Metal terminal and double-welding installation method thereof

Abstract

The invention discloses a metal terminal and a double-welding installation method thereof, and the metal terminal comprises terminal units which are symmetrically arranged, and each group of terminal units comprises a patch bonding pad which comprises a half-surrounded frame and an auxiliary bonding pad which is located at the side part of the half-surrounded frame; the surrounding elastic piece is located above the patch bonding pad and comprises a vertical face end, a plane end and a bent end which are connected in sequence, the plane end has a preset size, and the top face of the plane end is provided with a smooth plane; and the positioning pin is located on the side portion of the half-surrounded frame and connected with the vertical face end, a column groove is punched in the positioning pin, and the positioning pin has a preset length. The invention belongs to a plug-in metal terminal, can be operated through a chip mounter, improves the efficiency, improves the placement precision, has the characteristics of a plug-in terminal, is provided with a plug-in pin, and achieves the double-welding installation through the solidification of reflow soldering and the reinforcement of wave soldering.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor processing, in particular to a metal terminal and a double welding installation method thereof. Background Art

[0002] SMT is surface mount technology, the most popular technology and process in the electronic assembly industry. Electronic circuit surface assembly technology is called surface mounting or surface mounting technology. It is a connection technology that mounts pinless or short-lead surface mount components (abbreviated as SMC / SMD, called chip components in Chinese) on the surface of printed circuit boards or other substrates and assembles circuits through welding.

[0003] Metal terminals are also a type of sheet component, in which metal terminals are often connected to pads on a circuit board using a planar welding method.

[0004] There are two shortcomings in connecting metal terminals and pads using plane welding:

[0005] First, because the contact area between the pad and the metal terminal is very small, when the height of the metal terminal itself is relatively high, the stress on the left and right will be weakened, which makes the connection between the pad and the metal terminal not very stable and easy to fall off;

[0006] Secondly, once the vacuum suction cup is used for moving and loading in the SMT equipment, the adsorption position between the existing metal terminal and the suction cup is small, and stable adsorption cannot be guaranteed. There will be a certain deviation during loading, which will affect the processing quality and the reliability of welding. Summary of the invention

[0007] Purpose of the invention: To provide a metal terminal and a double welding installation method thereof to solve the above-mentioned problems existing in the prior art.

[0008] Technical solution: A metal terminal and a double welding installation method thereof, comprising:

[0009] Two sets of symmetrically arranged terminal units are formed by metal stamping, and each set of terminal units includes:

[0010] The patch pad includes a semi-enclosed frame and an auxiliary pad located on the side of the semi-enclosed frame. The shape and size of the auxiliary pad and whether the auxiliary pad is needed to increase the welding position can be selected according to actual conditions;

[0011] The design of the auxiliary pad allows the molten solder paste to climb up the two pairs of positioning pins, increasing the contact area between the bottom of the terminal and the pad, thereby increasing the firmness of the patch;

[0012] A surrounding spring sheet is located above the patch pad and includes a vertical end, a plane end, and a bent end connected in sequence, wherein the plane end has a predetermined size, and the top surface of the plane end has a smooth plane;

[0013] A positioning pin is located at a side of the semi-enclosed frame and connected to the vertical surface end. A column groove is punched on the positioning pin, and the positioning pin has a predetermined length.

[0014] The present invention belongs to a plug-in metal terminal, but can be operated by a placement machine to improve efficiency and placement accuracy. A smooth plane with a predetermined size is designed on the plane end to be sucked by an automatic suction nozzle in the SMT placement machine, thereby improving the placement efficiency of the metal terminal in the welding area of ​​the circuit board. At the same time, a positioning pin is designed. When the metal terminal is placed in the welding area, the positioning pin is used to position the terminal to avoid misalignment of the terminal.

[0015] Compared with the single-position soldering of traditional SMD terminals and the pin soldering of plug-in terminals, this terminal is fixed to the circuit board after reflow soldering and wave soldering. When fixing, the positioning pins are soldered in the positioning holes, and the SMD pads are soldered on the circuit board. There is double-position welding, which makes the fixation of the metal terminal more stable. At the same time, during welding, the positioning pins do not exceed the circuit board to adapt to the use of SMT placement machines.

