JPH04164383A - Metallic printed board and its manufacture - Google Patents

Abstract

PURPOSE:To prevent an insulating board from being damaged by burrs produced at the time of punching even when the burrs are incorporated in a heat sink by means of the insulating board by providing a notched section at the peripheral section on one surface of a metallic board, on the other surface of which a wiring pattern is formed with an insulating layer in between. CONSTITUTION:A groove-like notched section 22 is provided at the peripheral section on the lower surface of a metallic board 21. On the upper surface of the board 21, an insulating layer 23 is formed and a wiring pattern 24 composed of copper foil, etc., is formed on the layer 23. In addition, solder resist layers are formed on the pattern 24, with necessary lands being left on the pattern 24. While burrs 28 are formed at the time of forming the metallic board 21 by punching, the burrs 28 can be controlled to occur in the notched section 22 at the peripheral section on the lower surface of the board 21 by deciding the punching direction. Therefore, when the depth of the notched section 22 is decided by paying sufficient attention to the height of the produced burrs 28, the protrusion of the burrs 28 from the lower surface of the board 21 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a metal printed circuit board used in various electronic devices and a method for manufacturing the same.

Conventional technology Conventionally, metal printed circuit boards used in various electronic devices are
Surface-mounted components that generate a large amount of heat, such as power semiconductors and square chip resistors, are mounted on a metal printed circuit board made of a relatively small area and relatively high thermal conductivity, such as an aluminum plate, and used as a circuit module. .

As shown in FIG. 6, the metal printed circuit board is provided with an insulating layer 2 on the upper surface of a gold + The surface-mounted components 4 were connected between the lands of the wiring pattern 3 by solder 5 to form a circuit module.

This metal printed circuit board was manufactured as shown in FIGS. 7a-C. That is, as shown in FIG. 7a, an insulating layer 2 is formed on the upper surface of a base material 10 of a large metal plate that can constitute a plurality of metal printed circuit boards, and a copper foil is etched on this insulating layer 2. and predetermined wiring pattern 3
A multi-cavity matrix formed by applying solder resist to the entire surface of the wiring pattern 3 except for necessary lands is brought into contact with the mold 6 to receive the surface on which the wiring pattern 3 is formed, and the metal plate The metal printed circuit boards 8 are punched from the first side using a press die 7 corresponding to the size of one metal printed circuit board, and individual metal printed circuit boards 8 are formed as shown in FIG. Then, as shown in FIG. 7C, each of the punched metal printed circuit boards 8 is pushed into the punched part of the base material 10 with a pusher piece 9 so that the parts fit together, It was manufactured in a structure in which a plurality of metal printed circuit boards 8 were held by a material 10.

This is done by connecting various surface mount components 4 at the same time with embedded solder 5 to form a large number of circuit modules at the same time, and then
It is extruded individually from scratch and utilized as individual circuit modules, which is extremely advantageous in improving the efficiency of parts assembly.

This type of construction is usually called the Pushyuva-7ri construction method, and is increasingly being adopted.

Problems to be Solved by the Invention However, in the metal printed circuit board 8 manufactured by the above-described structure and manufacturing method, burrs 11 are generated on the peripheral edge of the seven pressing dies when punching the individual metal printed circuit boards 8 from the base material 10. When using the metal printed circuit board 8 as a circuit module and attaching it to the heat sink of various electronic devices through an insulating plate, it may cause dielectric breakdown, cause lacerations to the installation worker, or cause serious safety problems. This became a problem, and this Bali 11
This required removal work, resulting in poor productivity.

Furthermore, in order to remove the burr 11, the burr 11 can be crushed when press-fitting into the base material 10, but the stress applied at this time may cause cracks or disconnections in the insulating layer 2 or the wiring pattern 3. There were drawbacks.

The present invention eliminates the above-mentioned conventional drawbacks, and aims to provide a metal printed circuit board in which burrs generated during punching do not have an adverse effect.

Means for Solving the Problems In order to solve the above problems, the present invention has a structure in which a metal plate is formed with a wiring pattern on one side via an insulating layer, and a notch is provided at the peripheral edge of the other side of the metal plate. .

Effect: By having the above structure, even if there are burrs generated during punching, it is possible to prevent dielectric breakdown and injury to workers when assembling into electronic equipment.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings FIGS. 1 to 5.

First, in FIG. 1, reference numeral 21 denotes a metal plate made of metal such as aluminum. A groove-shaped notch 22 is provided at the peripheral edge of the lower surface of the metal plate 21, and an insulating layer is formed on the entire upper surface of the metal plate 21. A wiring pattern 24 made of Ti4 foil or the like is formed on this insulating layer 23, and a solder resist layer (not shown) is formed on this wiring pattern 24, leaving necessary lands.

Surface mount components 26 such as power semiconductors and chip resistors are assembled on the metal printed circuit board 25 having such a configuration.

It is connected to the land of the wiring pattern 24 by solder 27 to form a circuit module. Note that burrs 28 are generated on the metal plate 21 when the metal plate 21 is punched;
By determining the punching direction, this bar 1J28 is generated so as to be located within the notch 22 at the peripheral edge of the lower surface of the metal plate 21.

