JPH0461517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing printed wiring boards used in electronic and electrical equipment.

Conventional technology Conventionally, printed wiring boards have been manufactured using a subtractive method in which a wiring pattern is created on a copper-clad laminate using a screen printing method or a photoresist method, and then the wiring pattern is replaced with copper by etching or electroplating. Copper foil is pasted with an uncured adhesive, and then a die with a wiring pattern-shaped blade is used to punch out the copper foil into a wiring pattern. After the adhesive in the wiring pattern area has hardened, unnecessary parts are removed. A die stamp method is commonly used.

Problems to be Solved by the Invention Although the above subtractive method is suitable for manufacturing printed wiring boards with precise wiring patterns, a large amount of copper foil must be removed by etching, and further electroplating is required. Moreover, since it is an electrochemical treatment method, it is necessary to take measures to prevent pollution such as treatment chemicals and waste water treatment, and there are problems in that expensive treatment equipment must be introduced. Furthermore, since it is an electrochemical treatment method, it has the disadvantage that it takes a long time to manufacture.

Furthermore, the subtractive method makes it difficult to increase the thickness of the wiring pattern, making it unsuitable for manufacturing printed wiring boards for circuits with large current capacity. This is because when the copper foil is made thicker, the etching efficiency during manufacturing is significantly reduced.
On the other hand, the die stamping method is a dry method for manufacturing printed wiring boards, so there is no pollution problem like the subtractive method, and the process is simple and suitable for mass production. The foil cannot be punched cleanly and processing takes a long time.
In addition, it is difficult to carve a precise wiring pattern on a stamping die and it is difficult to remove unnecessary parts, so there is a problem that it is difficult to manufacture printed wiring boards with precise wiring patterns.

Furthermore, although it can be used as a substrate material for resin laminates, it will damage the blade shape for hard substrates such as ceramics, and will also cut the substrate for film-like substrates such as flexible wiring boards. However, there were various problems that made it unusable.

Means for Solving the Problems The present invention solves the above problems, and uses an electromagnetic forming method using an electromagnetic forming coil and a die (female mold) to form a conductive thin plate material for forming printed wiring boards. By using it, you don't need a male type,
The purpose is to easily produce precise printed wiring boards without pollution, in a short time, and at low cost, without using dies or punches having blade shapes.

Function An electromagnetic forming device that uses a combination of an electromagnetic forming coil and a die to form a conductive thin plate material for forming a printed wiring pattern generates the electric power necessary for forming by applying the charging energy stored in a capacitor to the circuit containing the coil. By releasing the current, a current is induced in the conductive thin plate material used as the workpiece, and a strong pulse-like electromagnetic force acts between the thin plate material and the coil.
As a wiring pattern cutting die, the wiring pattern is punched out instantly at high speed by hitting a die with slits formed in a pattern negative to the wiring pattern and in a plane symmetrical opposite pattern. The punched reverse wiring pattern is temporarily fixed on an adhesive film placed at the bottom of the die, and the adhesive-coated surface of a printed wiring board substrate coated with an uncured thermosetting adhesive or ultraviolet curable adhesive is overlapped. By peeling off the resin film after curing the adhesive, only the reverse wiring pattern is transferred and fixed onto the printed wiring board substrate, making it possible to create precision printed wiring boards that are difficult to press with punches and dies. Continuously produced in a short period of time.

An embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 As shown in FIGS. 1 and 2, a large current is instantaneously applied to a forming coil 5 by a capacitor 3 that stores the current generated by a charging switch 2 below a DC high voltage generator 1 and a discharge switch 4. A slit 6 forming a reverse wiring pattern is formed at the bottom of a forming coil 5 of an electromagnetic forming device that emits a strong magnetic field to form a strong magnetic field around the coil and utilizes the Coulomb force (also referred to as electromagnetic force) in this magnetic field. A die 7 is placed, and a conductive thin plate material 8 is placed on the die 7 to bring it into close contact with the coil. Further, at the bottom of the die, a film or tape 10 coated with an adhesive 9, such as cellophane, acetate, kraft paper, polyester, polyamide, non-woven fabric, crepe paper, PP, etc.
By arranging the conductive thin plate material 8 selected from PE etc. and generating electromagnetic force in the formed coil
At the same time as punching out, the punched reverse wiring pattern 11 is temporarily adhered onto the adhesive film 10. Next, as shown in FIG. 3, the reverse wiring pattern 1 is temporarily attached.
1 and the adhesive-coated surface of a printed wiring board substrate 13 coated with a heat-curing adhesive 12 in advance, and heat and pressurize the adhesive with a heat press machine 14 to harden the adhesive and form a reverse wiring pattern on the wiring board. After fixing it to a printed wiring board, the adhesive film is peeled off to form a printed wiring board. As the adhesive used in the adhesive film, polyvinyl ether, polyisobutylene, SBR, butyl rubber, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, etc. can be used, and it is preferable to use a thinly applied adhesive with low adhesive strength.

Furthermore, although copper foil with a thickness of 50 μm and 100 μm was used as the conductive thin plate material 8 used in the above example, any conductive material other than copper foil with a thickness of 5 μm to 1 mm may be punched. is possible.
Further, the amount of energy of electromagnetic force in the above electromagnetic forming is expressed by the following formula. That is, E=1/2CV ₂ . However, E: energy amount (J), C: capacitor capacity (μF), V: charging voltage (KV). For copper foil with a thickness of 50μm, set C = 100μF, V = 5KV, energy amount 1250J, for copper foil with a thickness of 100μm, C = 100μF, V
= 7KV, and punching was performed with an energy amount of 2450J.

Embodiment 2 As shown in FIG. 4, when punching a wiring pattern, a conductive thin plate material 8 and a die 7 having slits 6 in an inverse pattern symmetrical to the wiring pattern are placed at a predetermined distance. The conductive thin plate material 8 is struck against the die 7 by the electromagnetic force generated by the forming coil 5, and the wiring pattern is punched out.The punched wiring pattern is temporarily adhered onto the adhesive film placed at the bottom of the die. After that, the printed wiring board substrate coated with an ultraviolet curable adhesive is stacked on top of the other, and the adhesive is cured using an ultraviolet irradiation device to fix the wiring pattern.The adhesive film is then peeled off and the printed wiring board is assembled. Formed. Incidentally, the setting interval between the conductive thin plate material and the die is suitably 10 mm or less, and if it is more than that, it is not desirable because a larger electromagnetic force is required.

Example 3 As shown in FIG. 5, when punching a wiring pattern, a conductive thin plate material 8 was placed on the surface of a die 7 in which slits 6 of a reverse wiring pattern were formed, and an adhesive was applied to the bottom surface of the die 7. An adhesive film 10 or an adhesive tape coated with is placed, a knock plate 15 and a back plate 16 are placed above the conductive thin plate material at a predetermined interval, and a forming coil is positioned above the back plate. By generating an electromagnetic force in 5, the knock plate 15 and the back plate 16 are struck against the conductive thin plate material 8, thereby punching out a reverse wiring pattern and temporarily adhering it onto the printed wiring board substrate. The adhesive was cured in the same manner as in 1 to form a printed wiring board.

In addition, the knock plate may be flat plate-like,
In addition to urethane rubber, plastic or metal may be used as the material. Further, the material of the back plate may be a metal having excellent conductivity in addition to a copper alloy.
Further, the knock plate and the back plate should be bonded together in advance, and if the knock plate is made of a metal with excellent conductivity, the back plate may not be used. The spacing between the conductive material and the knock plate was set in the same manner as in Example 2.

Effects of the Invention As described above, according to the present invention, when manufacturing a printed wiring board, an electromagnetic forming coil and a die having a slit that follows the printed wiring pattern are combined, and conductivity is generated by the electromagnetic force generated in the coil. By quickly and easily punching out a precise wiring pattern from a flexible thin sheet material, temporarily adhering it onto an adhesive film or adhesive tape, and then transferring it onto a printed wiring board that has been previously coated with a heat or ultraviolet curable adhesive. It has become possible to manufacture printed wiring boards in a short time and at low cost.

Therefore, unlike the conventional subtractive method, there is no need to remove a large amount of copper foil or electroplating, and there is no need for treatment chemicals or equipment for wastewater treatment, making it very economical. In addition, unlike the die stamping method, there is no restriction on the type of printed wiring board, and there is no need for a male die, so it is pollution-free, inexpensive, and precise wiring without using a die or punch with a cutting edge. This invention has excellent effects such as being able to obtain a printed wiring board with a pattern.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of an electromagnetic forming apparatus used for carrying out the present invention, Fig. 2 is a partially enlarged view showing a state in which the forming coil and die are combined and formed, and Fig. 3 is a configuration showing the same thermally pressurized state. 4 and 5 are structural sectional views showing other embodiments of the present invention, respectively. 1... DC high voltage generator, 2... Charging switch, 3... Capacitor, 4... Discharging switch, 5
... Coil for forming, 6 ... Slit, 7 ... Die, 8 ... Conductive thin plate material, 9 ... Adhesive, 10
... Film or tape, 11 ... Reverse wiring pattern, 12 ... Heat curing adhesive, 13 ... Printed wiring board substrate, 14 ... Heat press machine, 15 ...
Notsuku plate, 16...back plate.

Claims (1)

[Claims] 1. A reverse wiring pattern formed by punching a conductive thin plate material using electromagnetic force and a die in which slits are formed in a pattern negative to the wiring pattern and in a reverse pattern that is plane symmetrical. After temporarily fixing it on the adhesive film, the reverse wiring pattern is overlapped with the adhesive-coated side of the printed wiring board substrate, which is coated with heat-curing adhesive or ultraviolet-curing adhesive on one side in advance, and heated and pressurized or exposed to ultraviolet rays. A method for manufacturing a printed wiring board, which comprises curing the adhesive and subsequently peeling off the adhesive film to form a wiring pattern on a printed wiring board substrate. 2. When punching a reverse wiring pattern using electromagnetic force, a predetermined interval is provided between the die and the conductive thin plate material, and the conductive thin plate material is punched against the die using the electromagnetic force generated in the electromagnetic forming coil to punch out the wiring pattern. A method for manufacturing a printed wiring board according to claim 1, characterized in that: 3. When punching a wiring pattern using electromagnetic force, a notch plate and a back plate having a gentle convex portion are arranged above the die on which a conductive thin plate material is placed, and the above-mentioned notch is punched by the electromagnetic force generated by the electromagnetic forming coil. 2. The method of manufacturing a printed wiring board according to claim 1, wherein the wiring pattern is punched out by punching a plate onto a conductive thin plate material.