JPH05309693A - Multicolor molding method - Google Patents

Abstract

PURPOSE:To enhance positional accuracy in the process on and after the secondary molding after primary molding is performed. CONSTITUTION:A primary side resin is injected into the cavity formed between upper and lower molds 40,50 in such a state that both molds are closed to be cured and, thereafter, a core 59 is moved to form a gap at least above the cured resin and a secondary side resin is injected in the gap to be cured to integrate the primary and secondary side resins. Since it becomes unnecessary to feed a primary molded product to a secondary molding side, the accuracy of the molding position of a secondary molded product with respect to the primary molded product and the uniformization of the molded products can be achieved. By enhancing the accuracy of the molding position of the secondary molded product with respect to the primary molded product; a trouble such as taking-out of a product after secondary molding is eliminated and the deformation of a frame can be prevented and, therefore, the disconnection or bending of a wire is not generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor molding method for forming a product by using two or more kinds of resins with a single mold composed of an upper mold and a lower mold.

[0002]

2. Description of the Related Art For example, an optical system of an optical pickup is supported by an actuator base as a base member via a suspension unit in a cantilever manner so as to be moved in a focus direction and a track direction with respect to a disk.

FIG. 1 shows such an optical pickup, in which a lens holder 4 having an objective lens 3 is mounted on an overhanging portion 2 provided on an actuator base 1 as a substrate via a suspension unit 10. It is considered to be a supported structure.

The suspension unit 10 has a structure in which a wire 13 is stretched between resin coupling members 11 and 12.

Such a suspension unit 10
Is molded by, for example, the insert molding apparatus shown in FIG.

That is, the wire 2 is formed from the drums 20 and 21.
3 and the frame 22 are supplied via the supply mechanism 241 to the insert molding apparatus 30 side that performs the primary molding. The wire 23 and the frame 22 sent to the insert molding device 30 side have the insert molding device 3 in order to eliminate slack and the like.
A plurality of tension rollers 31, 3 arranged near 0
A predetermined tension is applied by 2 in the direction of the arrow.
This prevents the wire 23 from being displaced or deformed due to the pressure applied at the time of resin insertion, which will be described later.

In this state, when a cylinder mechanism (not shown) is actuated differentially and the rod 33 is pulled downward, the upper mold 35 attached to the movable base 34 descends to the lower mold 36 to perform mold clamping. Be seen.

When the mold clamping is completed, a predetermined amount of resin is injected from the injection machine 37, the molten resin is filled in the predetermined cavities in the upper mold 35 and the lower mold 36, and is cooled and solidified.

As a result, as shown in FIG.
3, the coupling blocks 11a and 12a and the bridge portion 12b are integrated. During this insert molding, four sets (eight in total) of the suspension units 10 are molded at one time. In FIG. 3, reference numeral 12c
Is a resin protrusion fixed by insert molding, and is joined to the joining block 12a.

However, the viscoelastic members 12d, 12 shown in FIG.
Since e is molded in the next step, it has not been molded in the steps so far.

The primary molded product produced by the insert molding apparatus 30 is sent to the insert molding apparatus 40 side in the next step. On the insert molding device 40 side, the wire 2
A predetermined tension is applied to the frame 3 and the frame 22 by a plurality of tension rollers 41 and 42 arranged near the insert molding device 40 in the arrow direction.

In this state, similarly to the above, a cylinder mechanism (not shown) differentially pulls the rod 43 downward, and the upper die 45 attached to the movable base 44 descends to the lower die 46, The mold is clamped.

When the mold clamping is completed, a predetermined amount of the elastomeric engineering plastic is injected from the insert machine 47, so that the viscoelastic member 12 shown in FIG.
d and 12e are molded.

As a result, the suspension unit 10
The two insert molding apparatuses 30 and 40 perform two-color molding with resin and elastomer-like engineering plastic.

Here, the wire 23 and the coupling block 11
As the resin which is the material of a and 12a, those having the same linear expansion coefficient are selected. With such selection,
The sagging of the wire 23 due to the difference in linear expansion coefficient that occurs during cooling after molding is prevented.

The product unit which has been subjected to the secondary molding by the insert molding device 40 is obtained by cutting the frame 22 into a predetermined length by a cutter machine (not shown).

Further, in FIG. 3, four parts 10a ...
By cutting 10d, the suspension unit 10 which is a product shown in FIG. 4 is obtained.

