Metal shielding cover welding structure and welding method

Abstract

The invention relates to the field of microwave circuit assemblies, in particular to a metal shielding case welding structure and method, and the structure comprises a special U-shaped iron head, a PCB and a metal shielding case. The bottoms of the four side walls of the metal shielding case are respectively provided with a clamping block in a protruding manner. The PCB is provided with clamping grooves at corresponding positions, wherein the clamping blocks are embedded in the clamping grooves. A metalized bonding pad is arranged on the inner wall of each clamping groove; during welding, firstly, the metal shielding case is inserted into the PCB through the clamping grooves and the clamping blocks to form positioning, and the clamping blocks and exposed metalized bonding pads of the corresponding clamping grooves are heated and welded through the specially-made U-shaped solder tip; the shielding cover does not occupy the installation space of components on the surface of the PCB, and high-density welding installation of the shielding cover and the side edge of the PCB is achieved.

Description

Technical Field

[0001] The invention relates to the field of microwave circuit components, and in particular to a metal shielding cover welding structure and a welding method. Background Art

[0002] Printed circuit boards (PCBs) on existing electronic devices are developing towards high density and high integration. Electromagnetic interference between components of microwave circuits and between internal and external environments is crucial to the normal functioning of products. Metal shielding can shield the PCB area that needs to be shielded to form an electromagnetic shield, thereby suppressing electromagnetic interference. Therefore, it is widely used in radio frequency microwave circuits.

[0003] At present, the metal shield in the industry is fixed by using a metal shell through screws or mechanical structure limiters and surface welding methods. The screw or mechanical structure limit method has relatively mature application cases, but it also occupies too much PCB board area and cannot meet the miniaturization requirements of the product. Although the surface welding method has some improvements in installation space occupation, it also has problems such as metal shield limit positioning and difficulty in rework after welding. Therefore, it also has certain limitations in practical applications. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a metal shielding cover welding structure and a welding method.

[0005] In the first aspect, the present invention proposes a metal shielding cover welding structure, including a PCB board and a metal shielding cover; the bottom of the four side walls of the metal shielding cover are respectively protruded with card blocks, and the four side walls of the PCB board are provided with card slots that are engaged with the card blocks; the inner wall of each card slot is provided with a metallized pad through metallization treatment; when welding, the metal shielding cover is first inserted into the PCB board through the card slot and the card block, and the card block is located in the middle position of the card slot after being inserted into the card slot, and there are gaps between the left side of the card block and the left inner wall of the card slot, and between the right side of the card block and the right inner wall of the card slot; then a special U-shaped soldering iron head matching the gap is used to perform welding at the metallized pad of each card slot.

[0006] Furthermore, the inner wall of the card slot is provided with a metallized pad by metallization treatment, including: copper coating the surface of the inner wall of the card slot, and then electroplating Ni or Au on the surface of the copper layer to form a metallized pad.

[0007] Furthermore, the metal shielding cover is made of a pressed, stretched or bent metal sheet.

[0008] Furthermore, the thickness of the metal shielding cover is 0.2-0.5 mm; the length of the block arranged on the metal shielding cover is 0.5-1.5 mm, and the width is 1-3 mm.

[0009] Furthermore, the number of the card blocks is consistent with the number of the metallized card slots, and the number of the card blocks is 4 to 10.

[0010] Furthermore, the size of the card block is smaller than that of the metallized card slot; after the card block is inserted into the card slot, it is located in the middle of the card slot; there are gaps between the left side of the card block and the left inner wall of the card slot, and between the right side of the card block and the right inner wall of the card slot, and the size of the gaps is 0.2 to 0.5 mm.

[0011] In a second aspect, based on the welding structure mentioned in the first aspect, the present invention provides a metal shield welding method, characterized in that it includes the following steps:

[0012] S1. Insert the card block of the metal shield into the corresponding card slot on the PCB board so that the bottom of the four side walls of the metal shield fits tightly with the PCB board;

[0013] S2. Place the characteristic U-shaped soldering iron tip in the gap between the card block and its corresponding card slot, use the characteristic U-shaped soldering iron tip to heat the exposed metallized pads of the card block and its corresponding card slot, add solder paste to the metallized pads for welding after heating, and finally form a sealed welding installation structure.

