A circuit board connection process and connection structure

Abstract

The application discloses a circuit board connecting process and connecting structure, comprising the following steps: providing an injection molding part, the injection molding part comprising an embedded part and an insulating part, the embedded part comprising a plurality of pins, each pin being wrapped by the insulating part, and the part of the pin extending out of the insulating part serving as an electrical connection end; providing a substrate, the substrate comprising a conductive layer, an intermediate dielectric layer and a bottom plate which are sequentially stacked, the conductive layer having an electrical connection area on the top, the electrical connection end of the pin being connected with the electrical connection area of the conductive layer, and the insulating part being in contact with the hole wall of the through hole. The application has the beneficial effect that the metal material strip is punched to form the embedded part, the pins of the embedded part are then subjected to the glue encapsulation injection molding treatment, and the embedded part and the insulating part are inserted into the substrate as a whole; the whole process does not need to perform the insulation treatment on the substrate, a plurality of processes are saved, the glue encapsulation injection molding mode of the pin meets the insulation isolation requirement, the production manufacturing cost is greatly reduced, and the production efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of circuit board connection technology, and particularly relates to a circuit board connection process and connection structure. Background Technology

[0002] Aluminum-based copper-clad laminates are metal-based structures mainly composed of three layers: an aluminum metal base, a thermally conductive and insulating dielectric layer, and a copper foil conductive circuit layer on the surface. Aluminum, as the bottom layer of the substrate, has excellent thermal conductivity and heat dissipation properties, enabling it to quickly dissipate the heat generated by high-power devices during operation, thereby ensuring stable circuit operation.

[0003] In practical applications, various electronic components or inserts need to be mounted on aluminum substrates. The pins of these components are fixed to the aluminum substrate by plugging them in, forming a stable electrical connection with the conductive layer. Because the aluminum substrate itself is conductive, appropriate insulation treatment is required when plugging in the pins.

[0004] The existing insulation process involves first partially hollowing out the aluminum substrate, then backfilling the hollowed-out area with insulating materials such as resin. This filled area serves both load-bearing and insulation functions, and the pins inserted into the insulating material can achieve electrical isolation. However, this process requires multiple steps, including trenching, filling, and curing, resulting in a complex production process, high manufacturing costs, and low yield, which is not conducive to large-scale, high-efficiency production. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a circuit board connection process and connection structure that can reduce the cost of the insulation process between the pins and the aluminum base plate.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a circuit board connection process comprising the following steps: providing an injection molded part, the injection molded part including an insert and an insulating part, the insert including a plurality of pins, each pin being wrapped by the insulating part, and the portion of the pin extending out of the insulating part serving as an electrical connection terminal; providing a substrate, the substrate including a conductive layer, an intermediate dielectric layer and a base plate stacked sequentially, the top of the conductive layer having an electrical connection area, the substrate including a through hole, the through hole penetrating the conductive layer, the intermediate dielectric layer and the base plate, the pin passing through the through hole, the electrical connection terminal of the pin being connected to the electrical connection area of ​​the conductive layer, and the insulating part contacting the hole wall of the through hole.

[0007] Optionally, providing the injection molded part includes the following steps: providing a strip of metal material, stamping the strip to form the insert of a preset shape; electroplating the surface of the insert to form a plating layer; and performing encapsulation injection molding at the pins to form the insulating part.

[0008] Optionally, the encapsulation injection molding process at the pin specifically includes: providing an injection mold, fixing the insert inside the injection mold, and ensuring that the area to be encapsulated at the pin is located within the cavity; closing the injection mold and injecting molten plastic into the cavity according to a preset injection speed and injection pressure; after injection, holding pressure according to a preset holding pressure and holding time; after holding pressure, cooling the injection mold through a cooling water circuit to control the temperature, allowing the molten plastic to solidify and form the insulating component at the pin of the insert; removing the injection molded part and inspecting it.

[0009] Optionally, pretreatment of the insert's surface may also be included.

[0010] Optionally, the pretreatment includes sandblasting the area of ​​the pin to be coated.

[0011] Optionally, the pretreatment includes chemical etching of the area of ​​the pin to be coated.

[0012] Optionally, the pretreatment includes applying a primer to the area of ​​the pin to be coated.

[0013] Optionally, the thickness of the plating layer of the insert is 3-15 μm, and the plating layer is made of tin, silver or gold.

[0014] Optionally, the thickness of the insulating element is 0.3-0.7 mm.

