A soldering jig

Abstract

The application relates to a welding jig which comprises a base assembly provided with a position-giving part, an upper pressing assembly provided with a pressing correction part and a locking mechanism, when the upper pressing assembly and the base assembly are locked, the pressing correction part forces the local part of a to-be-welded plate into the position-giving part, so that the plate generates a preset elastic deformation. The welding jig effectively overcomes the problem that the plate cannot be closely attached due to its own warping by forced deformation through the above structure, ensures the close contact of the plate, components and frames at the welding position, eliminates the welding gap, effectively avoids the virtual welding and false welding phenomenon, and significantly improves the welding quality and connection strength of the electronic assembly.

Description

Technical Field

[0001] This invention relates to mechanical tooling fixtures, and more particularly to a welding fixture for aligning and fixing components and frames to be welded with plates to be welded. Background Technology

[0002] In the production and assembly of electronic modules or precision components, in order to ensure welding quality, it is usually necessary to use jigs to precisely stack and position the small components to be welded, frames, and PCB boards (or metal substrates), and keep them relatively fixed by clamping mechanisms. Then, they are sent into heating equipment to complete welding and curing to form a complete electronic component.

[0003] Existing welding fixtures typically employ a planar clamping structure where a base and a top cover mate. Specifically, the base has positioning slots for placing components and a frame, while the top cover (or upper pressure plate) is locked to the base via latches or screws. In existing solutions, to secure the board, the side of the top cover facing the base is usually designed as a flat pressing surface. The vertical pressure generated when the top cover and base are closed presses the board flat against the frame and components below, attempting to eliminate gaps between components and ensure a close fit between the welding surfaces through planar clamping.

[0004] However, in actual production, the plates to be welded often exhibit a certain degree of localized warping or deformation (e.g., slight arching in the center or upward curling at the edges) due to processing techniques, material properties, or transportation and storage. For these plates with initial warping, existing planar clamping fixtures can only provide uniform downward pressure and cannot apply concentrated corrective force to the warped areas. When the warping stress of the plate is large, planar clamping often fails to completely flatten and adhere the plate to the underlying components or frame, resulting in tiny gaps at the welding point and subsequently causing quality problems such as incomplete soldering, false soldering, or insufficient weld strength. Therefore, there is an urgent need to propose a welding fixture to solve these problems. Summary of the Invention

[0005] The purpose of this invention is to provide a welding fixture to solve the technical problem in the prior art where the plate to be welded is warped, which prevents it from fitting tightly with the components and frame to be welded during the welding process, resulting in incomplete welding, false welding, or insufficient welding strength.

[0006] The technical solution adopted by the present invention to solve the above problems is: a welding fixture for aligning and fixing the components and frame to be welded with the plate to be welded, comprising:

[0007] A base assembly, wherein the base assembly is provided with a clearance portion;

[0008] The upper pressure component opens and closes in a controlled manner relative to the base component; the upper pressure component has a pressure-correcting part on the side facing the base component, and the position of the pressure-correcting part corresponds to the clearance part;

[0009] A locking mechanism is disposed between the upper pressing assembly and the base assembly to provide a locking force after the upper pressing assembly and the base assembly are closed.

[0010] Wherein, after the upper pressure component and the base component are closed and locked by the locking mechanism, the pressure correction part forces a portion of the plate to be welded into the relief part, causing the plate to be welded to produce a preset elastic deformation.

[0011] Preferably, the pressure-correcting part is constructed as a protruding structure disposed in the central region of the upper pressure component facing the base component, and the protruding structure has a spherical or arc-shaped abutment surface.

[0012] The clearance portion is constructed as a groove or through hole provided in the base assembly facing the upper pressure assembly. The size of the groove or through hole is configured such that after the upper pressure assembly and the base assembly are closed and locked by the locking mechanism, it can accommodate the portion of the plate to be welded that generates a preset elastic deformation after being pressed.

[0013] Preferably, the base assembly is further provided with a plurality of floating support units located around the clearance portion. The floating support units are configured to support the components to be welded and have a degree of freedom to float elastically in the direction toward the upper pressure assembly.

[0014] During the process of the pressure correction part pressing a portion of the plate to be welded into the relief part, the side of the plate to be welded facing the base assembly abuts against the floating support unit, forcing the floating support unit to sink synchronously, so that the elastic support force of the floating support unit keeps the component to be welded and the plate to be welded in close contact.

[0015] Preferably, the floating support unit includes:

[0016] An ejector, the top end of which is configured to abut against the side of the component to be welded away from the upper pressure assembly when the upper pressure assembly and the base assembly are closed;

[0017] An elastic element is disposed between the ejector and the base assembly and configured to apply the elastic support force to the ejector in the direction toward the upper pressure assembly.

[0018] Preferably, the pressing component has an abutment surface on the side facing the base component.

[0019] The base assembly facing the upper pressing assembly is further provided with a positioning and bearing module. The positioning and bearing module is provided with a limiting groove for limiting the horizontal position of the component to be welded. The positioning and bearing module facing the upper pressing assembly is provided with a rigid stop surface that cooperates with the abutment surface. The positioning and bearing module is configured to allow the component to be welded to at least partially protrude from the rigid stop surface. The rigid stop surface is configured to abut against the abutment surface of the upper pressing assembly when the locking mechanism is locked, so as to limit the minimum closed height of the upper pressing assembly relative to the base assembly, so that the depth to which the plate to be welded is pressed into the relief portion reaches the preset elastic deformation.

[0020] Preferably, the positioning and bearing module is constructed as a plate-shaped structure, and the positioning and bearing module has a plurality of clearance holes corresponding to a plurality of floating support units. The floating support units pass through the corresponding clearance holes and at least a portion of the floating support units protrude from the rigid stop surface to support the components to be welded.

[0021] When the contact surface of the upper pressing component is in contact with the rigid stop surface, the floating support unit is in a compressed state, and the elastic support force of the floating support unit is used to press the component to be welded against the side of the plate to be welded facing the base component.

[0022] Preferably, the pressing assembly includes an auxiliary pressing surface for pressing against the peripheral area of ​​the plate to be welded. The auxiliary pressing surface is disposed on the periphery of the pressing and straightening part, and the friction coefficient of the auxiliary pressing surface is less than that of the surface of the pressing and straightening part. This is configured such that, during the welding process, the pressing and straightening part forms a fixed anchor point relative to the center of the plate to be welded, so that the auxiliary pressing surface allows the peripheral area of ​​the plate to be welded to undergo radial slippage relative to the auxiliary pressing surface when it expands due to heat.

[0023] Preferably, the surface of the pressure-correcting part is provided with a high-friction texture or a high-friction material layer; the auxiliary pressing surface is constructed as a smooth polished surface or coated with a low-friction coating.

[0024] Preferably, the upper pressing component has a contour groove on one side facing the base component that matches the contour of the plate to be welded, and the pressure correction part is located at the bottom of the contour groove; the positioning and bearing module is fixed on the base component, and the material hardness of the positioning and bearing module is higher than that of the plate to be welded.

[0025] Preferably, the base assembly includes a base, the positioning and bearing module is disposed on the side of the base facing the upper pressing component, and the base facing the upper pressing component has a plurality of receiving grooves corresponding to each of the clearance holes along the direction away from the upper pressing component. The elastic elements of each floating support unit are respectively disposed in the corresponding receiving grooves, one end of the elastic element abuts against the base, and the other end of the elastic element abuts against the end of the ejector that is away from the component to be welded.

[0026] The beneficial effects of the embodiments of the present invention are as follows:

[0027] 1. Because this invention employs a technique of setting a pressure-correcting part on the side of the upper pressure component facing the base component and a corresponding clearance part on the base component, and using the locking force provided by the locking mechanism to force a portion of the board to be welded into the clearance part to generate a preset elastic deformation, it effectively solves the technical problem in the prior art where the simple planar pressing method cannot make the board to be welded fit tightly with the components and frame to be welded due to the warping of the board itself. It achieves the overcoming of its own warping stress by forcing the board to generate a specific elastic deformation, ensuring close contact between the board to be welded and the components and frame below at the welding position, eliminating welding gaps, effectively avoiding the occurrence of false soldering and cold soldering, and significantly improving the welding quality and connection strength of electronic components.

