JPH03143614A - Two-color molding method - Google Patents

Abstract

PURPOSE:To obtain a two-color molded product whose facial accuracy is high, by a method wherein a runner is cut off at the time of mold break after molding of the primary molded product by making use of a side gate, and after ejection of the runner, the secondary molded product is molded with a secondary side cavity. CONSTITUTION:In the case where an optical parts 1 are molded, mold clamping is performed by moving a movable side mold 5 from a broken state of a mold and when acrylic resin in a molten state is filled into the primary side cavity 14 and a cavity 28 through a nozzle, the same becomes a light conduction body 2. Then when a movable side mold 5 is moved downward, the same is lowered under a closed state of a mold breaking surface PL, becomes the broken state of the mold, a runner generated with the primary shot is cut with a small diameter part P when a rotary body 31 is turned. Then when the second product ejector plate 27 is moved upward after lowering of the primary molded product 2, a sprue and the runner Y are discharged. When polycarbonate resin in a molten state is filled into the secondary side cavity 15 through a nozzle by performing mold clamping after the primary molded product 2 is confronted with the secondary side cavity 15, the polycarbonate resin becomes a light shielding body 3 and the light shielding body 3 is stuck to a part of the light conduction body 2.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a two-color molding method in which primary molding and secondary molding are performed using one mold clamping device, and in particular, a transparent resin is used as the resin for the primary molding. The present invention relates to a two-color molding method suitable for use in the case of using.

[Conventional technology]

The two-color molding method injects two types of resin into one mold clamping device to perform primary molding and secondary molding, and is widely used as a molding method for various parts such as dials and key tops. There is.

The conventional two-color molding method is
After injecting the first resin into the next cavity and molding the primary molded product, the mold is opened, and the movable side is rotated so that the primary molded product is positioned in the secondary cavity, and then again. Close the mold and inject the second resin into the secondary cavity 7.
A secondary molded product is formed in which a first resin and a second resin are integrated. Here, when feeding the primary molded product to the secondary cavity, the primary molded product must be separated from the nozzle for primary molding, so for the primary side, the gate is closed when the mold is opened. A tunnel gate (also called a submarine gate) that can be cut is used.

[Problem to be solved by the invention]

By the way, in the conventional two-color molding method mentioned above, since a tunnel gate is used as the gate on the primary molding side, the pressure loss of the resin at the gate part is large and the primary bottom shaped product has whiskers. The problem was that it was easy to occur. For this reason, it is unsuitable for moldability of optical components that require high surface precision such as light guides, and when molding such optical components, a side gate with low pressure loss is equivalent to a primary molded product. After the parts are molded, a light-shielding paint, which corresponds to secondary molding, is manually applied to some parts of the parts, which inevitably increases manufacturing costs.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art, to enable a color molding method without shrinkage, and to provide a two-color molded product with high surface precision.

[Means to solve the problem]

In order to achieve the above object distantly, the present invention provides a primary molded product by filling a primary cavity with a first resin, and then opening the mold and transferring the primary molded product to a secondary cavity. In the two-color molding method, in which the secondary molded product is formed by filling the secondary side cavity with a second resin after closing the mold at the position, the primary molded product is molded using a side gate. After molding, when opening the mold of this primary molded product, the mold opening force is converted into rotational force to cut the runners of the primary molded product, and then the unnecessary cut runners are ejected. , the secondary molded product is molded in the secondary cavity.

[Effect]

When the primary molded product is molded using a side gate, there is less pressure loss, so it is difficult to order the primary molded product to have sink marks. then 1
When opening the mold of the next molded product, if the mold opening force is converted into rotational force and drives the rotation mechanism, the lunch of the primary molded product can be cut in the mold clamping device by this rotation mechanism, so the primary molded product Secondary forming can be performed on the material.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

First, the optical component molded by the two-color molding method according to this embodiment will be explained using FIGS. 8 to 1O. FIG. 8 is a plan view of the optical component, FIG. 9 is a front view thereof, and FIG.
The figure is a sectional view taken along line CC in FIG. 9.

