Three-coordinate measuring tool and detection method

Abstract

The application discloses a three-coordinate measuring tool and a detection method, and belongs to the technical field of aero-engine part detection. The three-coordinate measuring tool comprises a base, a first clamping seat, a second clamping seat and a third clamping seat. The base is used for being placed on a workbench of a three-coordinate detector, and a positioning surface for cooperating with a positioning reference of the workbench of the three-coordinate detector is arranged on the base. The first clamping seat is fixed on the base, a first positioning end surface is formed on the first clamping seat, a first positioning pin and a clamping piece matched with the first positioning pin are arranged on the first positioning end surface. The second clamping seat is in sliding cooperation with the base, the sliding direction is parallel to the first positioning end surface, a second positioning end surface parallel to the first positioning end surface is formed on the second clamping seat, a second positioning pin parallel to the first positioning pin and a clamping piece matched with the second positioning pin are arranged on the second positioning end surface. The application has the effect of improving the three-coordinate detection efficiency.

Description

Technical Field

[0001] This invention relates to the technical field of aero-engine component inspection, and in particular, to a coordinate measuring machine tool and inspection method. Background Technology

[0002] Aero engines are extremely complex and highly precise products that provide the power required for aircraft. Their stability directly affects the aircraft's performance, reliability, and economy. The turbine components of an aero engine are exposed to high temperatures during engine operation, and these temperatures can cause deformation, ablation, and changes in the dimensions of the parts. During engine repair, the turbine casing components require strict dimensional control. Numerous dimensions need to be measured with high precision, necessitating the use of a coordinate measuring machine (CMM) for accurate measurements.

[0003] The turbine casing of a certain type of turboshaft aero-engine has a complex structure and requires the measurement of numerous dimensions. The references and orientations for these dimensions also differ. The current measurement method involves placing the part directly on a coordinate measuring machine (CMM) platform and measuring each dimension sequentially. However, due to the inconsistent references and orientations, all dimensions cannot be measured at once. Each time a dimension is measured from a different reference or orientation, the part must be repositioned and the reference manually established before the CMM can automatically measure that dimension. Therefore, measuring a complex part requires repeated placement and manual reference positioning. This repeated placement and positioning wastes significant time and labor. Measuring one casing using the current method takes 2.5 hours. With increasing workload, the existing measurement capabilities are insufficient to meet the demands, necessitating an urgent improvement in measurement efficiency. Summary of the Invention

[0004] This invention provides a coordinate measuring fixture and inspection method to solve the technical problem in the prior art where repeated manual positioning of the reference points is required when inspecting the dimensions of multiple different reference points, resulting in low inspection efficiency.

[0005] According to one aspect of the present invention, a coordinate measuring machine (CMM) fixture is provided, comprising a base, a first clamping seat, a second clamping seat, and a third clamping seat; the base is used to be placed on the worktable of a CMM, and a positioning surface is provided on the base for cooperating with the positioning reference of the CMM worktable; the first clamping seat is fixed on the base, and a first positioning end face is formed on the first clamping seat, a first positioning pin and a clamping member cooperating with the first positioning pin are provided on the first positioning end face; the second clamping seat is slidably engaged with the base, the sliding direction being parallel to the first positioning end face, a second positioning end face coplanar with the first positioning end face is formed on the second positioning end face, a second positioning pin parallel to the first positioning pin and a clamping member cooperating with the second positioning pin are provided on the second positioning end face; the third clamping seat is disposed on the base, and a third positioning pin parallel to the first positioning pin and a clamping member cooperating with the third positioning pin are provided on the third clamping seat.

[0006] Optionally, the clamping member includes a clamping sleeve, a clamping rod, and a clamping block; the clamping sleeve is used to be fixedly connected to a first clamping seat, a second clamping seat, or a third clamping seat; the clamping rod passes through the clamping sleeve and slides axially with the clamping sleeve; one end of the clamping rod is fixedly connected to the clamping block; and the other end of the clamping rod is threadedly connected to a locking member.