[0028] 2. By employing a floating support unit with elastic floating degrees of freedom on the base assembly, and specifically using the cooperation of the ejector and elastic components to support the components to be soldered, the technical problem of rigid pressure directly acting on fragile components and solder pads due to large displacement along the thickness direction caused by the pressure on the board during forced correction of board warping is effectively solved. This can lead to component damage or solder pad crushing, resulting in short circuits. Furthermore, it achieves synergistic cooperation between rigid correction and flexible support. While the pressure correction part forces the board to deform to eliminate warping gaps, the floating support unit can sink synchronously with the downward movement of the board to provide buffering. The continuous and stable elastic support force of the elastic component ensures that the components to be soldered are always tightly attached to the board surface, ensuring good soldering wetting conditions and effectively protecting the integrity of the components and solder pads.

[0029] 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.

[0030] 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

[0031] Figure 1 A schematic exploded view of a welding fixture according to an embodiment of this application is shown.

[0032] Figure 2 A schematic exploded cross-sectional view of a welding fixture according to an embodiment of this application is shown.

[0033] Figure 3 A schematic structural view of a welding fixture according to an embodiment of this application is shown.

[0034] Figure 4 A schematic structural diagram of the plate to be welded mentioned in an embodiment of this application is shown.

[0035] The components include: 1. Base assembly; 110. Base; 111. Receiving groove; 120. Positioning and bearing module; 121. Limiting groove; 122. Rigid stop surface; 123. Clearance hole; 130. Clearance part; 2. Pressing assembly; 210. Pressing and correcting part; 211. Arc-shaped support surface; 220. Abutment surface; 230. Auxiliary pressing surface; 240. Contouring groove; 3. Locking mechanism; 4. Floating support unit; 410. Ejector; 5. Plate to be welded; 6. Frame; 7. Components. Detailed Implementation

[0036] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0037] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0038] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] In the production and assembly of precision components, to ensure welding quality, jigs are typically used to precisely stack and position the small components to be welded (7), the frame (6), and the PCB board (or metal substrate), and hold them relatively fixed by clamping mechanisms. They are then fed into heating equipment to complete the welding and solidification process, forming a complete electronic component. It should be noted that solder pads are usually sandwiched between the component to be welded (7) and the PCB board, and between the welding points of the frame (6) and the PCB board. The melting point of these solder pads is much lower than that of the component to be welded and the jig. After the jig and the component to be welded are heated and cooled as a whole, the solder pads undergo a melting and resolidification process, welding the component to be welded (7) to the PCB board and the frame (6) to the PCB board as a single unit.

[0040] Existing welding fixtures typically employ a planar clamping structure where a base 110 and a top cover engage. The base 110 has positioning slots for placing components 7 and the frame 6. The top cover is locked to the base 110 by a latch or screws. The side of the top cover facing the base 110 is typically designed as a flat pressing surface. The vertical pressure generated after the top cover and base 110 are closed presses the sheet metal flat onto the frame 6 and components 7 below. The planar clamping method eliminates gaps between components and ensures the fit of the welding contact surfaces.

[0041] However, in actual production, the plates to be welded often have a certain degree of local warping or deformation due to processing technology, material and structural characteristics, or transportation and storage. The plates targeted in this application are usually slightly arched in the middle. For these plates with initial warping, existing planar clamping fixtures can only provide uniform planar downward pressure and cannot apply concentrated corrective force to the warped parts of the plate. When the warping stress of the plate is large, planar clamping often fails to completely flatten and adhere the plate to the component 7 or frame 6 below, resulting in small gaps at the welding position, which in turn leads to problems such as incomplete welding, false welding, or insufficient welding strength.

[0042] Figure 1 A schematic exploded view of a welding fixture according to an embodiment of this application is shown; Figure 2 A schematic exploded cross-sectional view of a welding fixture according to an embodiment of this application is shown; Figure 3 A schematic structural view of a welding fixture according to an embodiment of this application is shown; Figure 4 A schematic structural diagram of the plate to be welded mentioned in an embodiment of this application is shown.

[0043] Based on this, a preferred embodiment of this application provides a welding fixture for aligning and fixing the component 7 and frame 6 to be welded to the plate 5 to be welded. 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] A locking mechanism 3 is disposed between the upper pressure assembly 2 and the base assembly 1 to provide a continuous and stable locking force after the fixture is closed. The locking mechanism 3 can be a snap-fit, latch, rotary clamping cylinder, or threaded locking component disposed on the edge of the fixture. Its main function is to overcome the elastic restoring force of the plate to be welded 5 itself and the reaction force generated during the straightening process, and to lock the upper pressure assembly 2 tightly onto the base assembly 1, thereby maintaining the pressure applied to the plate by the pressure straightening part 210.

[0048] When using the welding fixture in this embodiment, the operator or automated equipment first needs to open the fixture and sequentially load the component to be welded 7, the welding sheet, the frame 6, and the plate to be welded 5 into the positioning area of ​​the base assembly 1. At this time, if the plate to be welded 5 has warping phenomena such as a slight arch in the middle, the center of the plate may be suspended or not fully attached to the component below. Next, the upper pressure assembly 2 is operated to close towards the base assembly 1. During the closing process, the pressure correction part 210 on the upper pressure assembly 2 first contacts the warping high point (usually the center position) of the plate to be welded 5. Subsequently, the upper pressure assembly 2 and the base assembly 1 are locked using the locking mechanism 3. During this process, the strong mechanical locking force applied by the locking mechanism 3 is converted into vertical pressure on the plate to be welded 5 by the pressure correction part 210. This pressure forces the plate to be welded 5 to overcome its own warping stress, not only flattening it, but also forcibly pressing the part of the plate (i.e., the warped part) into the relief part 130 of the base assembly 1. This process causes the plate 5 to be welded to undergo a preset elastic deformation (i.e., maintained by straightening or flattening). Finally, the locked fixture is sent into the heating equipment. During the high-temperature welding stage, the plate remains in close contact with the lower frame 6 and components 7 under the action of the pressure straightening part 210 until the weld melts and re-solidifies. After cooling, the fixture is unlocked, the stress on the plate is released or solidified, and the welding is completed.

[0049] This welding fixture is suitable for various high-temperature welding environments in the field of precision electronic assembly, including but not limited to reflow ovens, vacuum welding ovens, vapor phase welding equipment, and constant temperature heating tables. The applicable operating temperature range is typically between room temperature and 300 degrees Celsius, which requires the materials of the base assembly 1 and the upper pressure assembly 2 to have excellent heat creep resistance.

[0050] This technical solution is particularly suitable for welding boards that possess a certain degree of rigidity but exhibit initial flatness deviations, such as PCB printed circuit boards, metal substrates (e.g., aluminum and copper substrates), and ceramic substrates. It is especially applicable to boards that naturally exhibit an arched warp with a higher center and lower edges. Furthermore, this fixture is particularly suitable for power device packaging or IGBT module assembly scenarios where extremely high consistency in solder layer thickness is required and voids are unacceptable.

[0051] In practical applications, the forms of the pressure-correcting part 210 and the relief 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 pressure-correcting part 210 can be designed as a long, raised rib, and the relief part 130 can be designed as a long groove accordingly; if the plate has a large area of ​​planar warping, the pressure-correcting part 210 can be designed as an array of raised points, and the relief part 130 can be a series of recesses. Regarding material selection, the pressure-correcting part 210 can be a rigid structure integrally formed with the upper pressure component 2, or it can be an elastomer made of high-temperature resistant rubber or silicone embedded in the upper pressure component 2, so as to increase the protection of the plate surface while providing corrective force. Regarding the locking mechanism 3, in addition to manual locking, magnetic adsorption locking or external pneumatic clamping can also be used, as long as sufficient holding force can be provided to maintain the deformation state of the plate.