In these figures, 1 generally indicates an optical component, and the optical component 1 consists of a light guide 2 and a light shield 3, which are molded by the two-color molding method described later. The light guide 2
is made of transparent resin (acrylic resin in the case of this embodiment) and has an inclined portion 2a divided into three parts and two semi-cylindrical portions 2b.

On the other hand, the light shielding body 3 is made of opaque resin (white polycarbonate resin in the case of this embodiment), and is provided on a part of the side surface of the light guide 2 except for the inclined part 2a and the semi-cylindrical part 2b. . Therefore, if key tops (not shown) are arranged to face each of the inclined parts 2a, and light sources (not shown) are arranged to face each of the semi-cylindrical parts 2b, the light emitted from the light sources can be directed to the light guide 2. The light can be guided to each key top through the light guide 2, and the light shield 3 can prevent light from leaking from the side surface of the light guide 2.

Next, the method for molding the optical component 1 will be described in FIGS. 1 to 72.
This will be explained using figures.

Fig. 1 is a sectional view showing the schematic structure of the mold clamping device, Fig. 2 is a bottom view of the stationary side plate provided in the mold clamping device, and Fig. 3 is a bottom view of the fixed side plate provided in the mold clamping device.
The figure is a plan view of the movable side plate provided in the mold clamping device, and FIG. 1 is a cross section taken along the line A-A in FIG. 2 and B-B'! in FIG. 3. Each corresponds to the fA cross section.

In FIG. 1, reference numerals 4 and 5 collectively indicate a stationary mold and a movable mold, and PL indicates a mold opening surface.

The fixed mold 4 includes a fixed mounting plate 6, a template 7, and a fixed plate 8, and the template 7 and the fixed plate 8 are integrated with each other.

One end of a stop pin 9 is fixed to the fixed side mounting plate 6, the other end of the stop pin 9 is inserted through the template 7 and the fixed side plate 8, and a washer 10 is attached to the tip of the bolt 11.
is fixed by. The washers 10 protrude from four locations on the lower surface of the fixed plate 8, and the template 7 and the fixed plate 8 are attached to the fixed side until the fixed plate 8 contacts each washer 10, as shown in FIG. It is designed to be able to slide against the plate 6. Further, a first spool 12 and a second spool 13 are formed on the fixed side mounting plate 6, and these spools 12° 13 are connected to the template 7 and the fixed side plate 8. Although not shown, the nozzles of different injection machines are connected to both spools 12 and 13, and in this embodiment, acrylic resin is supplied from the first spool 12, and polycarbonate resin is supplied from the second spool 13. is now ejected.

As is clear from FIG. 2, a pair of primary cavities 14 are formed in the right half of the stationary plate 8, and a pair of secondary cavities 15 are formed in the left half of the fixed plate 8. The side cavity 15 is the primary flight cavity 14
It is formed thicker than the . Primary cavity 1
4 communicates with the first spool 12 via a primary gate part 16 and a primary runner part 17, and a secondary cavity 15 communicates with the first spool 12 through a primary gate part 18 and a secondary runner part 19.
The primary side gate part 16 and the secondary side gate part 18 are side gates located on the mold opening surface.

The base ends of a pair of bottle bodies 20 are fixed to the fixed side mounting plate 6, and these pin bodies 20 pass through the mold plate 7 and the fixed side plate 8 and face the movable side mold 5. Both bottle bodies 20 face each other with the first spool 12 interposed therebetween, and a pin 21 is fixed to each free end thereof. Furthermore, lock holes 22 are formed at the four corners of the fixed side plate 8.

On the other hand, the movable mold 5 includes a movable plate 23, a backing plate 24 fixed to the movable plate 23, and a tζ runner projecting plate 25 that is slidable with respect to the movable plate 23.
first and second slideable with respect to the launch protrusion plate 25;
It is equipped with product protruding plates 26, 27, etc., and can be rotated about a rotation axis K shown by a dashed line in FIG. As is clear from FIG. 3, in the movable plate 23, a cavity 28 corresponding to the primary cavity 14 of the fixed plate 8 and a cavity 29 corresponding to the secondary cavity 15 are all formed in the same shape. A rotation mechanism 30 is provided at the center of the spool launch portion of each of these cavities 28 and 29.