[0016] By fixing the patch pad, the resilience of the surrounding spring can be improved.

[0017] The fixation by wave soldering can improve the fixing ability of the metal terminal and prevent the metal terminal from falling off due to impact.

[0018] Through wave soldering, the metal terminals can be inserted in either the forward or reverse direction, because the positioning gives the pins a strong fixing ability for penetrating soldering.

[0019] By punching column grooves on the positioning pins and increasing the rigidity of the positioning pins, deformation of the pins can be effectively prevented, and the metal terminals can be reliably in place when the patch falls.

[0020] In a further embodiment, the planar end has a width of 2 mm and a length of 1.3 mm.

[0021] In a further embodiment, the length of the positioning pin is less than the thickness of the circuit board on which the metal terminal is mounted.

[0022] In a further embodiment, when symmetrically arranged, there is a gap between the two groups of patch pads (when symmetrically arranged, there is a gap between the two groups of semi-enclosing frames and the auxiliary pads), and the two groups of enclosing spring sheets abut against each other (abutted by the bent ends);

[0023] If the gap is used without welding, the gap will be stretched when the surrounding spring sheet is deformed, resulting in weakened elastic force. Therefore, we need to weld the metal terminal and the pad area of ​​the circuit board together through the first round of reflow soldering. Due to the connection characteristics of the pad area itself, the bottom of the metal terminal body (chip pad) will also be reinforced after welding. The reinforced chip pad has a supporting effect on the surrounding spring sheet. When the plug-in is inserted into the metal terminal, it brings greater elasticity to the surrounding spring sheets on both sides; when the plug-in is pulled out of the terminal, it also helps the surrounding spring sheets on both sides to bring elastic force to return to normal;

[0024] In a further embodiment, there is a transitional curved surface between the vertical end and the plane end. Through this design, in order to prevent the deformation of the metal terminal from causing elastic failure of the surrounding spring sheet or even breaking of the spring sheet, the elastic effect is increased through the transition of the curved surface;

[0025] The connection between the plane end and the bent end has a predetermined transition angle. This design avoids hard right-angle turns, reduces right-angle stress, and increases deformation elasticity.

[0026] In a further embodiment, the facade end is connected to the semi-enclosing frame.

[0027] In a further embodiment, the length of the positioning pin is 1.5 mm less than the thickness of the circuit board is 1.6 mm;

[0028] A double welding installation method for a metal terminal, comprising:

[0029] Step 1, preparing a circuit board corresponding to the metal terminal, and a scraper for filling solder into the pad area of ​​the circuit board, wherein the pad area includes a pin hole and a patch pad welding area;

[0030] Step 2. Fix the scraper on the pad area, and use the placement machine to evenly apply solder paste to the pad area. The solder paste of the pin hole is fully covered. After applying, remove the scraper;

[0031] The fixing method can be selected based on the working scenario. You can use a clamp or directly press the hanging net with a manipulator, or fix it manually.

[0032] Step 3: Use a manipulator with a vacuum suction cup to absorb the flat end and move the metal terminal to the top of the circuit board so that the positioning pin corresponds to the pin hole. The vacuum suction cup releases the absorption of the metal terminal, and the metal terminal falls freely. The positioning pin falls into the pin hole to complete the positioning. The positioning pin does not exceed the bottom of the circuit board. Since the solder paste fully covers the pin hole, part of the solder paste is brought into the pin hole and the column groove under the drive of the positioning pin.

[0033] Step 4: At this time, there is a gap between the two groups of patch pads. Reflow soldering is performed, and the solder paste melts and fills the gap between the patch pads by itself. The patch pads are soldered to the circuit board, and the copper sinking welding of the positioning pins and the inner wall of the pin holes is completed at the same time, realizing the preliminary space welding of the metal terminals.

[0034] After welding, the two sets of SMD pads are integrated, and the metal terminals and pad areas are integrated;

[0035] Step 5. After the metal terminal is reflow soldered, the contact surface between the metal terminal and the circuit board is firmly soldered. Since the positioning pin does not exceed the bottom of the circuit board, there is a gap between the positioning pin in the pin hole and the bottom area of ​​the circuit board.