[0015] A circuit board connection structure, manufactured using circuit board connection technology, includes: an injection molded part comprising an insert and an insulating part, the insert comprising a plurality of pins, each pin being wrapped by the insulating part, and the portion of the pin extending out of the insulating part serving as an electrical connection terminal; a substrate comprising a conductive layer, an intermediate dielectric layer, and a base plate stacked sequentially, the conductive layer having an electrical connection area at its top, the substrate including a through-hole penetrating the conductive layer, the intermediate dielectric layer, and the base plate, the pins passing through the through-hole, the electrical connection terminals of the pins being connected to the electrical connection area of ​​the conductive layer, and the insulating part contacting the wall of the through-hole.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0017] 1. By stamping metal strips to form inserts, electroplating is performed on the surface of the inserts to improve conductivity and oxidation resistance. Then, the leads of the inserts are encapsulated and injection molded, and insulating parts are formed at the leads. The inserts and insulating parts are inserted into the substrate as a whole. The unencapsulated area of ​​the leads, i.e., the electrical connection terminal, is connected to the conductive layer of the substrate to achieve circuit conduction. The encapsulated area of ​​the leads, i.e., the insulating part, is inserted into the through holes of the substrate to achieve plug-in fixation. The entire process does not require insulation treatment of the substrate, saving multiple steps. The use of lead encapsulation and injection molding meets the insulation and isolation requirements, greatly reducing manufacturing costs and improving production efficiency.

[0018] 2. By pre-treating the area to be encapsulated on the insert pins, such as by sandblasting, chemical etching, or applying a primer, the adhesion at the pins is increased, and the bonding strength and stability between the insert and the insulating component are improved after encapsulation injection molding. Attached Figure Description

[0019] Figure 1 The diagram shown illustrates the use of insulating fillers in the prior art. Figure 2 The diagram shown is a disassembled schematic of the circuit board connection structure of the present invention; Figure 3 The diagram shown is a cross-sectional view of the circuit board connection structure of the present invention. Figure 4 The diagram shown is a schematic representation of the plug-in insert of the present invention. Figure 5 The diagram shown is a schematic diagram of the patch insert of the present invention.

[0020] In the diagram: 1. Injection molded part; 2. Substrate; 101. Insert; 102. Insulator; 1011. Electrical connection terminal; 201, Conductive layer; 202, Intermediate dielectric layer; 203, Base plate; 2011, Electrical connection area. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance, or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] Example 1 Reference Figures 2 to 5 This embodiment provides a circuit board connection process, specifically including the following steps: providing an injection molded part 1, the injection molded part 1 including an insert 101 and an insulating part 102, the insert 101 including a plurality of pins, each pin being wrapped by the insulating part 102, and the portion of the pin extending out of the insulating part 102 serving as an electrical connection end 1011; providing a substrate 2, the substrate 2 including a conductive layer 201, an intermediate dielectric layer 202 and a base plate 203 stacked sequentially, the top of the conductive layer 201 having an electrical connection area 2011, the substrate 2 including a through hole, the through hole penetrating the conductive layer 201, the intermediate dielectric layer 202 and the base plate 203, the pin passing through the through hole, the electrical connection end 1011 of the pin being connected to the electrical connection area 2011 of the conductive layer 201, and the insulating part 102 contacting the hole wall of the through hole.

[0025] The insulating component 102 is in close contact with the hole wall, and the pins are positioned through it, realizing the dual functions of plug-in fixation and circuit conduction. It has strong anti-vibration and anti-plugging capabilities and is suitable for harsh working conditions such as battery pack controllers.

[0026] Insert 101 is divided into plug-in type and surface mount type, such as Figure 2 and Figure 4 The insert 101 shown is a plug-in type, such as... Figure 5The insert 101 shown is a patch type.

[0027] The plug-in insert 101 has its pins passing through a through-hole from below the substrate 2, with the pin ends extending outwards, such as... Figure 3 and Figure 4 As shown, the electrical connection terminal 1011 is the end of the pin, and the electrical connection terminal 1011 is connected to the electrical connection area 2011 by soldering.

[0028] The surface-mount insert 101 has pins including a pin body and a surface-mount portion located on one side of the pin body. An insulating member 102 covers the pin body, and the pin body passes downwards through a through-hole from the top of the substrate 2. Figure 5 As shown, the electrical connection terminal 1011 is the surface mount portion of the pin. The bottom of the insulating member 102 can be closed, that is, the end of the pin body is also wrapped inside the insulating member 102, and the part of the pin that extends out of the insulating member 102 is the surface mount portion.