FIG. 4 is a perspective view of the rotation mechanism 30. As shown in the figure, the rotation mechanism 30 is composed of a rotating body 31 and a support body 32 containing a bearing (not shown). It is fixed to the movable plate 23 and rotatably supports the rotating body 31. A concave groove 33 is formed on the upper surface of this rotary body 31, and the concave groove 33 is connected to the first and second grooves when the mold is closed.
It is arranged to face the spools 12 and 13 of. Further, a pair of guide grooves 34 are formed spirally around the rotating body 31, and these guide grooves 34 are connected to the pin 21.
For this purpose, the movable side plate 23 has an escape hole 35 that allows insertion of the pin body 20.
is formed.

As is clear from FIGS. 1 and 3, a plurality of product ejection pins 36 are provided on the first and second product ejection plates 26, 27.
These product ejecting pins 36 pass through the runner ejecting plate 25 and the backing plate 24 to reach the cavities 28 and 29 of the movable plate 23. Further, a plurality of runner protrusion pins 37 are fixed to the runner protrusion plate 25, and two of these launch protrusion pins 37 pass through the backing plate 24 and reach the groove 33 of the rotating body 31. The remaining launch protruding pins 37 pass through the backing plate 24 and reach the runner portion of the movable plate 23. Further, parting locks 38 made of synthetic resin are fixed to the four corners of the movable side plate 23.
Escape holes 39 are formed in the vicinity of the stop bins 9 to allow insertion of the stop bins 9 therein. The parting lock 38 protrudes from the upper surface of the movable plate 23 and is press-fitted into the lock hole 22 of the stationary plate 8 when the mold is closed.

FIGS. 5(a) to 5(h) are explanatory diagrams showing a certain molding process of the mold clamping device described above, and FIGS. 6 and 7 are explanatory diagrams of the operation of the rotating mechanism 30 during the molding process. First, Figure 5 (
From the mold open state shown in a), the movable mold 5 is moved upward by a drive source (not shown) to bring it into the mold closed state shown in FIG. 5(b). When the mold is closed, the molten acrylic resin is transferred from the nozzle of the injection machine to the first spool 12.
7. Primary side cavity 1 via primary side gate part 16
4 and fills into the cavity 28. This injected resin enters the light guide 2 (1) in the cavity 14.28.
Next molded product). In this case, since the primary side gate portion 16 is a side gate with little pressure loss, almost no sink marks occur in the primary molded product.

When the movable mold 5 is moved downward from the state shown in FIG.
is press-fitted into the lock hole 22, the fixed plate 8 moves down together with the movable play 1-23, that is, with the mold opening surface PL closed, and the lower surface of the fixed plate 8 touches the stop pin 9. When the movable plate 23 comes into contact with the washer 10, it separates from the fixed plate 8 and moves as shown in FIG.
) will be in an open state. In this initial state of mold opening, the pin body 20 fixed to the fixed side mounting plate 6 is displaced relative to the rotation mechanism 30 of the movable side plate 23, and the pin 21 moves from the bottom to the top along the guide groove 34 of the rotating body 31. In order to move to , the rotating body 31 rotates by a predetermined angle.

That is, the runner used in the primary shot of FIG. 5(b) is connected to the spool at the small diameter portion P as shown in FIG. 6, but when the rotating body 31 rotates as described above, the runner shown in FIG. As shown in , the runner is cut at the small diameter part P, and the primary molded product 2
Runner X on the side and runner Y on the rotating body 31 side (spool side)
It is separated into Note that this cutting process is performed while the template 7 is separated from the fixed mold mounting plate 6 by a predetermined stroke S, and since the mold opening surface PL is closed during this time, the lunch can be easily cut even with a small rotational force. be able to.

