Mim special-shaped product multi-dimension synchronous inspection jig

Abstract

The application discloses a kind of MIM special-shaped product multidimensional synchronous inspection fixture, for the defects of unstable scattered inspection data, relative position degree is difficult to verify, low efficiency of existing MIM special-shaped product, the fixture includes the jig main body of Cr12MoV die steel integrated forming, main body is equipped with the positioning cavity compatible with product, cavity bottom is equipped with reference plane of quenching and hardening, main body can be detachably installed with TiN coating insert needle assembly, positioning cavity inner wall is equipped with guide sliding slot, also be equipped with scale mark and limit boss with 0.01mm division value;When using, product enters cavity and adheres to reference surface, insert needle passes through shaft hole, and can be synchronously inspected along sliding slot sliding tongue thickness, left and right sliding tongue position degree, shaft hole coaxiality and relative position degree of shaft hole and sliding tongue;It does not need precision equipment, and multiple dimensions are inspected by once clamping, improve precision and efficiency, insert needle can be detachably adapted to multiple specifications products, and be suitable for MIM special-shaped product batch full inspection.

Description

Technical Field

[0001] This utility model relates to the field of product dimensional accuracy inspection technology in the metal injection molding (MIM) industry, specifically to a multi-dimensional synchronous inspection fixture for MIM irregular products. For MIM irregular products with complex structures and many assembly-related parameters, it can realize the synchronous inspection of sliding tongue thickness, left and right sliding tongue position, shaft hole coaxiality, and shaft hole and sliding tongue relative position. It is suitable for 100% full inspection scenarios after mass production of MIM products, and is especially suitable for the inspection of high-precision irregular parts with strict assembly function requirements. Background Technology

[0002] Metal injection molding (MIM) technology is widely used in the automotive, electronics, and medical device industries because it can achieve near-net-shape forming of complex structural parts. Among them, the assembly function of MIM irregular products with shaft holes and sliding tongues (such as precision transmission components and connector parts) directly depends on the accuracy of multiple parameters: on the one hand, the shaft hole must ensure coaxiality to ensure smooth assembly of the shaft; on the other hand, the thickness and left-right position of the sliding tongue must be precisely matched with the assembly mating parts, and the relative position of the shaft hole and the sliding tongue must strictly conform to the drawing requirements, otherwise it will lead to assembly jamming and functional failure.

[0003] Current MIM (Mechanical Manufacturing) industry practices for inspecting irregularly shaped products using a "decentralized equipment-assisted inspection" approach. This involves individually measuring parameters such as the thickness of the sliding tongue, the diameter of the shaft hole, and the position of the sliding tongue using customized, simple auxiliary fixtures in conjunction with equipment like Keyence image measuring instruments and coordinate measuring machines. This approach suffers from the following core flaws: 1. Poor data stability: During repeated clamping and multiple measurements, the superposition of human operation errors (such as product positioning deviation and measurement angle offset) and equipment calibration deviations leads to large fluctuations in the results of multiple measurements of the same parameter, making it difficult to guarantee data reliability. 2. Lack of relative positional accuracy inspection: Individual measurement can only obtain the absolute size of a single parameter, which cannot simulate the relationship between various structures in the actual assembly scenario (such as the relative position of the shaft hole and the sliding tongue). Even if a single parameter is qualified, assembly failure may still occur due to relative positional deviation. 3. Low inspection efficiency: A single device can only test 1-2 parameters at a time. For mass-produced products, full inspection requires a large investment of equipment and manpower, and the inspection cycle is long, which cannot match the high-efficiency output rhythm of the MIM production line. 4. High operational threshold: It requires professional personnel to operate precision measuring equipment and to perform post-calculation and analysis on the measurement data, making it unsuitable for rapid on-site inspection on the production line.