[0036] Step 6: Fill the gap with solder paste and use wave soldering to fill the gap and complete the secondary welding of the metal terminal;

[0037] Step 7, after welding is completed, insert the plug-in, and the plug-in is fixed by the surrounding spring sheet. When the plug-in is inserted and used together, since the patch pads and positioning pins of the metal terminal are welded to the circuit board, when the plug-in is inserted into the metal terminal, the surrounding spring sheets at both ends are squeezed outwards, and the patch pads and positioning pins of the metal terminal are welded to the circuit board, which brings greater elastic rebound retention force to the surrounding spring sheet;

[0038] Beneficial effects: The present invention discloses a metal terminal and a double-welding installation method thereof. The present invention belongs to a plug-in metal terminal, but can be operated by a patch machine, thereby improving efficiency and placement accuracy. At the same time, the present invention has the characteristics of a plug-in terminal, has a plug-in pin, and is cured by reflow soldering and reinforced by wave soldering, thereby realizing double-welding installation.

[0039] A smooth plane with a predetermined size is designed on the plane end to be sucked by the automatic suction nozzle in the SMT placement machine, thereby improving the placement efficiency of the metal terminal in the soldering area of ​​the circuit board. At the same time, positioning pins are designed. When the metal terminal is placed in the soldering area, the positioning pins are used to position the terminal to avoid terminal misalignment.

[0040] Compared with the single-position soldering of traditional SMD terminals and the pin soldering of plug-in terminals, this terminal is fixed to the circuit board after reflow soldering and wave soldering. When fixing, the positioning pins are soldered in the positioning holes, and the SMD pads are soldered on the circuit board. There is double-position welding, which makes the fixation of the metal terminal more stable. At the same time, during welding, the positioning pins do not exceed the circuit board to adapt to the use of SMT placement machines. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the structure after welding of the present invention.

[0042] Figure 2It is a schematic diagram of the metal terminal structure of the present invention.

[0043] Figure 3 It is a schematic diagram of the specific structure of the metal terminal of the present invention.

[0044] Figure 4 It is a cross-sectional schematic diagram of the metal terminal of the present invention after being inserted into a circuit board.

[0045] Figure 5 It is a schematic diagram of the flow direction of the reflow solder material of the present invention.

[0046] Figure 6 It is a schematic diagram of the flow direction of wave soldering material of the present invention.

[0047] The accompanying drawings are marked as follows:

[0048] 1. Metal terminal; 11. Surrounding spring; 111. Vertical end; 112. Plane end; 113. Bent end; 114. Transition curved surface;

[0049] 12. SMD pad; 121. Semi-enclosed frame; 122. Auxiliary pad;

[0050] 13. Positioning pins;

[0051] 2. Insert; 3. Circuit board; DETAILED DESCRIPTION

[0052] The present application relates to a metal terminal and a double welding installation method thereof, which is explained in detail below through a specific implementation method.

[0053] A metal terminal and a double welding installation method thereof, comprising:

[0054] Two sets of symmetrically arranged terminal units are formed by metal stamping, and each set of terminal units includes:

[0055] The patch pad 12 includes a semi-enclosing frame 121 and an auxiliary pad 122 located on the side of the semi-enclosing frame 121;

[0056] The design of the auxiliary pad 122 can allow the molten solder paste to climb up the two pairs of positioning pins 13, thereby increasing the contact area between the bottom of the terminal and the pad, thereby increasing the firmness of the patch;

[0057] The enclosing spring piece 11 is located above the patch pad 12, and includes a vertical end 111, a plane end 112, and a bent end 113 connected in sequence, wherein the plane end 112 has a predetermined size, and the top surface of the plane end 112 has a smooth plane;

[0058] The positioning pin 13 is located at the side of the semi-enclosed frame 121 and connected to the vertical surface end 111. A column groove is punched on the positioning pin 13, and the positioning pin 13 has a predetermined length.

