JPS63139718A - Sandwich molding method for resin molded form - Google Patents

Abstract

PURPOSE:To expose a core layer to a predetermined section in a sandwich molded form consisting of a skin layer and the core layer by setting up a movable pin to a desired section in the molded form and shifting the movable pin after a proper time during resin injection has passed. CONSTITUTION:A proper quantity of a skin material is injected into a cavity 48 through a skin sprue 41a, a bypass runner 41b, a core sprue 42a and a runner 42b from a skin-material injection cylinder 41. A core material is injected into the cavity 48, spreading the skin material previously injected through the core sprue 42a and the runner 42b from a core-material injection cylinder 42, and the inside of said cavity is filled completely with the skin material, thus molding a sandwich molded form. A movable pin 49a is retreated from the inside of the cavity 48 before the fluidity of said skin material is lost after the core material is injected, and a void formed by the retreat is covered with the layer of the skin material and the core material is allowed to flow in, thus shaping a desired core exposed section.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a resin molding method, and particularly to a sandwich molding method for molding a resin molded product consisting of a skin layer covering the surface and a core layer forming a conductive core. It is something.

[Background of the invention]

Conventionally, a sandwich molding method for forming a resin molded product consisting of a skin layer and a core layer has been described, for example, in Japanese Patent Publication No. 50
A method described in Japanese Patent No. 28464 is known. This is done by first injecting the skin material that will form the surface layer of the lens barrel into the cavity of a mold for molding a desired camera lens barrel member, and then injecting the core material that will form the core layer. In this method, a sandwich molded product consisting of a skin layer and a core layer is obtained.

In the above method, for example, by using an insulating resin material for the skin layer and using a conductive resin material mixed with conductive filler or foil for the core layer, the core layer can generate electrode waves. A product can be obtained that has the effect of eliminating problems caused by absorption and maintaining the insulation properties of the surface of the skin layer.

However, since the surface of the molded product molded by the above method is covered with a skin material, for example, when it is desired to establish partial electrical conduction to the core layer,
After molding, it is necessary to make a hole in the molded product by cutting or the like, or to remove the skin material to expose the core layer. This has caused problems such as deteriorating the appearance of the molded product and increasing the cost of post-processing.

Therefore, there has been a desire for a molding method that allows the core layer to be exposed in desired areas during molding and does not require post-processing.

[Purpose of the invention]

The present invention provides a novel molding method that eliminates the drawbacks of the conventional examples. Specifically, in the sandwich molding method, during molding, the core layer is exposed at a desired portion of the molded product. The purpose of the present invention is to provide a sandwich forming method that makes it possible to form a sandwich.

[Summary of the invention]

The feature of the sandwich molding method for resin products according to the present invention, which has been made to achieve the above object, is that a non-conductive skin layer on the surface and a thick inner layer are formed using a mold for molding sandwich molded products. In the molding method for molding a resin molded product having a conductive core layer, a movable pin that can protrude and retract with respect to the mold cavity is provided on a part of the inner surface of the mold that defines a molding cavity inside the mold. The movable pin is made to protrude into the cavity in order to form a region in which the gap in the thickness direction of the cavity is limited and the inflow of the injection material is excluded during injection of the skin material and subsequent injection of the core material. Next, the protruding movable pin is retreated from the cavity and the core material is injected into the surface where the injected skin material loses its fluidity.

In the above, the movable pin that protrudes and retreats from the cavity inside the mold may be a central rod-shaped one, or a cylindrical one that is slidably fitted to a fixed pin that protrudes and is fixed in the cavity. In the latter case, it is possible to obtain a molded product having a hole in the fixing pin portion.

In the present invention, the timing of the retraction of the movable pin from the cavity after the injection of the skin material and the injection of the core material is as follows:
The space formed by the retraction of the movable pin is set to satisfy the relationship that the core material flows sufficiently but the skin material does not flow. Specifically, for example, polycarbonate is used as the skin material. Carbon fiber and aluminiumide are used as core materials at a ratio of 4:1 for a total of 40%.
When the mixed polycarbon is a nate material and the flow length from the dart to the movable pin is in the range of 10 to SOW, and the skin material injection speed is 1 to 10 m/s (skin material resin temperature 300 to 330 ° C, The mold temperature is 80 to 130°C.) The void formed by the movable thin when injecting the skin material is 0.4
- Maintained at 0.8 questions, after completion of skin material injection, 0.6-1
．． Inject the core material within 5 s@a.

