Multifunctional clamping device capable of reducing welding voidage

Abstract

The invention discloses a multifunctional clamping device capable of reducing the welding void rate. The device comprises a base and a control mechanism which is arranged on the base and comprises a control device used for controlling a movement mechanism to work and a power supply device used for providing a power source needed by work for all the mechanisms; the clamping mechanism is mounted on the movement mechanism and used for clamping and fixing the cavity of the product to be welded; the movement mechanism is used for driving the clamping mechanism to alternately move in the X-axis direction and the Y-axis direction of the horizontal plane or independently move in a certain axis direction under the control action of the control mechanism; and the limiting mechanism is used for limiting and fixing the printed board in the to-be-welded product cavity and the components and the pin headers on the printed board, so that the printed board and the components and the pin headers are in a standing state in the moving process of the to-be-welded product cavity, and friction welding between the to-be-welded product cavity and the printed board is achieved. According to the invention, the welding void rate can be effectively reduced, one-time assembly welding of the components, the pin header, the printed board and the cavity can be realized, accurate limiting of the pin header is realized, processing steps are reduced, the production efficiency is improved, and the method is suitable for batch production of power modules.

Description

Technical Field

[0001] This invention belongs to the field of welding process technology, and in particular, it is a multifunctional clamping device for reducing the weld void rate. Background Technology

[0002] With the rapid development of electronic technology, power modules, as core components of electronic devices, are widely used in power supplies, motor drives, new energy fields, and other areas. The performance of power modules directly affects the reliability and stability of the entire system, and the internal connection structure and soldering voids of the power module are key factors affecting its performance.

[0003] Traditional power modules face the following technical challenges in process design and manufacturing: The traditional power module structure mainly includes a shell, a lower plate, an upper plate, and a cover plate, such as... Figure 10 As shown, the lower board is directly fixed to the housing through large-area welding, ensuring timely heat dissipation from the components. Simultaneously, the lower board and upper board are electrically connected via pin headers. Traditional process designs employ multiple welding steps: first, the components, pin headers, and printed circuit board are welded together, then the board with the components attached and the cavity are welded together. This method involves multiple welding steps, leading to remelting of component solder joints, affecting welding reliability. Furthermore, multiple welding processes can affect the perpendicularity and position of the pin headers, causing problems in subsequent assembly of the upper and lower boards. Moreover, the lower board in a power module is typically a copper or ceramic printed circuit board with good thermal conductivity. The welding area on the back of the printed circuit board is usually designed to be large. During the welding process, this large area prevents flux from escaping, resulting in weld voids. These voids are a common welding quality defect. The presence of weld voids not only affects heat dissipation from the power module, creating impedance and causing signal crosstalk, but also reduces welding reliability. Under prolonged operation, weld voids can lead to product failure. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by proposing a multifunctional clamping device and welding method to reduce the welding void rate. This invention's device limits the pin headers and fixes the printed circuit board (PCB), ensuring that during the friction welding process between the PCB and the cavity, the PCB and its components and pin headers are in a static state. This ensures both static welding between small components / pin headers and the PCB, and large-area friction welding between the back of the PCB and the cavity, reducing the large-area welding void rate between the PCB and the cavity. Simultaneously, it enables the entire assembly of components, pin headers, the PCB, and the cavity to be welded in a single operation, reducing processing steps and improving the overall reliability of the product.

[0005] The technical solution to achieve the purpose of this invention is: a multifunctional clamping device for reducing welding voids, the device comprising a base, and a control mechanism, a motion mechanism, a clamping mechanism and a limiting mechanism mounted on the base;

[0006] The control mechanism includes a control device and a power supply device; the power supply device is used to provide the power required for the operation of each mechanism; the control device is used to control the operation of the motion mechanism.

[0007] The clamping mechanism is mounted on the motion mechanism and is used to clamp and fix the cavity of the product to be welded;

[0008] The motion mechanism is used to drive the clamping mechanism to move alternately along the X-axis and Y-axis directions of the horizontal plane or move alone along a certain axis direction under the control of the control mechanism.

[0009] The limiting mechanism is used to limit and fix the printed circuit board and the components and pin headers on the printed circuit board in the cavity of the product to be welded, so that they are in a static state during the movement of the cavity of the product to be welded, thereby realizing friction welding between the cavity of the product to be welded and the printed circuit board.

[0010] Furthermore, the motion mechanism includes an X-axis drive mechanism and a Y-axis drive mechanism;

[0011] The X-axis drive mechanism, under the action of the control device, pushes the clamping mechanism to move along the X-axis direction of the horizontal plane;

[0012] The Y-axis drive mechanism, under the action of the control device, pushes the clamping mechanism to move along the Y-axis direction of the horizontal plane.

[0013] Furthermore, the X-axis drive mechanism includes a first motor control component and a first direction motion component, and the Y-axis drive mechanism includes a second motor control component and a second direction motion component; each motor control component includes at least a motor, and each direction motion component includes at least a platform and a displacement device that can drive the clamping mechanism to move under the drive of the motor;

[0014] The clamping mechanism is mounted on the platform of the first direction motion component;

[0015] The X-axis drive mechanism is mounted on the platform of the second direction motion component;

[0016] The motor driving second direction motion component in the second motor control component drives the X-axis drive mechanism to move along the Y-axis direction of the horizontal plane, and the motor driving first direction motion component in the first motor control component drives the clamping mechanism to move along the X-axis direction of the horizontal plane.

[0017] Furthermore, the clamping mechanism includes a base plate and a clamping device disposed on the base plate. The cavity of the product to be welded is placed on the base plate and clamped and fixed by the clamping device. The base plate is mounted on the motion mechanism.

[0018] Furthermore, the clamping device clamps and fixes the cavity of the product to be welded around its perimeter, including a positioning mechanism and a retractable pressing mechanism; the positioning mechanism is used to position the cavity of the product to be welded at its placement position, and the retractable pressing mechanism is used to press against the outer surface of the cavity of the product to be welded after positioning. The positioning mechanism and the retractable pressing mechanism cooperate to clamp and fix the cavity; the retractable pressing mechanism is adjustable to change the pressing force between it and the outer surface of the cavity of the product to be welded, thereby adapting to products of different sizes.

[0019] Furthermore, each of the retractable pressing mechanisms includes a guide seat, a guide rod, and a spring. The guide rod is perpendicular to the outer surface of the cavity of the product to be welded. One end of the guide rod is fixedly mounted with a pressing block for pressing against the outer surface of the cavity of the product to be welded. The other end extends through the guide seat and is slidably mounted in the guide seat. The spring is sleeved on the area of ​​the guide rod between the pressing block and the guide seat. By pushing or pulling the extended end of the guide rod, the pressing block can be moved closer to or away from the cavity of the product to be welded.

[0020] Furthermore, the limiting mechanism includes a first limiting mechanism and a second limiting mechanism;

[0021] The first limiting mechanism is used to limit and fix the printed circuit board and the components on the printed circuit board in the cavity of the product to be welded;

[0022] The second limiting mechanism is used to limit and fix the pins in the cavity of the product to be welded.

[0023] Furthermore, the first limiting mechanism includes a bracket mounted on the base, a second adjusting mechanism mounted on the bracket, and a printed circuit board limiting plate. The four corners of the printed circuit board limiting plate are provided with limiting grooves and pressure plate step grooves, wherein the limiting grooves are used to limit the offset of the printed circuit board in the planar direction, and the pressure plate step grooves are used to fix the movement of the printed circuit board. The size of the printed circuit board limiting plate is adjustable to accommodate printed circuit boards of different sizes. The printed circuit board limiting plate is fixedly mounted on the second adjusting mechanism, which is movably mounted on the bracket. By changing the position of the second adjusting mechanism, the position of the printed circuit board limiting plate is adjusted so that it is positioned directly above or away from the printed circuit board to be limited in the cavity of the product to be soldered. The second adjusting mechanism is used to adjust the up-and-down movement of the printed circuit board limiting plate to limit or release the printed circuit board to be limited.

[0024] Furthermore, the second limiting mechanism includes a pin header limiting plate fixedly installed on the upper surface of the printed circuit board limiting plate, and a pin header pressure plate disposed on the upper surface of the pin header limiting plate. The printed circuit board limiting plate is provided with a plurality of through holes for penetrating the pin headers in the cavity of the product to be soldered. The pin header limiting plate is provided with a protrusion at a position corresponding to the plurality of through holes, and the side of the protrusion is provided with a first arc-shaped groove. The pin header pressure plate is provided with a limiting groove at a position corresponding to the protrusion, and the inner wall of the limiting groove is provided with a second arc-shaped groove. When the protrusion and the limiting groove are engaged, the second arc-shaped groove and the first arc-shaped groove are engaged to form a space for clamping and limiting the pin headers.

[0025] Furthermore, the device also includes a protective mechanism for providing mounting space for the control mechanism and the motion mechanism.

[0026] Compared with the prior art, the significant advantages of this invention are:

[0027] (1) Traditional reflow soldering is fixed position soldering, which cannot solve the problem of solder voids. However, the device of the present invention is suitable for places with large soldering area, large pin spacing, fast heat dissipation of the soldering substrate and solder joint in a relatively closed soldering space, and can effectively solve the problem of solder voids.

[0028] (2) The control system of the device of the present invention controls the movement of the product during the welding process, realizes automatic friction between the back of the printed circuit board and the cavity during the large-area welding process, improves the discharge of flux gas, and reduces the large-area welding void rate between the printed circuit board and the cavity. At the same time, in the original production process, components, pin headers, printed circuit boards and cavities need to be welded multiple times. Through the multi-functional clamping device to limit the pin headers and fix the printed circuit board, the overall assembly of components, pin headers, printed circuit boards and cavities can be completed in one go, reducing processing steps, improving production efficiency, improving the overall reliability of the product, and is suitable for mass production of power modules.

[0029] (3) The multi-functional clamping device proposed in this invention, when used in conjunction with the welding process, can ensure the consistency of welding quality and is suitable for mass production.

[0030] (4) The multifunctional clamping device proposed in this invention can realize differential counterweight welding of pins to meet the needs of different power modules.

[0031] (5) The multifunctional clamping device proposed in this invention can realize a welding method that combines reflow soldering and friction soldering.

[0032] (6) The control mechanism and motion mechanism in the multifunctional clamping device proposed in this invention can control the alternating motion of the X-axis and Y-axis, or control the motion of a single axis independently, and the sliding stroke of the product can be satisfied from micrometers to millimeters.

[0033] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 This is a perspective view of a multifunctional clamping device in one embodiment.

[0035] Figure 2 A bottom view of the multifunctional clamping device in one embodiment, with the base bottom cover removed.

[0036] Figure 3 This is a partial side view of a multifunctional clamping device in one embodiment.

[0037] Figure 4 This is a partial front view of a multifunctional clamping device in one embodiment.

[0038] Figure 5 This is a perspective view of the clamping mechanism of a multifunctional clamping device in one embodiment.

[0039] Figure 6 This is a perspective view of the second limiting mechanism of the multifunctional clamping device in one embodiment.

[0040] Figure 7 This is a perspective view of the pin rack limiting plate of a multifunctional clamping device in one embodiment.

[0041] Figure 8 This is a perspective view of the base plate of the multifunctional clamping device in one embodiment.

[0042] Figure 9 This is a perspective view of the first limiting mechanism of the multifunctional clamping device in one embodiment.

[0043] Figure 10 This is a schematic diagram of a power module (product) in one embodiment.

[0044] Figure 11 This is a flowchart of a welding method based on a multi-functional clamping device in one embodiment. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0046] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0047] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0048] In one embodiment, combined Figures 1 to 9 A multifunctional clamping device for reducing welding voids is provided. The device includes a base 1, and a control mechanism, a motion mechanism, a clamping mechanism 3 and a limiting mechanism mounted on the base 1.

[0049] The control mechanism includes a control device and a power supply device; the power supply device 7 is used to provide the power required for the operation of each mechanism; the control device 6 is used to control the operation of the motion mechanism.

[0050] The clamping mechanism 3 is mounted on the motion mechanism and is used to clamp and fix the cavity of the product 25 to be welded;

[0051] The motion mechanism is used to drive the clamping mechanism 3 to move alternately along the X-axis and Y-axis directions of the horizontal plane or move alone along a certain axis direction under the control of the control mechanism.

[0052] The limiting mechanism 13 is used to limit and fix the printed circuit board and the components and pin headers on the printed circuit board in the cavity of the product to be welded 25, so that it is stationary during the movement of the cavity of the product to be welded, thereby realizing friction welding between the cavity of the product to be welded 25 and the printed circuit board.

[0053] Preferably, the base 1 is made of a high-temperature resistant material to ensure that the temperature of the protection control mechanism is always below the safe temperature. At the same time, the control mechanism is equipped with temperature monitoring and control components. When the temperature is detected to exceed the safe temperature, the device will automatically alarm.

[0054] Preferably, the control device 6 uses, but is not limited to, a control circuit board, which is internally programmed with software. The software program can set the process, frequency, and time according to different products to control the operation of the motion mechanism and realize the combination of friction and welding in the large-area welding process between the printed circuit board and the cavity.