[0029] It is compatible with the connection of circuit boards in various scenarios and can flexibly realize two connection forms: bottom insertion and top soldering (plug-in type) and top insertion and bottom mounting (surface type). It is adaptable to different circuit board layouts, soldering processes and installation spaces, and has strong versatility.

[0030] Providing injection molded part 1 includes the following steps: providing a strip of metal material, stamping the strip to form an insert 101 of a preset shape; electroplating the surface of the insert 101 to form a plating layer; and performing encapsulation injection molding at the pins to form an insulating part 102.

[0031] The encapsulation process at the pins specifically includes: providing an injection mold, fixing the insert 101 inside the injection mold, and ensuring that the encapsulation area of ​​the pin is located within the cavity; closing the injection mold and injecting molten plastic into the cavity according to a preset injection speed and injection pressure; after injection, holding pressure according to a preset holding pressure and holding time; after holding pressure, the injection mold is cooled by a cooling water circuit to solidify the molten plastic and form an insulating part 102 at the pin of the insert 101; removing the injection molded part 1 and inspecting it.

[0032] The preset-shaped inserts 101 include various types. For example... Figure 2 and Figure 3 As shown, one of the inserts 101 is U-shaped in general, with multiple symmetrically distributed pins on the top.

[0033] like Figure 4 As shown, one type of insert 101 is generally sheet-shaped, including a sheet portion, one end of which has multiple pins along the length direction of the sheet portion, and extension pieces are symmetrically arranged on both sides along the width direction of the sheet portion, with the extension pieces at a certain angle to the sheet portion.

[0034] like Figure 5As shown, one type of insert 101 includes an inverted U-shaped portion, with patch portions connected to both sides of the inverted U-shaped portion, and multiple pin bodies connected to the side of each patch portion.

[0035] It also includes pretreatment of the surface of insert 101.

[0036] Pretreatment includes sandblasting the area of ​​the pin to be coated.

[0037] Pretreatment includes chemical etching of the area of ​​the pin to be coated.

[0038] Pretreatment includes applying a primer to the area of ​​the pin to be coated.

[0039] Pre-treatment of the area to be coated improves adhesion. Combined with high-temperature injection molding, this significantly enhances the bonding force between the insert 101 and the insulator 102, meeting high pull-out force requirements and preventing plastic cracking and metal slippage during long-term use.

[0040] The plating thickness of insert 101 is 3-15um, and the plating material is tin, silver or gold.

[0041] Tin plating, silver plating, and gold plating can significantly improve the conductivity, oxidation resistance, and corrosion resistance of pins, enhance the contact stability of electrical connections, and prevent oxidation failure during long-term use.

[0042] The thickness of the insulating component 102 is 0.3-0.7 mm.

[0043] The vertical distance between the outer surface of the insulating component 102 and the outer surface of the pin is the thickness of the insulating component 102. The pin is encapsulated using injection molding to form an insulating layer with a precise thickness of 0.3-0.7mm. This one-step molding process meets the requirements for pressure resistance, fire resistance, and insulation, simplifying the process flow and eliminating the original complex steps. Insulation and isolation are achieved in a single injection molding step, resulting in a stable structure that effectively prevents short circuits and meets the requirements for insulation, pressure resistance, and structural strength. This simplifies the production process, significantly reducing costs. Furthermore, the injection molding process is suitable for mass production, offering high efficiency and stable quality.

[0044] The entire process flow is as follows: Insert preparation: Stamp the insert 101 of the preset shape from metal strips such as brass and phosphor bronze; plate the surface of the insert 101 with tin, silver or gold to improve conductivity and oxidation resistance; for products with high adhesion requirements, sandblast, chemically etch or coat the area to be coated with special primer to increase the bonding force between plastic and metal; check the size, flatness and oil stains of the finished product.

[0045] Plastic material preparation: Select engineering plastics such as nylon, PBT, PET, and PPA to ensure good insulation, heat resistance, flame retardancy (such as UL94V-0), and compatibility with metals; thoroughly dry the plastic granules (such as drying PBT at 120-130℃ for 3-4 hours) to remove moisture and prevent air bubbles or silver streaks during injection molding.