[0004] To address the aforementioned issues, the industry urgently needs an integrated fixture that does not rely on complex equipment, can simultaneously inspect multi-dimensional assembly-related parameters, and is easy to operate, in order to overcome the limitations of existing decentralized inspection solutions and ensure the assembly function qualification rate of MIM irregular products. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of existing MIM (Mechanical Manufacturing) irregular product inspection solutions, such as "unstable data, difficulty in verifying relative position, and low efficiency," and to provide a multi-dimensional synchronous inspection fixture for MIM irregular products: through integrated design, positioning, guidance, and synchronous inspection functions are integrated to simulate the actual product assembly process, realize one-time clamping and synchronous inspection of the thickness of the sliding tongue, the position of the left and right sliding tongues, the coaxiality of the shaft hole, and the relative position of the shaft hole and the sliding tongue, while improving inspection accuracy and efficiency, reducing the operation threshold, and meeting the needs of batch full inspection.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a multi-dimensional synchronous inspection fixture for MIM irregular-shaped products, comprising a fixture body, wherein the fixture body is provided with a positioning cavity adapted to the shape of the MIM irregular-shaped product, and a reference plane is provided at the bottom of the positioning cavity, the reference plane being used to fit and position the product against the reference surface to be inspected; a pin insertion assembly is detachably installed on the fixture body, the axis of the pin insertion assembly is perpendicular to the reference plane, and the outer diameter of the pin insertion assembly is adapted to the designed inner diameter of the product shaft hole, for passing through the product shaft hole to achieve shaft hole positioning; the inner sidewall of the positioning cavity is provided with a guide structure, the guide structure extending in a direction parallel to the reference plane, for guiding the product to slide along the guide structure to simulate the assembly process.

[0007] In a preferred embodiment, the pin assembly includes a positioning pin and a locking member. The fixture body has a pin mounting hole, the positioning pin passes through the pin mounting hole, the locking member is threadedly connected to the fixture body and abuts against the positioning pin, and the coaxiality tolerance of the positioning pin is ≤0.005mm.

[0008] In a preferred embodiment, the guide structure consists of two guide grooves symmetrically arranged on the inner sidewall of the positioning cavity. The groove width tolerance of the guide groove is ±0.002mm, and the straightness tolerance of the groove wall is ≤0.003mm.

[0009] In a preferred embodiment, the reference plane is hardened by quenching, with a surface hardness ≥ HRC50 and a surface roughness Ra ≤ 0.8 μm.

[0010] In a preferred embodiment, the main body of the fixture is integrally formed from Cr12MoV mold steel, and the inner wall of the positioning cavity is provided with a polished layer.

[0011] In a preferred embodiment, the fixture body is provided with scale markings along the extension direction of the guide structure, and the scale markings have a graduation value of 0.01mm, which are used to visually display the product sliding stroke and the position deviation of the sliding tongue; the two ends of the positioning cavity are provided with limiting bosses, which are used to limit the extreme position of the product sliding.

[0012] In a preferred embodiment, the fitting clearance between the pin assembly and the product shaft hole is 0.002-0.008 mm, and the surface of the positioning pin is provided with a TiN coating with a coating thickness of 3-5 μm.

[0013] Due to the application of the above technical solution, the beneficial effects of this application compared with the prior art are as follows: 1. Synchronous inspection to solve the problem of relative position accuracy: Through integrated positioning and guiding functions, the actual assembly sliding process is simulated, and the thickness of the sliding tongue, the position accuracy of the left and right sliding tongues, the coaxiality of the shaft hole and the relative position accuracy of the shaft hole and the sliding tongue are inspected at one time. This avoids the defect that individual measurements cannot verify the related parameters and ensures that the product assembly function is qualified.

[0014] 2. High precision and data stability: The main body of the fixture is integrally formed from Cr12MoV steel. The reference plane is quenched and precision ground. The coaxiality tolerance of the pin assembly is ≤0.005mm, and the guide groove width tolerance is ±0.002mm. The precision of all key structures is controllable, which greatly reduces human error. The fluctuation range of measurement data is ≤0.003mm, which is far superior to the existing decentralized inspection scheme.

[0015] 3. Convenient operation and significantly improved efficiency: No need to rely on precision equipment such as Keyence or coordinate measuring machines. Inspection can be completed in just three steps: "place-slide-observe". The inspection time for a single piece is reduced from 3-5 minutes in the existing solution to 10-15 seconds, improving efficiency by 12-30 times, and is suitable for batch full inspection needs.