After the primary molded product 2 is lowered together with the runner and spool by opening the mold as shown in FIG. 5(C), the second product projecting plate 27 is moved by a drive source (not shown) as shown in FIG. 5(d). Move upwards. When the second product protrusion plate 27 rises in this way, the runner protrusion plate 25 approaches the backing plate 24 in conjunction with this, so the runner protrusion pin 37 protrudes from the upper surface of the movable side plate 23, and the launch protrusion pin 37 The spool and unnecessary runner Y are discharged. In this case, since the product ejection pin 36 fixed to the first product ejection plate 26 does not rise, the primary molded product 2 and the runner X connected thereto remain on the movable side 11/-t 23.

Next, as shown in FIG. 5(e), the movable mold 5 is rotated 180 degrees around the rotation axis K, and the above-mentioned primary molded product 2 is
is opposed to the secondary cavity 15 of the stationary plate 8.

Thereafter, as shown in FIG. 5(f), the mold is closed again, and the molten polycarbonate resin is injected into the second spool 13.secondary launch part 19.2 from the nozzle of another injection machine.
The secondary side cavity 15 is filled through the next side gate part 18. This injected resin enters the secondary cavity 15.
The light shielding body 3 becomes the light shielding body 3 inside, and thereby a secondary molded product in which the light shielding body 3 is adhered to a part of the light guide body 2 is obtained.

Thereafter, the mold is opened as shown in FIG. 5(g), and finally, as shown in FIG. 5(h), when the first product ejecting plate 26 is moved upward, the product ejecting pin 36 and the runner ejecting pin At 37, the secondary molded product is discharged together with the runner and the spool, and the optical component 1 described above is obtained. In this way, the series of two-color molding steps is completed.

It goes without saying that the resin used in the first shot and the second shot is not limited to the above examples, and it is also possible to use an opaque resin for both shots.
In this case, sink marks can also be prevented.

〔Effect of the invention〕

As explained above, according to the present invention, when opening the mold after primary molding, the mold opening force can be converted into rotational force to cut the runners of the primary molded product, so it is possible to cut the runner of the primary molded product. It is possible to use a side gate with little pressure loss, and it is possible to provide a two-color molded product with high surface accuracy.

[BRIEF DESCRIPTION OF THE DRAWINGS] All the figures relate to embodiments of the present invention, and FIG. 1 is an explanatory diagram showing the schematic structure of the mold clamping device, FIG. 2 is a bottom view of the fixed side play 1-, and FIG. A plan view of the movable side plate, FIG. 4 is a perspective view of the rotating mechanism, FIG. 5 is an explanatory diagram of the molding process, FIGS. 6 and 7 are explanatory diagrams of the operation of the rotating mechanism, and FIG. 8 is a plane view of the optical component. Figure 9 is the front view, Figure 10 is the C-C of Figure 9.
It is a sectional view along a line. ４・・・・・・・・・Fixed side mold, ５・・・・・・・・・
・Movable side mold, 6...Fixed side mounting plate, 8
......Fixed side plate, 9...
...Stop pin, 12...First spool, 13...Second spool, 16.
......Primary side gate section, 20...
...Pin body, 21...Pin, 22...
......Lock hole, 23...Movable side plate, 30...Rotation mechanism, 31.
...... Rotating body, 32... Support body, 38... Parting lock. Figure 2 Figure 3 Figure 7 Figure 4 Ward 6? Figure I5! IA (C) (d) Figure 5 26 f Shoes (h) Figure 1i8 Figure 9 Figure 10

Claims (1)

[Claims] After filling the primary cavity with the first resin and molding the primary molded product, the mold is opened to position the primary molded product in the secondary cavity, the mold is closed at that position, and then the 2
In a two-color molding method in which a second molded product is molded by filling the next cavity with a second resin, after the primary molded product is molded using a side gate, when the mold of this primary molded product is opened, The mold opening force is converted into rotational force to cut the runners of the primary molded product, and then the cut unnecessary runners are ejected, and after that, the secondary molded product is molded in the secondary cavity. A two-color molding method characterized by: