Welding jig

Abstract

The invention relates to a welding jig which comprises a base assembly provided with a receding part, an upper pressing assembly provided with an abutting correction part and a locking mechanism, and when the upper pressing assembly and the base assembly are closed and locked, the abutting correction part forces a part of a to-be-welded plate to enter the receding part, so that the plate generates preset elastic deformation quantity. According to the welding jig, by means of the structure, forced deformation is used for effectively solving the problem that the plates are not tightly attached due to warping of the plates, it is ensured that the plates are tightly contacted with the components and the frame at the welding positions, welding gaps are eliminated, the phenomena of pseudo soldering and false soldering are effectively avoided, and the welding quality and the connecting strength of electronic assemblies are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to mechanical tooling fixtures, in particular to a welding fixture for aligning and fixing components to be welded and a frame with a plate to be welded. BACKGROUND

[0002] In the production and assembly process of electronic modules or precision components, in order to ensure the welding quality, it is usually necessary to use a fixture to accurately stack and position the small components to be welded, the frame and the PCB plate (or metal substrate), and then send them into a heating device for welding and solidification to form a complete electronic assembly.

[0003] The existing related welding fixture usually adopts a planar clamping structure with a base and an upper cover. Specifically, the base is provided with a positioning groove for placing components and a frame, and the upper cover (or upper pressing plate) is locked with the base by buckling or screwing. In the existing technical solution, in order to fix the plate, the side of the upper cover facing the base is usually designed as a flat pressing surface, and the vertical pressure generated after the upper cover and the base are closed is used to press the plate on the underlying frame and components, trying to eliminate the gap between the components by planar clamping to ensure the fit of the welding contact surface.

[0004] However, in actual production process, the plate to be welded often has a certain degree of local warping or deformation (such as middle arch or edge warping) due to processing technology, material properties or transportation and storage. For such plates with initial warping, the existing planar pressing type fixture can only provide uniform planar downward pressure and cannot apply concentrated correction force to the warped parts of the plate. When the warping stress of the plate is large, planar pressing often cannot completely press the plate to fit the underlying components or frame, resulting in small gaps in the welding position, which may cause virtual welding, false welding or insufficient welding strength and other quality problems. Therefore, it is urgent to propose a welding fixture to solve the above problems. SUMMARY

[0005] The purpose of the present application is to provide a welding fixture to solve the technical problem that the plate to be welded cannot be closely fitted with the components to be welded and the frame in the welding process due to its own warping, resulting in virtual welding, false welding or insufficient welding strength.

[0006] The technical solution adopted by the present application to solve the above problems is: a welding fixture for aligning and fixing components to be welded and a frame with a plate to be welded, comprising: a base assembly, the base assembly being provided with a clearance portion; an upper pressing assembly which is controlled to open and close relative to the base assembly; one side of the upper pressing assembly is provided with a pressing and correcting part, the position of the pressing and correcting part corresponds to the accommodating part; a locking mechanism which is arranged between the upper pressing assembly and the base assembly to provide locking force after the upper pressing assembly and the base assembly are closed.

[0007] After the upper pressing assembly and the base assembly are closed and locked by the locking mechanism, the pressing and correcting part forces the local part of the to-be-welded plate into the accommodating part, so that the to-be-welded plate generates a preset elastic deformation amount.

[0008] Preferably, the pressing and correcting part is configured as a convex structure arranged in the central area of the side of the upper pressing assembly facing the base assembly, and the convex structure has a spherical or arc-shaped abutting surface.

[0009] The accommodating part is configured as a groove or a through hole arranged on the side of the base assembly facing the upper pressing assembly, and the size of the groove or the through hole is configured to accommodate the part of the to-be-welded plate generating the preset elastic deformation amount after being pressed.

[0010] Preferably, the base assembly is further provided with a plurality of floating support units around the accommodating part, and the floating support units are configured to carry the to-be-welded component and have the freedom of elastic floating in the direction facing the upper pressing assembly.

[0011] During the process that the pressing and correcting part presses the local part of the to-be-welded plate into the accommodating part, the side of the to-be-welded plate facing the base assembly abuts against the floating support unit, forcing the floating support unit to sink synchronously, so that the to-be-welded component and the to-be-welded plate are kept in close contact through the elastic supporting force of the floating support unit.

[0012] Preferably, the floating support unit comprises: an ejection member, the top end of the ejection member is configured to abut against the side of the to-be-welded component away from the upper pressing assembly when the upper pressing assembly and the base assembly are closed; an elastic member arranged between the ejection member and the base assembly and configured to apply the elastic supporting force of the ejection member in the direction facing the upper pressing assembly.

[0013] Preferably, the side of the upper pressing assembly facing the base assembly is provided with an abutting surface.

[0014] The base assembly is further provided with a positioning and bearing module on the side facing the upper pressing assembly, the positioning and bearing module is provided with a limiting groove for limiting the horizontal position of the components to be welded; the positioning and bearing module is provided with a rigid stop surface matched with the abutting surface of the upper pressing assembly on the side facing the upper pressing assembly, the positioning and bearing module is configured to make the components to be welded at least partially protrude from the rigid stop surface; the rigid stop surface is configured to abut with the abutting surface of the upper pressing assembly when the locking mechanism is locked, so as to limit the minimum closing height of the upper pressing assembly relative to the base assembly, so that the depth of the board to be welded pressed into the accommodation part reaches the preset elastic deformation amount.

[0015] Preferably, the positioning and bearing module is configured as a plate structure, the positioning and bearing module is provided with a plurality of avoiding holes corresponding to a plurality of floating support units, the floating support units are arranged in the corresponding avoiding holes and at least partially protrude from the rigid stop surface, so as to bear the components to be welded.

[0016] Preferably, the positioning and bearing module is configured as a plate structure, the positioning and bearing module is provided with a plurality of avoiding holes corresponding to a plurality of floating support units, the floating support units are arranged in the corresponding avoiding holes and at least partially protrude from the rigid stop surface, so as to bear the components to be welded.

[0017] Preferably, the upper pressing assembly comprises an auxiliary pressing surface for pressing the peripheral region of the board to be welded, the auxiliary pressing surface is arranged on the peripheral side of the pressing and correcting part, and the friction coefficient of the surface of the auxiliary pressing surface is smaller than the friction coefficient of the surface of the pressing and correcting part, so as to be configured to form a fixed anchor point of the pressing and correcting part relative to the center of the board to be welded during welding, so that the auxiliary pressing surface allows the peripheral region of the board to be welded to slide radially relative to the auxiliary pressing surface when heated and expanded.

[0018] Preferably, the surface of the pressing and correcting part is provided with a high-friction texture or a high-friction material layer; the auxiliary pressing surface is configured as a smooth and polished surface or coated with a low-friction coating.

[0019] Preferably, the upper pressing assembly is provided with a profiling groove on the side facing the base assembly, the profiling groove is matched with the profile of the board to be welded, and the pressing and correcting part is located at the groove bottom of the profiling groove; the positioning and bearing module is fixed on the base assembly, and the material hardness of the positioning and bearing module is higher than the material hardness of the board to be welded.

[0020] Preferably, the base assembly comprises a base, the positioning and bearing module is arranged on one side of the base facing the upper pressing assembly, and a plurality of accommodating grooves corresponding to the avoiding holes are arranged on the side of the base facing the upper pressing assembly and away from the upper pressing assembly, the elastic members of the floating support units are arranged in the accommodating grooves respectively, one end of the elastic member abuts against the base, and the other end of the elastic member abuts against the one end of the ejecting member away from the to-be-welded component.

[0021] The embodiment of the present application has the following beneficial effects: 1. Since the pressing and correcting part is arranged on the side of the upper pressing assembly facing the base assembly, the accommodating part is arranged on the base assembly correspondingly, and the elastic deformation of the to-be-welded plate is forced to enter the accommodating part under the locking force provided by the locking mechanism, the technical means that the to-be-welded plate is forced to enter the accommodating part to generate a preset elastic deformation is adopted, the technical problem that the to-be-welded plate cannot be tightly attached to the to-be-welded component and the frame by the simple planar pressing method due to the warping of the to-be-welded plate itself is effectively solved, and the warping stress of the to-be-welded plate is overcome by forcing the plate to generate a specific elastic deformation, so that the close contact between the to-be-welded plate and the to-be-welded component and the frame at the welding position is ensured, the welding gap is eliminated, the occurrence of false welding and false soldering is effectively avoided, and the welding quality and the connection strength of the electronic assembly are significantly improved.

[0022] 2. Since the floating support unit with elastic floating freedom is arranged on the base assembly, and the to-be-welded component is carried by the cooperation of the ejecting member and the elastic member, the technical problem that the rigid pressure is directly applied to the fragile to-be-welded component and the soldering sheet due to the large displacement of the plate in the thickness direction caused by the pressing of the plate during the forced correction of the warping of the plate, so that the component is pressed and damaged or the soldering sheet is crushed to cause tin short circuit is effectively solved, and the cooperative action of the rigid correction and the flexible support is realized, that is, the plate is deformed by the pressing and correcting part to eliminate the warping gap, at the same time, the floating support unit can sink and buffer with the pressing action of the plate, and the elastic support force of the elastic member ensures that the to-be-welded component is always tightly attached to the surface of the plate, so that the good welding wetting condition is ensured, and the integrity of the component and the soldering sheet is effectively protected.

[0023] 3. By employing a positioning and bearing module with a rigid stop surface on the base assembly, and utilizing the contact surface of this rigid stop surface with the upper pressing assembly to strictly limit the minimum closed height of the fixture, while configuring a floating support unit that passes through the clearance hole of the positioning and bearing module and is in a compressed state, the technical problems of uncertain pressing depth along the thickness direction and difficulty in accurately controlling the plate correction amount caused by the introduction of floating support are effectively solved. This achieves depth synergy between rigid limiting and flexible clamping. That is, a reference surface is constructed through the rigid stop surface to ensure that the plate to be welded is accurately pressed into the clearance part to the preset elastic deformation required by the design, avoiding over-correction or under-correction caused by pressure fluctuations. At the same time, under this determined closed height, the constant and controllable elastic force generated by the compressed floating support unit is used to tightly press the components onto the plate, thereby ensuring the plate deformation correction accuracy while achieving constant pressure protection for precision components.

[0024] 4. By employing an auxiliary pressing surface with a low coefficient of friction on the periphery of the pressing and straightening part of the upper pressure component, and by making the coefficient of friction of the pressing and straightening part surface greater than that of the auxiliary pressing surface, the technical problem of secondary arching deformation or weld shear stress accumulation leading to desoldering of the plate to be welded during the welding heating process due to the obstruction of thermal expansion under a certain rigid closing height is effectively solved. This achieves a dynamic balance between center anchoring and radial thermal compensation. During the welding process, the high-friction pressing and straightening part firmly anchors the center of the plate within the clearance part to maintain the straightening shape, while the low-friction auxiliary pressing surface allows the peripheral area of ​​the plate to undergo a small amount of radial thermal expansion and sliding around the center. This effectively releases the thermal stress of the plate without compromising the flatness correction effect, avoiding component desoldering or delamination caused by uneven thermal expansion and contraction. Attached Figure Description

[0025] Figure 1 A schematic exploded view of a welding fixture according to an embodiment of this application is shown.

[0026] Figure 2 A schematic exploded cross-sectional view of a welding fixture according to an embodiment of this application is shown.

[0027] Figure 3 A schematic structural view of a welding fixture according to an embodiment of this application is shown.

[0028] Figure 4 A schematic structural diagram of the plate to be welded mentioned in an embodiment of this application is shown.

[0029] Wherein: 1, base assembly; 110, base; 111, containing groove; 120, positioning bearing module; 121, limiting groove; 122, rigid stop face; 123, avoiding hole; 130, let go of part; 2, upper pressing assembly; 210, pressing correction part; 211, arc-shaped pressing face; 220, abutting face; 230, auxiliary pressing face; 240, profiling groove; 3, locking mechanism; 4, floating support unit; 410, ejector; 5, to-be-welded plate; 6, frame; 7, component. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but not to limit the scope of the present application.

[0031] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the scope of protection of the present application. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified and limited, the term "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0032] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the scope of protection of the present application. In addition, the terms "first", "second" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified and limited, the term "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood through specific circumstances.

[0033] In the production and assembly process of precision components, in order to ensure the welding quality, it is usually necessary to use a jig to accurately stack and position the small to-be-welded components 7, the frame 6 and the PCB board (or metal substrate), and to keep them relatively fixed through a clamping mechanism, and then to send them into a heating device to complete welding and solidification, so as to form a complete electronic component. It should be noted that the welding points between the to-be-welded components 7 and the PCB board and between the frame 6 and the PCB board are usually sandwiched with solder pieces, and the melting point of the solder pieces is much lower than the melting points of the to-be-welded components and the jig. After the jig and the to-be-welded components are heated and cooled as a whole, the solder pieces undergo the process of melting and re-solidification, thereby welding the to-be-welded components 7 and the PCB board and the frame 6 and the PCB board into one body.

[0034] The existing related welding jig usually adopts a planar clamping structure with a base 110 matched with an upper cover. The base 110 is provided with a positioning groove for placing the components 7 and the frame 6. The upper cover is locked with the base 110 by buckling or screwing. The side of the upper cover facing the base 110 is usually designed as a flat pressing surface. After the upper cover and the base 110 are closed, the vertical pressure generated thereby presses the board flat on the underlying frame 6 and components 7, and the gap between the components is eliminated by planar clamping to ensure the fit of the welding contact surface.

[0035] However, in actual production process, the to-be-welded board often has a certain degree of local warping or deformation due to processing technology, material and structural characteristics or transportation and storage, etc. The board targeted in the present application usually has a slight arch in the middle. For such a board with initial warping, the existing planar pressing type jig can only provide uniform planar downward pressure and cannot apply concentrated correction force to the warped parts of the board. When the warping stress of the board is large, the planar pressing often cannot completely press the board flat and fit it to the underlying components 7 or frame 6, resulting in a small gap at the welding site, which in turn causes problems such as false welding, false welding or insufficient welding strength.

[0036] Figure 1 An illustrative exploded view of the welding jig according to an embodiment of the present application is shown; Figure 2 A cross-sectional view of the illustrative exploded view of the welding jig according to an embodiment of the present application is shown; Figure 3 An illustrative structural view of the welding jig according to an embodiment of the present application is shown; Figure 4 An illustrative structural view of the to-be-welded board according to an embodiment of the present application is shown.

[0037] Based on this, a preferred embodiment of the present application proposes a welding jig for aligning and fixing the to-be-welded components 7 and the frame 6 with the to-be-welded board 5. Please refer to Figures 1 to 4The fixture mainly consists of three parts: a base assembly 1, an upper pressure assembly 2, and a locking mechanism 3. Each part works together to achieve active correction of board warping and precision welding.

[0038] The base assembly 1 has a clearance portion 130; the upper pressing assembly 2 opens and closes in a controlled manner relative to the base assembly 1; the upper pressing assembly 2 has a pressure-correcting portion 210 on the side facing the base assembly 1, the position of the pressure-correcting portion 210 corresponding to the clearance portion 130; a locking mechanism 3 is disposed between the upper pressing assembly 2 and the base assembly 1 to provide a locking force after the upper pressing assembly 2 and the base assembly 1 are closed. When the upper pressing assembly 2 and the base assembly 1 are closed and locked by the locking mechanism 3, the pressure-correcting portion 210 forces a portion of the workpiece 5 to be welded into the clearance portion 130, causing the workpiece 5 to produce a preset elastic deformation.

[0039] The base assembly 1 serves as the load-bearing foundation of the entire fixture. It is typically made of high-temperature resistant, low-thermal-expansion-coefficient, and high-hardness materials, such as aluminum alloy or special ceramics, to ensure dimensional stability during the high-temperature environments of reflow soldering or vacuum welding. The upper surface of the base assembly 1 has a positioning area for placing the components 7 to be welded, the frame 6, and the plate 5 to be welded. At a location on the base assembly 1 corresponding to the area where the plate 5 is prone to warping (usually the center area of ​​the plate), a recessed structure, namely a clearance portion 130, is provided. This clearance portion 130 can be a blind groove of a certain depth or a through hole penetrating the base assembly 1. Its opening area and depth are designed to accommodate the maximum deformation of the plate 5 under external pressure, preventing the plate from failing to achieve the expected flatness due to bottoming out during deformation correction.

[0040] The upper pressure assembly 2 is movably or rotatably connected to one side of the base assembly 1, and can be opened and closed in a controlled manner relative to the base assembly 1. The upper pressure assembly 2 has a protruding structure, namely the pressure-correcting part 210, on the side facing the base assembly 1 (i.e., the inner side after closing). The position of this pressure-correcting part 210 spatially corresponds precisely to the clearance part 130 on the base assembly 1. The shape of the pressure-correcting part 210 is preferably spherical, arc-shaped, or a blunt structure with chamfers to avoid scratching the surface of the workpiece 5 or causing stress concentration damage when in contact with it. The height of the pressure-correcting part 210 is preset to ensure that when the fixture is closed, this part can contact and press against the workpiece 5 before or deeper than other planes of the upper pressure assembly 2.

[0041] The locking mechanism 3 is arranged between the upper pressing assembly 2 and the base assembly 1, and is used to provide a continuous and stable locking force after the jig is closed. The locking mechanism 3 can be a buckle, a snap, a rotating pressing cylinder or a threaded locking piece arranged on the edge of the jig. Its main function is to overcome the elastic restoring force of the to-be-welded plate 5 itself and the reaction force generated during the correction process, and tightly lock the upper pressing assembly 2 on the base assembly 1, so as to maintain the pressing state of the pressing and correcting part 210 on the plate.

[0042] When using the welding jig in the embodiment, first, an operator or an automatic device is required to open the jig, and then sequentially load the to-be-welded component 7, the soldering sheet, the frame 6 and the to-be-welded plate 5 in the positioning area of the base assembly 1. At this time, if the to-be-welded plate 5 has a central micro-arch or other warping phenomenon, the center of the plate may be suspended or not completely attached to the underlying assembly. Then, the upper pressing assembly 2 is closed towards the base assembly 1. During the closing process, the pressing and correcting part 210 on the upper pressing assembly 2 first contacts the warping high point (usually the center position) of the to-be-welded plate 5. Then, the locking mechanism 3 is used to lock the upper pressing assembly 2 and the base assembly 1. During this process, the strong mechanical locking force exerted by the locking mechanism 3 is converted into a vertical pressure of the pressing and correcting part 210 on the to-be-welded plate 5. This pressure forces the to-be-welded plate 5 to overcome its own warping stress, not only flattens it, but further forces the local part (i.e. the warping part) of the plate into the accommodation part 130 of the base assembly 1. This process makes the to-be-welded plate 5 produce a preset elastic deformation (i.e. maintains the state by correction or flattening). Finally, the locked jig is sent to a heating device. During the high-temperature welding stage, the plate always maintains close contact with the underlying frame 6 and component 7 under the action of the pressing and correcting part 210, until the soldering sheet melts and re-solidifies to connect. After cooling, the jig is unlocked, the stress of the plate is released or solidified, and the welding is completed.

[0043] The welding jig is suitable for various high-temperature welding environments in the field of electronic precision assembly, including but not limited to reflow soldering furnace, vacuum welding furnace, vapor phase welding equipment and constant temperature heating table, etc. The applicable working temperature range is usually between room temperature and 300 degrees Celsius, which requires that the materials of the base assembly 1 and the upper pressing assembly 2 have excellent resistance to thermal creep.

[0044] The technical scheme is particularly suitable for welding of plate materials with certain rigidity but initial flatness deviation, such as PCB printed circuit board, metal substrate (such as aluminum substrate, copper substrate) and ceramic substrate. In particular, for those plates that naturally present a central high and peripheral low arch-shaped warping, the scheme has significant applicability. In addition, for power device packaging or IGBT module assembly scenarios that require extremely high consistency of welding layer thickness and do not allow voids, the jig is particularly suitable.

[0045] In practical applications, the forms of the pressing correction part 210 and the giving space part 130 can be adjusted according to the specific warping shape of the plate. For example, if the plate is long and curved along the axial direction, the pressing correction part 210 can be designed as a long protruding rib, and the giving space part 130 is correspondingly designed as a long groove; if the plate is a large-area planar warping, the pressing correction part 210 can be designed as an array of several protruding points, and the giving space part 130 is correspondingly designed as several concave pits. Regarding the material selection, the pressing correction part 210 can be a rigid structure integrally formed with the upper pressing assembly 2, or an elastic body made of high-temperature-resistant rubber or silicone inlaid on the upper pressing assembly 2, so as to provide correction force and increase protection for the surface of the plate. Regarding the locking mechanism 3, in addition to manual buckling, magnetic adsorption locking or external pneumatic clamp pressing can also be used, as long as sufficient holding force can be provided to maintain the deformed state of the plate.

[0046] In this embodiment, by adopting the technical means of setting the pressing correction part 210 on the upper pressing assembly 2 and cooperating with the giving space part 130 on the base assembly 1, and using the locking force of the locking mechanism 3 to force the plate to be welded 5 to locally enter the giving space part 130 to generate a preset elastic deformation amount, the technical problem that the simple planar pressing method cannot make the plate to be welded 5 tightly adhere to the components to be welded 7 and the frame 6 due to the warping of the plate to be welded 5 itself in the prior art is effectively solved, and the welding reliability and yield of the electronic assembly are significantly improved.

[0047] Further, in order to further optimize the correction effect of the plate warping and protect the surface of the plate, the pressing correction part 210 of the upper pressing assembly 2 and the giving space part 130 of the base assembly 1 are specifically designed. Please refer to Figure 1 , the pressing correction part 210 is configured as a protruding structure arranged on the central area of the side of the upper pressing assembly 2 facing the base assembly 1, and the protruding structure has a spherical or arc-shaped pressing surface 211; the giving space part 130 is configured as a groove or through hole arranged on the side of the base assembly 1 facing the upper pressing assembly 2, and the size of the groove or through hole is configured to accommodate the part of the plate to be welded 5 that generates a preset elastic deformation amount after being pressed after the upper pressing assembly 2 and the base assembly 1 are closed and locked by the locking mechanism 3.

[0048] Specifically, the pressing correction part 210 is configured as a protruding structure arranged in the central area of the side of the upper pressing assembly 2 facing the base assembly 1. The protruding structure is precisely machined so that the abutting surface 220 is a smooth spherical or arc surface. The protruding structure can be integrally formed with the upper pressing assembly 2, or it can be a separate insert (e.g., a ball pin made of stainless steel or ceramic) fixed to the central position of the upper pressing assembly 2. The radius of curvature of the spherical surface is designed to be small enough to generate concentrated downward pressure and large enough to avoid leaving pressure marks on the surface of the plate. Correspondingly, the allowance part 130 is configured as a groove or a through hole arranged on the base assembly 1. The groove or the through hole is located directly below the protruding structure, i.e., the two are coaxially aligned in the vertical direction. The opening size (diameter or length-width) of the allowance part 130 is slightly larger than the projected size of the protruding structure, and the depth of the through hole must satisfy a key design, i.e., after the jig is closed and locked, the space must be sufficient to accommodate the maximum downward displacement of the plate to be welded after being pressed by the protruding structure, i.e., the preset elastic deformation amount, so as to ensure that the plate does not contact the solid part of the base assembly 1 before being bent to the predetermined extent, thereby avoiding rigid interference.

[0049] When the upper pressing assembly 2 is closed downward, since the pressing correction part 210 is a protruding structure, the spherical or arc top end will first contact the center point of the plate to be welded 5 (which is usually also the high point of the plate warping). As the locking mechanism 3 applies the locking force, the upper pressing assembly 2 continues to press down, and the protruding structure acts as a force application fulcrum to concentrate pressure on the center of the plate. Since the base assembly 1 has a groove or a through hole at the corresponding position, the area below the center of the plate is in a suspended state. Under the strong extrusion of the spherical protrusion, the center of the plate is forced to bend downward and enter the inside of the groove or the through hole. In this process, the spherical or arc abutting surface ensures that the contact between the force application point and the surface of the plate is always smooth, and even if the plate changes the bending angle, the contact point will smoothly roll on the spherical surface, thereby uniformly converting the vertical pressure into a bending moment of the plate, achieving smooth forced deformation.

[0050] As an optional implementation, the height of the protruding structure can be adjustable. For example, the protruding structure can be mounted on the upper pressing assembly 2 through threaded connection, and its protruding height can be fine-tuned by rotating, so as to set different preset elastic deformation amounts for plates of different thicknesses or different warping degrees. In addition, the shape of the groove or the through hole of the allowance part 130 is not limited to circular. For rectangular plates, the protruding structure can be designed as a bar-shaped ridge structure with rounded corners at both ends, and the corresponding allowance part 130 is designed as a long slot to adapt to the correction needs of the plate along the long axis direction.

[0051] In this embodiment, the pressing and correcting part 210 is configured as a convex structure with a spherical or arc-shaped pressing surface 211, and the accommodation part 130 is configured as a size-fitted groove or through hole, so that the technical problems in the prior art, such as scratching the surface of the plate part when forcibly flattening the warped plate part with a flat or angular structure, causing local stress concentration damage, and the plate part cannot reach the over-corrected state due to the lack of avoidance space at the bottom, are effectively solved, and further, the plate part is subjected to deep and controllable elastic bending deformation under the premise of protecting the surface integrity of the to-be-welded plate part 5, and the initial warping stress of the plate part is more thoroughly eliminated by using the over-correcting principle to ensure the welding quality.

[0052] In some embodiments, in order to protect the fragile to-be-welded components 7 while forcibly deforming and correcting the plate part, a plurality of floating support units 4 are specially designed on the base assembly 1. Please refer to Figure 2 , the floating support unit 4 is configured to carry the to-be-welded components 7 and has the freedom of elastic floating in the direction towards the upper pressing assembly 2; wherein, in the process that the pressing and correcting part 210 presses the local part of the to-be-welded plate part 5 into the accommodation part 130, the side of the to-be-welded plate part 5 towards the base assembly 1 abuts against the floating support unit 4, forcing the floating support unit 4 to sink synchronously, so as to keep the to-be-welded components 7 and the to-be-welded plate part 5 in close contact through the elastic supporting force of the floating support unit 4.

[0053] These floating support units 4 are distributed around the accommodation part 130 (i.e. the recessed area for accommodating the deformation of the plate part) of the base assembly 1, and their positions correspond one-to-one to the coordinate points of the to-be-welded components 7 on the to-be-welded plate part 5. Each floating support unit 4 mainly consists of an ejector 410 and an elastic member. The ejector 410 is usually configured as a columnar or block-shaped rigid body. The elastic member is arranged between the bottom of the ejector 410 and the base body of the base assembly 1. A guide hole is provided on the base assembly 1 for the up-and-down sliding of the ejector 410, and the elastic member is accommodated in the guide hole. The elastic member can be selected from a precision coil spring, a high-temperature-resistant elastic rubber column, a wave spring or a micro pneumatic spring. In the natural state (i.e. without placing the plate part or closing the jig), the elastic member is in an extended or slightly pre-pressed state, which lifts the ejector 410, so that the height of the ejector 410 carrying the components 7 is slightly higher than the theoretical reference surface height of the plate part after correction, thereby giving it the freedom of elastic floating in the vertical direction (i.e. towards the upper pressing assembly 2).

[0054] When the upper pressing assembly 2 is closed downward, the pressing and correcting part 210 on the upper pressing assembly 2 starts to forcibly press the local part of the plate to be welded 5 into the accommodation part 130, and the plate will be bent and deformed towards the base assembly 1. As the deformation of the plate increases, the side of the plate towards the base 110 will gradually contact the components to be welded 7 (and the welding pads above them) placed on the floating support unit 4. At this time, since the floating support unit 4 is not rigidly fixed but has elasticity, the great correcting force of the plate pressing will not directly and rigidly act on the components 7. On the contrary, the pressing action of the plate will force the floating support unit 4 to sink (i.e. retreat) synchronously by overcoming the resistance of the elastic member. During the sinking process, the elastic member is compressed, generating an elastic restoring force in the opposite direction. This elastic restoring force is transmitted to the components 7 through the ejector 410, continuously pressing the components 7 upwards, so that they are tightly attached to the plate at the welding position. In short, the deeper the plate is pressed, the more the floating support unit 4 retreats, but the contact pressure between the two is always determined by the characteristics of the elastic member, rather than directly by the mechanical pressure of the correcting plate.

[0055] As an optional embodiment, the stiffness of the elastic member of the floating support unit 4 can be selected or adjusted according to the pressure limit of the components 7. For fragile components 7, soft springs can be selected; for scenarios that require greater adhesion to break the oxide layer, hard springs can be selected. In addition, the floating support unit 4 can not only be an independent single ejector, but also be designed as a group of linked floating plates. For example, multiple components 7 are placed on the same floating plate, and the floating plate as a whole is floating through multiple springs at the bottom to ensure the coplanarity of the components 7 in the region.

[0056] In this embodiment, by using the technical means of setting the floating support unit 4 with elastic floating freedom on the base assembly 1 and sinking synchronously during the plate correcting process, the technical problem of rigidly correcting the plate warping to cause large Z-axis displacement of the plate and then rigidly pressing the components to be welded 7 or crushing the welding pads to cause short circuit in the prior art is effectively solved, thereby realizing the plate being forcibly flattened while absorbing the geometric displacement tolerance by the flexible floating mechanism and ensuring the stable, damage-free and tight welding and attachment between the components 7 and the plate by the elastic support force, and significantly improving the yield.

[0057] Further, the floating support unit 4 comprises an ejector 410 and an elastic member, wherein the top end of the ejector 410 is configured to abut against the side of the components to be welded 7 away from the upper pressing assembly 2 when the upper pressing assembly 2 and the base assembly 1 are closed; the elastic member is arranged between the ejector 410 and the base assembly 1 and is configured to apply the elastic support force towards the upper pressing assembly 2 to the ejector 410.

[0058] The ejector 410, as the direct contact part with the component 7 to be welded, is usually processed into a columnar, block or T-shaped stepped structure. In terms of material selection, considering the high-temperature environment of the welding process and the electrical characteristics of the electronic component 7, the ejector 410 is preferably made of a special engineering plastic with high temperature resistance, high strength and good insulation performance. The top end of the ejector 410 is designed as a bearing surface, which is configured to form a physical abutment with the bottom surface of the component 7 to be welded (i.e. the side away from the upper pressing assembly 2) when the jig is closed. In order to prevent the component 7 from sliding horizontally, the top end of the ejector 410 can also be processed with a limiting groove or positioning step according to the shape of the component 7.

[0059] The elastic member is a power source that provides floating capability and compression force. It is arranged between the bottom of the ejector 410 and the entity of the base assembly 1. Usually, a counterbore or guide groove for accommodating the elastic member is provided on the base assembly 1, and the elastic member is placed therein. One end of the elastic member is supported on the hole bottom of the base assembly 1, and the other end directly abuts against the lower surface of the ejector 410. The elastic member is configured to always apply an elastic support force to the ejector 410 in the direction of the upper pressing assembly 2 (i.e. vertically upward), so that the ejector 410 remains in the extended state when no external force is applied.

[0060] When the upper pressing assembly 2 is not closed, the elastic member is in a pre-pressed or free expansion state, and the elastic force released by the elastic member will lift the ejector 410 upward, so that it is in the highest waiting position. At this time, the operator places the component 7 to be welded on the top end of the ejector 410. When the upper pressing assembly 2 is closed and locked, forcing the plate 5 to be welded to be pressed down and corrected, the lower surface of the plate compresses the component 7, and then transmits the pressure to the ejector 410. At this time, the ejector 410 is forced to move downward, compressing the elastic member below it. The elastic member then produces elastic deformation (compression) and generates a reverse restoring force according to Hooke's law. This restoring force is the elastic support force, which continuously acts on the bottom surface of the component 7 through the ejector 410, and the component 7 is lifted upward to the plate 5 to be welded, so as to form a stable clamping pressure between the component 7 and the plate. Regardless of the depth of the plate pressing (within the range of travel), the structure always automatically adjusts the support force through the compression amount of the spring, realizing flexible contact.

[0061] In this embodiment, the floating support unit 4 is refined into a rigid ejector 410 and an elastic element, and the elastic element is used to apply an elastic support force to the ejector 410 in the direction of the upper pressing assembly 2. Therefore, the technical problem of crushing the precision component 7 due to the inability to buffer the pressure by yielding when the plate is deformed under pressure in the prior art is effectively solved. The flexible buffering and constant output force characteristics of the elastic element are used to absorb the Z-axis displacement tolerance while providing continuous, stable and non-destructive contact pressure for the component 7 to be welded, ensuring the tight contact of the welding interface and the physical safety of the component 7.

[0062] In some embodiments, in order to further improve the Z-axis (the thickness direction of the clamped plate) precision control ability after the closure of the jig, ensure the accurate control of the correction deformation amount of the plate, a precise limiting mechanism is introduced between the base assembly 1 and the upper pressing assembly 2. Please refer to Figures 1 to 2 , the upper pressing assembly 2 is provided with an abutting surface 220 towards the base assembly 1; the base assembly 1 is also provided with a positioning and bearing module 120 towards the upper pressing assembly 2, the positioning and bearing module 120 is provided with a limiting groove 121 for limiting the horizontal position of the component 7 to be welded; the positioning and bearing module 120 is provided with a rigid stop surface 122 cooperating with the abutting surface 220 towards the upper pressing assembly 2, the positioning and bearing module 120 is configured to make the component 7 to be welded at least partially protrude from the rigid stop surface 122; the rigid stop surface 122 is configured to abut with the abutting surface 220 of the upper pressing assembly 2 when the locking mechanism 3 is locked, so as to limit the minimum closing height of the upper pressing assembly 2 relative to the base assembly 1, so that the plate 5 to be welded is pressed into the depth of the accommodating portion 130 to reach the preset elastic deformation amount.

[0063] Specifically, the upper pressing assembly 2 is provided with a finished plane, i.e. the abutting surface 220, on one side of the base assembly 1. The abutting surface 220 is usually located at the edge or non-functional area of the upper pressing assembly 2, serving as a reference datum for the closing stroke. The base assembly 1 is provided with a positioning and bearing module 120. The module is usually configured as a plate-shaped member with a certain thickness and high rigidity, which is fixed on the base assembly 1 by screws or pins. The positioning and bearing module 120 has two key structural features, i.e. the limiting groove 121 and the rigid stop surface 122. The limiting groove 121 is provided with a plurality of through holes or grooves on the surface of the module, which are adapted to the profile of the component 7 to be welded, for strictly limiting the movement of the component 7 in the horizontal direction (perpendicular to the plane of the thickness direction of the plate in the clamped state), preventing the component 7 from shifting during welding. In addition, the rigid stop surface 122 is machined to a high-precision plane on the upper surface of the positioning and bearing module 120, i.e. the rigid stop surface 122. In particular, the positioning and bearing module 120 has a specific spatial positional cooperation relationship with the floating support unit 4 described above: the positioning and bearing module 120 is configured to allow the floating support unit 4 arranged below it to lift the component 7 to be welded, so that in the natural state of the jig being not closed, the top end surface of the component 7 to be welded at least partially protrudes above the rigid stop surface 122. This means that the height reference of the component 7 is slightly higher than the rigid limiting reference. It should be noted that the allowance portion 130 is usually provided on the base 110 described below, and at this time, the positioning and bearing module 120 needs to provide a through groove (not shown in the figure) corresponding to the position of the allowance portion 130 for the allowance portion 130 to protrude, but in some embodiments, the allowance portion 130 can also be arranged at the middle position of the positioning and bearing module 120, depending on the specific product structure.