[0016] 4. High versatility and reduced costs: The pin assembly adopts a detachable design. By replacing the positioning pins of different sizes, it can be adapted to MIM irregular products with different shaft hole specifications in the same series. There is no need to customize fixtures for each product, which greatly reduces the fixture development cost.

[0017] 5. Good durability and low maintenance cost: The surface hardness of the fixture body is ≥HRC50, and the positioning pins are coated with TiN. After long-term use (≥50,000 inspections), there is no obvious wear or deformation, which reduces the frequency of fixture replacement and lowers maintenance costs. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Appendix Figure 1 This is a structural schematic diagram of the multi-dimensional synchronous inspection fixture for MIM irregular-shaped products of this utility model; Appendix Figure 2 An exploded view of the MIM irregular-shaped product multi-dimensional synchronous inspection fixture of this utility model; The components include: 1. Fixture body; 2. Positioning cavity; 3. Reference plane; 4. Pin assembly; 5. Guide structure; 6. Positioning pin; 7. Pin mounting hole; 8. Guide groove; 9. Irregularly shaped product. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the present invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0023] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this utility model according to the specific circumstances.

[0024] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linked," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] Example 1 Appendix Figure 1 and 2 The technical solution of the multi-dimensional synchronous inspection fixture for irregularly shaped MIM products described in this utility model is as follows: I. Overall Structural Composition The fixture mainly includes the fixture body 1, the reference positioning structure, the pin assembly 4, and the guide structure 5. It also includes auxiliary function scale markings and limit bosses. The various structures work together to achieve multi-dimensional synchronous inspection. The specific structure and parameters are as follows: (1) Jig body 1 Materials and forming methods: Cr12MoV mold steel is used for one-piece forming (such as precision machining by CNC milling or wire cutting). Cr12MoV steel has high hardness, high wear resistance and good dimensional stability, which can avoid inspection errors caused by fixture deformation after long-term use. Core structure: The top of the fixture body 1 has a positioning cavity 2 that is 1:1 adapted to the outer contour of the MIM irregular product 9 to be inspected. The inner wall shape and depth of the positioning cavity 2 strictly match the outer contour dimensions of the product (if the product has an arc surface or stepped structure, the inner wall of the positioning cavity 2 is set with a matching arc segment or stepped surface to ensure that there is no radial movement after the product is placed in, providing a stable positioning basis for subsequent inspection. Surface treatment: The inner wall of the positioning cavity 2 is polished to form a polished layer with a surface roughness Ra≤0.4μm, which reduces the frictional resistance when the product slides, avoids scratching the product surface, and ensures the smoothness of the sliding process.

[0027] (2) Reference positioning structure Position and function: The reference positioning structure is a reference plane 3 opened at the bottom of the positioning cavity 2. This plane is completely in contact with the reference surface to be inspected on the bottom of the product. It serves as the reference for the entire inspection process, ensuring that all parameter inspections are based on the same reference and avoiding inspection errors caused by reference deviation. Precision and performance parameters: The reference plane 3 is precision machined by "quenching + grinding" - firstly, the surface hardness is made to reach ≥HRC50 through overall quenching to ensure that it will not deform during long-term use; then, precision grinding is carried out to ensure that the flatness tolerance is ≤0.003mm and the surface roughness Ra is ≤0.8μm, ensuring a tight fit with the product reference plane (fitting gap ≤0.002mm).

