JP3304065B2 - Electronic substrate manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electronic substrate, and more particularly to a method for manufacturing an electronic substrate in which a conductive metal plate is punched into a wiring pattern and a required area is covered with a synthetic resin material for insulation. Things.

[0002]

2. Description of the Related Art A conventional electronic substrate is simply a substrate made of an insulating material. An electronic component group is arranged on one surface of the electronic substrate, and connection terminals of these electronic component groups are projected from the other surface. The terminal group was connected by printed wiring made of solder. In this case, since the cross-sectional area of the lead wire portion of the printed wiring cannot be set to be too large, the electric resistance increases, which is not suitable for a substrate of an electronic component having a large electric capacity.

Therefore, recently, a conductive metal plate having a predetermined thickness is punched as an electronic substrate on which such a large electronic component group is arranged, in accordance with the arrangement of the lead wires, and a required area thereof is insulated. A type coated with a synthetic resin material is employed. In this case, since the cross-sectional area of each lead wire portion constituting the wiring pattern is larger than the cross section of the conventional lead wire portion made of solder, an electronic component group having a large electric capacity can be arranged. However, the insulating synthetic resin material is injected into the mold while a required portion of the wiring pattern in which a group of lead wires connecting the electronic components is arranged is supported between the upper mold and the lower mold. Since the required portion is covered with the insulating synthetic resin material layer, it is necessary to support the wiring pattern in a state of floating in a molding space formed by the upper mold and the lower mold. Conventionally, a thin support pin is projected from a lower mold to support the wiring pattern thereon.

Accordingly, the cover layer of the insulating synthetic resin material has a hole corresponding to the support pin, and the surface of the lead wire is exposed at the hole. Although this hole is provided in a range that does not significantly affect the insulation performance, there is a concern that electric leakage may occur through this hole, and this problem cannot be ignored especially when the electric capacity is large.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of the following problem. "A required portion of a wiring pattern in which a group of lead wires for connecting electronic components are arranged is formed by an upper mold and a lower mold. And a method of manufacturing an electronic substrate in which the insulating portion of the wiring pattern is covered with the insulating synthetic resin material by injecting the insulating synthetic resin material into the mold in a state where the insulating synthetic resin material is sandwiched between the molds. In order to ensure the insulation performance, it is a specific object of the present invention to prevent a hole which is a support mark of a support pin for supporting a wiring pattern from being generated.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problem, a solution of the present invention is to provide a movable support in which a flexible portion of a lead wire portion of the wiring pattern is provided in a lower mold. Supported by a pin, in this state, the molten resin of the insulating synthetic resin material is injected into the injection space of the mold to fill the molten resin, and the molten resin immediately after the completion of the injection of the molten resin is uncured. The support pin is forcibly separated from the lead wire at the time and while the injection pressure is acting on the molten resin. "

The above solution works as follows. When the molten resin of the insulating synthetic resin material is injected into the injection space formed by the upper mold and the lower mold, the injection space is filled with the molten resin and the portions other than the portion supported by the support pins are filled. The portion other than the portion and the portion where the upper mold and the lower mold are partially in contact with each other is covered with the molten resin. Next, when the support pin is separated from the lead wire at the time when the molten resin is uncured after the completion of the injection filled with the molten resin, the pressure at the time of injection acts on the molten resin. Resin flows between the support pin and the lead wire in the separated state, and the lead wire portion that has been in contact with the support pin is covered with the molten resin, which has conventionally occurred in the support portion by the support pin. No holes will be formed.

[0008]

According to the present invention having the above configuration, the following specific effects are obtained. The entire surface of the part other than the electronic part connection part, including the part supporting the lead wire part by the support pins, is covered with the insulating synthetic resin material, so that the problem of the electric leakage or the insulation failure as in the past is solved. it can.