[0055] Furthermore, in one embodiment, the motion mechanism includes an X-axis drive mechanism and a Y-axis drive mechanism;

[0056] The X-axis drive mechanism, under the action of the control device, pushes the clamping mechanism to move along the X-axis direction of the horizontal plane;

[0057] The Y-axis drive mechanism, under the action of the control device, pushes the clamping mechanism to move along the Y-axis direction of the horizontal plane.

[0058] Preferably, in some embodiments, combined with Figure 3 and Figure 3 The X-axis drive mechanism includes a first motor control component 8 and a first direction motion component 10, and the Y-axis drive mechanism includes a second motor control component 9 and a second direction motion component 11; each motor control component includes at least a motor, and each direction motion component includes at least a platform and a displacement device that can drive the clamping mechanism to move under the drive of the motor.

[0059] The clamping mechanism 3 is mounted on the platform of the first direction motion component 10;

[0060] The X-axis drive mechanism is mounted on the platform of the second direction motion component 11;

[0061] The motor driving second direction motion component 11 in the second motor control component 9 drives the X-axis drive mechanism to move along the Y-axis direction of the horizontal plane, and the motor driving first direction motion component 10 in the first motor control component 8 drives the clamping mechanism to move along the X-axis direction of the horizontal plane.

[0062] Here, the displacement device can be a transmission assembly, a push rod assembly, or the like, without any special limitation, as long as it can achieve the specific function of the above mechanism.

[0063] Furthermore, in one embodiment, the clamping mechanism 3 includes a base plate 12 and a clamping device disposed on the base plate 12. The cavity of the product to be welded is placed on the base plate 12 and clamped and fixed by the clamping device; the base plate 12 is mounted on the motion mechanism. Here, based on the above embodiment, the base plate 12 is specifically mounted on the platform of the second direction motion component 11.

[0064] Here, the base plate 12 works together with the motion mechanism, and the alternating cooperation causes the cavity and the base plate 12 to move in the planar direction, thereby realizing the friction welding between the cavity of the product and the printed circuit board.

[0065] Preferably, the base plate 12 is made of a highly thermally conductive synthetic stone material, and the surface in contact with the product 25 is made of plastic to prevent scratches from forming on the product surface.

[0066] Preferably, in some embodiments, the clamping device clamps and fixes the cavity of the product to be welded around its perimeter, including a positioning mechanism and a retractable pressing mechanism 24; the positioning mechanism is used to position the cavity of the product to be welded 25 at its placement position, and the retractable pressing mechanism 24 is used to press against the outer surface of the cavity of the product to be welded 25 after positioning. The positioning mechanism and the retractable pressing mechanism 24 cooperate to clamp and fix the cavity; the retractable pressing mechanism 24 is adjustable to change the pressing force between it and the outer surface of the cavity of the product to be welded 25, thereby adapting to products of different sizes.

[0067] More preferably, in some embodiments, the positioning mechanism includes an L-shaped limiting protrusion or at least two limiting protrusions 23 forming a virtual L-shaped structure for positioning the first apex of the cavity of the product to be welded.

[0068] More preferably, in some embodiments, the retractable pressing mechanism 24 is provided in at least two sets, which are used to press down on the two adjacent sides at the diagonal of the first apex corner in the cavity of the product to be welded 25.

[0069] More preferably, in some embodiments, the retractable pressing mechanism 24 is slidably mounted on the base plate 12 to adjust its position on the base plate 12 so as to achieve pressing at different positions on the cavity side of the product 25 to be welded.

[0070] More preferably, in some embodiments, in combination with Figure 5 and Figure 8 Each of the retractable pressing mechanisms 24 includes a guide seat 28, a guide rod 27, and a spring. The guide rod 27 is perpendicular to the outer surface of the cavity of the product to be welded 25. One end of the guide rod 27 is fixedly mounted with a pressing block for pressing against the outer surface of the cavity of the product to be welded 25. The other end extends through the guide seat 28 and is slidably mounted in the guide seat 28. The spring is sleeved on the area of ​​the guide rod 27 between the pressing block and the guide seat 28. By pushing or pulling the extended end of the guide rod 27, the pressing block can be moved closer to or away from the cavity of the product to be welded 25.

[0071] In a further preferred embodiment, the retractable pressing mechanism 24 further includes a first adjusting mechanism 26 for adjusting the compression of the spring, thereby adjusting the pressing force between the pressing block and the cavity of the product to be welded 25.

