An arc measurement gauge and measurement method for a power module metal backplane

Abstract

The application provides a curvature measuring tool and a measuring method for a power module metal base plate. The curvature measuring tool is low in cost, greatly reduces the equipment investment for measuring the curvature of the metal base plate, and reduces the cost. In addition, the curvature measuring tool is simple and convenient to operate, and can improve the curvature measuring efficiency of the metal base plate.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductors and relates to a radian measurement tool and a measurement method for a metal base plate of a power module. Background Art

[0002] As an important component of power electronics systems, power modules are widely used in many fields such as industrial automation, electric vehicles, and photovoltaic energy storage. Among them, power modules that use a flat metal base coated with silicone grease and then bonded to a water channel radiator for indirect heat dissipation are the most widely used.

[0003] During the power module packaging process, the metal base plate (usually a copper plate) will warp due to the stress caused by the mismatch in thermal expansion coefficients between the materials and the high temperature. In order to ensure the flatness of the contact surface between the metal base plate and the heat sink, the metal base plate needs to be pre-bent before packaging to offset the deformation caused by the packaging process.

[0004] Usually, the curvature of the metal base plate in the finished power module after packaging is measured using a profilometer or a 2.5-dimensional image measuring instrument, which is expensive. If the curvature of the metal base plate as raw material is also measured using a profilometer or a 2.5-dimensional image measuring instrument, the equipment investment expenditure is large and the cost is high.

[0005] Therefore, how to provide a measuring tool and method for measuring the curvature of the metal base plate of a power module to reduce equipment investment expenditure and reduce costs has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a measuring tool and method for measuring the curvature of a metal base plate of a power module, so as to solve the problem of high equipment investment in measuring the curvature of a metal base plate in the prior art.

[0007] To achieve the above-mentioned and other related objectives, the present invention provides a radian measurement tool for a metal base plate of a power module, comprising:

[0008] A frame having a first surface and a second surface arranged opposite to each other, wherein the second surface of the frame is provided with a guide rail, and the frame is provided with a through hole penetrating the frame in a direction from the first surface of the frame to the second surface;

[0009] a digital dial indicator having a dial indicator body and a retractable probe connected to each other, wherein the dial indicator body is mounted on the first surface of the frame and extends into the through hole, and the retractable probe protrudes from the second surface of the frame;

[0010] a first slider mounted on the guide rail, the first slider being movable along the guide rail and being fixed on the guide rail, and a first positioning post being provided on a side of the first slider away from the frame;

[0011] a second slider mounted on the guide rail, the second slider being movable along the guide rail and being fixed to the guide rail, a second positioning post being provided on a side of the second slider away from the frame, the first slider and the second slider being separately provided on both sides of the retraction probe;

[0012] a limit frame located below the frame, the limit frame being provided with a groove, the depth of the groove being greater than the thickness of the metal base plate of the power module to be measured, the size of the groove matching that of the metal base plate of the power module, the groove being used to limit the position of the metal base plate of the power module, and the convex surface of the metal base plate of the power module facing the frame;

[0013] In which, the preset position of the limit frame is provided with a first positioning hole, a second positioning hole and a probe through-hole passing through the limit frame, the first positioning column can pass through the first positioning hole and contact the convex surface of the metal base plate of the power module, the second positioning column can pass through the second positioning hole and contact the convex surface of the metal base plate of the power module, the shrinkage probe can pass through the probe through-hole and contact the convex surface of the metal base plate of the power module, and the shrinkage probe can be compressed.

[0014] Optionally, the number of the first positioning holes is multiple, the number of the second positioning holes is multiple, a portion of the first positioning holes and a portion of the second positioning holes are separated and arranged on both sides of the probe perforation in the first direction, and a portion of the first positioning holes and a portion of the second positioning holes are separated and arranged on both sides of the probe perforation in the second direction, wherein the first direction and the second direction are perpendicular to each other.

[0015] Optionally, a support platform is provided on the first surface of the skeleton, and the support platform is used to support and fix the dial indicator body.

[0016] Optionally, a scale is provided on a side surface of the skeleton, and the scale is used to read the displacement positions of the first positioning post and the second positioning post.

[0017] Optionally, one end of the first positioning post away from the first sliding block and one end of the second positioning post away from the second sliding block are both provided with spherical ends.

[0018] Optionally, the diameter of the spherical end is in the range of 1 mm to 4 mm.

[0019] Optionally, a spherical needle is provided at one end of the retraction probe away from the skeleton.