[0052] In this embodiment, by employing a pressure-correcting part 210 on the upper pressure component 2 and a clearance part 130 on the base component 1, the locking force of the locking mechanism 3 forces the plate to be welded 5 to partially enter the clearance part 130 to generate a preset elastic deformation. Therefore, this effectively solves the technical problem in the prior art where the simple planar pressing method cannot make the plate to be welded 5 tightly fit with the component to be welded 7 and the frame 6 due to the warping of the plate to be welded itself. This achieves the overcoming of the warping stress of the plate by forced physical deformation, ensuring that the plate and the lower component always maintain a zero-gap fit throughout the welding process, thereby completely eliminating the hidden dangers of false soldering and significantly improving the welding reliability and yield of electronic components.

[0053] Furthermore, to further optimize the correction effect on the warped sheet and protect the sheet surface, specific structural designs were implemented for the pressure-correcting part 210 of the upper pressure assembly 2 and the clearance part 130 of the base assembly 1. Please refer to... Figure 1 The pressure-correcting part 210 is a protruding structure located in the central region of the upper pressure component 2 facing the base component 1, and the protruding structure has a spherical or arc-shaped abutment surface 211; the clearance part 130 is a groove or through hole located in the base component 1 facing the upper pressure component 2, and the size of the groove or through hole is configured to accommodate the portion of the plate to be welded 5 that generates a preset elastic deformation after being pressed, after the upper pressure component 2 and the base component 1 are closed and locked by the locking mechanism 3.

[0054] Specifically, the pressure-correcting part 210 is configured as a protrusion located in the central region of the upper pressure assembly 2 facing the base assembly 1. This protrusion is precision-machined so that its contact surface 220 is a smooth spherical or arc-shaped surface. This protrusion can be integrally formed with the upper pressure assembly 2 or fixed at the center of the upper pressure assembly 2 as a separate insert (e.g., a ball-head pin made of stainless steel or ceramic). The radius of curvature of its spherical surface is designed to be small enough to generate concentrated downward pressure, yet large enough to avoid indentations on the plate surface. Correspondingly, the clearance part 130 is configured as a groove or through-hole on the base assembly 1. This groove or through-hole is located directly below the protrusion, i.e., the two are coaxially aligned in the vertical direction. The opening size (diameter or length and width) of the clearance portion 130 is slightly larger than the projected size of the protrusion structure, and its depth or the design depth of the through hole must meet a key design requirement: after the fixture is closed and locked, the space must be sufficient to accommodate the maximum downward displacement of the plate to be welded 5 after being squeezed by the protrusion structure, i.e. the preset elastic deformation, so as to ensure that the plate will not contact the solid part of the base assembly 1 before being bent to a predetermined degree, thereby avoiding rigid interference.

[0055] When the upper pressure assembly 2 closes downwards, the spherical or arc-shaped tip of the pressure-correcting part 210, being a protruding structure, will first contact the center point of the plate to be welded 5 (usually the highest point of the plate's warping). As the locking mechanism 3 applies locking force, the upper pressure assembly 2 continues to press down, with the protruding structure acting as a force fulcrum, concentrating the pressure on the center of the plate. Because the base assembly 1 has a groove or through hole at the corresponding position, the center of the plate is suspended. Under the strong pressure of the spherical protrusion, the center of the plate is forced to bend downwards and enter the groove or through hole. During this process, the spherical or arc-shaped abutment surface ensures that the force application point of 211 maintains smooth contact with the plate surface at all times. Even if the plate bends at a different angle, the contact point will roll smoothly on the spherical surface, thereby uniformly converting the vertical pressure into the bending moment of the plate, achieving smooth forced deformation.

[0056] As an optional implementation, the height of the protrusion structure can be adjustable. For example, the protrusion structure can be installed on the upper pressure assembly 2 via a threaded connection, and its protrusion height can be finely adjusted by rotation, thereby setting different preset elastic deformation values ​​for plates of different thicknesses or degrees of warping. Furthermore, the shape of the groove or through-hole of the relief portion 130 is not limited to a circle. For rectangular plates, the protrusion structure can be designed as a strip-shaped ridge structure with rounded corners at both ends, and the corresponding relief portion 130 can be designed as a long strip groove to accommodate the correction requirements of the plate along its long axis.

[0057] In this embodiment, by constructing the pressure-correcting part 210 as a protruding structure with a spherical or arc-shaped abutment surface 211 and the clearance part 130 as a groove or through hole of a suitable size, the technical problems of easily scratching the surface of the plate, causing local stress concentration damage, and preventing the plate from reaching the overcorrected state due to the lack of clearance space at the bottom are effectively solved when using a planar or angular structure to forcibly flatten the warped plate in the prior art. Thus, it is possible to apply a deep and controllable elastic bending deformation to the plate while protecting the surface integrity of the plate to be welded 5, and to more thoroughly eliminate the initial warping stress of the plate by utilizing the overcorrection principle, thereby ensuring the welding quality.

[0058] In some embodiments, to protect the fragile components 7 to be soldered while forcibly deforming and correcting the sheet metal, a number of floating support units 4 are specially designed on the base assembly 1. (See also...) Figure 2 The floating support unit 4 is configured to support the component 7 to be welded and has the freedom to float elastically in the direction toward the upper pressure assembly 2; wherein, during the process of the pressure correction part 210 pressing a portion of the plate 5 to be welded into the relief part 130, the side of the plate 5 to be welded facing the base assembly 1 abuts against the floating support unit 4, forcing the floating support unit 4 to sink synchronously, so that the elastic support force of the floating support unit 4 keeps the component 7 to be welded and the plate 5 to be welded in contact.

[0059] These floating support units 4 are distributed around the clearance portion 130 (i.e., the recessed area for accommodating plate deformation) of the base assembly 1, and their positions correspond one-to-one with the coordinate points of the components 7 to be welded on the plate 5. Each floating support unit 4 mainly consists of two parts: an ejector 410 and an elastic element. The ejector 410 is usually constructed as a rigid column or block. The elastic element is disposed between the bottom of the ejector 410 and the base of the base assembly 1. The base assembly 1 has a guide hole for the ejector 410 to slide up and down, and the elastic element is accommodated in the guide hole. The elastic element can be a precision helical spring, a high-temperature resistant elastic rubber column, a wave spring, or a miniature gas spring. In the natural state (i.e., no plate is placed or the fixture is not closed), the elastic element is in an extended or slightly pre-compressed state, lifting the ejector 410 so that the height of the component 7 it supports is slightly higher than the theoretical reference surface height of the plate after correction, thereby giving it elastic floating freedom in the vertical direction (i.e., towards the upward pressure assembly 2).

[0060] When the upper pressure assembly 2 closes downwards, its pressure-correcting part 210 begins to forcefully press against the partial entry clearance part 130 of the plate to be welded 5, causing the plate to bend and deform towards the base assembly 1. As the deformation of the plate increases, the side of the plate facing the base 110 gradually contacts the component 7 to be welded (and the solder pads above it) placed on the floating support unit 4. At this time, since the floating support unit 4 is not rigidly fixed but elastic, the huge corrective force of the plate pressing down will not directly and rigidly act on the component 7. Instead, the pressing action of the plate will force the floating support unit 4 to overcome the resistance of the elastic element and sink synchronously (i.e., retreat). During the sinking process, the elastic element is compressed, generating a reverse elastic restoring force. This elastic restoring force is transmitted to the component 7 through the ejector 410, continuously pressing the component 7 upwards, making it tightly adhere to the welding position on the plate. In short, the deeper the plate is pressed, the more the floating support unit 4 retracts, but the contact pressure between the two is always determined by the characteristics of the elastic element, rather than by the mechanical pressure of the straightening plate.