[0064] When the locking mechanism 3 is operated to close the upper pressing assembly 2, the upper pressing assembly 2 first drives the to-be-welded plate 5 to contact and press the to-be-welded components 7 that protrude from the rigid stop surface 122. With the increase of the pressure, the floating support unit 4 is compressed and sinks, and the components 7 retreat accordingly. When the upper pressing assembly 2 continues to move downward until the abutting surface 220 of the upper pressing assembly 2 physically contacts the rigid stop surface 122 of the positioning and bearing module 120, the downward movement of the upper pressing assembly 2 is forcibly terminated. At this time, the detection jig reaches the designed minimum closing height. Since the height of the rigid stop surface 122 is precisely pre-set, this closing height directly determines the depth at which the plate center is pressed into the accommodation portion 130 by the plate center pressing and correcting portion 210. In other words, the rigid stop surface 122 locks the final deformation amount of the plate, so that it accurately reaches the pre-set elastic deformation amount and is no longer affected by the size of the artificial locking force. At the same time, since the components 7 are protruding in the natural state, when the jig is closed to the rigid stop surface 122, the components 7 are necessarily in a position pressed back to be flush with or slightly lower than the stop surface, which means that the elastic member below is necessarily in a compressed state, thereby ensuring that the components 7 are subjected to a constant elastic pressing force.

[0065] The technical solution is suitable for precise electronic assembly scenarios that have extremely high requirements for welding height consistency and plate flatness. In particular, for components 7 with high pin density and small pitch, a small deviation in Z-axis height can lead to poor welding. The solution requires that the material of the positioning and bearing module 120 must have extremely high hardness and pressure resistance (such as hard alloy, stainless steel, or reinforced synthetic stone) to ensure that the rigid stop surface 122 does not collapse or wear out under thousands of high-pressure locking impacts, thereby maintaining long-term precision stability.

[0066] In some optional embodiments, the rigid stop surface 122 can be the entire upper surface of the positioning and bearing module 120, or the top surface of a plurality of limiting columns locally protruding on the module, to reduce the contact area, increase the pressure, and prevent foreign matter from affecting the limiting precision. In order to adapt to to-be-welded plates 5 of different thicknesses or components 7 of different specifications, precise shims can be provided between the positioning and bearing module 120 and the base assembly 1. By adding or removing shims, the height of the positioning and bearing module 120 is fine-tuned, and the Z-axis coordinate of the rigid stop surface 122 is changed, so that the pre-set elastic deformation amount of the plate and the pressing interference amount of the components 7 are adjusted without replacing the module.

[0067] In this embodiment, the positioning and bearing module 120 with a rigid stop surface 122 is arranged on the base assembly 1 and cooperates with the abutting surface 220 of the upper pressing assembly 2 to form a hard limit of the closed stroke, and the technical means of protruding the components 7 to be welded from the rigid stop surface 122 in a natural state is configured, so that the technical problems of the prior art that the final depth of the correction of the plate cannot be controlled by simply relying on the floating support and the elastic pressing force of the components 7 cannot be controlled due to the fluctuation of the locking force are effectively solved, and the minimum closed height of the jig is accurately locked by the rigid stop surface 122, the bending correction amount of the plate 5 to be welded is strictly consistent with the preset value, and the elastic pressing force of the components 7 is determined at a constant closed height, so that the plate correction accuracy and the protection safety of the components 7 are considered.

[0068] Further, referring to Figure 2 , the positioning and bearing module 120 is configured as a plate structure, the positioning and bearing module 120 is provided with a plurality of avoiding holes 123 corresponding to a plurality of floating support units 4, the floating support units 4 are arranged in the corresponding avoiding holes 123 and at least part of the floating support units 4 protrude from the rigid stop surface 122 to bear the components 7 to be welded; wherein, when the abutting surface 220 of the upper pressing assembly 2 and the rigid stop surface 122 are in the abutting state, the floating support units 4 are in the compressed state, and the elastic support force of the floating support units 4 is used to press the components 7 to be welded to the side of the plate 5 to be welded facing the base assembly 1.

[0069] The positioning and bearing module 120 is configured as a plate-shaped structure (for example, a positioning cover plate or a positioning template) with a certain thickness. The plate-shaped structure is horizontally overlaid above the base assembly 1 and is fixedly connected with the base assembly 1 by bolts or pins. On the plate body of the positioning and bearing module 120, a through hole, i.e., an avoiding hole 123, is precisely machined through the plate body from top to bottom, corresponding to the position of each floating support unit 4, and the avoiding hole 123 is arranged on the bottom surface of the limiting groove 121. The floating support unit 4 (mainly referring to the ejection part 410 portion thereof) is configured to be penetrated in the corresponding avoiding hole 123. The inner diameter or inner contour size of the avoiding hole 123 is slightly larger than the outer diameter or outer contour size of the floating support unit 4, and a precise fitting sliding gap is left between the two, so that the floating support unit 4 can smoothly reciprocate up and down in the avoiding hole 123 without being stuck or laterally shaken. The key structural feature lies in the design of the height difference. In the natural state of the detection jig being not closed, the top end (i.e., the surface bearing the to-be-welded component 7) of the floating support unit 4 penetrating through the avoiding hole 123 is not flush with the upper surface (rigid stop surface 122) of the positioning and bearing module 120, but at least partially protrudes above the rigid stop surface 122. The protruding height difference (reserved floating stroke) is calculated to be usually slightly greater than or equal to the expected compression amount of the to-be-welded component 7.

[0070] In the open state of the jig, the floating support unit 4 is ejected upward under the action of the bottom elastic member, and the bearing end thereof penetrates through the avoiding hole 123 of the positioning and bearing module 120 and is higher than the rigid stop surface 122. The operator places the to-be-welded component 7 on the protruding floating support unit 4, and at this time, the component 7 is in a suspended state and is higher than the rigid stop surface 122. Then, the upper pressing assembly 2 is pressed downward. The to-be-welded plate 5 first contacts the to-be-welded component 7. With the continuous pressing of the upper pressing assembly 2, the plate compresses the component 7 and drives the floating support unit 4 to overcome the elastic resistance and retract downward to the deep part of the avoiding hole 123. When the abutting surface 220 of the upper pressing assembly 2 finally rigidly abuts against the rigid stop surface 122 of the positioning and bearing module 120, the upper pressing assembly 2 stops downward movement. At this time, the floating support unit 4 is forced to be maintained in the compressed state. In this state, the elastic member at the bottom of the floating support unit 4 accumulates sufficient potential energy, which is converted into an upward elastic supporting force to continuously and closely press the to-be-welded component 7 against the side surface of the to-be-welded plate 5 facing the base assembly 1 through the avoiding hole 123.

[0071] In some alternative embodiments, the shape of the avoidance hole 123 can be adjusted according to the cross-sectional shape of the floating support unit 4, which can be a circular hole, a square hole, or a waist-shaped hole. In order to prevent the floating support unit 4 from escaping the avoidance hole 123 when it is ejected too high, the lower part of the floating support unit 4 can be designed with a flange or a limiting step, and the bottom of the avoidance hole 123 of the positioning and bearing module 120 can be designed with a corresponding counterbore step, which uses the positioning and bearing module 120 itself as an upper limiting baffle for the upward movement of the floating support unit 4, thereby simplifying the overall structure and eliminating the need for additional limiting mechanisms in the deep base 110. In addition, the height of the protrusion can be adjusted by replacing the positioning and bearing module 120 (plate structure) with different thicknesses to accommodate different height specifications of the components 7.

[0072] In this embodiment, by using the technical means of constructing the positioning and bearing module 120 as a plate structure with an avoidance hole 123 and allowing the floating support unit 4 to pass through it and protrude naturally from the rigid stop surface 122, the problem of the floating component lacking effective guidance and being easily tilted in the prior art is effectively solved, and the problem of not being able to ensure constant adhesion of the components 7 in the rigid limiting state is also solved. Furthermore, the positioning and bearing module 120 achieves the dual function of rigid limiting reference and floating guide support, ensuring that the floating support unit 4 is necessarily in a compressed working state when the jig is closed to the dead point, thereby reliably compressing the components 7 to be welded against the back of the plate using a certain elastic support force, and ensuring the stability and consistency of the welding adhesion.

[0073] In some embodiments, referring to Figure 1 , the upper pressing assembly 2 includes an auxiliary pressing surface 230 for pressing the peripheral area of the plate to be welded 5, which is arranged on the side of the pressing and correcting part 210, and the friction coefficient of the surface of the auxiliary pressing surface 230 is less than that of the pressing and correcting part 210, so as to form a fixed anchor point for the center of the plate to be welded 5 during welding, so that the auxiliary pressing surface 230 allows the peripheral area of the plate to be welded 5 to slide radially relative to the auxiliary pressing surface 230 when it expands due to heat.

[0074] This embodiment focuses on the surface friction design of the upper pressing assembly 2 for the thermal expansion characteristics of the plate. The side of the upper pressing assembly 2 facing the base assembly 1 (i.e. the pressing surface) is functionally divided into two concentric physical regions: the center pressing and correcting part 210 and the auxiliary pressing surface 230 surrounding the periphery. The auxiliary pressing surface 230 corresponds to the edge or frame 6 area of the plate to be welded 5, and its surface has undergone special low-friction treatment.

[0075] Specifically, the auxiliary pressing surface 230 is configured as a high-precision mirror-polished surface, or coated with a high-temperature-resistant low-friction coefficient coating, such as a polytetrafluoroethylene (Teflon) coating, a diamond-like carbon (DLC) coating, or a molybdenum disulfide dry film lubricant. In contrast, the surface of the centrally located pressing correction portion 210 (i.e., the aforementioned protruding structure) is configured to have a higher friction coefficient. Its surface can retain the natural roughness after mechanical processing, or be treated with sandblasting or knurling to form microscopic biting textures, or even be inlaid with high-temperature-resistant hard rubber or high-friction composite material pads. Through this structural design, a key physical property difference is established: the friction coefficient of the surface of the auxiliary pressing surface 230 is significantly smaller than that of the surface of the pressing correction portion 210, thereby creating a differential friction distribution on the same pressing surface of the upper pressing assembly 2, with high resistance in the center and low resistance on the periphery.

[0076] When the jig is closed and locked, the pressing correction portion 210 tightly presses the center of the to-be-welded plate 5 with a large pressure and a high friction force, firmly fixing it and forming a mechanical anchor point. At this time, the plate center is absolutely stationary relative to the upper pressing assembly 2. At the same time, the auxiliary pressing surface 230 presses on the peripheral area of the plate. Although there is also a vertical pressing force here (limited by the rigid stop), the horizontal shear resistance between the plate and the auxiliary pressing surface 230 is very small due to the extremely low friction coefficient. When the jig enters the reflow soldering furnace along with the plate and is heated, the thermal expansion coefficient of the to-be-welded plate 5 (usually a PCB or metal substrate) is usually greater than that of the jig material, causing the plate to tend to elongate. Since the center is anchored, the plate cannot move as a whole and can only expand radially with the center as the origin. At this time, the low-friction auxiliary pressing surface 230 allows the peripheral area of the plate to overcome the weak friction resistance and undergo a small amount of radial slip (i.e., outward creep) relative to the upper pressing assembly 2. This slip releases the thermal stress accumulated inside the plate. When the welding is completed and the plate cools and shrinks, it will also contract radially under the action of the shrinkage force.

[0077] This technical solution is particularly suitable for welding large-size, thin-type, or different material spliced (such as copper substrate and synthetic stone jigs) electronic assemblies. In these scenarios, due to the mismatch of the thermal expansion coefficient (CTE), if the jig tightly clamps the plate around, the plate will inevitably deform upward in the Z-axis direction where the resistance is the smallest when it elongates under heat, which will instantly pull off the still un-solidified solder joints.

[0078] In some alternative embodiments, besides the coating, the difference in material can also be used. For example, the pressing correction part 210 uses a rough carbide head, while the auxiliary pressing surface 230 is inlaid with a smooth ceramic sheet. Alternatively, a microstructure design can be combined: the surface of the pressing correction part 210 is processed with fine tooth patterns to increase grip, while the auxiliary pressing surface 230 is processed with a fine radial guiding texture centered on the center (not a mirror surface, but in line with the sliding direction) to reduce the resistance of radial flow. In addition, it can also be combined with the aforementioned rigid limiting design, so that the auxiliary pressing surface 230 and the plate member leave a very small physical gap (for example, a few microns), so as to reduce the friction to almost zero, and realize pure limiting guidance rather than pressing friction.

[0079] In this embodiment, by using the technical means of setting the auxiliary pressing surface 230 with a smaller friction coefficient around the pressing correction part 210 of the upper pressing assembly 2 and using the high-friction characteristics of the pressing correction part 210 as the center anchor point, the technical problem of the prior art that the excessive rigid constraint of the jig on the periphery of the plate causes the plate to be forced to deform in the Z-axis arch when the plate expands in the horizontal direction during welding, thereby causing the weld to be sheared and damaged or detached, is effectively solved. In turn, it realizes the effective dissipation and release of the welding thermal stress, ensures that the plate flatness is corrected while allowing the plate to freely expand and contract in the horizontal plane, thereby minimizing residual stress and ensuring the structural stability of the weld during solidification.

[0080] In order to accurately control the mechanical behavior of the plate to be welded 5 in the jig, especially the friction force distribution in the horizontal direction, the surface is further processed differently, and the surface of the pressing correction part 210 is provided with a high-friction texture or a high-friction material layer; the auxiliary pressing surface 230 is constructed as a smooth polished surface or coated with a low-friction coating.

[0081] For the center pressing and correcting part 210, its surface is specially designed as a high friction area. The specific implementation can be physical texture construction or material layer composite. If physical texture is adopted, the surface of the metal base of the center pressing and correcting part 210 is processed with interlaced net-like knurl texture, micro-tooth array or rough surface formed by high-strength sand blasting to increase the surface roughness. If material layer composite is adopted, a layer of high-temperature-resistant high-friction material such as hardened silicone rubber gasket or polymer film containing abrasive particles is covered on the surface of the center pressing and correcting part 210 by vulcanization bonding or inlaying process. For the auxiliary pressing surface 230 surrounding the center pressing and correcting part 210, its surface is constructed as a low friction area. The specific implementation includes extremely fine mechanical polishing and chemical coating. In the mechanical polishing scheme, the auxiliary pressing surface 230 is polished to mirror level, eliminating micro convex and scratches. In the chemical coating scheme, the auxiliary pressing surface 230 is uniformly sprayed or deposited with a layer of low-friction coating, and the coating material is preferably polytetrafluoroethylene (Teflon) with self-lubricating properties, molybdenum disulfide dry film or diamond-like carbon film. This differential surface treatment makes the upper pressing assembly 2 form two functional areas with significantly different friction coefficients on the same contact plane.

[0082] When the jig is closed, the upper pressing assembly 2 presses the to-be-welded plate 5, and the center pressing and correcting part 210 generates a large static friction force with the center of the plate due to its high-friction texture or high-friction material layer. This static friction force is much greater than the outward thrust generated by the thermal expansion of the plate, so that the center area of the plate is firmly locked, becoming the fixed origin or zero anchor point of the entire plate in thermodynamics. At the same time, the auxiliary pressing surface 230 on the periphery also contacts the plate and provides vertical limiting action, but due to its smooth surface or lubricating coating, the friction coefficient between the auxiliary pressing surface 230 and the plate is extremely low. When the jig enters the high-temperature welding environment, the plate begins to expand radially outward due to heat, and the thermal expansion thrust generated by the edge of the plate can easily overcome the weak friction resistance of the auxiliary pressing surface 230. Therefore, the peripheral area of the plate can smoothly slide outward below the auxiliary pressing surface 230. The whole process shows that the center of the plate does not move, and the periphery freely expands radially, like breathing, and naturally releases thermal stress.

[0083] The technical solution is designed for reflow soldering process which experiences severe temperature change. Its applicable environment requirement is extremely strict, especially for those scenarios which use flux that softens easily at high temperature. The low-friction coating of the auxiliary pressing surface 230 usually also has the characteristics of oil and water repellency, which not only reduces friction, but also prevents the condensed flux from adhering to the surface of the fixture, reducing the frequency of cleaning the fixture. At the same time, this solution is particularly suitable for large size, thin wall or heterogeneous plate welding. In these cases, the absolute value of thermal expansion is large, and if there is a lack of this friction release mechanism, the plate is prone to irreversible warping deformation.

[0084] In optional embodiments, the form of high-friction texture can be adjusted according to the characteristics of the solder resist layer on the surface of the plate. If the surface of the plate is soft, a blunt wave-shaped texture can be used to prevent piercing the solder resist layer; if the surface of the plate is bare copper or metal-based, a sharp diamond texture can be used to enhance grip. For low-friction coatings, in addition to Teflon, nano-ceramic coatings can also be used. This coating not only has a low friction coefficient, but also has extremely high hardness and better wear resistance, making it suitable for use in high-volume, high-strength automated production lines.

[0085] In this embodiment, by using the technical means of setting high-friction texture or material layer on the surface of the pressing and correcting part 210 to increase the friction force, and constructing the auxiliary pressing surface 230 as a smooth polished surface or coating a low-friction coating to reduce the resistance, the technical problem of the prior art that the plate is forced to deform arch or generate destructive internal stress when the plate expands horizontally during welding due to uneven distribution or overall excessive frictional restraint force of the fixture on the surface of the plate is effectively solved, and the precise control of the thermal expansion behavior of the plate is realized, i.e. the center is anchored to maintain positioning accuracy, and the periphery slides radially to release thermal stress, thereby eliminating the risk of weld cracking or plate delamination caused by thermal deformation, and greatly improving the reliability of the welded assembly.

[0086] It should be further pointed out that another significant advantage of the soldering fixture in this application is the organic combination and deep synergy between the above-mentioned embodiments, which solves the complex process contradictions that cannot be overcome by a single technical means.

[0087] Firstly, based on the synergy of rigid limiting and floating support, the contradiction between precision and safety is solved.

[0088] In the prior art, pursuing Z-axis accuracy usually means adopting rigid limit, but this is easy to crush the components 7; while pursuing the protection of the components 7 usually adopts flexible support, but this will lead to the loss of control of Z-axis accuracy. The embodiment creates a quantitative flexible pressing mechanism by combining the rigid stop surface 122 of the positioning bearing module 120 and the floating support unit 4. The rigid stop surface 122 locks the absolute end point of the downward movement of the upper pressing assembly 2, eliminating the displacement error caused by pressure fluctuation; while the floating support unit 4 provides constant elastic counterforce at the determined end point position. This cooperation enables the jig to have both the dimensional accuracy of rigid jigs and the protection capability of flexible jigs, realizing the dual effect of accurate pressing and non-damage, which cannot be achieved by a single means.

[0089] Secondly, based on the cooperation of floating support and differential friction, the contradiction between thermal deformation and contact stability is solved.

[0090] During the welding heating process, the plate member experiences radial thermal expansion slip. If the lower support is rigid, the horizontal slip of the plate member will generate shear friction with the fixed components 7, causing the components 7 to shift or the solder pads to misalign. In the embodiment, the floating support unit 4 not only provides vertical support, but also allows the ejector 410 to follow the plate member for micro lateral follow-up or tilting in the small fitting gap in the avoidance hole 123. When the plate member peripheral area slips under the low-friction auxiliary pressing surface 230, the lower floating support unit 4 can use its floating feature to adsorb on the bottom surface of the plate member and move with it, thereby ensuring that the relative position between the components 7 and the plate member remains stationary during the dynamic process of thermal expansion slip of the plate member, avoiding the damage of dynamic shear force to the un-solidified solder joints.

[0091] Finally, based on the cooperation of rigid limit and differential friction, the contradiction between thermal stress release and positioning accuracy is solved.

[0092] Generally, in order to release thermal stress, a gap needs to be left for the plate member, but this will sacrifice the positioning accuracy. In an embodiment of the present application, the rigid stop surface 122 accurately limits the closed height, so that the contact state between the auxiliary pressing surface 230 and the plate member periphery is in a subtle critical pressing state, i.e. the pressure is just enough to limit the Z-axis jump, but not enough to generate a large friction lock. This subtle pressure contact guaranteed by rigid limit perfectly matches the low-friction coating of the auxiliary pressing surface 230, so that the thermal expansion slip resistance of the plate member periphery is minimized. If the accurate height control of rigid limit is lacking, the upper pressing assembly 2 may cause the auxiliary pressing surface 230 to lock the plate member due to excessive friction, or the Z-axis of the plate member to be unstable due to insufficient pressure. Therefore, rigid limit is a prerequisite for the realization of the differential friction heat release mechanism, and the combination of the two realizes the precise dredging of thermal stress at the sub-millimeter level.

[0093] To sum up, the technical features of the present application are not isolated, but interdependent and mutually promoting, and together constitute a high-performance welding process system integrating forced orthopedics, precise height setting, flexible protection and thermal stress dissipation.

[0094] In some embodiments, the upper pressing assembly 2 is provided with a profiling groove 240 on one side thereof facing the base assembly 1, the profiling groove 240 being adapted to the profile of the plate to be welded 5, and the pressing and correcting portion 210 being located at the bottom of the profiling groove 240; the positioning and bearing module 120 is fixed to the base assembly 1, and the material hardness of the positioning and bearing module 120 is higher than that of the plate to be welded 5.

[0095] The side of the upper pressing assembly 2 facing the base assembly 1 (i.e. the inner side of the pressing) is not a full plane structure, but is provided with a recessed profiling groove 240. The opening profile of the profiling groove 240 is adapted to the outer profile (length, width and edge features) of the plate to be welded 5, and the size is slightly larger than the profile of the plate to form a clearance fit. The pressing and correcting portion 210 (i.e. the protruding structure mentioned above) is not isolated on the plane, but is located at the bottom (i.e. the recessed bottom plane) of the profiling groove 240. This means that when the upper pressing assembly 2 is closed, the side wall of the profiling groove 240 will surround the periphery of the plate to be welded 5, and the pressing and correcting portion 210 at the bottom will protrude and act on the center of the plate. The positioning and bearing module 120 is rigidly fixed to the base assembly 1 by high-strength bolts or pins, forming a non-movable stator structure. In material engineering design, the material hardness of the positioning and bearing module 120 is strictly selected to be higher than that of the plate to be welded 5. For example, if the plate to be welded 5 is a common epoxy glass fiber plate or a copper substrate, the positioning and bearing module 120 is made of materials such as quenched stainless steel and titanium alloy with higher hardness.

[0096] When the upper pressing assembly 2 is closed downward, the edge side wall of the profiling groove 240 will first or simultaneously cover the periphery of the plate to be welded 5 before or at the same time the pressing and correcting portion 210 contacts the plate. If there is a slight initial placement deviation of the plate on the base 110, the lead-in bevel (chamfer) of the profiling groove 240 will push the plate edge to perform rough positioning or secondary centering, ensuring that the plate is located on the correct correcting center line. Then, the pressing and correcting portion 210 presses the plate, and the lower surface of the plate is pressed against the positioning and bearing module 120. Since the hardness of the positioning and bearing module 120 is significantly higher than that of the plate, under the huge locking pressure, the positioning and bearing module 120 will not be plastically deformed or significantly elastically compressed. On the contrary, the plate to be welded 5 with lower hardness will be elastically deformed to tightly fit on the reference surface defined by the module. This difference in hardness ensures that all deformations occur on the plate side rather than the jig side, achieving the purpose of eliminating warping.

[0097] In a specific implementation, the depth of the profiling groove 240 should be designed to be less than the sum of the thickness of the plate to be welded 5 and the protruding height of the pressing and correcting part 210, so as to ensure that when the upper pressing assembly 2 is closed to the bottom, the pressing and correcting part 210 presses the plate, and the bottom surface of the profiling groove 240 does not press against the edge of the plate.

[0098] In this embodiment, by adopting the technical means of arranging the profiling groove 240 on the upper pressing assembly 2 and placing the pressing and correcting part 210 at the bottom of the groove, and setting the material hardness of the positioning and bearing module 120 to be higher than the hardness of the plate, the technical problems in the prior art that the plate is prone to lateral movement during the closing process, which causes the correction point to deviate, and the long-term use of the jig bearing surface with insufficient hardness causes the reference surface to wear and collapse, thereby affecting the correction accuracy and welding coplanarity, are effectively solved, and the automatic centering and guiding during the closing process is realized by using the profiling groove 240, and a long-term stable rigid reference datum is constructed by using the material hardness difference, which ensures that the deformation correction amount of the plate in each welding operation is accurate, consistent and effective.

[0099] In some embodiments, the base assembly 1 includes a base 110, and the positioning and bearing module 120 is arranged on the side of the base 110 facing the upper pressing assembly 2, and a plurality of accommodation grooves 111 corresponding to each of the avoiding holes 123 are arranged on the side of the base 110 facing the upper pressing assembly 2 and away from the upper pressing assembly 2, and the elastic members of each floating support unit 4 are arranged in the corresponding accommodation grooves 111, one end of the elastic member abuts against the base 110, and the other end of the elastic member abuts against the end of the ejection member 410 away from the component to be welded 7.