[0014] S3. Dip a small amount of anhydrous ethanol with a dust-free cloth or a cotton ball, and then wipe to remove the flux from the solder joints of the soldering installation structure.

[0015] Furthermore, the heating temperature of the characteristic U-shaped Luo iron head is set to 350° C. to 450° C., and the heating time is 3 to 5 seconds.

[0016] Beneficial effects of the present invention:

[0017] The present invention provides a metal shielding cover and a PCB board through the embedded structure design and a special U-shaped electric soldering iron head, so as to realize the welding installation of the shielding cover and the side of the PCB board. The shielding cover occupies a small area on the printed circuit board, has high welding assembly strength, is easy to disassemble and rework, is simple and efficient to operate, and is conducive to mass production.

[0018] The present invention opens a card slot on the side of the PCB board, and sets a soldering pad inside the card slot (i.e., the side wall of the PCB board); welding and assembly are performed through the card block and the soldering pad in the card slot; the present invention does not need to set a soldering pad on the surface of the PCB board, and the shielding cover does not occupy the component installation space on the surface of the PCB board, thereby realizing high-density welding installation of the shielding cover and the side of the PCB board. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the welding structure of the metal shielding cover of the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the metal shielding cover of the present invention;

[0021] Figure 3 This is a schematic diagram of heating the U-shaped soldering iron tip characterized by the present invention;

[0022] Among them, 1-metal shielding cover, 2-card block, 3-card slot. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The present invention provides a metal shielding cover welding structure, such as Figure 1 , Figure 2 As shown, it includes a PCB board and a metal shielding cover 1; the bottoms of the four side walls of the metal shielding cover 1 are respectively protruded with card blocks 2, and the four side walls of the PCB board are provided with card slots 3 that are engaged with the card blocks 2 and have corresponding positions; the inner wall of each card slot 3 is provided with a metallized pad through metallization treatment; when welding, the metal shielding cover 1 is first inserted into the PCB board through the card slot 3 and the card block 2, and then the characteristic U-shaped soldering iron head is used to perform welding at the pad of each card slot.

[0025] Specifically, the card slot is located at the side (or side wall) of the PCB board, and the card slot is metallized when the PCB board pad is made; the inner wall of the card slot is provided with a metallized pad by metallization, including: copper is coated on the inner wall surface of the card slot, and then Ni or Au is electroplated on the surface of the copper layer to form a metallized pad. The metallized pad is used for subsequent card block installation and welding.

[0026] Specifically, the metal shield is usually made of a metal sheet that has been pressed, stretched or bent. The metal sheet is mostly made of kovar, nickel silver, etc. It is recommended that the surface of the metal sheet be plated with nickel or gold to make it have good solderability.

[0027] Specifically, as shown in Figure 1, a small part of the side wall of the PCB board is dug out to form a card slot, and the card slot has only three surfaces: the left inner wall, the right inner wall and the rear inner wall. Metallization is applied to the inner wall of the card slot to form a metallized pad.

[0028] Specifically, the thickness of the metal shielding cover is 0.2-0.5 mm; the length of the clamping block arranged on the metal shielding cover is 0.5-1.5 mm, and the width is 1-3 mm.

[0029] Specifically, the bottom of the four side walls of the metal shielding cover are respectively protruded with card blocks at different positions, so that the installation direction of the metal shielding cover can be accurate and reverse installation can be avoided. The number of card blocks is consistent with the number of card slots, and the number of card blocks is 4 to 10.

[0030] Specifically, the card block should not protrude from the bottom surface of the printed circuit board, that is, the length and height of the card block are both smaller than the length and height of the card slot; after the card block is inserted into the card slot, the card block is located in the center of the card slot, and the metallized pads on the left inner wall and the right inner wall of the card slot do not contact the card block, that is, there are gaps between the left side of the card block and the left inner wall of the card slot, and between the right side of the card block and the right inner wall of the card slot, and the two gaps are the same size, both 0.2~0.5mm.