[0061] As an optional implementation, the stiffness of the elastic element of the floating support unit 4 can be selected or adjusted according to the pressure resistance limit of the component 7. For fragile components 7, a soft spring can be used; for scenarios requiring greater contact force to break the oxide layer, a hard spring can be used. Furthermore, the floating support unit 4 can be not only an independent single ejector pin, but also designed as a group of interconnected floating plates. For example, multiple components 7 can be placed on the same floating plate, which floats as a whole through multiple springs at its bottom to ensure the coplanarity of the components 7 within the area.

[0062] In this embodiment, by employing a floating support unit 4 with elastic floating degrees of freedom on the base assembly 1 and allowing it to sink synchronously during the board straightening process, the technical problem in the prior art that the board warping caused by forced straightening results in a large Z-axis displacement, which rigidly crushes the component 7 to be welded or crushes the solder pad, leading to a short circuit, is effectively solved. This achieves the goal of ensuring that the board is forcefully straightened while absorbing geometric displacement tolerances using a flexible floating mechanism and using elastic support force to ensure stable, undamaged, and tight welding between the component 7 and the board, significantly improving the yield rate.

[0063] Furthermore, the floating support unit 4 includes an ejector 410 and an elastic member, wherein the top end of the ejector 410 is configured to abut against the side of the component 7 to be welded away from the upper pressure assembly 2 when the upper pressure assembly 2 and the base assembly 1 are closed; the elastic member is disposed between the ejector 410 and the base assembly 1 and is configured to apply the elastic support force toward the upper pressure assembly 2 to the ejector 410.

[0064] As the actuator that directly contacts the component 7 to be welded, the ejector 410 is typically machined into a columnar, block-shaped, 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 excellent insulation properties. The top end of the ejector 410 is designed as a bearing surface, configured to physically abut against the bottom surface of the component 7 (i.e., the side away from the upper pressure assembly 2) when the fixture is closed. To prevent the component 7 from sliding horizontally, the top end of the ejector 410 can also be machined with a limiting groove or positioning step according to the shape of the component 7.

[0065] The elastic element is the power source providing floating capability and clamping force. It is disposed between the bottom of the ejector 410 and the solid body of the base assembly 1. Typically, the base assembly 1 has a countersunk hole or guide groove for accommodating the elastic element, which is placed therein. One end of the elastic element is supported at the bottom of the hole in the base assembly 1, and the other end directly abuts against the lower surface of the ejector 410. The elastic element is configured to always apply an elastic supporting force to the ejector 410 in the direction of the pressing assembly 2 (i.e., vertically upward), so that the ejector 410 remains in the extended state when no external force is applied.

[0066] When the upper pressure assembly 2 is not closed, the elastic element is in a pre-compressed or freely extended state. Its released elastic force pushes the ejector 410 upwards, placing it in its highest waiting position. At this time, the operator places the component 7 to be welded on the top of the ejector 410. When the upper pressure assembly 2 closes and locks, forcing the plate 5 to be welded downwards for correction, the lower surface of the plate presses against the component 7, thus transmitting pressure to the ejector 410. At this time, the ejector 410 moves downwards under force, compressing the elastic element below it. The elastic element then undergoes 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, pushing the component 7 upwards towards the plate 5 to be welded, thereby forming a stable clamping pressure between the component 7 and the plate. Regardless of the depth of the plate's downward pressure (within the stroke range), this structure always automatically adjusts the support force through the spring compression to achieve flexible contact.

[0067] In this embodiment, by employing a structure in which the floating support unit 4 is refined into a rigid ejector 410 that cooperates with an elastic element, and by using the elastic element to apply an elastic support force toward the ejector 410 in the direction of the upper pressure assembly 2, the technical problem in the prior art that the use of an integrated rigid support means that the pressure cannot be buffered by yielding when the plate is deformed under pressure, thus crushing the precision component 7, is effectively solved. This achieves the use of the flexible buffering and constant output force characteristics of the elastic element to absorb the displacement tolerance in the Z-axis direction while providing continuous, stable and non-destructive bonding pressure for the component 7 to be welded, ensuring close contact of the welding interface and physical safety of the component 7.

[0068] In some embodiments, to further improve the Z-axis (thickness direction of the clamped plate) precision control capability after the fixture is closed and to ensure precise and controllable correction deformation of the plate, a precision limiting mechanism is introduced between the base assembly 1 and the upper pressure assembly 2. Please refer to... Figures 1 to 2 The upper pressing component 2 has an abutment surface 220 facing the base component 1; the base component 1 also has a positioning bearing module 120 facing the upper pressing component 2, the positioning bearing module 120 has a limiting groove 121 for limiting the horizontal position of the component 7 to be welded; the positioning bearing module 120 has a rigid stop surface 122 that cooperates with the abutment surface 220 facing the upper pressing component 2, the positioning 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 against the abutment surface 220 of the upper pressing component 2 when the locking mechanism 3 is locked, so as to limit the minimum closed height of the upper pressing component 2 relative to the base component 1, so that the depth of the plate 5 to be welded into the relief portion 130 reaches the preset elastic deformation.

[0069] Specifically, the upper pressure component 2 has a precision-machined flat surface, namely the abutment surface 220, on the side facing the base component 1. This abutment surface 220 is usually located at the edge or non-functional area of ​​the upper pressure component 2, serving as a reference for the closed stroke. A positioning and bearing module 120 is installed on the base component 1. This module is usually constructed as a plate-shaped component with a certain thickness and high rigidity, and is fixed to the base component 1 by screws or pins. The positioning and bearing module 120 has two key structural features: a limiting groove 121 and a rigid stop surface 122. The limiting groove 121 has several through holes or grooves on the surface of the module, the shape of which is adapted to the contour of the component 7 to be welded, and is used to strictly limit the movement of the component 7 in the horizontal direction (the plane perpendicular to the thickness direction of the plate in the clamped state) to prevent displacement during the welding process; secondly, the rigid stop surface 122 makes the upper surface of the positioning and bearing module 120 facing the upper pressure component 2 a high-precision flat surface, namely the rigid stop surface 122. Specifically, the positioning support module 120 and the aforementioned floating support unit 4 have a specific spatial relationship: the positioning support module 120 is configured to allow the floating support unit 4 located below it to lift the component 7 to be welded, such that in the natural state where the fixture is not closed, the top 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 limit reference. It should be noted that the clearance portion 130 is usually located on the base 110 described later. In this case, the corresponding position of the positioning support module 120 and the clearance portion 130 needs a through groove (not shown in the figure) for the clearance portion 130 to be exposed. However, in some embodiments, the clearance portion 130 can also be located in the middle position of the positioning support module 120, depending on the specific product structure.

[0070] When the locking mechanism 3 closes the upper pressure assembly 2, the upper pressure assembly 2 first drives the plate to be welded 5 to contact and press against the components 7 protruding from the rigid stop surface 122. As the pressure increases, the floating support unit 4 is compressed and sinks, and the components 7 retract accordingly. When the upper pressure assembly 2 continues to descend until its contact surface 220 makes physical contact with the rigid stop surface 122 of the positioning bearing module 120, the downward stroke of the upper pressure assembly 2 is forcibly terminated. At this time, the detection fixture reaches the designed minimum closing height. Since the height of the rigid stop surface 122 is precisely set in advance, this closing height directly determines the depth to which the center of the plate is pressed into the relief part 130 by the pressure correction part 210. In other words, the rigid stop surface 122 locks the final deformation of the plate, making it accurately reach the preset elastic deformation, no longer affected by the magnitude of the manual locking force. Meanwhile, since component 7 protrudes in its natural state, when the fixture closes to contact the rigid stop surface 122, component 7 will inevitably be pressed back by the plate to a position flush with or slightly lower than the stop surface. This means that the elastic component below will inevitably be in a compressed state, thereby ensuring that component 7 is subjected to a constant elastic clamping force.