[0059] The present invention belongs to a plug-in metal terminal 1, but can be operated by a placement machine to improve efficiency and placement accuracy. A smooth plane with a predetermined size is designed on the plane end 112 to be sucked by an automated suction nozzle in the SMT placement machine, thereby improving the placement efficiency of the metal terminal 1 in the welding area of ​​the circuit board 3. At the same time, a positioning pin 13 is designed. When the metal terminal 1 is placed in the welding area, the positioning pin 13 is used to position the terminal to avoid misalignment of the terminal.

[0060] Compared with the single-position soldering of traditional SMD terminals and the pin soldering of plug-in terminals, this terminal is fixed to the circuit board 3 after reflow soldering and wave soldering. When fixed, the positioning pin 13 is welded in the positioning hole, and the SMD pad 12 is welded on the circuit board 3. There is double-position welding, which makes the fixation of the metal terminal 1 more stable. At the same time, during welding, the positioning pin 13 does not exceed the circuit board 3 to adapt to the use of the SMT placement machine.

[0061] By fixing the patch pad 12 , the resilience of the surrounding spring sheet 11 can be improved.

[0062] The fixing by wave soldering can improve the fixing ability of the metal terminal 1 and prevent the metal terminal 1 from falling off due to impact.

[0063] By fixing with wave soldering, the metal terminal 1 can be inserted in the forward direction or reverse direction, because the positioning gives the pin a strong fixing ability for penetrating soldering.

[0064] By punching a column groove on the positioning pin 13 to increase the rigidity of the positioning pin 13, deformation of the pin can be effectively prevented, and the metal terminal 1 can be reliably in place when the patch falls.

[0065] The flat end 112 has a width of 2 mm and a length of 1.3 mm.

[0066] The length of the positioning pin 13 is smaller than the thickness of the circuit board 3 on which the metal terminal 1 is mounted.

[0067] When symmetrically arranged, there is a gap between the two groups of patch pads 12 (when symmetrically arranged, there is a gap between the two groups of semi-enclosing frames 121 and the auxiliary pads 122), and the two groups of enclosing spring sheets 11 abut against each other (abutted by the bent ends 113);

[0068] If the gap is used without welding, the gap will be stretched when the surrounding spring sheet 11 is deformed, resulting in weakened elastic force. Therefore, we need to weld the metal terminal 1 and the pad area of ​​the circuit board 3 together through the first round of reflow soldering. Due to the connection characteristics of the pad area itself, the bottom of the main body of the metal terminal 1 (the patch pad 12) will also be reinforced after welding. The reinforced patch pad 12 has a supporting effect on the surrounding spring sheet 11. When the plug-in 2 is inserted into the metal terminal 1, it brings greater elasticity to the surrounding spring sheets 11 on both sides; when the plug-in is pulled out of the terminal, it also helps the surrounding spring sheets 11 on both sides to bring elastic force to return to normal;

[0069] There is a transition curved surface 114 between the vertical end 111 and the plane end 112. Through this design, in order to prevent the deformation of the metal terminal 1 from causing elastic failure of the surrounding spring 11 or even breaking of the spring, the elastic effect is increased through the transition of the curved surface;

[0070] The connection between the flat end 112 and the bent end 113 has a predetermined transition angle. This design avoids hard right-angle turns, reduces right-angle stress, and increases deformation elasticity.

[0071] The facade end 111 is connected to the semi-enclosing frame 121 .

[0072] The length of the positioning pin 13 is 1.5 mm, which is lower than the thickness of the circuit board 3 which is 1.6 mm;

[0073] A double welding installation method for a metal terminal 1, comprising:

[0074] Step 1, preparing a circuit board 3 corresponding to the metal terminal 1, and a scraper for filling solder into the pad area of ​​the circuit board 3, wherein the pad area includes a pin hole and a soldering area of ​​the patch pad 12;

[0075] Step 2. Fix the scraper on the pad area, and use the placement machine to evenly apply solder paste to the pad area. The solder paste of the pin hole is fully covered. After applying, remove the scraper;

[0076] The fixing method can be selected based on the working scenario. You can use a clamp or directly press the hanging net with a manipulator, or fix it manually.