[0020] Optionally, the diameter of the spherical needle is in the range of 1 mm to 4 mm.

[0021] The present invention also provides a method for measuring the curvature of a metal base plate of a power module, comprising the following steps:

[0022] Providing a radian measurement tool for a metal base plate of a power module as described above, fixing a first slider and a second slider to preset positions of a guide rail;

[0023] Calibrate the first positioning post, the second positioning post, and the retraction probe on a calibration platform, wherein after calibration, the bottom end of the first positioning post, the bottom end of the second positioning post, and the bottom end of the retraction probe are located in the same plane;

[0024] Place the metal base plate of the power module to be measured in the groove of the limit frame, align the first positioning post with the first positioning hole at a preset position, align the second positioning post with the second positioning hole at a preset position, wherein the shrink probe and the probe perforation are aligned;

[0025] The movable skeleton moves in a direction toward the metal base plate of the power module, so that the first positioning column and the second positioning column contact the metal base plate of the power module. During the movement of the skeleton, the contraction probe contacts the metal base plate of the power module and is compressed, and the reading of the digital micrometer is recorded.

[0026] Optionally, the flatness of the calibration platform is -0.002 mm to 0.002 mm.

[0027] As described above, in the curvature measuring instrument and measurement method of the power module metal base plate of the present invention, the curvature measuring instrument is low in cost, which greatly reduces the equipment investment expenditure for measuring the curvature of the metal base plate and reduces costs; moreover, the curvature measuring instrument is simple and convenient to operate, which can improve the efficiency of measuring the curvature of the metal base plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Shown is an exploded view of a curvature measuring tool for a metal base plate of a power module according to an embodiment of the present invention.

[0029] Figure 2 Shown is an assembly drawing of the skeleton, the digital dial indicator, the first slider and the second slider in an embodiment of the present invention.

[0030] Figure 3 Shown is a schematic diagram of a skeleton in an embodiment of the present invention.

[0031] Figure 4 Shown is a top view of the limiting frame in an embodiment of the present invention.

[0032] Figure 5A side view of the limiting frame is shown in the embodiment of the present application.

[0033] Figure 6 A top view of the power module metal base plate to be measured is shown in the embodiment of the present application.

[0034] Figure 7 A side view of the power module metal base plate to be measured is shown in the embodiment of the present application.

[0035] Figure 8 A schematic diagram of the contact between the retractable probe and the power module metal base plate is shown in the embodiment of the present application.

[0036] Figure 9 A schematic diagram of the compression of the retractable probe is shown in the embodiment of the present application.

[0037] Figure 10 A schematic diagram of the arc measurement of the power module metal base plate in the second span in the X direction is shown in the embodiment of the present application.

[0038] Figure 11 A schematic diagram of the division of different areas in the probe perforation in the limiting frame is shown in the embodiment of the present application.

[0039] Element number explanation: 1 - skeleton, 100 - guide rail, 101 - through hole, 102 - support table, 103 - scale; 2 - digital dial micrometer, 200 - micrometer body part, 201 - retractable probe; 3 - first sliding block, 300 - first positioning column; 4 - second sliding block, 400 - second positioning column; 5 - limiting frame, 500 - groove, 501 - first positioning hole, 502 - second positioning hole, 503 - probe perforation; 6 - power module metal base plate. DETAILED DESCRIPTION

[0040] The embodiments of the present application will be described in detail by specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure. The present application can also be implemented or applied by other different specific embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application.

[0041] Please refer to Figures 1 to 11 It should be noted that the diagrams provided in the embodiments only schematically illustrate the basic concept of the present application, and the diagrams only show the components related to the present application, not the number, shape and size of the components when actually implemented. The actual implementation of each component may be randomly changed in terms of shape, number and proportion, and the layout pattern of the components may be more complex.