When incorporating the suspension unit 10 obtained by the two-color molding method into an optical pickup, the work of simply fixing the coupling blocks 11a and 12a of the suspension unit 10 to the actuator base 1 and the lens holder 4 is performed. Therefore, not only skill is not required, but also the whole mounting work can be simplified.

[0019]

However, in the above-described conventional two-color molding method, after the primary molding is performed by the insert molding device 30, the primary molded product is sent to the insert molding device 40 side which performs the secondary molding. A process is needed.

Therefore, when the feed accuracy of the primary molded product in the insert molding device 40 is inferior, the positioning accuracy of the primary molded product in the insert molding device 40 decreases, and the elastomeric engineering to be molded on the primary molded product. Since the molding position of the plastic is displaced, the molded products vary.

When a product with such variations is incorporated in an optical pickup, the adjustment of focus and tracking of the optical system differs depending on the product with variations, which makes the adjustment extremely complicated and the optical system. It becomes difficult to keep the accuracy of the constant.

In addition to this, since the feeding accuracy of the primary molded product is inferior, the frame 22 is deformed when the product enters the upper mold 45 and the lower mold 46 in the secondary molding by the insert molding device 40. However, the wire 23 may be broken or bent, and in this case, there is a problem that the yield of the product is reduced. The present invention has been made in response to such a situation, and by performing multicolor molding with a single mold, it is possible to eliminate variations in molded products and to improve product yield. It is an object of the present invention to provide a multicolor molding method which can be performed.

[0023]

The multicolor molding method of the present invention comprises:
In order to achieve the above object, in a multicolor molding method of forming a product by using two or more kinds of resins with a single mold including an upper mold and a lower mold, the upper mold and the lower mold are After injecting the primary side resin into the cavity of the mold in a closed state to cure the resin, the core is moved to form a void in at least the upper, lower, left or right side of the cured resin, and the void is formed in the void. It is characterized in that the secondary resin is injected and cured to integrate the primary resin and the secondary resin.

[0024]

In the multicolor molding method of the present invention, it is intended to improve the positional accuracy and the like in the steps after the secondary molding after the primary molding, and the upper mold and the lower mold are closed. After injecting the primary side resin into the cavity of the mold and curing it, move the core to form voids on at least top, bottom, left and right of the cured resin, and inject the secondary side resin into this void Then, the primary side resin and the secondary side resin are integrated.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, the same parts as those in FIG. 2 are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 5 shows an insert molding apparatus according to an embodiment of the multicolor molding method of the present invention.

The insert molding apparatus shown in the figure applies a predetermined tension in the arrow direction to the wire 23 and the frame 22 supplied from the drums 20 and 21 via the supply mechanism 24 by a plurality of tension rollers 31 and 32. Two-color molding is performed in the closed state.

FIG. 6 shows the internal structure of the upper mold 40 and the lower mold 50. As shown in the figure, the upper die 40
The lower die 50 is provided with slide pieces 41 and 51. A recess 42 is formed in the slide piece 41. The slide piece 51 is provided with an engagement protrusion 52 that matches the shape of the recess 42. Slide pieces 41, 51
Are connected by fitting the engaging projections 52 into the recesses 42.

A movable shaft 61 of a hydraulic cylinder 60 is attached to the side surface of the slide piece 51.

When the hydraulic cylinder 60 is driven and the movable shaft 61 is drawn and drawn in the directions of arrows a and b, the slide pieces 41 and 51 are drawn and drawn in the same direction.

The rails 4 are attached to the slide pieces 41 and 51.
3, 53 are provided. On each rail 43, 53,
Inclined surfaces 44, 45, 54, 55 are provided.

Rails 46 and 56 are provided at positions close to the inner surfaces of the rails 43 and 53. Each rail 4
Slopes 47, 48, 57, 58 are provided on the sides of the rails 6, 56 facing the inner surfaces of the rails 43, 53.
The inclined surfaces 47 and 48 of the rail 46 are engaged with the inclined surface 71 of the movable piece 70 having the injection hole 72 shown in FIG.