[0077] Step 3, the plane end 112 is sucked by a manipulator with a vacuum suction cup, and the metal terminal 1 is moved to the top of the circuit board 3, so that the positioning pin 13 corresponds to the pin hole, and the vacuum suction cup releases the adsorption of the metal terminal 1, and the metal terminal 1 falls freely, and the positioning pin 13 falls into the pin hole to complete the positioning, and the positioning pin 13 does not exceed the bottom of the circuit board 3. Since the solder paste fully covers the pin hole, part of the solder paste is brought into the pin hole and the column groove under the drive of the positioning pin 13;

[0078] Step 4: At this time, there is a gap between the two groups of patch pads 12. Reflow soldering is performed, and the solder paste melts and fills the gap between the patch pads 12 by itself. The patch pads 12 are soldered to the circuit board 3. At the same time, the copper deposition welding of the positioning pins 13 and the inner wall of the pin hole is completed to achieve the preliminary space welding of the metal terminal 1.

[0079] After welding, the two groups of patch pads 12 are integrated, and the metal terminal 1 and the pad area are integrated;

[0080] Step 5: After the metal terminal 1 is reflow soldered, the contact surface of the metal terminal 1 and the circuit board 3 is firmly soldered. Since the positioning pin 13 does not exceed the bottom of the circuit board 3, there is a gap between the positioning pin 13 and the bottom of the circuit board in the pin hole;

[0081] Step 6: Fill the gap with solder paste and use wave soldering to fill the gap, completing the secondary welding of the metal terminal 1;

[0082] Step 7, after the welding is completed, insert the plug 2, and the plug 2 is fixed by the surrounding spring sheet 11. When the plug 2 is inserted and used, since the patch pad 12 and the positioning pin 13 of the metal terminal 1 are welded with the circuit board 3, when the plug 2 is inserted into the metal terminal 1, the surrounding spring sheets 11 at both ends are squeezed outward, and the patch pad 12 and the positioning pin 13 of the metal terminal 1 are welded with the circuit board 3 to bring greater elastic rebound holding force to the surrounding spring sheet 11;

[0083] Working principle description:

[0084] Prepare a circuit board 3 corresponding to the metal terminal 1, and a scraper for filling solder into the pad area of ​​the circuit board 3, wherein the pad area includes a pin hole and a patch pad 12 welding area;

[0085] Fix the scraper on the pad area, use the placement machine to evenly apply solder paste to the pad area, and the solder paste on the pin holes should be fully covered. After applying, remove the scraper;

[0086] The plane end 112 is sucked by a manipulator with a vacuum suction cup, and the metal terminal 1 is moved to the top of the circuit board 3, so that the positioning pin 13 corresponds to the pin hole. The vacuum suction cup releases the suction of the metal terminal 1, and the metal terminal 1 falls freely. The positioning pin 13 falls into the pin hole to complete the positioning, and the positioning pin 13 does not exceed the bottom of the circuit board 3. Since the solder paste fully covers the pin hole, part of the solder paste is brought into the pin hole and the column groove under the drive of the positioning pin 13;

[0087] At this time, there is a gap between the two groups of patch pads 12, and reflow soldering is performed. The solder paste melts and fills the gap between the patch pads 12 by itself, and the patch pads 12 are soldered on the circuit board 3. At the same time, the copper deposition welding of the positioning pins 13 and the inner wall of the pin hole is completed, and the preliminary space welding of the metal terminal 1 is realized.

[0088] After welding, the two groups of patch pads 12 are integrated, and the metal terminal 1 and the pad area are integrated;

[0089] After the metal terminal 1 is reflow soldered, the contact surface of the metal terminal 1 and the circuit board 3 is firmly soldered. Since the positioning pin 13 does not exceed the bottom of the circuit board 3, there is a gap between the positioning pin 13 and the bottom of the circuit board in the pin hole.