At this time, the movable pin moves from 0.1 to 0.0 from the start of core material injection.
Begin reversing within 3 seconds. Core material injection completed and #I
J'! 'At the same time, the retraction of the movable pin is completed.

[Embodiments of the invention]

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

Fig. 1 shows a structural outline of the camera 2 lens barrel including the lens barrel when molded by the method of the present invention and a conductive core layer is formed in the thick inner core. FIG. 8 shows the structure of a camera lens barrel when the lens barrel is molded from a single material according to a conventional method other than the Sand-Deutsch method.

Referring to FIGS. 1 and 8, the function of a molded product formed by the method of the present invention and having a conductive core layer in its thick portion will first be briefly described.

FIG. 8 shows the structure of a lens barrel suitable for applying the present invention, and as shown in FIG. 8, a focusing lens L, #variable lens Lse correction lens L.

and an imaging lens L, the focusing lens Ll is held in a focusing lens holder 1, and this focusing lens holder 1 is connected to a lens fixed lens barrel 2 by a heliphide coupling, and the focusing lens Ll is held in a focusing lens holder 1. By rotating the focusing lens L8, the focusing lens L8 is extended in the optical axis direction.

Further, the variable magnification lens L and the correction lens L are held in a lens holder 3 and a lens holder 44C, respectively, and these lens holders 3 and 4 are attached to the υ guide bar 5 etc. by a well-known three-way system. It is now possible to be guided and move in the direction of the optical axis. Variable magnification lens L3 and correction lens L1
The amount of movement in the optical axis direction is determined by a cam rift provided in a cam ring 6 that is rotatably held on the fixed lens barrel 2.
Controlled by a e 6 b. The cam ring G rotates in conjunction with a movement shaft 8 implanted in the cam ring 6 in accordance with the rotation of the zoom operation ring 7 fitted on the outer periphery of the lens fixed barrel 2. In addition, the imaging lens L is held in a relay holder 14 at the rear of the imaging lens holder 13 through an aperture 12, and is fixed with screws 15.

The cam ring 6 is held between a front mask plate 8 and a rear mask plate 9 that hold three guide bars 5 inside the lens fixed barrel 2.

FIG. 1 is a sectional view of the sandwich molded product of the present invention applied as is to the lens barrel shown in FIG. 8, and in this example, the fixed lens barrel 2. Relay tube 18. Relay holder 14
Each sandwich is inch molded. In this example, the skin layer is made of, for example, PC (polycarbonate).
For the core layer, a resin made by mixing carbon fiber 401 in PC resin can be used, but as the skin layer material, POM (polyacetal) resin, modified PPO (polyphenylene oxide) can also be used.
Examples include resins, AB8 resins, PBT (lipterene terephthalate) resins, etc., and examples include At fibers or flakes, brass fibers, glass fibers coated with surface conductivity as the conductive filler material of the core layer material. I can do it.

In the example shown in FIG. 1, the fixed lens barrel 2 and the relay barrel 18 are fixedly electrically connected through 17 pins in order to conduct the conductive core layers of each member, and the relay barrel 18 and the relay holder 1
4 and is fixed and electrically connected with 19 screws.

As a result, electronic components and circuits (none of which are shown) inside the lens barrel and near the mount holder 16 are protected from electromagnetic interference.

Figure 2 (1) and Figure 2 6) show the fixed lens barrel 2 in this example.
1 is an enlarged cross-sectional view of the connecting portion of the relay tube 18 and the screw 17. As can be seen from these figures, the screw thread of the screw 17 and the engaging portion 32 of the screw fixing pilot hole 33 of the fixed lens barrel 2 are The skin film thickness is the thread height h of screw 17.
By setting the width smaller than 8, when the screw 17 is fitted and screwed, the cell 7 is tapped by the screw, and the conductive core material 2a is in contact with the threaded part of the screw when the screw is screwed together. You can leave it as In addition, the relay tube 18 of this example has a surface 31a*31b around the hole where the screw 17 is fitted through,
The conductive core layer is exposed so that electrical conduction can be established between the screw and the relay cylinder through the surfaces 31m and 31b that are joined by the screw. Relay f418 and relay holder 14
Conductivity is maintained between the two in the same manner as described above.