[0031] Specifically, the conventional cylindrical soldering iron tip will heat the pin, or block the tinning position, and cannot form a metallized soldering pad, which is not conducive to production operation; for this reason, the present invention adopts Figure 3 The width of the special U-shaped soldering iron tip shown is adapted to the width of the card slot. During welding, the present invention places the characteristic U-shaped soldering iron tip in the gap between the card block and the card slot, which can not only ensure the heating efficiency, but also perform tinning welding on the exposed metallized pads on both sides at the same time.

[0032] The present invention provides a metal shielding cover welding method, comprising the following steps:

[0033] S1. Insert the card block of the metal shield into the corresponding card slot on the PCB board so that the bottom of the four side walls of the metal shield fits tightly with the PCB board;

[0034] S2. Use the characteristic U-shaped iron head to heat the card block and the metallized pad exposed outside the corresponding card slot. After heating, add solder paste to the metallized pad for welding; finally, a firm welding installation structure is formed;

[0035] S3. Dip anhydrous ethanol with a dust-free cloth or a cotton ball, and then wipe to remove the flux from the solder joints of the soldering installation structure.

[0036] Specifically, the heating temperature of the characteristic U-shaped iron head is set to 350° C. to 450° C., and the heating time is 3 to 5 seconds.

[0037] Specifically, the composition of the solder paste is not limited, and may be 63Sn37Pb, SAC305, etc.

[0038] In the structure of the present invention, if the metal shielding cover is to be removed, it is only necessary to heat the exposed metallized pads on both sides of the card block with a characteristic U-shaped soldering iron tip, and remove the melted solder with a solder wick, and the metal shielding cover can be removed smoothly.

[0039] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installation", "setting", "connection", "fixation" and "rotation" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0040] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A metal shielding cover welding structure, characterized in that: It comprises a PCB board and a metal shielding cover; the bottoms of the four side walls of the metal shielding cover are respectively protruded with card blocks, and the four side walls of the PCB board are provided with card slots that are engaged with the card blocks; the inner wall of each card slot is provided with a metallized pad through metallization treatment; when welding, the metal shielding cover is first inserted into the PCB board through the card slot and the card block, and the card block is located in the middle position of the card slot after being inserted into the card slot, and gaps are left between the left side of the card block and the left inner wall of the card slot, and between the right side of the card block and the right inner wall of the card slot; then a special U-shaped soldering iron head matching the gap is used to perform welding at the metallized pad of each card slot.

2. A metal shielding cover welding structure according to claim 1, characterized in that: The metallization pad is provided on the inner wall of the card slot by metallization treatment, including: copper coating the inner wall surface of the card slot, and then electroplating Ni or Au on the surface of the copper layer to form the metallization pad.

3. The metal shielding cover welding structure according to claim 1, characterized in that: Metal shields are made from pressed, stretched or bent metal sheets.

4. The metal shielding cover welding structure according to claim 1, characterized in that: The thickness of the metal shielding cover is 0.2-0.5 mm; the length of the clamping block arranged on the metal shielding cover is 0.5-1.5 mm, and the width is 1-3 mm.

5. The metal shielding cover welding structure according to claim 1, characterized in that: The number of card blocks is consistent with that of metallized card slots, and the number of card blocks is 4 to 10.

6. The metal shielding cover welding structure according to claim 1, characterized in that: The gaps between the left side of the card block and the left inner wall of the card slot, and between the right side of the card block and the right inner wall of the card slot are the same in size, and the gap size is 0.2-0.5 mm.

7. A metal shield welding method for a metal shield welding structure according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Insert the card block of the metal shield into the corresponding card slot on the PCB board so that the bottom of the four side walls of the metal shield fits tightly with the PCB board; S2. Place the characteristic U-shaped soldering iron tip in the gap between the card block and its corresponding card slot, use the characteristic U-shaped soldering iron tip to heat the exposed metallized pad of the card block and its corresponding card slot, add solder paste to the metallized pad for welding after heating, and finally form a firm welding installation structure; S3. Dip anhydrous ethanol with a dust-free cloth or a cotton ball, and then wipe to remove the flux from the solder joints of the soldering installation structure.

8. A metal shield welding method according to claim 7, characterized in that: The heating temperature is 350°C to 450°C, and the heating time is 3 to 5s.

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