed mold plate is a female mold. The template 10 is a fixed receiving plate 11. It is attached to the fixed mounting plate 12 via IIA and IIB. Further, a male movable mold plate 13 is movably provided opposite to the fixed mold plate 10, and this movable mold plate 13 includes a movable receiving plate 14° 14A,
14B and a spacer block 15, it is attached to a movable mounting plate 16. and these templates 10.1
A cavity 17 is provided on each opposing surface of the audio cassette half 4, with carved surfaces forming the outer and inner surfaces of the audio cassette half 4, respectively.

As shown in FIG. 4, the cavities 17 include an audio half cassette molding cavity 17A on the negative side and an audio half cassette molding cavity 17 on the other side.
Two sets of B are formed as a pair, and three groups of these two sets are provided to form a total of 12 audio half cassette molding cavities 17A and 17B.

A core pack assembly 18 is provided inside the movable mold plate 13 and the movable receiving plate 14 so as to be movable in the direction of the fixed mold plate 10 of each cavity 17. This core pack assembly 18 is composed of a core mold body 19 for forming the window portion 3 of the audio cassette half 4, and a receiver 20 that supports this core mold body 19. is connected to a piston rod 22 of a hydraulic cylinder 21 disposed inside the movable receiving plate 14B, and by advancing the piston rod 22 of this hydraulic cylinder 21 when closing the mold, the tip surface of the core mold body 19 is By abutting the fixed mold plate 10 and retracting the piston rod 22, the tip surface of the core mold body 19 is configured to be open to the engraved surface of the movable mold plate 13.

The fixed mounting plate 12 has a pair of rogate rings 23.
24 is attached, and sprue bushes 25, 26 are inserted through the fixed mounting plate 12. And these sprue bushes 25, 26 and each manifold 27
The manifold block 28, fixed receiving plate 11 and both mold plates 10.13 each have a first passage 29 for the primary injection material (opaque) and a second passageway 29 for the secondary injection material (transparent).
A passage 30 is formed. In addition, the manifold 27
The length is such that it can be equally distributed from the branch point to the primary and secondary sides. Further, a first sprue 31 is connected to the tip of the first passage 29, and this first sprue 31 corresponds to the symbol forming portion 5 for distinguishing between side A and side B of the tape. The first direct gate 32 is formed by these. The first sprue 31 is provided with a first tobead 34 for sealing the gate of the first nozzle 33, and this tobead 34 is activated by air pressure from an air cylinder (not shown) during injection during molding. It is provided so that it sometimes rises and retreats to open the gate, and then closes the gate at the same time as injection is completed. Further, a second sprue 35 is connected to the tip of the second passage 30, and a second nozzle 36 of the second sprue 35 is used to form the frame portion 2 as the core mold body 19 retreats. A second direct gate 39 is disposed approximately at the center of the window molding space 38 formed within the frame molding space 37 . Further, the second sprue 35 is provided with a second torpedo 40 for sealing the gate of the second nozzle 36.

Next, a method of molding the audio cassette half 4 using the two-color mold configured as described above will be described.

First, at the same time as mold clamping starts, the tip end surface of the core mold body 19 is brought into contact with the engraved surface of the fixed mold plate 10. In this state, the gate of the first nozzle 33 is opened by the first toad 34, and the primary injection material A that has passed through the first passage 29 is transferred from a portion corresponding to the outer surface of the frame portion 2 of the audio cassette half 4 to the frame of the cavity 17. The molding space 37 is filled with the resin, and the frame 2 is thereby molded.

Next, when the piston rod 22 of the hydraulic cylinder 21 is retreated, the core mold body 19 returns, and the distal end surface of the core mold body 19 is in contact with the engraving surface of the movable template 13. A window molding space 38 is formed between them.

In this state, the second nozzle 36 is connected to the second torpedo 4
0, and the secondary injection material B that has passed through the second passage 30 is filled into the window molding space 38 from a portion corresponding to the outer surface of the window 3 of the audio cassette half 4. The gate of the nozzle 36 is closed by the second torpedo 40, thereby forming the audio cassette half 4 in two colors.

After solidification, opening of the mold is started and the audio cassette half 4 is released from the mold.

According to the above two-color molding method, the window molding space 38 is filled with the secondary injection material B via the second direct gate 39, and the frame molding space 37 is filled with the primary injection material A through the first direct injection. By filling through the gate 32, the projected area of the molded product on the fixed mold plate 10 and the movable mold plate 13 can be made the same as that of the plurality of audio cassette halves 4, and more cavities 17 can be provided. Therefore, more audio cassette halves 4 can be molded using the set of fixed mold plate 10 and movable mold plate 13, and productivity can be improved.

Furthermore, in the above-mentioned embodiment, there is no generation of chips associated with the runner after the mold is opened, so that the commercial value can be improved.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and the layout of the cavity may be changed, for example, by appropriately changing the shape of the frame and the window, or by arranging the cavity in the template so that the head corresponding part faces outward. etc., various modifications are possible.

[Effects of the Invention] The present invention fills the primary injection material into the molding space of the frame portion of the cavity through the first direct gate, and fills the secondary injection material into the molding space of the window portion of the cavity through the second direct gate. By filling with cassettes, the projected area of the molded product and the cavities for multiple cassette halves can be increased.
Productivity can be improved by manufacturing more cassette half molded products in one cycle, and product deterioration due to chips can be prevented.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a sectional view, FIG. 2 is a sectional view after primary molding,
FIG. 3 is a partially cutaway perspective view of the first direct gate, FIG. 4 is a plan view of the fixed template, and FIG. 5 is a perspective view of the audio cassette half. 2... Frame 3... Window 4... Audio cassette half 10... Fixed template (female type) 13... Movable template (male type) 17... Cavity 32... First direct gate 37...Frame molding space 38...Window molding space 39...Second direct gate A...Primary injection material B...Secondary injection material Patent applicant Mitsubishi Metals Co., Ltd. Agent Patent Attorney Choshi Taki No. 1 Figure 13 Figure 2

Claims (1)

[Claims] By sequentially filling the cavity defined between the opposing male and female molds with the primary injection material and the secondary injection material, the frame of the cassette half is molded with the primary injection material and the cassette half is In a two-color molding method for a cassette half in which a window portion is molded with a secondary injection material, the primary injection material is filled into the frame molding space of the cavity through a first direct gate, and the secondary injection material is filled into the molding space of the cavity through a first direct gate. A two-color molding method for a cassette half, characterized in that the window molding space of the cavity is filled through a second direct gate.