Next, the product of the above member will be described in detail.

FIG. 4(1) is a diagram showing a molding apparatus used in the method of the present invention, 41 is a skin material injection cylinder, 42 is a core material injection cylinder, 43 is a fixed side mounting plate, 44 is a fixed plate,
45 is a runner grate, 46 is a template, 47 is a movable side fixed plate, and 48 is for molding the molded product provided in the plate! 2
vj (cavity), 41a is skins gel, 42m
Is Cores Glue %41b a Pineo J that inherits skin sprue and core sprue? Srunner, 42b is runner, 4
9tj: Movable pin unit.

fJ, 4 (b) is a cross-sectional view of the movable pin unit, 4
49C is a spring for controlling the movable pin, and 49C is a sweeter for controlling the gap T created by the movable pin. Figure 4 (b
The movable pin shown in ) maintains the gap t determined by the spring 4 and the spacer 49c when the skin material is injected (the internal pressure is almost 0 when the skin material is injected), and then the core material is injected. When the cavity begins to be filled with resin, pressure is generated in the resin, so the slide pin 49
m begins to push up spring 4k, filling it completely.

Further, FIG. 4(c) shows a structure of a type in which the slide pin 49& is forcibly moved by an air cylinder 411.

In such a device, first of all, the skin material is injected into the skin material injection cylinder 41 through the skin material injection cylinder 41.
a, Pine-arm Srunner 41b, :! 7 sp A/-4
2m, and an appropriate amount is injected into the cavity 48 through the runner 42b. Next, the core material is injected into the cavity 48 through the core sprue 421 and the runner 42b through the core injection cylinder 42 and the core sprue 421 while spreading out the previously injected skin material to completely fill the cavity and produce a sandwich molded product. is formed.

Next, after injecting the core material, before the skin material loses its fluidity, the movable pin 49& is retracted from the cavity 48, and the layer of the skin material is broken into the void formed by this retraction, and the core material is injected into the cavity. can be allowed to flow in to form a desired core exposed portion.

FIGS. 5(a) and 5(b) are enlarged sectional views for explaining such a movable pin portion and its movement.

In FIG. 5(a), the movable pin 49a is in contact with the fixed pin 49b at the sliding surface 5&, and remains at rest with an interval TI between the movable pins 49a and the fixed pins 49b until a suitable period of time has elapsed after the injection of the core material. After injecting the skin material, at the same time as injecting the core material, or at 0.
After 6~1.5s@e, as shown in Figure 5(b),
The movable pin 49& is moved while being guided by the fixed pin 49b until an appropriate gap amount T is reached, and then held still. Due to this movement of the movable pin, in the state shown in Fig. 5(a), the skin material that has flowed near the movable pin cannot fill the void because the gap is narrow and the flow resistance is large, and other flow The flow will flow to the part with low resistance (omitted), but after moving the movable pin and widening the gap as shown in Figure (b), the flow resistance of the core material in that part will decrease and the core material will be injected. The skin material, which was previously injected in a small amount near the movable pin, is pushed and broken to form a portion where the core material is exposed.

Example skin material 11? Licargenate core material Polycarbonate (contains 30% carbon fiber and 10% aluminum fiber) Skin material resin temperature 320℃ Core material resin temperature 330℃ Mold temperature 110℃ Skin material injection speed 10%/3・C injection Time Q, 5s
EC core material injection speed 3%/Easy C injection time 1.
8sec movable pin movement start time 0.
4S/C movable pin movement completed 1 1
．． 0 sec movable pin operating source Air cylinder Resin pressure during injection of skin material 3 K4f/cm Core material 1 950 Kff/cIn A sandwich structure molded product was molded.

FIG. 6 shows a cross-sectional view of the movable pin vicinity of the above-mentioned well-molded product, and 45 m is a skin layer.

6b indicates a core layer, and 61, 62, and 63 indicate exposed portions of the core material.

In this embodiment, a lens barrel member was used, but the lens barrel member was used in a copying machine.

Applications to word processors, calculators, kombi islands, etc. can also be molded using the same method.

FIGS. 7(a) to 7(e) show another embodiment, in which the core layer is exposed on the front and back surfaces of the molded product.