[0042] The embodiments provide an arc measurement gauge for a power module metal base plate, please refer to Figures 1 to 5 The arc measuring tool of the power module metal base plate includes a frame 1, a digital dial gauge 2, a first slider 3, a second slider 4 and a limit frame 5. The frame 1 has a first surface and a second surface arranged opposite to each other. The second surface of the frame 1 is provided with a guide rail 100. In the direction from the first surface of the frame 1 to the second surface, the frame 1 is provided with a through hole 101 passing through the frame 1; the digital dial gauge 2 has a dial gauge body 200 and a shrinkage probe 201 connected to each other. The dial gauge body 200 is installed on the first surface of the frame 1. The first slider 3 is mounted on the guide rail 100, and the first slider 3 can move along the guide rail 100 and can be fixed on the guide rail 100. A first positioning column 300 is provided on the side of the first slider 3 away from the frame 1. The second slider 4 is mounted on the guide rail 100, and the second slider 4 can move along the guide rail 100 and can be fixed on the guide rail 100. The second slider 4 is away from the frame 1. A second positioning column 400 is provided on one side of the frame 1, and the first slider 3 and the second slider 4 are separately provided on both sides of the shrinkage probe 201; the limit frame 5 is located below the frame 1, and a groove 500 is provided in the limit frame 5. The depth of the groove 500 is greater than the thickness of the metal base plate 6 of the power module to be measured, and the size of the groove 500 and the metal base plate 6 of the power module match. The groove 500 is used to limit the metal base plate 6 of the power module, and the convex surface of the metal base plate 6 of the power module faces the frame 1; the limit frame 5 is provided with a first positioning hole 501, a second positioning hole 502 and a probe through-hole 503 penetrating the limit frame 5 at a preset position, the first positioning column 300 can pass through the first positioning hole 501 and contact the convex surface of the metal base plate 6 of the power module, the second positioning column 400 can pass through the second positioning hole 502 and contact the convex surface of the metal base plate 6 of the power module, the shrinkage probe 201 can pass through the probe through-hole 503 and contact the convex surface of the metal base plate 6 of the power module, and the shrinkage probe 201 can be compressed.

[0043] As an example, the skeleton 1 is made of metal with higher strength and higher hardness, which has higher dimensional stability and wear resistance.

[0044] As an example, a support platform 102 is provided on the first surface of the skeleton 1, and the support platform 102 is used to support and fix the micrometer body 200; specifically, a clamping groove is provided in the support platform 102, and a threaded hole passing through the support platform 102 is provided on the side of the support platform 102. The micrometer body 200 is placed in the clamping groove, and the micrometer body 200 is clamped and fixed to the first surface of the skeleton 1 by tightening bolts and cooperating with the threaded holes on the side of the support platform 102.

[0045] As an example, the main body of the skeleton 1, the support platform 102 and the guide rail 100 are integrally formed to improve mechanical strength.

[0046] As an example, a scale 103 is provided on the side of the skeleton 1. The scale 103 is used to read the displacement positions of the first positioning post 300 and the second positioning post 400. The scale 103 can be formed by laser engraving, pasting patterns, or other methods. Specifically, the scale mark at the position corresponding to the retraction probe 201 is 0. The number of scale marks 103 gradually increases in the direction from the retraction probe 201 to the first positioning post 300 and in the direction from the retraction probe 201 to the second positioning post 400. For example, the number of scale marks is 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, and so on.

[0047] As an example, the contraction probe 201 is a spring contraction probe. When the contraction probe 201 contracts, a reading can be taken from the gauge head of the digital micrometer 2 to read the contraction amount of the contraction probe 201 .

[0048] As an example, a spherical needle is provided at the end of the shrinkage probe 201 away from the skeleton 1, that is, a spherical needle is provided at the end of the shrinkage probe 201 that contacts the metal base plate 6 of the power module, so as to avoid scratching the metal base plate 6 of the power module when the shrinkage probe 201 contacts the metal base plate 6 of the power module; specifically, the diameter range of the spherical needle is 1mm~4mm, which is selected according to needs.

[0049] As an example, a threaded hole is provided in the first slider 3, and a thread is provided on the end of the first positioning column 300 facing the first slider 3. The thread of the first positioning column 300 cooperates with the threaded hole in the first slider 3 to install and fix the first positioning column 300 on the first slider 3. When the first slider 3 moves on the guide rail 100, the first positioning column 300 is driven to move; and a threaded through hole is provided in the first slider 3. When the first slider 3 moves to the target position, the first slider 3 is fixed to the guide rail 100 by fastening bolts and cooperating with the threaded through hole in the first slider 3.

[0050] Similarly, a threaded hole is provided in the second slider 4, and a thread is provided on the end of the second positioning column 400 facing the second slider 4. The thread of the second positioning column 400 cooperates with the threaded hole in the second slider 4 to install and fix the second positioning column 400 to the second slider 4. When the second slider 4 moves on the guide rail 100, the second positioning column 400 is driven to move; and a threaded through hole is provided in the second slider 4. When the second slider 4 moves to the target position, the second slider 4 is fixed to the guide rail 100 by fastening bolts and cooperating with the threaded through holes in the second slider 4.