[0046] Insert Injection Molding: Insert 101 is placed into the injection mold and positioned manually or automatically to ensure that it will not shift or deform under the mold closing pressure. The injection molding equipment used is a common model in this field. The equipment parameters are finely adjusted according to the specific product, material, and mold. For example, an injection molding equipment with a maximum injection speed of 100 mm / s and a maximum injection pressure of 200 MPa is used. Medium-high injection speed (machine setting percentage 40%-80%) and medium injection pressure (machine setting percentage 50%-70%) are used to inject molten plastic into the cavity, ensuring that the molten plastic fills the cavity without displaced the insert 101.

[0047] Holding pressure: After injection, maintain a certain pressure to compensate for the volume of plastic shrinkage during cooling, prevent shrinkage marks and ensure dimensional accuracy. The holding pressure is 60%-80% of the injection pressure. The holding time is based on the gate freezing to ensure no shrinkage. The holding time is 1.5-3 seconds.

[0048] Cooling: The mold is cooled by a cooling water system to control the temperature and allow the plastic to solidify and set. The cooling time depends on the thickness of the thickest part of the plastic, and generally requires 20-60 seconds. This ensures that the product is fully cured and ejected without deformation.

[0049] Remove the injection molded part: Open the mold and smoothly eject the overmolded insert 101 from the injection mold; cut off the gate and runner waste.

[0050] Inspection: Check the integrity of the coating (no missing material, no air bubbles), positional accuracy, insulation resistance, pull-out force, etc.

[0051] When injecting molten plastic, controlling the injection speed and injection pressure is crucial. Too slow a speed can lead to cold material and poor bonding, while too fast a speed may cause the insert 101 to deviate or produce flash. The injection pressure needs to be as low as possible while ensuring mold filling, in order to reduce the impact and internal stress on the insert 101.

[0052] During injection molding, the mold temperature is 80℃-120℃ (for crystalline materials such as PBT and nylon). High mold temperatures facilitate plastic flow, reduce internal stress, improve surface gloss, and enhance adhesion to metals. The barrel temperature needs to be determined based on the type of plastic; for example, it is approximately 240℃-260℃ for PBT to ensure uniform plasticization.

[0053] Precise control of process parameters such as injection speed, injection pressure, holding pressure and time, and cooling time avoids cold material, material shortage, flash, and misalignment, ensuring stable dimensional accuracy and insulation performance in mass production.

[0054] This process employs an integrated encapsulation technique for metal components requiring insulation (such as pins / copper pillars), forming a partial encapsulation that wraps around an insulator. The insulator material is made of engineering plastic particles that are pressure-resistant, fire-resistant, and highly insulating. After injection molding, it can form an insulating layer of a certain thickness between the insulator and the component. Ultimately, the requirements for insulation, pressure resistance, and mechanical strength can be met at the battery pack controller board substrate level.

[0055] This process involves injection molding adhesive onto the area to be coated on the pins of insert 101. Insert 101 and insulating component 102 are stably connected together and inserted as a whole into the through-hole of substrate 2. Figure 3 As shown, for the plug-in insert 101, the area to be coated is below the electrical connection terminal 1011, as follows: Figure 5 As shown, for the surface mount insert 101, the area to be encapsulated is on the side of the electrical connection terminal 1011. The electrical connection terminal 1011 is in stable contact with the electrical connection area 2011, ensuring circuit continuity; the insulating component 102 is inserted into the through hole of the substrate 2, and the substrate 2 provides stable load-bearing capacity for the insert 101 and the insulating component 102; eliminating multiple processes such as grooving, filling, and curing, the lead encapsulation injection molding method meets the insulation and isolation requirements, overcoming the core problems of complex and cumbersome processes, high costs, and low yield in existing processes, greatly reducing manufacturing costs and improving production efficiency.

[0056] Example 2 Reference Figures 2 to 5 This embodiment provides a circuit board connection structure, manufactured using circuit board connection technology, specifically including: an injection molded part 1, which includes an insert 101 and an insulating part 102. The insert 101 includes multiple pins, each pin being wrapped by the insulating part 102, and the portion of the pin extending out of the insulating part 102 serving as an electrical connection terminal 1011; a substrate 2, which includes a conductive layer 201, an intermediate dielectric layer 202, and a base plate 203 stacked sequentially. The top of the conductive layer 201 has an electrical connection area 2011. The substrate 2 includes a through hole that penetrates the conductive layer 201, the intermediate dielectric layer 202, and the base plate 203. The pins pass through the through hole, and the electrical connection terminals 1011 of the pins are connected to the electrical connection areas 2011 of the conductive layer 201. The insulating part 102 is in contact with the hole wall of the through hole.