[0028] (3) Pin assembly 4 Structural components: including positioning pin 6 and locking component, wherein positioning pin 6 is cylindrical and locking component is an internal hexagon set screw; Installation method: A pin mounting hole 7 is provided on the top of the fixture body 1 at the position corresponding to the product shaft hole (the hole diameter is clearance-fitted with the outer diameter of the positioning pin 6, with a fit clearance of 0.001-0.003mm). The positioning pin 6 is inserted into the pin mounting hole 7, and the axis of the pin mounting hole 7 is strictly perpendicular to the reference plane 3 (perpendicularity tolerance ≤0.002mm). The locking member is screwed in through the threaded hole (connected to the pin mounting hole 7) opened on the side wall of the fixture body 1, and its end abuts against the side wall of the positioning pin 6, realizing the detachable fixation of the positioning pin 6. When inspecting products with different shaft hole sizes, the locking member can be loosened to replace the appropriate positioning pin 6, improving the versatility of the fixture. Key parameters: The coaxiality tolerance of the positioning pin 6 is ≤0.005mm to ensure no offset of its own axis; the clearance between its outer diameter and the designed inner diameter of the product shaft hole is 0.002-0.008mm (e.g., when the designed inner diameter of the product shaft hole is φ5mm, the outer diameter of the positioning pin 6 is φ4.995-φ4.998mm), which ensures that the positioning pin 6 can smoothly pass into the shaft hole, and also allows for a direct judgment of the coaxiality of the shaft hole through the tightness of the fit (if the coaxiality of the shaft hole is not up to standard, the positioning pin 6 will jam or have excessive clearance on one side when it is inserted). Surface strengthening: The outer surface of the positioning pin 6 is coated with TiN by physical vapor deposition (PVD) process. The coating thickness is 3-5μm. The TiN coating has the characteristics of high hardness (HV≥2000) and low coefficient of friction, which can extend the service life of the positioning pin 6 and reduce frictional damage with the product shaft hole.

[0029] (4) Guide structure 5 Structural form: Two guide grooves 8 are symmetrically arranged on the inner side wall of the positioning cavity 2. The extension direction of the guide grooves 8 is completely consistent with the sliding direction during actual product assembly (e.g., if the product slides horizontally during assembly, the guide grooves 8 extend horizontally). Precision parameters: The groove width tolerance of guide groove 8 is ±0.002mm (if the product tongue design thickness is 2mm, the groove width of guide groove 8 is 2±0.002mm), and the straightness tolerance of the groove wall is ≤0.003mm (within every 100mm length); the groove depth is adapted to the extension height of the product tongue to ensure that the tongue is fully embedded in the groove, and the fit clearance between the inner wall of the groove and the side of the tongue is ≤0.003mm; Function: After the product is placed in the positioning cavity 2, the sliding tongue is embedded in the guide groove 8. When the product is slid, the guide groove 8 restricts the radial displacement of the product and guides the product to slide smoothly along a fixed trajectory, simulating the motion state in the actual assembly process. At the same time, the thickness of the sliding tongue and the left and right position are judged by the fit gap between the groove and the sliding tongue (if the thickness of the sliding tongue is out of tolerance, the groove will be stuck or the gap will be too large; if the left and right position is out of tolerance, the sliding tongue will stick to the groove wall on one side).

[0030] (5) Auxiliary structure Scale markings: The scale markings are engraved on the top surface of the fixture body 1 along the extension direction of the guide groove 8. The scale markings have a graduation value of 0.01mm, and the zero scale line is aligned with the reference edge of the reference plane 3. When the product slides, the sliding stroke of the product can be read intuitively by the corresponding position of the product edge and the scale markings, and the position deviation of the sliding tongue can be judged at the same time (for example, if the product sliding tongue should correspond to the scale "10.00mm", but actually corresponds to "10.05mm", then the position deviation is 0.05mm). Limiting boss: It is a raised structure integrally formed at both ends of the positioning cavity 2. The height of the boss is 30.5-1mm higher than the reference plane, and the inner side wall of the boss is adapted to the end face of the product's sliding limit position. Its function is to limit the maximum stroke of the product's sliding, avoid excessive sliding and damage to the product or fixture, and at the same time provide a clear positioning reference for the product's sliding end point.