[0051] As an example, after the first positioning column 300 is installed on the first slider 3 and the second positioning column 400 is installed on the second slider 4 , the bottom end of the first positioning column 300 and the bottom end of the second positioning column 400 are in the same plane.

[0052] As an example, the end of the first positioning column 300 away from the first slider 3 and the end of the second positioning column 400 away from the second slider 4 are both provided with spherical ends to prevent the first positioning column 300 and the second positioning column 400 from scratching the power module metal base plate 6 when they come into contact with the power module metal base plate 6.

[0053] As an example, the main bodies of the first positioning column 300 and the second positioning column 400 are made of metal, and the spherical ends of the first positioning column 300 and the second positioning column 400 can be made of ruby, ceramic, white steel, tungsten steel, plastic steel and the like. The diameter of the spherical end can be selected from 1mm to 4mm, depending on the needs.

[0054] As an example, in this embodiment, the number of the first positioning post 300 is one, and the number of the second positioning post 400 is two. The provision of multiple positioning posts is intended to ensure balance and stability during measurement, reducing operational difficulty and measurement errors. In another example, the number of the first positioning post 300 and the number of the second positioning post 400 can be one, or the total number of the first positioning post 300 and the second positioning post 400 can be greater than three, that is, the total number of the first positioning post 300 and the second positioning post 400 can be selected from 2 to 6, depending on the needs.

[0055] As an example, the material of the limit frame 5 can be metal, ceramic or bakelite. In this embodiment, the material of the limit frame 5 is bakelite to avoid scratching the power module metal base plate 6 when limiting the power module metal base plate 6.

[0056] As an example, the sizes of the groove 500 and the power module metal base plate 6 match, that is, after the power module metal base plate 6 is placed in the groove 500 , the center of the power module metal base plate 6 corresponds to the center of the groove 500 .

[0057] As an example, the number of the first positioning holes 501 is multiple, and the number of the second positioning holes 502 is multiple. A portion of the first positioning holes 501 and a portion of the second positioning holes 502 are separated in a first direction on both sides of the probe through-hole 503 for measuring the curvature of the power module metal base plate 6 in the first direction; a portion of the first positioning holes 501 and a portion of the second positioning holes 502 are separated in a second direction on both sides of the probe through-hole 503 for measuring the curvature of the power module metal base plate 6 in the second direction, wherein the first direction and the second direction are perpendicular. Specifically, in this embodiment, the first direction is the X direction, and the second direction is the Y direction.

[0058] As an example, the size of the first positioning hole 501 is slightly larger than the size of the first positioning column 300 to ensure that the first positioning column 300 can pass through the first positioning hole 501 and the gap between the two is small; specifically, in this embodiment, the first positioning hole 501 is a circular hole, the body of the first positioning column 300 is a truncated cone, and the diameter of the first positioning hole 501 is 0.5 mm larger than the maximum diameter of the first positioning column 300.

[0059] Similarly, the size of the second positioning hole 502 is slightly larger than the size of the second positioning column 400 to ensure that the second positioning column 400 can pass through the second positioning hole 502 with a small gap between the two; specifically, in this embodiment, the second positioning hole 502 is a circular hole, the body of the second positioning column 400 is a frustum, and the diameter of the second positioning hole 502 is 0.5 mm larger than the maximum diameter of the second positioning column 400.

[0060] As an example, see Figure 6 and Figure 7 In this embodiment, the arc of one position is measured in the X direction, with a span of L and an arc value of h; the arc of three positions is measured in the Y direction, with spans of W1, W2, and W3 respectively. Figure 4In the limit frame 5, a group of the first positioning holes 501 and the second positioning holes 502 are set in the X direction, and the spacing between the first positioning holes 501 and the second positioning holes 502 in the X direction is L. Three groups of the first positioning holes 501 and the second positioning holes 502 are set in the Y direction, and the spacing between the three groups of the first positioning holes 501 and the second positioning holes 502 in the Y direction are W1, W2, and W3 respectively, wherein the first positioning holes 501 and the second positioning holes 502 are located at the end positions of the corresponding span in the corresponding test position.