[Others] Item a In the above invention, "a press pin is provided at a position opposite to the support pin, and the molten resin is injected while the lead wire is held between the support pin and the press pin. The support pin and the presser pin are simultaneously separated from the lead wire. ''), The lead wire portion is sandwiched between the support pin and the presser pin from above and below. Further, deformation due to the influence of the flow of the molten resin at the time of injection, deformation due to injection pressure, and the like can be prevented. Specifically, in the case of support using only the support pins, the lead wire may be deviated from the support position due to the flow of the molten resin or the like at the time of the injection depending on the conditions of the lead wire. Does not cause such a problem.

Item b. In the items up to item a, "a plurality of positioning pins are provided which operate synchronously with the support pin and position the lead wire by sandwiching the lead wire from the side. When the lead wire is separated from the lead wire, the positioning pin also separates from the lead wire. ”In the case where the lead wire is positioned in the horizontal direction by the plurality of positioning pins, the movement of the lead wire due to the flow of the molten resin is further increased. It can be reliably prevented.

Item c, wherein one or both of the end portions of the support pin and the holding pin are formed so as to become thinner toward the end, the support pin or the holding pin may lead in the uncured molten resin. When separating from the wire, the pressure inside the molten resin allows the molten resin to be efficiently filled between the leading end of the “shape tapering toward the tip” and the surface of the lead wire. In the case where each of the pins is a cylindrical pin and the front end surface is a plane that comes into contact with the lead wire, when the respective pins separate from the lead wire in the molten resin, the pins are separated at a high speed. Therefore, there is a disadvantage that a vacuum space is generated between the distal end surface and the lead wire to cause deformation of the lead wire due to residual pressure and a space is generated in the coating layer (see FIG. 7). In those that adopt the shape of the part,
Such inconvenience can be prevented.

Here, the shape that becomes thinner toward the tip means not only a conical shape and a pyramid shape, but also a shape manufactured to produce the above-mentioned action, that is, a shape whose cross-section gradually decreases toward the tip. Including. Clause d: In the case where one or both of the tips of the support pin and the holding pin are separated from the molten resin injection area, the insulation covering both the portion supported by the pin and the portion held by the holding pin is provided. Since the thickness of the synthetic resin material for use is sufficient, the insulation performance is further ensured.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described together with the illustrated example. As shown in FIGS. 4 and 5, the electronic substrate manufactured according to this embodiment includes a lead wire (L).
The wiring pattern (1) made of (L) or the like is covered from the front and back with a synthetic resin material for insulation, and the covering material (2) has terminal holes (12 ) (1
Electronic component (3) arranged on one side of the covering material (2) in (2)
(3) The terminals (31) and (31) of the group are inserted, and the terminals and the peripheral portions of the terminal holes (12) and (12) are soldered to form a solder portion (3
2) According to (32), the lead wire (L) of the wiring pattern (1)
(L) and the terminal (31) are electrically connected.

In this electronic substrate, first, a wiring pattern (1) as shown in FIG. 1 is prepared. This wiring pattern
(1) is arranged in a rectangular frame (10), and is connected to the wiring pattern (1) by legs (11) (11). The wiring pattern (1) is covered on its front and back with a synthetic resin material for insulation, and then cut at the inner ends of the legs (11) and (11) to form the substrate shown in FIG. In addition, for example, an extension connecting portion (13) is provided at a portion where the lead wires (L) and (L) become unstable during the coating, and this portion is provided with an opening of the coating material (2). (21), and the extension connecting portion (13) in the opening (21) is also cut at the same time as the leg (11). As a result, a predetermined wiring pattern (1) is formed.

The coating material (2) comprises an upper mold (4a) and a lower mold (4).
The wiring pattern (1) is interposed between the wiring pattern (b) and the frame (10) and the legs (11) and (11) on the outer periphery of the wiring pattern (1), as well as the extension connecting parts (13) and (13). The corresponding portions are injection-molded in a state where they are set in a state of being sandwiched by the upper mold (4a) and the lower mold (4b), thereby being configured as shown in FIGS.