[0071] This technical solution is suitable for precision electronic assembly scenarios with extremely high requirements for weld height consistency and board flatness. Especially for components 7 with high pin density and small spacing, even a slight deviation in Z-axis height can lead to poor soldering. This solution requires the material of the positioning and bearing module 120 to possess extremely high hardness and compressive strength (such as hard alloy, stainless steel, or reinforced synthetic stone) to ensure that the rigid stop surface 122 will not collapse or wear under thousands of high-pressure locking impacts, thereby maintaining long-term precision stability.

[0072] 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 several locally protruding limiting posts on the module, to reduce the contact area, increase pressure, and prevent foreign matter from affecting the limiting accuracy. To accommodate weldable plates 5 of different thicknesses or components 7 of different specifications, precision 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 can be finely adjusted, thereby changing the Z-axis coordinate of the rigid stop surface 122, thus adjusting the preset elastic deformation of the plate and the clamping interference of the component 7 without changing the module.

[0073] In this embodiment, by employing a positioning and bearing module 120 with a rigid stop surface 122 on the base assembly 1, and having it cooperate with the abutment surface 220 of the upper pressing assembly 2 to form a hard limit for the closed stroke, and by configuring the component 7 to be welded to protrude from the rigid stop surface 122 in its natural state, the technical problem of the prior art that the final depth of the plate correction cannot be controlled by simply relying on floating support and that the component 7 is subjected to uncontrollable pressure due to fluctuations in locking force is effectively solved. This achieves the precise locking of the minimum closed height of the fixture using the rigid stop surface 122, ensuring that the bending correction amount of the plate 5 to be welded strictly conforms to the preset value, while ensuring that the component 7 obtains a certain elastic fitting force at a constant closed height, thus taking into account both the plate correction accuracy and the protection and safety of the component 7.

[0074] For further information, please refer to [link / reference]. Figure 2 The positioning and bearing module 120 is constructed as a plate structure. The positioning and bearing module 120 has a plurality of clearance holes 123 corresponding to a plurality of floating support units 4. The floating support units 4 are inserted into the corresponding clearance holes 123 and at least part of the floating support units 4 protrudes from the rigid stop surface 122 to support the component 7 to be welded. When the abutting surface 220 of the upper pressing component 2 is in abutting state with the rigid stop surface 122, the floating support unit 4 is in a compressed state. The elastic support force of the floating support unit 4 is used to press the component 7 to be welded against the side of the plate 5 to be welded facing the base component 1.

[0075] The positioning and bearing module 120 is constructed as a plate-like structure (e.g., a positioning cover plate or positioning template) with a certain thickness. This plate-like structure horizontally covers the base assembly 1 and is fixedly connected to the base assembly 1 by bolts or pins. On the plate body of the positioning and bearing module 120, corresponding to the position of each floating support unit 4, a through hole, i.e., a clearance hole 123, is precisely machined through the plate body from top to bottom, and the clearance hole 123 is opened on the bottom surface of the limiting groove 121. The floating support unit 4 (mainly referring to its ejector part 410) is configured to pass through the corresponding clearance hole 123. The inner diameter or inner contour dimension of the clearance hole 123 is slightly larger than the outer diameter or outer contour dimension of the floating support unit 4, and there is a precisely fitted sliding clearance between the two, so that the floating support unit 4 can smoothly move up and down within the clearance hole 123 without jamming or lateral shaking. The key structural feature lies in the height difference design. When the testing fixture is in its unclosed, natural state, the top of the floating support unit 4 passing through the clearance hole 123 (i.e., the surface supporting the component 7 to be welded) is not flush with the upper surface (rigid stop surface 122) of the positioning support module 120, but rather protrudes at least partially above the rigid stop surface 122. This protruding height difference (reserved for floating stroke) is calculated to be slightly greater than or equal to the expected amount of compression of the component 7 to be welded.

[0076] With the fixture in the open state, the floating support unit 4 is pushed upward by the bottom elastic element, its bearing end passing through the clearance hole 123 of the positioning bearing module 120 and exceeding the rigid stop surface 122. The operator places the component 7 to be welded on the protruding floating support unit 4, at which point the component 7 is suspended and above the rigid stop surface 122. Next, the upper pressure component 2 presses down. The plate to be welded 5 first contacts the raised component 7. As the upper pressure component 2 continues to apply pressure, the plate compresses the component 7, causing the floating support unit 4 to overcome elastic resistance and retract downward into the depth of the clearance hole 123. When the contact surface 220 of the upper pressure component 2 finally rigidly contacts the rigid stop surface 122 of the positioning bearing module 120, the upper pressure component 2 stops descending. At this time, the floating support unit 4 is forcibly maintained in a compressed state. In this state, the elastic element at the bottom of the floating support unit 4 accumulates sufficient potential energy, which is converted into an upward elastic support force that passes through the clearance hole 123 and continuously and tightly presses the component 7 to be welded against the side surface of the plate 5 to be welded facing the base assembly 1.

[0077] In some optional implementations, the shape of the clearance hole 123 can be adjusted according to the cross-sectional shape of the floating support unit 4, and can be a circular hole, a square hole, or an oblong hole. To prevent the floating support unit 4 from dislodging from the clearance hole 123 when it is pushed out too high, the lower part of the floating support unit 4 can be designed with a flange edge or a limiting step, and the bottom of the clearance hole 123 of the positioning bearing module 120 can be designed with a corresponding countersunk step. The positioning bearing module 120 itself is used as the upper limit baffle for the upward movement of the floating support unit 4, thereby simplifying the overall structure and eliminating the need to design a separate limiting mechanism deep in the base 110. In addition, the amount of protrusion can be adjusted by replacing the positioning bearing module 120 (plate structure) of different thicknesses to accommodate components 7 of different height specifications.

[0078] In this embodiment, by constructing the positioning and bearing module 120 as a plate-like structure with clearance holes 123 and inserting the floating support unit 4 through it, which protrudes from the rigid stop surface 122 in its natural state, the problem of easy skewness of floating components due to lack of effective guidance and inability to ensure constant bonding force of component 7 under rigid limiting state in the prior art is effectively solved. Thus, the positioning and bearing module 120 is used to perform the dual functions of rigid limiting reference and floating guide support, ensuring that the floating support unit 4 is in a compressed working state when the fixture is closed to the dead point. In this way, the determined elastic support force is used to reliably press the component 7 to be welded onto the back of the plate, ensuring the stability and consistency of welding bonding.

[0079] In some embodiments, please refer to Figure 1 The upper pressure assembly 2 includes an auxiliary pressing surface 230 for pressing against the peripheral area of ​​the plate to be welded 5. The auxiliary pressing surface 230 is disposed on the periphery of the pressing and straightening part 210, and the friction coefficient of the surface of the auxiliary pressing surface 230 is less than the friction coefficient of the surface of the pressing and straightening part 210. This is configured such that during the welding process, the pressing and straightening part 210 forms a fixed anchor point relative to the center of the plate to be welded 5, so that the auxiliary pressing surface 230 allows the peripheral area of ​​the plate to be welded 5 to undergo radial slippage relative to the auxiliary pressing surface 230 when it expands due to heat.

[0080] This embodiment focuses on the surface friction design of the upper pressure assembly 2 in response to the thermal expansion characteristics of the plate. The side of the upper pressure assembly 2 facing the base assembly 1 (i.e., the pressure surface) is functionally divided into two concentric physical regions: a central pressure-correcting part 210 and an auxiliary pressing surface 230 surrounding the periphery. The auxiliary pressing surface 230 corresponds to the edge of the plate 5 to be welded or the frame 6 area, and its surface has undergone a special low-friction treatment.

[0081] Specifically, the auxiliary pressing surface 230 is constructed as a high-gloss 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 layer. In contrast, the surface of the central pressure-correcting portion 210 (i.e., the aforementioned raised structure) is configured to have a higher coefficient of friction. Its surface can retain the natural roughness after machining, or be sandblasted or knurled to form microscopic interlocking textures, or even be inlaid with high-temperature resistant hard rubber or high-friction composite material gaskets. Through this structural design, a key physical characteristic difference is established: the coefficient of friction of the auxiliary pressing surface 230 is significantly lower than that of the pressure-correcting portion 210, thereby creating a differential friction distribution with high resistance at the center and low resistance at the periphery on the same pressure surface of the upper pressure assembly 2.