[0061] As an example, a method for measuring the radian of a metal base plate of a power module using the radian measuring tool described above includes the following steps:

[0062] S1: Fixing the first slider 3 and the second slider 4 to the preset positions of the guide rail 100;

[0063] S2: Calibrate the first positioning post 300 , the second positioning post 400 , and the retraction probe 201 on a calibration platform, wherein after calibration, the bottom ends of the first positioning post 300 , the second positioning post 400 , and the retraction probe 201 are located in the same plane;

[0064] S3: placing the power module metal base plate 6 to be measured in the groove 500 of the limiting frame 5, aligning the first positioning column 300 with the first positioning hole 501 at a preset position, aligning the second positioning column 400 with the second positioning hole 502 at a preset position, wherein the retracted probe 201 is aligned with the probe through-hole 503;

[0065] S4: Move the skeleton 1 in the direction toward the metal base plate 6 of the power module so that the first positioning column 300 and the second positioning column 400 are in contact with the metal base plate 6 of the power module. During the movement of the skeleton 1, the contraction probe 201 is in contact with the metal base plate 6 of the power module and the contraction probe 201 is compressed, and the reading of the digital micrometer is recorded.

[0066] As an example, in step S1, for example, when measuring an arc with a span of L (L is 110 mm) in the X direction, the first slider 3 is moved and fixed when the first positioning post 300 corresponds to a scale of 5.5 cm. The second slider 4 is moved and fixed when the second positioning post 400 corresponds to a scale of 5.5 cm.

[0067] As an example, in step S2 , the flatness of the calibration platform is -0.002 mm to 0.002 mm to ensure that the bottom ends of the first positioning post 300 , the second positioning post 400 and the shrinkage probe 201 are located in the same plane after calibration.

[0068] As an example, Figure 8 As shown, since the power module metal base plate 6 has an arc, during the process of moving the skeleton 1, the shrinking probe 201 will first contact the power module metal base plate 6, and then, as shown in FIG. Figure 9 As shown, the skeleton 1 continues to move, and the shrinkage probe 201 is compressed. When the first positioning column 300 and the second positioning column 400 contact the power module metal base plate 6, the shrinkage probe 201 stops being compressed. The compression amount of the shrinkage probe 201 is the radian value h of the span L in the X direction.

[0069] Similarly, when measuring the arc in the Y direction, for example, measuring the arc with a measuring distance of W1, move the first slider 3 so that the first positioning column 300 corresponds to the scale of W1 / 2, and move the second slider 4 so that the second positioning column 400 corresponds to the scale of W1 / 2; then calibrate on the calibration platform; then align the first positioning column 300 with the first positioning hole 501 at the corresponding position, and align the second positioning column 400 with the second positioning hole 502 at the corresponding position; finally, move the skeleton 1 to drive the first positioning column 300, the second positioning column 400 and the shrinkage probe 201 to move for measurement.

[0070] As an example, Figure 7 Only the arc measurement of the span L in the X direction is shown. In another example, in order to prevent the power module metal base plate 6 from being stamped into an "M" shape, as shown in FIG. Figure 10 As shown, another arc measurement of span L1 can be performed in the X direction, where L1 is smaller than L; correspondingly, as shown Figure 11 As shown, the probe through-hole 503 is divided into a plurality of regions, and the first positioning hole 501 and the second positioning hole 502 are provided at the bridge portion of adjacent regions to measure the arc value h1 of the span L1.

[0071] As an example, for the power module metal base plate 6 of different specifications, the arc measurement of different spans can be performed as required, without being limited to this embodiment, wherein, in the limit frame 5, the positions of the first positioning hole 501 and the second positioning hole 502 are set according to the end point positions of the span.

[0072] As an example, the curvature measuring instrument for the metal base plate of the power module of this embodiment has a low cost, which is 1 / 150 or less of the cost of a profilometer or a 2.5-dimensional image measuring instrument, greatly reducing the equipment investment expenditure for measuring the curvature of the metal base plate and reducing costs; because of its low cost, more inspection personnel or workstations can be equipped with the curvature measuring instrument for the metal base plate of the power module, which can enhance product quality control.

[0073] As an example, the curvature measuring tool for the metal base plate of the power module of this embodiment is simple and convenient to operate, and can improve the efficiency of measuring the curvature of the metal base plate.

[0074] As an example, for the measurement of metal base plates of power modules of different sizes or curvatures at different positions, it is only necessary to change the structure of the limit frame 5. There is no need to change the structure of the skeleton 1, the digital micrometer 2, the first slider 3 and the second slider 4, which can also reduce costs.