[0072] Furthermore, in one embodiment, the limiting mechanism includes a first limiting mechanism and a second limiting mechanism;

[0073] The first limiting mechanism 5 is used to limit and fix the printed circuit board and the components on the printed circuit board in the cavity of the product to be welded 25.

[0074] The second limiting mechanism is used to limit and fix the pins in the cavity 25 of the product to be welded.

[0075] Preferably, in some embodiments, the first limiting mechanism 5 includes a bracket mounted on the base 1, a second adjusting mechanism mounted on the bracket, and a printed circuit board limiting plate 14. The printed circuit board limiting plate 14 has limiting grooves and pressure plate step grooves at its four corners. The limiting grooves limit the offset of the printed circuit board in the planar direction, and the pressure plate step grooves fix the movement of the printed circuit board. The size of the printed circuit board limiting plate 14 is adjustable to accommodate printed circuit boards of different sizes. The printed circuit board limiting plate 14 is fixedly mounted on the second adjusting mechanism 30, which is movably mounted on the bracket. By changing the position of the second adjusting mechanism, the position of the printed circuit board limiting plate 14 is adjusted so that it is positioned directly above or away from the printed circuit board to be limited in the cavity of the product 25 to be soldered. The second adjusting mechanism is used to adjust the up-and-down movement of the printed circuit board limiting plate 14 to limit or release the printed circuit board to be limited.

[0076] Here, the printed circuit board limiting plate 14 can be used for printed circuit boards of different shapes. It should be noted that the area of ​​the printed circuit board limiting plate 14 that is in direct contact with the printed circuit board is designed to be made of a soft and elastic material and meets the requirements for high temperature resistance.

[0077] Here, by setting a second adjustment mechanism, the printed circuit board is fixed and limited, while also accommodating products of different heights. Furthermore, while ensuring the motion mechanism controls the base plate 12 to move the cavity of the product 25 in the planar direction, the printed circuit board and its components and pin headers remain stationary. This ensures both stationary soldering of small components and pin headers with the printed circuit board and a combination of large-area friction and reflow soldering between the back of the printed circuit board and the cavity.

[0078] Preferably, the limiting groove is designed with a chamfered edge.

[0079] In a further preferred embodiment, the first limiting mechanism 5 further includes a pressure measuring device 29 for real-time detection of the pressure between the printed circuit board limiting plate 14 and the printed circuit board.

[0080] Here, the pressure measuring device 29 employs, but is not limited to, a pressure sensor.

[0081] Preferably, in some embodiments, the second limiting mechanism includes a pin header limiting plate 15 fixedly installed on the upper surface of the printed circuit board limiting plate 14, and a pin header pressure plate 16 disposed on the upper surface of the pin header limiting plate 15. The printed circuit board limiting plate 14 is provided with a plurality of through holes for penetrating the pin headers in the cavity of the product to be soldered 25. The pin header limiting plate 15 is provided with protrusions 21 at positions corresponding to the plurality of through holes, and the side of the protrusions 21 is provided with a first arc-shaped groove 22. The pin header pressure plate 16 is provided with limiting grooves at positions corresponding to the protrusions 21, and the inner wall of the limiting groove is provided with a second arc-shaped groove. When the protrusions 21 cooperate with the limiting grooves, the second arc-shaped grooves and the first arc-shaped grooves 22 cooperate to form a space for clamping and limiting the pin headers.

[0082] In a further preferred embodiment, the needle press plate 16 is slidably mounted on the needle limit plate 15, and the second limiting mechanism further includes a third adjusting mechanism 18 fixedly mounted on the needle limit plate 15 for adjusting the position of the needle press plate 16 so that the second arc groove cooperates with the first arc groove 22.

[0083] In a further preferred embodiment, the third adjustment mechanism 18 includes a knob 19 and a spring 20. The knob 19 is mounted through a protrusion on the pin header limiting plate 15, and the spring 20 is mounted in a guide groove on the pin header limiting plate 15. One end of the spring 20 is connected to the knob 19, and the other end is connected to the pin header pressing plate 16. By adjusting the knob 19 in both directions, the pin header pressing plate 16 is driven to move, so that the second arc-shaped groove cooperates with the first arc-shaped groove 22 to press the pin header tightly and prevent it from falling off. In addition, the pressure can be adjusted to prevent the plating on the surface of the pin header from being worn away.

[0084] Here, it is not limited to using knob 19 and compression spring 20; it can be designed as a structure that can be clamped in one step.

