JP3358469B2 - Manufacturing method of molded article with plastic parts inserted - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method applicable to all fields in which plastic products are used.
In particular, in industrial fields such as electric equipment, electronic equipment, communication equipment, and mobile machines, the present invention relates to a keyboard switch which is an aggregate of a plurality of switches mounted on equipment in these fields and a method useful for manufacturing the same. Keyboard switch is telephone switch, AV remote control switch, pocket switch,
Used in personal computer keyboards, car panels, and countless other places. The present invention is particularly useful for manufacturing a keyboard switch with a key top made of resin.

For example, telephones, especially mobile phones, PHS,
Keyboard switches used in commercial portable radios and the like must be thin and lightweight, and a resin keytop is adhered to the upper surface of the switch so that the display of numbers is clear and difficult to erase. The present invention can be suitably used for a method of manufacturing a keyboard switch for such an application.

[0003]

2. Description of the Related Art Conventionally, keyboard switches have been manufactured mainly using silicone rubber. That is, the keyboard switch has a large number of key buttons (pressing portions) having a thickness of 1 m.
m, are arranged in a plate-shaped portion (base portion) of about m, and these pressing portions and the base portion are connected and integrated by a thin skirt-shaped portion (skirt portion), and are made of silicone rubber. I have used it. However, with rubber materials, the dimensional accuracy of molded products is inferior, and the production efficiency is poor, such as requiring a considerable amount of time in the vulcanization process.In recent years, keyboard switches have been manufactured by injection molding using thermoplastic elastomers as raw materials. Has become.

Whatever material is used, these days,
It is common to put a resin key top, particularly a transparent resin key top, on the pressing portion of the keyboard switch. For this reason, in the manufacture of a keyboard switch with a key top, a receiving jig is prepared, and a group molded product of the key top is formed, printed, etc., and then cut into each key top member.
It is necessary to fit the key top member into a receiving jig, apply an adhesive to the back surface of the key top or the keyboard switch side, and press and cure the keyboard switch while aligning the keyboard switch to bond it.

[0005]

However, insert molding, such as the method of manufacturing a keyboard switch with a keytop shown in the above example, requires a number of steps and has a drawback that a long molding time is required. Was. Then, as a result of studying to solve these difficulties, the present invention has been reached. That is, taking a keyboard switch as an example, once a molded product of key tops is obtained by injection molding, characters and the like can be printed and displayed on the back surface, and at the same time, a heat-sensitive adhesive is also printed on the uppermost layer. I do. This key top member is loaded into some kind of automatic machine, and this automatic machine carries out / cuts /
A method has been found in which a keyboard switch with keytop can be manufactured by simply inserting each keytop member into a mold and then injecting a thermoplastic elastomer.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method of manufacturing a molded article in which a plastic part is inserted using a method capable of cutting a gate-like object in an insert hand without having a complicated mechanism. is there. That is, the present invention relates to a method for injection-molding the same or different kinds of thermoplastics using a mold in which one or more thermoplastic or thermosetting plastic parts 22 of the same or different shapes are inserted in advance. A step of previously manufacturing a plastic molded product 20 (hereinafter, referred to as a work) in which a component part 22 inserted into the frame part 21 is connected to the frame part 21 through a thin shape part 23, which is located at a front part of the insert hand 10, The step of mounting the work on the front surface of the work support plate 11 which can be moved back and forth and is pushed forward by a relatively strong force, the ejector pins 3 of the mold 1 are protruded forward, and the parts 22 of the work are In the process of supporting the insert, the insert hand 10 is advanced toward the mold 1 with strong force, and the component 22 is sandwiched between the ejector pin 3 and the insert pin 14. Then, the insert hand 10 is advanced, and the component part 22 of the work 20 sandwiched between the ejector pin 3 and the insert pin 14 is shifted from the surface of the work support plate 11 to cut the tip end of the shape part 23 to cut the part part 22. , The insert hand 10 is further advanced, and the component 22 sandwiched between the ejector pin 3 and the insert pin 14 is removed.
Inserting a plastic component into a predetermined position of the mold 1 by retreating the ejector pin.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.
FIG. 1 is a diagram showing a state at the time when a series of cutting / insert steps has just started. Reference numeral 1 denotes a mold having an ejector pin on one side of the mold, generally a movable mold. 2 is the template part, 3 is the ejector pin,
Reference numeral 4 denotes an ejector plate, and reference numeral 5 denotes a piston portion, which serves to push the ejector plate forward by air pressure supplied from a compressed air introduction passage 6. Reference numeral 10 denotes an insert hand. Reference numeral 11 denotes a work support plate, and reference numeral 12 denotes a piston portion which pushes the work support plate 11 forward by the air pressure supplied from the compressed air inlet 13. Reference numeral 14 denotes an insert pin, the rear of which is pushed forward by a spring 15. On the upper surface of the work support plate 11, a separately manufactured work 20 is placed. Although not shown in the figure, positioning holes are set on the work so that the position can be determined so that the insert hand mechanism can be used even with a horizontal injection molding machine, and this hole is supported on one work support plate Thus, an extendable needle-like pin can be provided.