[0031] II. Testing Principle When using it, follow these steps to perform multi-dimensional simultaneous verification: 1. Pin assembly: Select a suitable positioning pin 6 according to the shaft hole size of the product to be inspected, insert it into the pin mounting hole 7 of the fixture body 1, and fix it with locking parts; 2. Product positioning: Place the product into the positioning cavity 2, so that the bottom reference surface of the product is in close contact with the reference plane 3 at the bottom of the positioning cavity 2, and at the same time insert the positioning pin 6 into the shaft hole of the product; 3. Simulated sliding test: Push the product along the extension direction of guide groove 8 and observe and judge the following states: The fit between the product and the reference plane 3: If there is no warping or loosening during the sliding process, it means that the flatness of the product reference plane is qualified. The fit between the positioning pin 6 and the shaft hole: If the sliding is smooth and there is no jamming, it means that the coaxiality of the shaft hole is qualified; The fit between the product and the guide groove 8: If there is no jamming or obvious gap during sliding, it indicates that the thickness of the sliding tongue and the position of the left and right sliding tongues are qualified. Correspondence between product edge and scale mark: If the deviation between the product edge and scale mark at the sliding endpoint is within the allowable range of the drawing, it indicates that the relative position of the shaft hole and the sliding tongue is qualified. 4. Result judgment: If all the above states meet the requirements, the product's multi-dimensional parameters are qualified; if any state is abnormal, the corresponding parameter is unqualified.

[0032] Example 2 To enable those skilled in the art to more clearly understand the technical solution of the multi-dimensional synchronous inspection fixture for MIM irregular-shaped products described in this utility model, the following is a detailed description: (I) Parameter settings for the implementation example Taking a certain MIM irregular-shaped product 9 (used in automotive precision connectors, the structure includes: one φ4mm shaft hole, two 1.8mm thick sliding tongues, and a bottom reference surface) as an example, its inspection requirements are: Shaft hole coaxiality ≤ 0.005mm; The thickness tolerance of the sliding tongue is 1.8 ± 0.003 mm; The position of the left and right sliding tongues is ≤0.005mm; The relative positional tolerance between the shaft hole and the sliding tongue is ≤0.008mm.

[0033] The parameters of the fixture corresponding to this utility model are designed as follows: Fixture body 1: Made of Cr12MoV steel in one piece, the positioning cavity 2 is adapted to the outer contour of the product (length 25mm, width 12mm, depth 5mm), and the inner wall of the positioning cavity 2 is polished (Ra≤0.4μm). Reference plane 3: hardened (HRC52-55), flatness tolerance 0.002mm, surface roughness Ra≤0.8μm; Pin assembly 4: Positioning pin 6 with an outer diameter of φ3.996-φ3.998mm (with a clearance of 0.002-0.004mm between it and the product shaft hole), a coaxiality tolerance of 0.004mm, and a TiN coating thickness of 4μm; the locking component is an M3 socket head cap screw; Guide groove 8: groove width 1.8±0.002mm, groove wall straightness tolerance 0.002mm (within 100mm length), groove depth 2mm; Scale markings: graduation value 0.01mm, range 0-20mm, zero mark aligned with the reference edge on one side of positioning cavity 2; Limiting boss: height 0.8mm, inner wall distance from the two ends of positioning cavity 2 is 5mm and 15mm respectively (corresponding to product sliding stroke 10mm).

[0034] (II) Implementation Steps 1. Fixture pretreatment: Use a lint-free cloth dampened with alcohol to clean the surfaces of the positioning cavity 2, the reference plane 3, and the positioning pin 6 to ensure that no impurities affect the inspection accuracy; 2. Insert pin installation: Insert the positioning pin 6 into the pin installation hole 7 (hole diameter φ4.000mm) of the fixture body 1, and screw in the M3 socket head cap screw until the end of the screw is pressed against the positioning pin 6 to ensure that the pin is not loose; 3. Product clamping: Place the product to be inspected into the positioning cavity 2, so that the bottom reference surface of the product is in contact with the reference plane 3, and at the same time insert the positioning pin 6 into the φ4mm shaft hole of the product to confirm that the product is not obviously loose; 4. Sliding Inspection: Slowly push the product along the guide groove 8 with your finger, controlling the speed at approximately 5mm / s, and observe: The product is not warped relative to the reference plane 3, and there is no "clunking" sound during the sliding process, indicating that the flatness of the reference plane is qualified; The positioning pin 6 does not get stuck in the shaft hole, and the product can slide smoothly, indicating that the coaxiality of the shaft hole is qualified; The product and the guide groove 8 have no one side sticking tightly or obvious gap, and the sliding resistance is uniform, indicating that the thickness of the sliding tongue and the left and right position are qualified. When the product slides to the limiting boss, the scale mark "10.00mm" is on the edge of the product's sliding tongue. The deviation is ≤0.005mm, which indicates that the relative position of the shaft hole and the sliding tongue is qualified. 5. Determination of non-conforming products: If the product gets stuck when pushed, disassemble and inspect: If there are obvious scratches at the mating point between the positioning pin 6 and the shaft hole, it may be that the coaxiality of the shaft hole is out of tolerance; if there are wear marks on one side of the inner wall of the guide groove 8, it may be that the position of the sliding tongue is out of tolerance. The product needs to be marked and further verified by the equipment.