The head of the movable top 70 is in contact with the inclined surfaces 44 and 45 of the rail 43. The head of the movable top 70 is formed with a slight inclination so as to fit the inclined surfaces 44 and 45 of the rail 43. When the slide piece 41 is fed in the direction of the arrow b, the inclined surface 71 of the movable piece 70 is pushed up along the inclined surfaces 47 and 48. Movable piece 7
When 0 moves upward and the slide piece 41 is fed in the direction of arrow a, the head of the movable piece 70 is pushed down along the inclined surfaces 47 and 48, so that the movable piece 70 moves downward.

The inclined surfaces 57 and 58 of the rail 56 are engaged with the inclined surface (not shown) of the core 59. Here, the inclined surface of the core 59 has the same shape as the inclined surface 71 of the movable piece 70.

The head 59a of the core 59 contacts the lower end surface of the movable top 70 to close the injection hole 72. The lower end of the core 59 is in contact with the inclined surfaces 54 and 55 of the rail 53. The lower end of the core 59 has inclined surfaces 54, 55 of the rail 53.
It is formed with a slight inclination so as to conform to.

When the slide piece 51 is fed in the direction of arrow a, the lower end of the core 59 is pushed up along the inclined surfaces 54 and 55. When the core 59 moves upward and the slide piece 51 is fed in the direction of the arrow b, the inclined surface of the core 59 is pushed down along the inclined surfaces 57 and 58, so that the core 59 moves downward. Therefore, the gap between the lower end surface of the movable piece 70 and the head portion 59a of the core 59 is set by the amount of the slide pieces 41, 51 drawn and drawn.

Further, the rail 43 is provided with an injection path 49 which is tapered downward. A runner plate 80 is arranged on the upper surface of the rail 43. The runner plate 80 is formed with an injection path 81 which is tapered downward.

In the state of FIG. 6, when the slide piece 41 is pulled in the direction of the arrow b and the injection path 49 of the rail 43 coincides with the injection path 81 of the runner plate 80, it also coincides with the injection hole 72 of the movable piece 70. To do. In this state, a material used for secondary molding, for example, a thermoplastic elastomer is injected. Here, in order to prevent thermal deformation and the like of the primary molded product, it is preferable that the melting temperature of the material used for the secondary molding be the same as or lower than that of the primary molded product. Further, since it is inserted into the primary molded product, it is preferable that it has good physical properties and moldability.

Subsequently, an insert molding method by the insert molding apparatus 30A having the above-mentioned structure will be described with reference to FIG. In addition, in the drawings described below, the injection of the materials for the primary molding and the secondary molding may be performed by the method shown in FIG. 9A, for example.

First, as shown in FIG. 7A, the head portion 59a of the core 59 is brought into contact with the lower end surface of the movable piece 70 so that the injection hole 72 is formed.
The resin from the nozzle 100 is injected through the injection path 40a of the upper mold 40 when the nozzle is closed. The injected resin fills the cavity 50b of the lower mold 50 through the injection path 50a of the lower mold 50.

After the resin filled in the cavity 50b is hardened, the hydraulic cylinder 60 is driven to move its movable shaft 61.
When the slide pieces 41, 51 are drawn in the direction of the arrow b by pulling in, the inclined surface 71 of the movable piece 70 is pushed up along the inclined surfaces 47, 48, and the movable piece 70 moves upward. On the other hand, the inclined surface of the core 59 is the inclined surface 57,
By being pushed down along 58, the core 59 moves downward.

As a result, a predetermined gap is provided between the lower end surface of the movable top 70 and the head portion 59a of the core 59.

When the lower end surface of the movable piece 70 and the head portion 59a of the core 59 are separated in this way, as shown in FIG. 7B, the core 59 is placed at the center of the cured resin 90. A void 91 matching the shape of the head 59a is formed. Further, a gap 92 is formed between the lower end surface of the movable piece 70 and the cured resin 90 as the lower end surface of the movable piece 70 moves upward.

In this state, the above-mentioned secondary molding material having a lower melting temperature than the resin 90 is injected from the nozzle 101. The injected secondary molding material is filled into the voids 91, 92 from the injection path 81 of the runner plate 80, the injection path 49 of the rail 43 and the injection hole 72 of the movable top 70.

After the secondary molding material filled in the voids 91 and 92 is cured, the upper mold 40 and the lower mold 50 are separated from each other to obtain a product.