[0085] In a further preferred embodiment, the second limiting mechanism further includes a locking mechanism 17, which is used to lock the needle row limiting plate 15 and the needle row pressure plate 16 after the second arc-shaped groove and the first arc-shaped groove 22 are successfully engaged, so as to prevent the needle row pressure plate from falling off.

[0086] Here, the second limiting mechanism proposed in this invention is applicable to both surface mount headers and through mount headers.

[0087] Furthermore, in one embodiment, the device further includes a protective mechanism for providing mounting space for the control mechanism and the motion mechanism.

[0088] Preferably, in some embodiments, the protective mechanism includes a protective cover 4 covering the control mechanism and the motion mechanism, the upper opening of the protective cover 4 providing space for the assembly between the clamping mechanism and the motion mechanism.

[0089] Preferably, in some embodiments, the protective mechanism further includes a corrugated cover 31, which is flexibly connected between the base plate 12 and the protective cover 4, so that the base plate 12, the corrugated cover 31, and the protective cover 4 together form a sealed installation space.

[0090] In a further preferred embodiment, the bottom of the mounting groove of the pressing mechanism 24 on the base plate 12 is equipped with a sealing plate for heat insulation to prevent high-temperature gas from entering the interior of the protective cover 4, and the sealing plate is made of a high-temperature resistant material.

[0091] In one embodiment, a welding method based on the multifunctional clamping device is provided, the method comprising:

[0092] Step 1: Place the product in the clamping mechanism and adjust the pressure using the pressing mechanism;

[0093] Step 2: Assemble the printed circuit board into the corresponding position inside the limiting groove of the cavity of the product to be welded 25. Adjust the first limiting mechanism 5 to fix the printed circuit board with the limiting plate 14 and apply pressure to the printed circuit board to ensure that the printed circuit board does not shift during the welding process.

[0094] Step 3: Place the second limiting mechanism and adjust the third adjusting mechanism 18 to limit and fix the pins, ensuring the parallelism and perpendicularity between the pins.

[0095] Step 4: Lock the pin header limiting plate 15 and the pin header pressure plate 16 through the locking mechanism 17 to complete the product assembly;

[0096] Step 5: Place the assembled product into the reflow oven. Through the control mechanism, control the clamping mechanism 3 to drive the cavity of the product 25 to be soldered to move alternately along the X and Y axes or to move uniaxially. During this process, while the base plate 12 drives the cavity of the product 25 to move in the planar direction, the printed circuit board and the components and pin headers on the printed circuit board are still in a static state. This can ensure both static reflow soldering between small components and pin headers and the printed circuit board, and large-area friction and reflow soldering between the back of the printed circuit board and the cavity.

[0097] Here, the product in step 1 specifically refers to:

[0098] Assemble the welding pieces inside the cavity of the product 25 to be welded, place the cavity on the tooling, apply a small amount of flux or solder paste evenly to the four positions inside the limiting groove of the cavity, place the welding pieces on it, and then put it into the reflow oven for welding.

[0099] For soldering the back of the printed circuit board, multiple printed circuit boards are placed on a limiting fixture, and a small amount of flux or solder paste is evenly applied to four positions on the back of the printed circuit board. Then, solder pads are placed on top, and the board is placed in a reflow oven for soldering.

[0100] Remove the cavity and printed circuit board, and use automated equipment to clean away the flux and impurities.

[0101] The solder paste is screen-printed on the front of the printed circuit board, and the components on the front are automatically mounted.

[0102] Furthermore, in some embodiments, the overall assembly process of the power module is as follows: Figure 11 As shown, the specific implementation steps are as follows:

[0103] Design the welding area of ​​the shell, and design the size and depth of the limiting groove. The size of the limiting groove should be 0.05mm-0.1mm larger on each side than the size of the printed circuit board to be installed, and the depth of the limiting groove should be 0.5mm-0.6mm.

[0104] Design the solder pad size and thickness, and strictly control the flux content. The solder pad size should be the same as or slightly smaller than the printed circuit board size. The flux content should be controlled at 1.5%-2%, halogen-free, and the solder pad thickness should be 0.05mm-0.1mm to ensure that it can be cleaned with water or alcohol.

[0105] Assemble the welding pieces inside the cavity, place the cavity on the tooling, apply a small amount of flux or solder paste evenly to the four positions inside the limiting groove of the cavity, place the welding pieces on it, and then put it into the reflow oven for welding.

[0106] For soldering the back of the printed circuit board, multiple printed circuit boards are placed on a limiting fixture, and a small amount of flux or solder paste is evenly applied to four positions on the back of the printed circuit board. Then, solder pads are placed on top, and the board is placed in a reflow oven for soldering.