FIG. 2 is a view for explaining the work 20.
The workpiece 20 includes a component part 22 to be inserted and a frame part 2.
1 and a thin shaped portion 23 connecting them. It is usual to make a positioning hole for determining the position in the frame portion 21 as described above. A flat plate-like part that can use a suction pad to automatically supply workpieces one by one from the storage location onto the workpiece support plate, or to automatically remove and discard used workpieces on the workpiece support plate Can be made in the work. As a molding material for the work, any of a thermoplastic plastic and a thermosetting plastic can be used. In the case of keyboard switches for mobile phones, transparent thermoplastics are usually used to ensure mass productivity and nighttime illumination,
Particularly, use of a polycarbonate resin or the like is preferable. The method of manufacturing the work varies depending on the material type and shape, but the most efficient and rational one is a method by injection molding. Post-processing after the molding may be performed in order to form the inserted component part 22 neatly. For example, when the shape portion 23 becomes thick or wide in order to form the component portion 22 neatly, it can be cut or cut by post-processing. In short, it is only necessary that the positional relationship with the frame portion 21 is constant and the cutting by the insert hand can be performed without difficulty.

FIG. 3 shows a state in which the insert hand 10 has advanced toward the mold 1 with a stronger force through the state shown in FIG. When the insert hand 10 and the mold 1 approach each other,
Since the ejector pin 3 and the work support plate 11 are both pushed forward by relatively strong force, they are not lowered, and the frame portion 21 of the work 20 remains on the work support plate, but the component portion 22 is It is pushed into the ejector pin 3 and the spring 15 contracts and sinks into the hole of the work support plate 11. At this point, the thinnest shape portion 23 is cut by the shearing and tearing force at the thinnest portion, and each part 22
And placed in the work support plate.

FIG. 4 shows a state in which the insert hand 10 has advanced toward the mold 1 with a stronger force through the state shown in FIG. When the insert hand 10 is closer to the mold 2, the rear end of the insert pin 14 has already reached the bottom and cannot be lowered, and the part 22 remains in the mold plate of the mold 1 while the insert hand 10 moves. To move forward. That is, the ejector pin 3 and the ejector plate 4 are pushed through the component part 22 by the advance of the insert hand. At about this point, the mold plate 2 and the work supporting plate 11 are already in contact with each other, and when further pushed in, the piston 12 is completely pushed in so that there is no room for the piston 12 to be seen from the outside and the advance stops. Immediately before the advance stops, both ends of the work support plate 11 are stopped so that the insert hand stops moving slightly before reaching the innermost position (for example, 0.1 mm before) so that impact pressure is not applied to the component part 22. Is preferably designed. Also, a method of rapidly reducing the force pushing the ejector plate 4 forward in the step shown in FIG. 4 in order to reduce the pressure applied to the component 22 after cutting is very preferable. That is, in FIG. 4, the compressed air is sent to the piston 5 to control the pushing force of the ejector plate. However, a method of releasing the air pressure in a timely manner is very effective.

[0011]

First, a work 20 with two key tops for an oval telephone switch shown in FIG. 2 was prepared by injection molding of a polycarbonate resin. Here, part 2
2, that is, the key top part has a major axis of 10 mm and a minor axis of 8 m
The mold is embossed so that a weak emboss is applied to the upper surface. Thinned part 2
The cross-sectional area of the connection part with the component part 22 of No. 3 was 0.3 mm 2. The frame portion has a width of 2 mm and a thickness of 1 mm. As shown in FIG. 2, two wide ear portions are provided and a hole having an inner diameter of 3 mm is formed. The structure of the mold and the insert hand was the mold structure shown in FIGS. 1, 3 and 4. Here, the size of the part where the component part 22 of the mold 1 is inserted is
To the dimensions. To be more precise, the hole is designed to be 10 μm longer than the component part 22 in the long diameter. The surface of the tip of the ejector pin 3 that contacts the component 22 was textured so as not to crush the grain on the upper surface of the component 22, and was enlarged to cover almost the upper surface of the key top. The force for pushing the ejector plate forward could be controlled between 50 and 300 kg using air pressure. In the insert hand, the force for pushing the work support plate through the piston 12 can be controlled to 50 to 75 kgf, and the spring behind the insert pin is one that enters a narrow hole and is as strong as possible.