[0075] In summary, the curvature measuring tool and method for measuring the curvature of a power module's metal baseplate of the present invention offer low-cost advantages, significantly reducing equipment investment and costs. Furthermore, the tool is simple and convenient to operate, improving the efficiency of curvature measurement. Therefore, the present invention effectively overcomes the shortcomings of existing technologies and possesses high industrial value.

[0076] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A measuring tool for measuring the curvature of a metal base plate of a power module, characterized in that: include: A frame having a first surface and a second surface arranged opposite to each other, wherein the second surface of the frame is provided with a guide rail, and the frame is provided with a through hole penetrating the frame in a direction from the first surface of the frame to the second surface; a digital dial indicator having a dial indicator body and a retractable probe connected to each other, wherein the dial indicator body is mounted on the first surface of the frame and extends into the through hole, and the retractable probe protrudes from the second surface of the frame; a first slider mounted on the guide rail, the first slider being movable along the guide rail and being fixed on the guide rail, and a first positioning post being provided on a side of the first slider away from the frame; a second slider mounted on the guide rail, the second slider being movable along the guide rail and being fixed to the guide rail, a second positioning post being provided on a side of the second slider away from the frame, the first slider and the second slider being separately provided on both sides of the retraction probe; a limit frame located below the frame, the limit frame being provided with a groove, the depth of the groove being greater than the thickness of the metal base plate of the power module to be measured, the size of the groove matching that of the metal base plate of the power module, the groove being used to limit the position of the metal base plate of the power module, and the convex surface of the metal base plate of the power module facing the frame; In which, the preset position of the limit frame is provided with a first positioning hole, a second positioning hole and a probe through-hole passing through the limit frame, the first positioning column can pass through the first positioning hole and contact the convex surface of the metal base plate of the power module, the second positioning column can pass through the second positioning hole and contact the convex surface of the metal base plate of the power module, the shrinkage probe can pass through the probe through-hole and contact the convex surface of the metal base plate of the power module, and the shrinkage probe can be compressed.

2. The arc measuring tool for the metal base plate of a power module according to claim 1, characterized in that: There are multiple first positioning holes, and there are multiple second positioning holes. Some of the first positioning holes and some of the second positioning holes are separated and arranged on both sides of the probe through-hole in the first direction, and some of the first positioning holes and some of the second positioning holes are separated and arranged on both sides of the probe through-hole in the second direction, wherein the first direction and the second direction are perpendicular to each other.

3. The arc measuring tool for the metal base plate of a power module according to claim 1, characterized in that: A support platform is provided on the first surface of the frame, and the support platform is used to support and fix the dial indicator body.

4. The arc measuring tool for the metal base plate of a power module according to claim 1, characterized in that: A scale is provided on the side of the skeleton, and the scale is used to read the displacement positions of the first positioning post and the second positioning post.

5. The arc measuring tool for the metal base plate of a power module according to claim 1, characterized in that: A spherical end is provided on one end of the first positioning post away from the first sliding block and on one end of the second positioning post away from the second sliding block.

6. The arc measuring tool for the metal base plate of a power module according to claim 5, characterized in that: The diameter of the spherical end is in the range of 1 mm to 4 mm.

7. The arc measuring tool for the metal base plate of a power module according to claim 1, characterized in that: The end of the retraction probe away from the frame is provided with a spherical needle.

8. The arc measuring tool for the metal base plate of a power module according to claim 7, characterized in that: The diameter of the spherical needle is in the range of 1 mm to 4 mm.

9. A method for measuring the curvature of a metal base plate of a power module, characterized in that: The following steps are involved: A curvature measuring tool for a metal base plate of a power module according to any one of claims 1 to 8 is provided, wherein the first slider and the second slider are fixed to preset positions of the guide rail; Calibrate the first positioning post, the second positioning post, and the retraction probe on a calibration platform, wherein after calibration, the bottom end of the first positioning post, the bottom end of the second positioning post, and the bottom end of the retraction probe are located in the same plane; Place the metal base plate of the power module to be measured in the groove of the limit frame, align the first positioning post with the first positioning hole at a preset position, align the second positioning post with the second positioning hole at a preset position, wherein the shrink probe and the probe perforation are aligned; The movable skeleton moves in a direction toward the metal base plate of the power module, so that the first positioning column and the second positioning column contact the metal base plate of the power module. During the movement of the skeleton, the contraction probe contacts the metal base plate of the power module and is compressed, and the reading of the digital micrometer is recorded.

10. The method for measuring the curvature of a metal base plate of a power module according to claim 9, wherein: The flatness of the calibration platform is -0.002mm~0.002mm.

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