[0107] The cavity and printed circuit board are removed from the reflow oven, and the flux and impurities are automatically cleaned away using equipment.

[0108] The solder paste is screen-printed on the front of the printed circuit board, and the components are automatically mounted.

[0109] First, the product is placed in the clamping mechanism, and the pressure is adjusted by the pressing mechanism to accommodate different products.

[0110] Next, the printed circuit board with the mounted components is assembled into the cavity and placed in the product's positioning groove.

[0111] The pressure is adjusted by adjusting the second adjustment mechanism in the first limiting mechanism to apply pressure to the printed circuit board limiting plate. The four corner limiting grooves and stepped grooves of the printed circuit board limiting plate fix and restrict the offset of the printed circuit board in the plane direction.

[0112] After the needle headers are placed, the needle header limiting plate and the needle header pressure plate are placed, and the needle headers are fixed in place by adjusting the third adjustment mechanism. Finally, the needle header limiting plate and the needle header pressure plate are locked by the locking mechanism.

[0113] The control mechanism completes the program input, controlling the motion mechanism to drive the clamping mechanism to perform alternating X-axis and Y-axis movements or uniaxial movements. The movement time, frequency, and cycle are adjustable according to the final effect, and the sliding stroke of the product can meet the requirements from micrometers to millimeters. In addition, the multi-functional clamping fixture is set within a safe temperature range throughout the entire welding process; if the temperature exceeds the safe temperature line, the device will automatically alarm.

[0114] The assembled product is placed in the reflow oven. During the soldering process, the multi-functional clamping device ensures that while the motion mechanism drives the base plate and the product cavity to move in the planar direction, the printed circuit board (PCB) and the components and pin headers on the PCB remain stationary. This ensures both stationary soldering of small components and pin headers with the PCB and combined with large-area friction and reflow soldering between the back of the PCB and the cavity, reducing the large-area solder void rate between the PCB and the cavity. Simultaneously, it achieves a single-pass soldering of the entire assembly of components, pin headers, PCB, and cavity.

[0115] It should be noted that for components without special structural limitations, any component that can achieve the corresponding function in the existing technology is acceptable.

[0116] It should also be noted that the above-mentioned settings, installations, connections, and fixations can be made using, but are not limited to, bolts, threads, etc. Any existing fixed or movable connection scheme can be adapted, as long as the corresponding function can be achieved.

[0117] In summary, this invention combines a multifunctional device with a welding method. The welding interface is pre-tinned, and the multifunctional clamping device can automatically perform friction welding between the printed circuit board and the cavity during the welding process, reducing the welding void rate from 35% to less than 5%. In addition, this invention can realize one-time assembly welding of components, pin headers, printed circuit boards and cavities, achieve precise positioning of pin headers, reduce processing steps, improve production efficiency, and is suitable for mass production of power modules.

[0118] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention without departing from its spirit and scope should be included within the protection scope of the present invention.

Claims

1. A multi-functional clamping device for reducing the rate of welding voids, characterized by, The device comprises a base, a control mechanism, a movement mechanism, a clamping mechanism and a limiting mechanism mounted on the base; The control mechanism comprises a control device and a power supply device; The power supply device is used to provide power for the operation of each mechanism; the control device is used to control the operation of the movement mechanism; The clamping mechanism is mounted on the movement mechanism and is used to clamp and fix the cavity of the product to be welded; The movement mechanism is used to drive the clamping mechanism to move alternately along the X-axis and Y-axis directions of the horizontal plane or to move alone along a certain axis direction under the control of the control mechanism; The limiting mechanism is used to limit and fix the printed board in the cavity of the product to be welded and the components and pin headers on the printed board, so that they are in a stationary state during the movement of the cavity of the product to be welded, and realize the friction welding between the cavity of the product to be welded and the printed board.

2. The multi-functional clamping device for reducing the rate of weld voids of claim 1, wherein, The movement mechanism comprises an X-axis driving mechanism and a Y-axis driving mechanism; The X-axis driving mechanism drives the clamping mechanism to move along the X-axis direction of the horizontal plane under the action of the control device; The Y-axis driving mechanism drives the clamping mechanism to move along the Y-axis direction of the horizontal plane under the action of the control device.