[0100] The core component of the base assembly 1 is a solid base 110 with a certain thickness (usually a rectangular plate or block). The positioning and bearing module 120 (i.e. the aforementioned plate-shaped structure) is arranged horizontally on the top surface of the base 110, i.e. on the side facing the upper pressing assembly 2, and the two are connected by fasteners to form a stable base assembly. In order to provide the necessary power source installation space for the floating support unit 4 without increasing the overall thickness of the jig, a plurality of accommodation grooves 111 are arranged on the surface of the base 110 facing the upper pressing assembly 2 and away from the upper pressing assembly 2 (i.e. vertically downward). The positions of these accommodation grooves 111 are precisely laid out, corresponding to and coaxially aligned with each avoiding hole 123 on the positioning and bearing module 120 in the vertical direction.

[0101] The elastic members (such as coil springs) are respectively arranged in the corresponding accommodation grooves 111. The hole diameter of the accommodation groove 111 is slightly larger than the outer diameter of the elastic member, forming a clearance fit to accommodate the expansion and contraction of the elastic member.

[0102] In the assembly relationship, the lower end (one end) of the elastic member directly abuts against the groove bottom of the accommodating groove 111 (i.e. the solid part of the base 110), serving as the force application fulcrum; the upper end (the other end) of the elastic member abuts against the lower surface of the ejector 410 in the floating support unit 4 (i.e. the end away from the component 7 to be welded). Through this structure, the positioning and carrying module 120 covers the base 110 like a cover plate, the ejector 410 of the floating support unit 4 passes through the avoiding hole 123 of the positioning and carrying module 120, and the power source (elastic member) of the ejector 410 is hidden inside the base 110.

[0103] In assembly, first, the elastic members are placed in the accommodating grooves 111 of the base 110, then the ejector 410 is placed on the elastic members, and finally the positioning and carrying module 120 is covered and locked. At this time, the elastic members are enclosed in the semi-enclosed space formed by the accommodating grooves 111 and the bottom of the ejector 410. When the jig is working, the elastic members are compressed by the pressure on the ejector 410, and the elastic members are elastically deformed in the accommodating grooves 111. The inner wall of the accommodating groove 111 plays a key role in guiding and limiting, preventing the elastic members from bending or skewing laterally during compression. When the external force is removed, the elastic members stretch and push the ejector 410 to reset by relying on the reaction force of the bottom of the accommodating groove 111. This in-groove driving method makes the force transmission path very direct and has good verticality.

[0104] In specific implementation, the accommodating grooves 111 can be blind holes (counterbores) or stepped holes. If they are stepped holes, the small-diameter part can be used to accommodate the elastic members, and the large-diameter part can be used to accommodate the flange of the bottom of the ejector 410, thereby achieving the lower limit of the ejector 410 inside the base 110. As an alternative solution for easy maintenance, the accommodating grooves 111 can also be designed as through holes penetrating the base 110, and a detachable cover plate is added to the back (bottom) of the base 110. In this way, when it is necessary to replace the worn-out springs or adjust the elastic force, it is not necessary to disassemble the positioning and carrying module 120 and the ejector 410 above, but only to open the cover plate at the bottom to quickly replace the elastic members from below, thereby improving the production line maintenance efficiency.

[0105] In this embodiment, by means of opening the accommodating grooves 111 on the base 110 and placing the elastic members in the accommodating grooves 111, and covering the positioning and carrying module 120 on the base 110 and making the two ends of the elastic members abut against the base 110 and the ejector 410 respectively, the technical problems in the prior art that the exposed elastic elements are prone to dust accumulation and jamming, are prone to lateral instability, and the overall height of the jig is too large to adapt to the low hearth space due to the stacked installation are effectively solved, thereby realizing the integration and built-in protection of the elastic power system, providing physical guidance for the elastic members by the accommodating grooves 111 to prevent lateral bending, significantly reducing the Z-axis height of the jig, and achieving the floating support effect with compact structure, smooth operation and strong anti-pollution ability.

[0106] The above-described embodiments of the application are merely descriptive of its application and fall within the scope of the present application, as defined by the appended claims.

Claims

1. A welding fixture for aligning and fixing components and frames to be welded with and fixing plates to be welded, characterized in that, The welding jig comprises: a base assembly provided with a positioning portion; an upper pressing assembly controllably opened and closed relative to the base assembly; one side of the upper pressing assembly towards the base assembly is provided with a pressing and correcting portion, the position of the pressing and correcting portion corresponds to the positioning portion; a locking mechanism arranged between the upper pressing assembly and the base assembly to provide locking force after the upper pressing assembly and the base assembly are closed; wherein, after the upper pressing assembly and the base assembly are closed and locked by the locking mechanism, the pressing and correcting portion forces part of the to-be-welded plate into the positioning portion, so that the to-be-welded plate generates a preset elastic deformation amount.

2. The welding jig according to claim 1, wherein: the pressing and correcting portion is configured as a protruding structure arranged in the central region of the side of the upper pressing assembly towards the base assembly, and the protruding structure has a spherical or arc-shaped pressing surface; the positioning portion is configured as a groove or a through hole arranged on the side of the base assembly towards the upper pressing assembly, and the size of the groove or the through hole is configured to accommodate the part of the to-be-welded plate that generates the preset elastic deformation amount after being pressed, after the upper pressing assembly and the base assembly are closed and locked by the locking mechanism.

3. The soldering fixture of claim 1, wherein, The base assembly is further provided with a plurality of floating support units around the positioning portion, and the floating support units are configured to carry the to-be-welded component and have the freedom of elastic floating in the direction towards the upper pressing assembly; wherein, during the process of pressing part of the to-be-welded plate into the positioning portion by the pressing and correcting portion, the side of the to-be-welded plate towards the base assembly abuts against the floating support units, forcing the floating support units to sink synchronously, so that the to-be-welded component and the to-be-welded plate are kept in close contact through the elastic supporting force of the floating support units.

4. The soldering fixture of claim 3, wherein, The floating support unit comprises: an ejector, the top end of the ejector is configured to abut against the side of the to-be-welded component away from the upper pressing assembly when the upper pressing assembly and the base assembly are closed; a resilient member arranged between the ejector and the base assembly and configured to apply the elastic supporting force of the ejector towards the upper pressing assembly.

5. The welding jig according to claim 4, wherein: the side of the upper pressing assembly towards the base assembly is provided with an abutting surface; the side of the base assembly towards the upper pressing assembly is further provided with a positioning and carrying module, the positioning and carrying module is provided with a limiting groove for limiting the horizontal position of the to-be-welded component; the side of the positioning and carrying module towards the upper pressing assembly is provided with a rigid stop surface matched with the abutting surface, the positioning and carrying module is configured to make the to-be-welded component at least partially protrude from the rigid stop surface; the rigid stop surface is configured to abut against the abutting surface of the upper pressing assembly when the locking mechanism is locked, so as to limit the minimum closing height of the upper pressing assembly relative to the base assembly, so that the depth of the to-be-welded plate pressed into the positioning portion reaches the preset elastic deformation amount.

6. The welding jig according to claim 5, wherein: The positioning and bearing module is configured as a plate structure, and is provided with a plurality of avoiding holes corresponding to the plurality of floating support units; the floating support units are arranged in the avoiding holes, and at least part of the floating support units protrude from the rigid stop surface to bear the components to be welded. When the abutting surface of the upper pressing assembly is in abutting contact with the rigid stop surface, the floating support units are in a compressed state, and the elastic support force of the floating support units is used to press the components to be welded on the side of the plate to be welded facing the base assembly.

7. The soldering fixture of claim 5, wherein, The upper pressing assembly comprises an auxiliary pressing surface for pressing the peripheral region of the plate to be welded, and the auxiliary pressing surface is arranged on the side of the pressing and correcting part, and the friction coefficient of the surface of the auxiliary pressing surface is smaller than that of the surface of the pressing and correcting part, so that the pressing and correcting part forms a fixed anchor point relative to the center of the plate to be welded during welding, and the auxiliary pressing surface allows the peripheral region of the plate to be welded to slide radially relative to the auxiliary pressing surface when it expands under heat.

8. The soldering fixture of claim 7, wherein, The surface of the pressing and correcting part is provided with a high-friction texture or a high-friction material layer; and the auxiliary pressing surface is configured as a smooth and polished surface or coated with a low-friction coating.

9. The soldering fixture of claim 5, wherein, The side of the upper pressing assembly facing the base assembly is provided with a profiling groove matching the profile of the plate to be welded, and the pressing and correcting part is located at the bottom of the profiling groove; the positioning and bearing module is fixed to the base assembly, and the material hardness of the positioning and bearing module is higher than that of the plate to be welded.

10. The soldering fixture of claim 6, wherein, The base assembly comprises a base, and the positioning and bearing module is arranged on the side of the base facing the upper pressing assembly; and the side of the base facing the upper pressing assembly is provided with a plurality of accommodating grooves corresponding to the avoiding holes in a direction away from the upper pressing assembly, and the elastic members of the floating support units are arranged in the accommodating grooves, respectively; one end of the elastic member abuts against the base, and the other end of the elastic member abuts against the end of the ejecting member away from the components to be welded.

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