[0035] (III) Implementation Results This embodiment verifies that the inspection pass rate of the fixture for the MIM irregular product 9 is consistent with the detection results of the Keyence image measuring instrument at 99.8%. The average inspection time per piece is 12 seconds, which is 15 times more efficient than the existing solution (3 minutes / piece). Moreover, the operation does not require professional personnel. Ordinary workers on the production line can operate it proficiently after 1 hour of training, which fully meets the requirements of batch full inspection.

[0036] Finally, it should be noted that the above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A multi-dimensional synchronous inspection fixture for irregularly shaped MIM products, characterized in that, The fixture includes a main body with a positioning cavity adapted to the shape of the MIM (Mechanical Manufacturing) irregular product. A reference plane is located at the bottom of the positioning cavity, used to align and position the product against a reference surface to be inspected. A pin assembly is detachably mounted on the main body. The axis of the pin assembly is perpendicular to the reference plane, and the outer diameter of the pin assembly matches the designed inner diameter of the product's shaft hole, used to pass through the shaft hole for positioning. A guide structure is provided on the inner wall of the positioning cavity, extending in a direction parallel to the reference plane, used to guide the product to slide along the guide structure to simulate the assembly process.

2. The multi-dimensional synchronous inspection fixture for irregularly shaped MIM products according to claim 1, characterized in that, The pin assembly includes a positioning pin and a locking member. The fixture body is provided with a pin mounting hole. The positioning pin passes through the pin mounting hole. The locking member is threadedly connected to the fixture body and abuts against the positioning pin. The coaxiality tolerance of the positioning pin is ≤0.005mm.

3. The multi-dimensional synchronous inspection fixture for irregularly shaped MIM products according to claim 1, characterized in that, The guiding structure consists of two guide grooves symmetrically arranged on the inner sidewall of the positioning cavity. The groove width tolerance is ±0.002mm, and the straightness tolerance of the groove wall is ≤0.003mm.

4. The multi-dimensional synchronous inspection fixture for irregularly shaped MIM products according to claim 1, characterized in that, The reference plane is hardened by quenching, with a surface hardness ≥ HRC50 and a surface roughness Ra ≤ 0.8 μm.

5. The multi-dimensional synchronous inspection fixture for irregularly shaped MIM products according to claim 1, characterized in that, The main body of the fixture is integrally formed from Cr12MoV mold steel, and the inner wall of the positioning cavity is provided with a polished layer.

6. The multi-dimensional synchronous inspection fixture for irregularly shaped MIM products according to claim 1, characterized in that, The fixture body is provided with scale marks along the extension direction of the guide structure. The scale mark has a graduation value of 0.01mm and is used to visually display the product sliding stroke and the position deviation of the sliding tongue. The positioning cavity is provided with limiting bosses at both ends to limit the extreme position of the product sliding.

7. The multi-dimensional synchronous inspection fixture for irregularly shaped MIM products according to claim 1, characterized in that, The fitting clearance between the pin assembly and the product shaft hole is 0.002-0.008mm, and the surface of the positioning pin is coated with TiN with a coating thickness of 3-5μm.

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