As shown in FIG. 1, a work 20 is placed on a work support plate of an insert hand, an ejector plate is set at 70 kgf, and a pressing force of the work support plate is set at 30 kgf.
The insert hand was advanced toward the mold 1 at a speed of about 10 cm / sec with a force of 500 kGf. The compressed air is released from the passage 6 at the moment when the work support plate comes into contact with the template 2, so that excessive pressure is not applied to the cut part 22. When the piston 12 disappeared and the work support plate 11 and the insert hand main body were completely in contact with each other, the advance of the insert hand was stopped, but thereafter the insert hand was retracted and completely separated from the mold 1. As a result, the neatly cut part 22 was inserted into the mold 1. In addition, on the work supporting plate, a residue from which only the component 22 has been removed, that is, an object composed of the frame-shaped portion 21 and the thin shape portion 23 has been left.

The entire insert hand is temporarily moved from the molding machine, and the mold 1 is combined with a fixed mold for injection molding (not shown), and the mold is tightened and a thermoplastic elastomer is placed in the mold. After injection, cooling and mold opening, the ejector pins were driven to take out the product. As a result,
A molded product in which key tops were attached to a thermoplastic elastomer was obtained. Thereafter, a new work was set again on the work support plate of the insert hand, the insert hand was returned to the original position (into the molding machine), and the same process was repeated to perform the next forming. By automating the movement of the insert hand, the installation of the work, the removal and disposal of the used work, and the control of the change in the pressing force of the ejector plate, the plastic insert was fully automated. Further, even if the number of the component parts 22 is 20, one
Even if the number is 00, if each pressure is appropriately controlled, it can be inserted at once.

[0014]

According to the present invention, a molded product in which one or a plurality of plastic parts of the same or different shape are connected to a frame-like part via a thin shape part for holding a position, and this is cut at a stroke. A method is provided for separating and inserting the plastic part into a defined hole on a mold. The present invention uses a work in which a work is molded in advance with a transparent resin and further printed, and after inserting this into a mold by the method of the present invention, a molded article in which plastic parts are inserted by injection molding of a resin is used. It can be manufactured efficiently. For example, in the manufacture of keyboard switches,
If the injection resin is a thermoplastic elastomer, keyboard switches with hard key tops can be easily and efficiently produced. In particular, if both thermoplastic resins are heat-sealed or injection-bonded by any method, it is possible to efficiently manufacture molded articles useful for keyboard switches of mobile phones, PHSs, and other portable electronic terminals. INDUSTRIAL APPLICABILITY The present invention can efficiently produce a molded product in which a plastic component is inserted, even if molded products containing different types of plastics or molded products of the same type but different thermoplastics are used.

[Brief description of the drawings]

FIG. 1 is a schematic view of the relationship between a mold and an insert hand.
Part 1

FIG. 2 Shape diagram of the work

FIG. 3 is a schematic diagram showing a relationship between a mold and an insert hand.
Part 2

FIG. 4 is a schematic diagram showing the relationship between a mold and an insert hand.
Part 3

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Mold plate part 3 Ejector pin 4 Ejector plate 5 Piston 6 Compressed air introduction path 10 Insert hand 11 Work support plate 12 Piston 13 Compressed air introduction path 14 Insert pin 15 Spring 20 Work 21 Work frame part 22 Work part part 23 Work thin part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 33/00-33/76 B29C 45/00-45/84

Claims (1)

(57) [Claims] 1. A method for injection-molding the same or different kinds of thermoplastics by using a mold in which one or more thermoplastic or thermosetting plastic parts 22 of the same or different shape are inserted in advance. The component part 22 inserted into the thin part 2
3 is a process of manufacturing a plastic molded product 20 (hereinafter, referred to as a work) connected to the frame-shaped portion 21 in advance. The process is located at the front of the insert hand 10 and is movable forward and backward, and is pushed forward with relatively strong force. Work support plate 11
A step of mounting the work on the front surface of the mold, a step of protruding the ejector pin 3 of the mold 1 forward to support the component part 22 of the work, and advancing the insert hand 10 toward the mold 1 with strong force. Ejector pin 3 and insert pin 1
4, the insert hand 10 is advanced, and the part 22 of the work 20 sandwiched between the ejector pin 3 and the insert pin 14 is displaced from the surface of the work support plate 11 to cut the tip of the shape part 23. Separating the component part 22 by moving the insert hand 10 forward, and inserting the component 22 sandwiched between the ejector pin 3 and the insert pin 14 into a predetermined position of the mold 1 by retreating the ejector pin. A method for producing a molded product in which a plastic part is inserted.