Further, the manufacturing of this metal printed circuit board 25 is shown in FIG. 2a.
- It is performed as shown in C. That is, an insulating layer 23. Wiring pattern 24. A solder resist layer is formed and a concave groove 30 is formed on the lower surface in a portion corresponding to the outer shape of the metal printed circuit board 25. As shown in FIG. The metal plate is brought into contact with a receiving die 31, and a push die 33 having a cutting blade 32 protruding upward on the peripheral edge thereof is pressed against the metal plate side to perform punching.

This punched state is shown in Figure 2. This punching produces a burr 28 on the lower surface side of the cut surface, and this burr 28 is located in the notch 22 formed by cutting and punching the middle of the groove 30. Therefore, if the depth of the groove 30 is determined with due consideration to the height at which the bulge 28 is generated, the burr 28 will not protrude to the lower surface of the metal plate 21.

The metal printed circuit board 25 punched as described above is
As shown in FIG. C, the base material 29 is punched out by the push-in piece 34 and then press-fitted again to perform the punching process.

The state after being press-fitted again in this way is shown in FIG. 3. In this state, the surface mount components 26 are mounted on the respective metal printed circuit boards Fi 25 to form a circuit module, and then separated from the base material 29 for use. do.

In addition, as another embodiment, as shown in FIG.
It is also possible to have a configuration in which a notch 22 forming a tapered surface is provided at a part of the corner of the peripheral edge of the lower surface of the holder 1 .

A metal printed circuit board 25 having this structure can be manufactured as shown in FIGS. 5A to 5C. That is, the insulating layer 23. Wiring pattern 24. The wiring pattern 24 on which the solder resist layer is formed is shown in FIG. 5a.
The side is brought into contact with the receiving mold 31, and a pressing mold 33 is pressed, which has an inverted V-shaped cutting blade 32a protruding upward at a position corresponding to the outer shape of each metal printed circuit board 25 on the metal plate 21 side. Punch out by applying the punch.

Through this punching process, a notch 22 consisting of a tapered surface with chamfered corners is formed on the peripheral edge of the lower surface of the metal printed circuit board 25, as shown in FIG. It will be absorbed within the height range of this notch 22.

The metal printed circuit board 25 punched out in this way is shown in FIG.
As shown in FIG. 3, the base material 29 is again press-fitted after being punched out by the push-in piece 34.

Thereafter, the surface mount components 26 are assembled into a circuit module in the same manner as in the previous embodiment, and the circuit modules are taken out one by one from the base material 29 and assembled into electronic equipment.

Effects of the Invention Because the metal printed circuit board of the present invention is constructed as described above, the hari generated during punching will not pierce or damage the insulating plate even if it is incorporated into a heat sink or the like via an insulating plate. There is no need to remove generated burrs, and there is no need to remove burrs, which is highly productive and cost-effective. It has the effect of becoming
It has great industrial value.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the metal printed circuit board of the present invention in which surface-mounted components are incorporated, and FIGS. FIG. 3 is a perspective view of a state in which bunschback processing is performed to form multiple cavities using the same method, FIG. Diagram a
-C is a cross-sectional view of each process showing the manufacturing method of the same metal printed circuit board, Figure 6 is a cross-sectional view of a conventional metal printed circuit board with surface mount components mounted, and Figure 7a''-c is a cross-sectional view of the same metal printed circuit board. FIG. 8 is a cross-sectional view showing each step of the manufacturing method of the board, and a perspective view of a multi-piece shape manufactured by the same method. 21...Metal plate, 22... ...Notch, 2
3...Insulating layer, 24...Wiring pattern, 25...Metal printed circuit board, 28...
・Harness, 29...Base metal, 30...Concave groove, 31...Receiving mold, 32.32a...
・Cutting blade, 33...Pushing die, 34...
・Push piece. Name of agent Patent attorney Akira Okaji and two others Figure 1 Figure 2 Figure 3! Figure 4 Figure 5 Rod 6 Cause O Figure 7

Claims (2)

[Claims] (1) A wiring pattern is provided on one side of the metal plate via an insulating layer, and a notch is provided at the periphery of the other side of the metal plate to prevent burrs generated by punching multiple pieces from the base material from protruding to the other side. A metal printed circuit board with (2) forming an insulating layer on one side of a metal plate that is a base material large enough to accommodate a large number of metal printed circuit boards; forming a wiring pattern for each metal printed circuit board on this insulating layer; A concave groove is provided on the other surface of the base material in a portion corresponding to the outer shape of each metal printed circuit board to determine the outer shape of the metal printed circuit board. Punching is performed using a push die and a receiving die with upwardly protruding cutting blades. Alternatively, a metal printed circuit board is punched out using a push die and a receiving die that have an upwardly protruding cutting blade shaped like an inverted V, and the punched metal printed circuit boards are press-fitted together by pushback processing after punching out the base material. manufacturing method.