The two-color molding method described above is shown in FIG.
As shown in FIG. 9, the nozzle 100 and the nozzle 101 are arranged so as to be substantially orthogonal to each other. However, the present invention is not limited to this, and as shown in FIGS.
The nozzles 101 may be horizontally opposed to each other, or the nozzles 100 and 101 may be erected on the upper surface side of the upper mold 40.

FIG. 10 shows the nozzle 10 shown in FIG. 9 (b).
This is an example of a two-color molding method according to the arrangement configuration of 0 and 101, in which the primary molding material is injected from the nozzle 100 into the cavity of the lower mold 50 and the core 59a and the upper mold 40,
After this is hardened, the core 59a is lowered. At this time, the protrusion 59b of the core 59a is formed on the primary molding material 50b.
A void that matches the shape of is formed. Then, the nozzle 10
The secondary molding material 50c is injected into the cavity between the core 59a and the upper mold 40 by 1 and is cured. At this time, the primary molding material 50c is filled with the secondary molding material 50c filled in the space matching the shape of the protrusion 59b of the core 59a.
The adhesion between b and the secondary molding material 50c becomes more reliable.

As described above, in this embodiment, the primary mold resin is injected into the cavity of the mold with the upper mold 40 and the lower mold 50 closed to cure the resin, and then the core 59 is moved. A void is formed in at least an upper portion of the cured resin, and the secondary resin is injected into the void and cured to integrate the primary resin and the secondary resin.

Therefore, it is not necessary to feed the primary molded product to the secondary molded side as in the conventional case described above, so that the precision of the molding position of the secondary molded product with respect to the primary molded product can be improved and the molded product can be made uniform. Can be promoted.

Further, since the precision of the molding position of the secondary molded product with respect to the primary molded product is improved, there is no problem in taking out the product after the secondary molding and deformation of the frame 22 can be prevented. The wire 23 is not broken or bent.

Further, since the molded products can be made uniform, the product yield can be improved.

[0052]

As described above, according to the insert molding method of the present invention, after the upper side mold and the lower mold are closed, the primary side resin is injected into the cavity of the mold and cured. , A void is formed in at least the upper, lower, left, or right of the resin that is cured by moving the core, and the secondary resin is injected into the void and cured to integrate the primary resin and the secondary resin. I did it.

Therefore, by performing multi-color molding with a single mold, it is possible to eliminate variations in molded products and improve the product yield.

[Brief description of drawings]

FIG. 1 is a plan view for explaining a suspension unit for elastically supporting a lens holder on a conventional actuator base.

FIG. 2 is a view showing a conventional insert molding apparatus for molding the suspension unit of FIG.

FIG. 3 is a plan view showing a product of a suspension unit molded by the insert molding apparatus of FIG.

FIG. 4 is a plan view showing a suspension unit cut out from the frame of FIG.

FIG. 5 is a diagram showing an embodiment of an insert molding method according to the insert molding method of the present invention.

6 is a cross-sectional view showing the internal structure of the upper mold and the lower mold of FIG.

7 is a perspective view showing a movable top that moves up and down by the rail of FIG.

8 is a sectional view showing a two-color molding method by the insert molding apparatus of FIG.

FIG. 9 is a diagram showing a variation of the location of the nozzle in the insert molding apparatus of FIG.

FIG. 10 is a diagram showing an example of a molding method when the nozzles in FIG. 9B are opposed to each other.

[Explanation of symbols]

 26,68 Drum 22 Frame 23 Wire 24 Feeding mechanism 30A Insert molding device 40 Upper mold 50 Lower mold 41,51 Sliding piece 60 Hydraulic cylinder 43,46,53,56 Rail 59 Cores 70 Movable piece 80 Runner plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomoyoshi Arai 6-1, 1-1 Fujimi, Tsurugashima City, Saitama Pioneer Precision Co., Ltd. (72) Inventor Kazumasa Kobayashi 228-5 Morinoue, Kashiwara, Sayama, Saitama Prefecture Kobayashi Engineering Co., Ltd.

Claims (1)

[Claims] 1. A multicolor molding method for forming a product by using two or more kinds of resins in a single mold including an upper mold and a lower mold, wherein the upper mold and the lower mold are closed. After injecting the primary side resin into the cavity of the mold and curing it, a core is moved to form a void on at least the upper, lower, left or right side of the cured resin, and the secondary side resin is formed in this void. Is injected and cured to integrate the primary resin and the secondary resin into a multicolor molding method.