In the injection molding, the wiring pattern (1)
In the portion where the free area is long in the portion of the lead wires (L) and (L), the support pin (P ₁ ) provided on the lower mold (4b) as shown in FIG.
To prevent the lead wires (L) (L) from bending downward. In this state, the upper mold (4a)
When the molten resin of the insulating synthetic resin is injected into the injection space formed by the lower mold (4b), the portion filled with the molten resin and supported by the support pins (P ₁ ) as shown in FIG. The other portions and portions other than the partial contact between the upper mold (4a) and the lower mold (4b) are covered with the molten resin.

When the molten resin is in an uncured state, pressure is acting on the molten resin in the injection space. In this state, when the support pin (P ₁ ) is retracted into the lower mold (4b). The space between the tip of the support pin (P ₁ ) and the lead wire (L) is filled with the molten resin. Therefore, the support portion by the support pin (P ₁ ) does not remain as a hole as it is conventionally, and the lead wire (L) corresponding to the support portion is not exposed to the outside.

Particularly, in this example, as shown in FIG. 6, the tip of the support pin (P ₁ ) is formed in a truncated cone shape.
When the distal end of the support pin (P ₁ ) escapes from the uncured molten resin, a negative pressure portion hardly remains on the distal end side, and the support pin (P ₁ ) and the lead wire (L) in the retracted state are removed. During this time, the surrounding molten resin flows in and then hardens. In this example, the retracted position of the support pin (P ₁ ) is set to a certain degree from the inner surface of the upper mold (4a), so that the support pin (P ₁ ) is further outwardly separated from the surface of the coating material (2). I have to. Therefore, in this example, after the completion of the injection molding of the coating material (2), the convex portion (23) is formed at the portion coinciding with the tip portion of the support pin (P ₁ ) as shown in FIG.
Is formed.

Since the outer peripheral area of the terminal hole (12) for soldering is in contact with a part of the mold on the lower mold (4b) side, this part is formed after the completion of the injection molding. Lead wire to be the soldering surface (14) for soldering as shown in Figs.
(L) exposure area. After the covering material (2) is formed on both the front and back surfaces of the frame (10) as described above, as shown in FIG.
(11) When the portion outside the base end of the covering material (2) side of (11) and the frame portion (10) and the extension connection portion (13) in the opening (21) are cut off,
Electronic parts without electronic components (3) (3) are manufactured.
On this board, the protrusions (23) and (23) are on one side
(14) (14), the other surface is configured to open a hole to the terminal hole (12) (12) for mounting the electronic components (3) (3),
Electronic components (3) (3) are attached to the other surface and terminals (31) (3)
1) is attached to the corresponding terminal holes (12) and (12), and a solder shower is applied to the surface on the opposite side of the electronic board. As shown in FIG. 5, the electronic component (3) and the lead wire (L) ( L) is the soldering surface
It is connected in a conductive state by a solder portion (32) for bonding the tip of the terminal (31) to the terminal (14).

Thus, an electronic substrate having the electronic components (3) (3) is manufactured. In addition, the support pin (P ₁ )
As shown in FIG. 7A, the end face may be, for example, a cylindrical pin having a flat surface, but such a structure has the following problems depending on injection molding conditions. When the coating material (2) is injection-molded using this support pin (P ₁ ) and the support pin (P ₁ ) is retracted at a high speed at the time when the molten resin is not cured, as shown in FIG. , And the end face (P ₀ )
A space (K) is created between the lead wire (L) and the lead wire (L) as shown in FIG.
May be partially deformed and finished with a space remaining in the coating material (2). However, when the tip of the support pin (P ₁ ) is shaped like a truncated cone as shown in FIG. In such a case, such inconvenience does not occur for the reasons described above.

As shown in FIG. 8, the support pin (P ₁ ) and a holding pin (P ₂ ) for holding the lead wire (L) at a position facing the support pin (P ₁ ) may be provided. In this case, since the lead wire (L) is sandwiched by both the support pin (P ₁ ) and the holding pin (P ₂ ), even if the lead wire (L) is arranged in an unstable state, It is stably held and fixed. Therefore,
When the coating material (2) is injection-molded while the wiring pattern (1) is sandwiched between the upper mold (4a) and the lower mold (4b), the lead wire (L) is displaced by the flow of the molten resin. Can be prevented.