[0082] When the fixture closes and locks, the pressure-adjusting part 210 presses firmly against the center of the board 5 to be welded with high pressure and friction, fixing it securely and forming a mechanical anchor point. At this time, the center of the board is absolutely stationary relative to the upper pressure assembly 2. Simultaneously, the auxiliary clamping surface 230 presses against the peripheral area of ​​the board. Although there is also vertical clamping force here (limited by rigid limits), the horizontal shear resistance between the board and the auxiliary clamping surface 230 is very small due to the extremely low coefficient of friction. When the fixture enters the reflow oven along with the board and is heated, the coefficient of thermal expansion of the board 5 to be welded (usually a PCB or metal substrate) is typically greater than that of the fixture material, causing the board to elongate. Because the center is anchored, the board cannot move as a whole, but can only expand radially outwards from the center. At this time, the low-friction auxiliary clamping surface 230 allows the peripheral area of ​​the board to overcome the weak frictional resistance and undergo a small amount of radial slippage (i.e., outward creep) relative to the upper pressure assembly 2. This slippage releases the accumulated thermal stress inside the board. When the welding is completed and the plate cools and shrinks, the plate will shrink radially under the action of shrinkage force.

[0083] This technical solution is particularly suitable for soldering large-sized, thin, or multi-material electronic components (such as copper substrates and synthetic stone jigs). In these scenarios, due to the mismatch of coefficients of thermal expansion (CTE), if the jig tightly clamps the board around its perimeter, the board will have nowhere to release its expansion when heated, and will inevitably arch and deform in the direction of least resistance (i.e., above the Z-axis). This will instantly break the solder joints that have not yet solidified.

[0084] In some alternative embodiments, in addition to coatings, material differences can also be used. For example, the pressure-adjusting 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: fine serrations are machined on the surface of the pressure-adjusting part 210 to increase grip, while fine radial guide textures (not mirror-like, but conforming to the sliding direction) are machined on the auxiliary pressing surface 230 to reduce radial flow resistance. Furthermore, the aforementioned rigid limiting design can be used to maintain an extremely small physical gap (e.g., a few micrometers) between the auxiliary pressing surface 230 and the plate, thereby reducing friction to near zero and achieving pure limiting guidance rather than pressing friction.

[0085] In this embodiment, by employing an auxiliary pressing surface 230 with a low coefficient of friction on the periphery of the pressing and straightening part 210 of the upper pressing component 2 and utilizing the high frictional characteristics of the pressing and straightening part 210 as the central anchor point, the technical problem in the prior art that the excessive rigid constraint of the fixture on the periphery of the plate causes the plate to be unable to extend in the horizontal direction when it expands due to welding heat, thus forcing it to undergo Z-axis arching deformation, which in turn leads to shearing damage or detachment of the weld point, is effectively solved. This achieves effective guidance and release of welding thermal stress, ensuring that while the flatness of the plate is corrected, the plate is allowed to freely expand and contract in the horizontal plane, thereby minimizing residual stress and ensuring the structural stability of the weld point during the solidification process.

[0086] In order to precisely control the mechanical behavior of the plate to be welded 5 in the fixture, in particular, a differentiated surface treatment was carried out for the distribution of friction in the horizontal direction. Furthermore, the surface of the pressure straightening 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.

[0087] For the pressure-adjusting section 210 located at the center of the upper pressure assembly 2, its surface is specifically designed as a high-friction area. This can be achieved through physical texture construction or material layer composites. If physical texture is used, an interlaced knurled texture, a fine toothed array, or a roughened surface formed by high-intensity sandblasting is machined onto the metal substrate surface of the pressure-adjusting section 210 to increase surface roughness. If material layer composites are used, a high-temperature resistant, high-friction material layer, such as a hardened silicone rubber pad or a polymer film containing abrasive particles, is coated onto the surface of the pressure-adjusting section 210 through vulcanization bonding or inlay processes. For the auxiliary pressing surface 230 surrounding the pressure-adjusting section 210, its surface is constructed as a low-friction area. Specific implementation methods include extremely fine mechanical polishing and chemical coating. In the mechanical polishing scheme, the auxiliary pressing surface 230 is ground to a mirror finish, eliminating microscopic protrusions and scratches. In the chemical coating scheme, a low-friction coating is uniformly sprayed or deposited on the auxiliary pressing surface 230. The coating material is preferably polytetrafluoroethylene (PTFE), Teflon, molybdenum disulfide dry film, or diamond-like carbon film, which possess self-lubricating properties. This differentiated surface treatment results in two functional zones with significantly different coefficients of friction on the same contact plane of the pressing assembly 2.

[0088] When the fixture closes and the upper pressure component 2 presses against the plate to be welded 5, the central pressure-correcting part 210, with its high-friction texture or high-friction material layer, generates a huge static friction force with the center of the plate. This static friction force is much greater than the outward thrust generated by the thermal expansion of the plate, thus locking the central area of ​​the plate firmly, making it the thermodynamically fixed origin or zero-position anchor point of the entire plate. At the same time, although the peripheral auxiliary pressing surface 230 also contacts the plate and provides a vertical limiting function, its surface is smooth or coated with a lubricating coating, resulting in an extremely low coefficient of friction with the plate. When the fixture enters the high-temperature welding environment and the plate begins to expand radially outward due to heat, the thermal expansion thrust generated at the edge of the plate can easily overcome the weak frictional resistance of the auxiliary pressing surface 230. Therefore, the peripheral area of ​​the plate will smoothly slide outward below the auxiliary pressing surface 230. The entire process is characterized by the plate center remaining stationary while the periphery expands and contracts freely in a radial pattern, naturally releasing thermal stress like breathing.

[0089] This technical solution is specifically designed for reflow soldering processes that undergo drastic temperature changes. Its applicable environment requirements are extremely stringent, particularly for scenarios using fluxes that soften easily at high temperatures. The low-friction coating on the auxiliary clamping surface 230 typically also possesses oleophobic and hydrophobic properties, which not only reduces friction but also prevents vaporized flux from condensing and adhering to the fixture surface, reducing the frequency of fixture cleaning. Furthermore, this solution is particularly suitable for welding large-sized, thin-walled, or heterogeneous sheet metal components composed of materials with different coefficients of thermal expansion. In these cases, the absolute value of thermal expansion is large, and without this friction-relieving mechanism, the sheet metal is highly susceptible to irreversible warping deformation.

[0090] In optional embodiments, the form of the high-friction texture can be adjusted according to the characteristics of the solder mask on the board surface. If the board surface is soft, a blunter wavy texture can be used to prevent puncturing the solder mask; if the board surface is bare copper or a metal substrate, 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. These coatings not only have a low coefficient of friction but also extremely high hardness and stronger wear resistance, making them suitable for high-volume, high-intensity automated production lines.

[0091] In this embodiment, by employing a high-friction texture or material layer on the surface of the pressure-correcting part 210 to increase friction, and by constructing the auxiliary pressing surface 230 as a smooth polished surface or coating it with a low-friction coating to reduce resistance, the technical problem in the prior art that the uneven distribution or excessive overall friction constraint force of the fixture on the surface of the plate causes the plate to be unable to freely extend in the horizontal direction when it expands due to welding heat, thus forcing it to arch or generate destructive internal stress, is effectively solved. This achieves precise control over the thermal expansion behavior of the plate, that is, the center is anchored to maintain positioning accuracy, and the periphery slides radially to release thermal stress, thereby eliminating the hidden dangers of weld point cracking or plate delamination caused by thermal deformation, and greatly improving the reliability of the welding assembly.

[0092] It should be further noted that another significant advantage of the welding fixture in this application lies in the organic combination and deep synergy among the above embodiments, thereby solving the complex process contradictions that cannot be overcome by a single technical means.

[0093] First, the contradiction between accuracy and safety is resolved by combining rigid limiters and floating supports.

[0094] In existing technologies, pursuing Z-axis accuracy usually means using rigid limits, but this can easily damage component 7; while pursuing protection of component 7 usually involves flexible supports, but this can lead to loss of control over Z-axis accuracy. This embodiment creates a quantitative flexible pressing mechanism by combining the rigid stop surface 122 of the positioning bearing module 120 with the floating support unit 4. The rigid stop surface 122 locks the absolute endpoint of the downward movement of the upper pressing component 2, eliminating displacement errors caused by pressure fluctuations; while the floating support unit 4 provides a constant elastic reaction force at this defined endpoint position. This combination allows the fixture to possess both the dimensional accuracy of a rigid fixture and the protective capability of a flexible fixture, achieving the dual effect of accurate pressing without damage, which cannot be achieved by a single method.

[0095] Secondly, based on the synergy of floating support and differential friction, the contradiction between thermal deformation and contact stability is resolved.

[0096] During the welding heating process, the plate undergoes radial thermal expansion and slippage. If the lower support is rigid, the horizontal slippage of the plate will generate shear friction with the fixed component 7, causing component 7 to shift or solder joints to misalign. In this embodiment, the floating support unit 4 not only provides vertical support, but its ejector 410 also has a small mating clearance within the clearance hole 123, allowing it to follow the plate with slight lateral movement or tilting. When the peripheral area of ​​the plate undergoes low-friction slippage under the auxiliary clamping surface 230, the lower floating support unit 4 can utilize its floating characteristics to adhere to the bottom surface of the plate and move slightly with it, thereby ensuring that the relative position of component 7 and the plate remains stationary during the dynamic process of thermal expansion and slippage of the plate, avoiding damage to unsolidified solder joints by dynamic shear forces.

[0097] Finally, the contradiction between thermal stress release and positioning accuracy is resolved by combining rigid limiting and differential friction.

[0098] Typically, a gap is required between the plates to release thermal stress, but this sacrifices positioning accuracy. In one embodiment of this application, a rigid stop surface 122 precisely limits the closing height, ensuring that the contact state between the auxiliary pressing surface 230 and the periphery of the plate is in a delicate critical pressing state—the pressure is just sufficient to limit Z-axis runout, but not enough to cause significant frictional locking. This micro-pressure contact, guaranteed by rigid limiting, perfectly complements the low-friction coating of the auxiliary pressing surface 230, minimizing the thermal expansion sliding resistance around the plate. Without precise height control by rigid limiting, the upper pressing component 2 may cause excessive friction on the auxiliary pressing surface 230, locking the plate, due to overpressure, or cause Z-axis instability due to underpressure. Therefore, rigid limiting is a prerequisite for realizing the differential frictional heat release mechanism; the combination of the two achieves precise thermal stress dissipation at sub-millimeter level.

[0099] In summary, the various technical features of this invention do not exist in isolation, but are interdependent and mutually reinforcing, together constituting a high-performance welding process system that integrates forced straightening, precise height setting, flexible protection, and thermal stress relief.

[0100] In some embodiments, the pressing component 2 has a contour groove 240 adapted to the contour of the plate to be welded 5 on the side facing the base component 1, and the pressing and correcting part 210 is located at the bottom of the contour groove 240; the positioning and bearing module 120 is fixed on the base component 1, and the material hardness of the positioning and bearing module 120 is higher than that of the plate to be welded 5.

[0101] The side of the upper pressure component 2 facing the base component 1 (i.e., the inner side under pressure) is not a completely flat structure, but rather has a recessed contour groove 240. The opening contour shape of this contour groove 240 is adapted to the outer contour shape (length, width, and edge features) of the plate to be welded 5, and its size is slightly larger than the plate contour to form a clearance fit. The pressure correction part 210 (i.e., the aforementioned protruding structure) is not isolated on the plane, but is located at the bottom of the contour groove 240 (i.e., the recessed bottom plane). This means that when the upper pressure component 2 is closed, the sidewall of the contour groove 240 will surround the periphery of the plate to be welded 5, while the pressure correction part 210 at the bottom of the groove will extend and act on the center of the plate. The positioning and bearing module 120 is rigidly fixed to the base component 1 by high-strength bolts or pins, forming an immovable stator structure. In terms of material engineering design, the material hardness of the positioning and bearing module 120 is strictly selected to be higher than the material hardness of the plate to be welded 5. For example, if the plate to be welded 5 is a common epoxy resin fiberglass board or copper substrate, the positioning and bearing module 120 is made of materials with higher hardness, such as quenched stainless steel and titanium alloy.

[0102] When the upper pressure assembly 2 closes downwards, before or simultaneously with the contact of the pressure straightening part 210 with the plate, the edge sidewall of the contour groove 240 first or simultaneously covers the periphery of the plate to be welded 5. If there is a slight initial placement deviation of the plate on the base 110, the guide bevel (chamfer) of the contour groove 240 will push the edge of the plate for coarse positioning or secondary alignment, ensuring that the plate is located on the correct straightening center line. Subsequently, the pressure straightening part 210 presses the plate, and the lower surface of the plate is pressed against the positioning bearing module 120. Since the hardness of the positioning bearing module 120 is significantly higher than that of the plate, the positioning bearing module 120 will not undergo plastic deformation or significant elastic compression under huge locking pressure. Conversely, the plate to be welded 5, which has lower hardness, will undergo adaptive elastic deformation and fit tightly against the reference surface defined by the module. This hardness difference ensures that all deformation occurs on the plate side, rather than the jig side, in order to eliminate warping.

[0103] In specific implementation, the depth of the contour groove 240 should be designed to be less than the sum of the thickness of the plate to be welded 5 and the protrusion height of the pressure correction part 210, so as to ensure that when the upper pressure component 2 is closed to the bottom, the pressure correction part 210 presses down on the plate, and the bottom surface of the contour groove 240 is pressed against the edge of the plate.

[0104] In this embodiment, by employing a contour groove 240 adapted to the profile of the plate in the upper pressure component 2 and placing the pressure correction part 210 at the bottom of the groove, and by setting the hardness of the positioning bearing module 120 material to be higher than that of the plate, the technical problems in the prior art that the plate is prone to lateral movement during the closing process, leading to deviation of the correction point, and that the reference surface wears and collapses after long-term use due to insufficient hardness of the fixture bearing surface, thus affecting the correction accuracy and welding coplanarity, are effectively solved. This achieves automatic centering guidance during the closing process using the contour groove 240, and constructs a long-term stable rigid reference datum using the material hardness difference, ensuring that the deformation correction amount of the plate is accurate, consistent and effective in every welding operation.

[0105] In some embodiments, the base assembly 1 includes a base 110, the positioning and bearing module 120 is disposed on the side of the base 110 facing the upper pressing assembly 2, and the base 110 facing the upper pressing assembly 2 has a plurality of receiving grooves 111 corresponding to each of the clearance holes 123 in a direction away from the upper pressing assembly 2. The elastic members of each floating support unit 4 are respectively disposed in the corresponding receiving 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 ejector 410 away from the component 7 to be welded.

[0106] The core component of the base assembly 1 is a solid base 110 (typically a rectangular plate or block) with a certain thickness. The positioning and bearing module 120 (i.e., the aforementioned plate-like structure) is horizontally mounted on the top surface of the base 110, facing the upper pressure assembly 2, and the two are connected by fasteners to form a stable base assembly. In order to provide the necessary power source and installation space for the floating support unit 4 without increasing the overall thickness of the fixture, the base 110 has a number of receiving slots 111 on the surface facing the upper pressure assembly 2, along the direction away from the upper pressure assembly 2 (i.e., vertically downward). The positions of these receiving slots 111 are precisely arranged, corresponding one-to-one with each clearance hole 123 on the positioning and bearing module 120 in the vertical direction and coaxially aligned.