[0057] The base plate 203 is made of aluminum. The insulating component 102 wraps around a specific area of ​​the pins of the insert 101. The insert 101 and the insulating component 102 are then inserted into the through-hole of the substrate 2. The insulating component 102 forms a stable isolation area, thereby achieving insulation isolation between the pins and the aluminum layer. This connection structure is suitable for inserts 101 of various shapes, such as through-hole and surface mount types, and has a wide range of applications, reliable performance, and high production efficiency.

[0058] like Figure 3 and Figure 4 As shown, when the insert 101 is a plug-in type, the insulating member 102 has openings at the top and bottom, and is fitted onto the pin. A horizontal connecting piece is provided at the bottom of the insulating member 102, and multiple insulating members 102 are integrally formed with the horizontal connecting piece. For example... Figure 5 As shown, when the insert 101 is a surface mount type, the upper end of the insulating member 102 is open and the lower end is closed, covering the pin.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A circuit board connection process, characterized in that, Includes the following steps: An injection molded part (1) is provided, the injection molded part (1) including an insert (101) and an insulator (102), the insert (101) including a plurality of pins, each of the pins being wrapped by the insulator (102), and the portion of the pins extending out of the insulator (102) serving as an electrical connection terminal (1011). A substrate (2) is provided, the substrate (2) including a conductive layer (201), an intermediate dielectric layer (202) and a base plate (203) stacked sequentially, the conductive layer (201) having an electrical connection area (2011) on top, the substrate (2) including a through hole, the through hole penetrating the conductive layer (201), the intermediate dielectric layer (202) and the base plate (203), the pin passing through the through hole, the electrical connection end (1011) of the pin being connected to the electrical connection area (2011) of the conductive layer (201), and the insulating member (102) contacting the hole wall of the through hole.

2. The circuit board connection process according to claim 1, characterized in that, The provision of the injection molded part (1) includes the following steps: A strip of metal is provided, and the strip is stamped to form the insert (101) of a preset shape. Electroplating is performed on the surface of the insert (101) to form a plating layer; The insulating component (102) is formed by encapsulation injection molding at the pin.

3. The circuit board connection process according to claim 2, characterized in that, The specific steps of the encapsulation injection molding process at the pins include: Provide an injection mold to fix the insert (101) inside the injection mold and to place the area of ​​the pin to be covered in glue inside the cavity; Close the injection mold and inject molten plastic into the cavity according to the preset injection speed and injection pressure; After the injection is completed, maintain the pressure according to the preset holding pressure and holding time; After the pressure holding is completed, the injection mold is cooled by the cooling water circuit to solidify and shape the molten plastic, and the insulating part (102) is formed at the pin of the insert (101). Remove the injection molded part (1) and inspect it.

4. The circuit board connection process according to claim 2, characterized in that, It also includes pretreatment of the surface of the insert (101).

5. The circuit board connection process according to claim 4, characterized in that, The pretreatment includes sandblasting the area of ​​the pin to be coated.

6. The circuit board connection process according to claim 4, characterized in that, The pretreatment includes chemical etching of the area of ​​the pin to be coated.

7. The circuit board connection process according to claim 4, characterized in that, The pretreatment includes applying a primer to the area of ​​the pin to be coated.

8. The circuit board connection process according to claim 2, characterized in that, The thickness of the plating on the insert (101) is 3-15 μm, and the plating material is tin, silver or gold.

9. The circuit board connection process according to claim 2, characterized in that, The thickness of the insulating component (102) is 0.3-0.7 mm.

10. A circuit board connection structure, characterized in that, Fabricated using the circuit board interconnection process as described in any one of claims 1-9, comprising: Injection molded part (1), the injection molded part (1) includes an insert (101) and an insulator (102), the insert (101) includes a plurality of pins, each of the pins is wrapped by the insulator (102), and the portion of the pins extending out of the insulator (102) serves as an electrical connection terminal (1011). The substrate (2) includes a conductive layer (201), an intermediate dielectric layer (202) and a base plate (203) stacked sequentially. The top of the conductive layer (201) has an electrical connection area (2011). The substrate (2) includes a through hole that penetrates the conductive layer (201), the intermediate dielectric layer (202) and the base plate (203). The pin passes through the through hole, and the electrical connection end (1011) of the pin is connected to the electrical connection area (2011) of the conductive layer (201). The insulating member (102) is in contact with the hole wall of the through hole.

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