[0090] Fill the gap with solder paste, use wave soldering to fill the gap, and complete the secondary welding of metal terminal 1;

[0091] After welding is completed, insert the plug-in 2, and the plug-in 2 is fixed by the surrounding spring sheet 11. When the plug-in 2 is inserted and used in conjunction, since the patch pad 12 and the positioning pin 13 of the metal terminal 1 are welded to the circuit board 3, when the plug-in 2 is inserted into the metal terminal 1, the surrounding spring sheets 11 at both ends are squeezed outward, and the patch pad 12 and the positioning pin 13 of the metal terminal 1 are welded to the circuit board 3 to bring greater elastic rebound holding force to the surrounding spring sheet 11.

[0092] The preferred specific embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above specific embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical scheme of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A metal terminal, comprising: Two groups of symmetrically arranged terminal units are formed by metal stamping, wherein each group of terminal units comprises: A patch pad (12), comprising a semi-enclosing frame (121), and an auxiliary pad (122) located on a side of the semi-enclosing frame (121); A surrounding spring sheet (11) is located above the patch pad (12), comprising a vertical end (111), a plane end (112), and a bent end (113) connected in sequence, wherein the plane end (112) has a predetermined size, and the top surface of the plane end (112) has a smooth plane; A positioning pin (13) is located on the side of the semi-enclosed frame (121) and is connected to the vertical surface end (111). A column groove is punched on the positioning pin (13), and the positioning pin (13) has a predetermined length.

2. A metal terminal according to claim 1, characterized in that: The width of the flat end (112) is 2 mm and the length is 1.3 mm.

3. A metal terminal according to claim 1, characterized in that: The length of the positioning pin (13) is smaller than the thickness of the circuit board (3) on which the metal terminal (1) is mounted.

4. A metal terminal according to claim 1, characterized in that: When symmetrically arranged, there is a gap between the two groups of patch pads (12), and the two groups of surrounding spring sheets (11) abut against each other.

5. A metal terminal according to claim 1, characterized in that: A transition curved surface (114) is provided between the vertical surface end (111) and the plane end (112). The connection between the plane end (112) and the bent end (113) has a predetermined transition angle.

6. A metal terminal according to claim 1, characterized in that: The facade end (111) is connected to the semi-enclosing frame (121).

7. A double welding installation method for a metal terminal, implemented based on the metal terminal (1) according to any one of claims 1 to 6, comprising: Step 1, preparing a circuit board (3) corresponding to the metal terminal (1), and a scraper screen for filling solder into a pad area of ​​the circuit board (3), wherein the pad area includes a pin hole and a patch pad (12) welding area; Step 2. Fix the scraper on the pad area, and use the placement machine to evenly apply solder paste to the pad area. The pin holes are fully covered with solder paste. After applying, remove the scraper; Step 3, the flat end (112) is sucked by a manipulator with a vacuum suction cup, and the metal terminal (1) is moved above the circuit board (3) so that the positioning pin (13) corresponds to the pin hole. The vacuum suction cup releases the suction of the metal terminal (1), and the metal terminal (1) falls freely. The positioning pin (13) falls into the pin hole to complete the positioning, and the positioning pin (13) does not exceed the bottom of the circuit board (3). Since the solder paste completely covers the pin hole, part of the solder paste is brought into the pin hole and the column groove under the drive of the positioning pin (13); Step 4: At this time, there is a gap between the two groups of patch pads (12), and reflow soldering is performed. The solder paste melts and fills the gap between the patch pads (12) by itself, and the patch pads (12) are soldered to the circuit board (3). At the same time, the copper deposition welding of the positioning pins (13) and the inner wall of the pin hole is completed, and the preliminary spatial welding of the metal terminal (1) is realized. After welding, the two groups of patch pads (12) are integrated, and the metal terminal (1) and the pad area are integrated; Step 5: After the metal terminal (1) is reflow soldered, the contact surface of the metal terminal (1) and the circuit board (3) is firmly welded. Since the positioning pin (13) does not exceed the bottom of the circuit board (3), there is a gap between the positioning pin (13) and the bottom area of ​​the circuit board in the pin hole; Step 6: Fill the gap with solder paste and use wave soldering to fill the gap, thus completing the secondary soldering of the metal terminal (1).

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