[0107] Elastic elements (such as coil springs) are respectively placed into corresponding receiving grooves 111. The diameter of the receiving groove 111 is slightly larger than the outer diameter of the elastic element, forming a clearance fit to accommodate the expansion and contraction of the elastic element.

[0108] In terms of assembly, the lower end (one end) of the elastic element directly abuts against the bottom of the receiving groove 111 (i.e., the solid part of the base 110), serving as a fulcrum for applying force; the upper end (the other end) of the elastic element 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). With this structure, the positioning and bearing module 120 covers the base 110 like a cover plate, the ejector 410 of the floating support unit 4 passes through the clearance hole 123 of the positioning and bearing module 120, and its power source (elastic element) is hidden inside the base 110.

[0109] During assembly, each elastic element is first placed into the receiving groove 111 of the base 110, then the ejector 410 is placed on top of the elastic elements, and finally the positioning and bearing module 120 is covered and locked. At this time, the elastic elements are enclosed in a semi-enclosed space formed by the receiving groove 111 and the bottom of the ejector 410. When the fixture operates, the ejector 410 is compressed, causing the elastic elements to undergo elastic deformation within the receiving groove 111. The inner wall of the receiving groove 111 plays a crucial guiding and limiting role, preventing the elastic elements from bending or tilting laterally during compression. When the external force is removed, the elastic elements extend due to the reaction force at the bottom of the receiving groove 111, pushing the ejector 410 back to its original position. This in-groove driving method makes the force transmission path very direct and has good perpendicularity.

[0110] In practical implementation, the receiving groove 111 can be in the form of a blind hole (counter-hole) or a stepped hole. If it is a stepped hole, the smaller diameter portion can be used to accommodate the elastic element, and the larger diameter portion can be used to accommodate the flange edge at the bottom of the ejector 410, thereby achieving the lower limit of the ejector 410 inside the base 110. As an alternative solution for easier maintenance, the receiving groove 111 can also be designed as a through hole penetrating the base 110, with a removable sealing plate installed on the back (bottom) of the base 110. In this way, when it is necessary to replace a fatigued spring or adjust the elastic force, it is not necessary to disassemble the upper positioning bearing module 120 and the ejector 410; simply opening the bottom sealing plate allows for quick replacement of the elastic element from below, improving production line maintenance efficiency.

[0111] In this embodiment, by using a receiving groove 111 on the base 110 and placing the elastic element in the receiving groove 111, the positioning and bearing module 120 covers the base 110 and the two ends of the elastic element abut against the base 110 and the ejector 410 respectively, the technical problems in the prior art, such as easy dust accumulation and jamming due to exposed elastic elements, easy lateral instability, and excessive overall height of the fixture due to stacked installation that cannot adapt to the low furnace space, are effectively solved. This achieves the integration and built-in protection of the elastic power system, and the receiving groove 111 provides physical guidance for the elastic element to prevent lateral bending. At the same time, it significantly reduces the Z-axis height of the fixture, achieving a floating support effect that is compact in structure, stable in operation, and has strong anti-pollution ability.

[0112] The above description is merely illustrative of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not depart from the content of this specification or exceed the scope defined by the claims, all of which should fall within the protection scope of this invention.

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, include: A base assembly, wherein the base assembly is provided with a clearance portion; An upper pressure assembly is controllably opened and closed relative to the base assembly; the upper pressure assembly has a pressure-correcting part on one side facing the base assembly, the position of the pressure-correcting part corresponding to the clearance part; the upper pressure assembly also includes an auxiliary pressing surface for pressing the peripheral area of ​​the plate to be welded, the auxiliary pressing surface is disposed on the periphery of the pressure-correcting part, and the friction coefficient of the surface of the auxiliary pressing surface is less than the friction coefficient of the surface of the pressure-correcting part, so as to configure the pressure-correcting part to form a fixed anchor point relative to the center of the plate to be welded during the welding process, so that the peripheral area of ​​the plate to be welded is allowed to radially slide relative to the auxiliary pressing surface when heated and expanded; A locking mechanism is disposed between the upper pressing assembly and the base assembly to provide a locking force after the upper pressing assembly and the base assembly are closed; A plurality of floating support units are disposed on the base assembly and arranged around the relief portion. The floating support units are configured to support the components to be welded and have the freedom to float elastically in the direction toward the upper pressure assembly. During the process of the pressure correction portion pressing a part of the plate to be welded into the relief portion, the side of the plate to be welded facing the base assembly abuts against the floating support unit, forcing the floating support unit to sink synchronously, so as to keep the components to be welded and the plate to be welded in close contact through the elastic support force of the floating support unit. Wherein, after the upper pressure component and the base component are closed and locked by the locking mechanism, the pressure correction part forces a portion of the plate to be welded into the relief part, causing the plate to be welded to produce a preset elastic deformation.

2. The welding fixture according to claim 1, characterized in that: The pressure-correcting part is a protruding structure located in the central region of the upper pressure component facing the base component, and the protruding structure has a spherical or arc-shaped support surface; The clearance portion is constructed as a groove or through hole provided in the base assembly facing the upper pressure assembly. The size of the groove or through hole is configured such that after the upper pressure assembly and the base assembly are closed and locked by the locking mechanism, it can accommodate the portion of the plate to be welded that generates a preset elastic deformation after being pressed.

3. The welding fixture according to claim 1, characterized in that, The floating support unit includes: An ejector, the top end of which is configured to abut against the side of the component to be welded away from the upper pressure assembly when the upper pressure assembly and the base assembly are closed; An elastic element is disposed between the ejector and the base assembly and configured to apply the elastic support force to the ejector in the direction toward the upper pressure assembly.

4. The welding fixture according to claim 3, characterized in that: The upper pressure component has an abutment surface on the side facing the base component; The base assembly facing the upper pressing assembly is further provided with a positioning and bearing module. The positioning and bearing module is provided with a limiting groove for limiting the horizontal position of the component to be welded. The positioning and bearing module facing the upper pressing assembly is provided with a rigid stop surface that cooperates with the abutment surface. The positioning and bearing module is configured to allow the component to be welded to at least partially protrude from the rigid stop surface. The rigid stop surface is configured to abut against the abutment surface of the upper pressing assembly when the locking mechanism is locked, so as to limit the minimum closed height of the upper pressing assembly relative to the base assembly, so that the depth to which the plate to be welded is pressed into the relief portion reaches the preset elastic deformation.

5. The welding fixture according to claim 4, characterized in that: The positioning and bearing module is constructed as a plate-shaped structure. The positioning and bearing module has several clearance holes corresponding to several floating support units. The floating support units pass through the corresponding clearance holes and at least some of the floating support units protrude from the rigid stop surface to support the components to be welded. When the contact surface of the upper pressing component is in contact with the rigid stop surface, the floating support unit is in a compressed state, and the elastic support force of the floating support unit is used to press the component to be welded against the side of the plate to be welded facing the base component.

6. The welding fixture according to claim 5, characterized in that, The surface of the pressure-correcting part is provided with a high-friction texture or a high-friction material layer; the auxiliary pressing surface is constructed as a smooth polished surface or coated with a low-friction coating.

7. The welding fixture according to claim 4, characterized in that, The upper pressure component has a contour groove on one side facing the base component that matches the contour of the plate to be welded, and the pressure correction part is located at the bottom of the contour groove; the positioning and bearing module is fixed on the base component, and the material hardness of the positioning and bearing module is higher than that of the plate to be welded.

8. The welding fixture according to claim 5, characterized in that, The base assembly includes a base, the positioning and bearing module is disposed on the side of the base facing the upper pressing component, and the base facing the upper pressing component has a plurality of receiving grooves corresponding to each of the clearance holes along the direction away from the upper pressing component. The elastic elements of each floating support unit are respectively disposed in the corresponding receiving grooves, one end of the elastic element abuts against the base, and the other end of the elastic element abuts against the end of the ejector that is away from the component to be welded.

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