Even when the lead wire (L) is supported from one side, as shown in FIG. 9, a positioning pin (A) for holding the side of the lead wire (L) separately from the support pin (P1). (P3) (P3)
May be configured to move up and down synchronously with the support pin (P1). In this example, both sides of the cross section of the lead wire (L) are positioned by being sandwiched by plate-like positioning pins (P3) (P3), and the lower surface of the lead wire (L) is supported by the support pins (P1). It has a configuration. After the molten resin is injected, the support pin (P1) and the positioning pins (P3) (P3) are simultaneously retracted downward after the molten resin is injected (FIG. 9). -B), then the support pins
The support pin (P1) is raised again so that the tip of (P1) is flush with the surface of the other part of the covering material (2) (see FIG. 9C). ) Wait for the part to cure. As a result, the molding of the coating material (2) is completed. In this case, the displacement of the lead wire (L) during the injection molding can be prevented without using the holding pin (P2).

[Brief description of the drawings]

FIG. 1 is a plan view of a partially cutout of an electronic substrate manufactured by a method of the present invention immediately after injection molding.

FIG. 2 is a sectional view taken along line XX.

FIG. 3 is a sectional view taken along the line YY.

FIG. 4 is a plan view of a partially cutout of a finished electronic substrate alone.

FIG. 5 is a sectional view taken along the line ZZ.

FIG. 6 is an explanatory view of an injection step.

FIG. 7 is an explanatory view of an injection process of another example.

FIG. 8 is an explanatory view of an injection step when a lead wire (L) is sandwiched from both upper and lower surfaces.

FIG. 9 is an explanatory view of an injection process of another example.

[Explanation of symbols]

(1) ・ ・ ・ Wiring pattern (3) ・ ・ ・ Electronic components (4a) ・ ・ ・ Upper mold (4b) ・ ・ ・ Lower mold (P ₁ ) ・ ・ ・ Support pin (P ₂ ) ・ ・ ・Pressing pin (P ₃ ) ・ ・ ・ Positioning pin (L) ・ ・ ・ Lead wire

Claims (5)

(57) [Claims] An insulating synthetic resin material is placed in said mold in a state in which a required portion of a wiring pattern in which a group of lead wires for connecting electronic components are arranged is supported by being pressed between an upper mold and a lower mold. In the method of manufacturing an electronic substrate in which the insulating portion of the wiring pattern is covered with the insulating synthetic resin material by injecting the wiring pattern, a flexible portion of a lead wire portion of the wiring pattern is provided in a lower mold. In this state, the molten resin of the insulating synthetic resin material is injected into the injection space of the mold to fill the molten resin, and the molten resin immediately after the completion of the injection of the molten resin is uncured. A method for manufacturing an electronic substrate in which the support pins are forcibly separated from the lead wires while the injection pressure is being applied to the molten resin at the point of time. 2. A pressing pin is provided at a position opposite to the supporting pin, and the molten resin is injected while the lead wire is held between the supporting pin and the pressing pin. 2. The method for manufacturing an electronic substrate according to claim 1, wherein the substrate is simultaneously separated from the lead wire. 3. 3. A plurality of positioning pins which operate synchronously with the support pin and position the lead wire with the lead wire sandwiched from the side, wherein when the support pin is separated from the lead wire, 3. The method of manufacturing an electronic substrate according to claim 1, wherein the positioning pins are also separated from the lead wires. 4. The method for manufacturing an electronic substrate according to claim 1, wherein one or both of the end portions of the support pin and the holding pin are formed in a shape that becomes thinner toward the end. 5. The method of manufacturing an electronic substrate according to claim 1, wherein one or both ends of the support pin and the holding pin are separated from the outside of the injection area of the molten resin.