That is, in this example, the central bar-shaped movable pin 71 is moved in the same manner as in the above embodiment after an appropriate time has elapsed after the injection of the skin material and the injection of the core material, as shown in FIG. 7(b).

The molded product is moved to the state shown in Fig. 7 (,), and the core layer is exposed on the front and back surfaces at 72° and 73°, as shown in Fig. 7 (C), by the same filling method as shown in Fig. 5. .

The molded product shown in Fig. 7 has a grounded surface.
Alternatively, it is very effective to measure conductivity by joining surfaces together without using screws.

〔Effect of the invention〕

As explained above, in the mold used for sandwich molding, a movable pin is provided at the desired part of the molded product where continuity or grounding is desired, and the movable pin is moved after an appropriate amount of time has elapsed during resin injection. By doing so, it is possible to expose the core layer at a predetermined portion of a sandwich molded product consisting of a skin layer and a core layer, and as a result, it is possible to expose the core layer partially, unlike the conventional method. drilling,
It has become possible to provide a sandwich molded product that does not require post-processing such as cutting and removing, has a beautiful appearance, and does not require post-molding processing.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing an example of the structure of a camera lens barrel constructed using a molded product having a skin layer and a core layer of 2M formed by the method of the present invention, and Figure 2 is a cross-sectional view showing an example of the structure of a lens barrel of a camera constructed using a molded product having a skin layer and a core layer of 2M formed by the method of the present invention.
Figure 3 is a diagram showing the state before joining to explain the structure of the joining part that maintains conductivity between members having M.
Figure 4(a) is a sectional view showing the structural outline of an example of the mold device used in the method of the present invention, Figures 4(b) and (e) 5(a) and 5(b) are diagrams illustrating the movement of the movable pin of the mold device shown in FIG. 4(a), and FIG. 6 is a diagram showing the structure of the movable pin unit, respectively. Fig. 5 is a diagram for explaining the movement of the movable pin in another example of the apparatus, and Fig. 8 shows an example of the structure of a camera lens barrel constructed using a molded product without a core layer. FIG. 1... Focusing lens holder 2... Fixed lens barrel 2J1...
・Core [2b...Skin layer 3.4...Lens holder 5...Guide bar 6...Cam iJ1 6
m, 6 b...-Cam lift 7...Zoom operation ring 8...Front side mask plate 9...Rear side mask plate
12...Aperture 13...Lens holder 14...
Relay holder 15... Screw 16... Mount holder 17... Screw 18-... Relay tube 18m... Core layer 18b... Skin layer 19
...screw 31m...hole inner surface 31b...
Surface around the hole opening 32...Mating part 33...Prepared hole 4 for screw fixing
1...Skin material injection cylinder 41a...Skin sprue 4l b...Pine arm srunner 42...Core material injection cylinder 42m...Core sprue 42b...Runner 43.
... Fixed side mounting plate 44... Fixed plate 45... Runner plate 46... Template plate 47... Movable side fixed plate 48... Cavity (gap) 49... Movable pin unit 61.62 ,63...Core 'A exposed surface 71...e movable pin 72.73...Front and back exposed surfaces of core layer Honda Ko Part - ~ - Fig. 2 Fig. 3 Fig. 4 (b) 49b 4 so b Fig. 5 Fig. 7 Fig. 7 (C)

Claims (3)

[Claims] (1) In a molding method for molding a resin molded product having a non-conductive skin layer on the surface and a conductive core layer inside the thickness using a mold for molding a sandwich molded product, A movable pin capable of protruding and retracting with respect to the cavity is provided in a part of the inner surface of the mold defining the molding cavity,
When injecting the skin material for molding and the subsequent core material injection,
The movable pin is projected into the cavity in order to limit the gap in the thickness direction of the cavity to form a region that excludes the inflow of the injection material, and then, before the injected skin material loses its fluidity, the above-mentioned A sandwich molding method characterized by retreating the protruding movable pin from inside the cavity and injecting the core material. (2) The sandwich molding method according to claim (1), characterized in that the movable pin is a cylindrical body surrounding the outer periphery of a fixed pin discharged into a cavity. (3) A sandwich forming method according to claim (1), characterized in that a central rod-shaped body is used as the movable pin.