3. The multi-functional clamping device for reducing the rate of weld voids of claim 2, wherein, The X-axis driving mechanism comprises a first motor control assembly and a first direction movement assembly, and the Y-axis driving mechanism comprises a second motor control assembly and a second direction movement assembly; each motor control assembly comprises at least one motor, and each direction movement assembly comprises at least one platform and a displacement device capable of driving the clamping mechanism to move under the drive of the motor; The clamping mechanism is mounted on the platform of the first direction movement assembly; The X-axis driving mechanism is mounted on the platform of the second direction movement assembly; The motor in the second motor control assembly drives the second direction movement assembly to drive the X-axis driving mechanism to move along the Y-axis direction of the horizontal plane, and the motor in the first motor control assembly drives the first direction movement assembly to drive the clamping mechanism to move along the X-axis direction of the horizontal plane.

4. The multi-functional clamping device for reducing weld porosity of claim 1, wherein, The clamping mechanism comprises a bottom plate and a clamping device arranged on the bottom plate, the cavity of the product to be welded is placed on the bottom plate and clamped and fixed by the clamping device; and the bottom plate is mounted on the movement mechanism.

5. The multi-functional clamping device for reducing the rate of weld voids of claim 4, wherein, The clamping device clamps and fixes the cavity of the product to be welded, comprising a positioning mechanism and a telescopic pressing mechanism; the positioning mechanism is used to position the placement position of the cavity of the product to be welded, and the telescopic pressing mechanism is used to press the outer side of the positioned cavity of the product to be welded; the positioning mechanism and the telescopic pressing mechanism cooperate to clamp and fix the cavity; and the telescopic pressing mechanism is adjustable to change the pressing force between the telescopic pressing mechanism and the outer side of the cavity of the product to be welded, thereby adapting to products of different sizes.

6. The multi-functional clamping device for reducing weld porosity of claim 5, wherein, Each of the telescopic pressing mechanisms comprises a guide seat, a guide rod and a spring, the guide rod is arranged perpendicularly to the outer side of the cavity of the product to be welded, one end of the guide rod is fixedly installed with a pressing block for pressing the outer side of the cavity of the product to be welded, the other end of the guide rod penetrates through the guide seat and extends out of the guide seat and is slidably installed in the guide seat, the spring is sleeved on the region of the guide rod between the pressing block and the guide seat; the telescopic pressing mechanisms are used for making the pressing block close to or away from the cavity of the product to be welded by pushing and pulling the extending end of the guide rod.

7. The multi-functional clamping device for reducing weld porosity of claim 1, wherein, The limiting mechanism comprises a first limiting mechanism and a second limiting mechanism; The first limiting mechanism is used for limiting and fixing the printed board in the cavity of the product to be welded and the components on the printed board. The second limiting mechanism is used for limiting and fixing the pin header in the cavity of the product to be welded.

8. The multi-functional clamping device for reducing weld porosity of claim 7, wherein, The first limiting mechanism comprises a bracket installed on the base, a second adjusting mechanism and a printed board limiting plate installed on the bracket, the four corners of the printed board limiting plate are provided with limiting grooves and pressing plate step grooves, the limiting grooves are used for limiting the deviation of the printed board in the plane direction, and the pressing plate step grooves are used for fixing the movement of the printed board; the size of the printed board limiting plate is adjustable to adapt to printed boards of different sizes; the printed board limiting plate is fixedly installed on the second adjusting mechanism, the second adjusting mechanism is movably installed on the bracket, the position of the printed board limiting plate is adjusted to be above or away from the printed board to be limited in the cavity of the product to be welded by changing the position of the second adjusting mechanism; the second adjusting mechanism is used for adjusting the up-down movement of the printed board limiting plate to limit or release the printed board to be limited.

9. The multi-functional clamping device for reducing weld porosity of claim 8, wherein, The second limiting mechanism comprises a pin header limiting plate fixedly installed on the upper surface of the printed board limiting plate and a pin header pressing plate arranged on the upper surface of the pin header limiting plate, the pin header limiting plate is provided with a plurality of through holes for penetrating the pin header in the cavity of the product to be welded, the pin header limiting plate is provided with a protrusion at a position corresponding to each of the through holes, and the side surface of the protrusion is provided with a first arc-shaped groove; the pin header pressing plate is provided with a limiting groove matched with the protrusion at a position corresponding to the protrusion, and the inner wall of the limiting groove is provided with a second arc-shaped groove; when the protrusion is matched with the limiting groove, the second arc-shaped groove and the first arc-shaped groove are matched to form a space for clamping and limiting the pin header.

10. The multi-functional clamping device for reducing weld porosity of claim 1, wherein, The device further comprises a protection mechanism for providing installation space for the control mechanism and the movement mechanism.

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