[0007] Optionally, the outer wall of the clamping rod is provided with a guide groove along the axial direction, and a guide block that mates with the guide groove is fixed on the clamping sleeve.

[0008] Optionally, the base is provided with a guide rail along the horizontal direction, the second clamping seat and the third clamping seat slide in cooperation with the guide rail, the guide rail is provided with a plurality of positioning holes along the length direction, and the second clamping seat and the third clamping seat are provided with positioning pins that cooperate with positioning.

[0009] Optionally, the coordinate measuring fixture further includes a support seat mounted on the base, the support seat having a support surface that matches the outer contour of the part, the support seat and the base being movably coupled so that the position of the support surface relative to the base is adjustable.

[0010] Optionally, the support base includes a support base plate, a support bracket, and a support platform. The base plate has a longitudinal sliding groove along the direction perpendicular to the first positioning end face. The support base plate has a transverse sliding groove parallel to the first positioning end face. The support bracket has a vertical sliding groove that is perpendicular to both the transverse and longitudinal sliding grooves. The support base plate is provided with a longitudinal sliding rod that cooperates with the longitudinal sliding groove. The support bracket is provided with a transverse sliding rod that cooperates with the transverse sliding groove. The support platform is provided with a vertical sliding rod that cooperates with the vertical sliding groove.

[0011] Optionally, two support brackets are arranged in parallel, and the vertical slide rods on the two support brackets slide simultaneously or independently. After passing through the vertical slide groove, the vertical slide rods are threadedly connected with locking bolts.

[0012] Optionally, the coordinate measuring fixture further includes a loading device, which includes a material cart chassis assembly, a material cart lifting assembly, and a material cart upper base plate assembly. The material cart base is provided with rollers. One end of the material cart lifting assembly is connected to the material cart chassis assembly, and the other end is connected to the material cart upper base plate assembly to adjust the distance between the material cart chassis assembly and the material cart upper base plate assembly. The material cart upper base plate assembly has a support surface formed on it for supporting the base.

[0013] Optionally, the base includes an air cushion plate and a movable plate disposed on the air cushion plate. The air cushion plate is provided with an air inlet for connecting an air source, and the air inlet extends to the bottom surface of the air cushion plate.

[0014] According to another aspect of the present invention, a coordinate measuring method is also provided, comprising the following steps: setting a reference baffle on a worktable, establishing a preliminary detection coordinate system based on the reference baffle, the preliminary detection coordinate system including an X-axis, a Y-axis, and a Z-axis; installing a coordinate measuring fixture containing a part on the worktable, such that the coordinate measuring fixture cooperates with the reference baffle, and obtaining the coordinates of the reference point of the fixture in the preliminary detection coordinate system based on the dimensional relationship between the position of the reference point of the fixture and the reference baffle; obtaining the positional relationship between the part to be inspected and the reference point of the fixture based on the assembly relationship between the part and the fixture, and obtaining the coordinates of the part to be inspected in the preliminary detection coordinate system based on the coordinates of the reference point of the fixture; obtaining the measured coordinates of the part to be inspected by marking points on the part using a probe based on the coordinates of the part to be inspected in the preliminary detection coordinate system; establishing a measured coordinate system based on the measured coordinates of the part, and determining whether the machining dimensions of the part to be inspected are qualified based on the position of the measured coordinates of the part to be inspected in the measured coordinate system, combined with the theoretical position of the part in the measured coordinate system and the allowable tolerance.

[0015] In summary, this application includes at least one of the following beneficial technical effects:

[0016] 1. By cooperating with the positioning surface on the base and the positioning reference of the coordinate measuring machine's worktable, the position of the base on the worktable of the coordinate measuring machine can be accurately located, thereby improving the positioning accuracy of the parts;

[0017] 2. The parts can be accurately positioned by the cooperation of the first positioning pin, the second positioning pin and the third positioning pin. At the same time, by cooperating with the clamping parts, the parts can be fully supported and the parts can be removed from the worktable of the coordinate measuring machine. In this way, during the inspection, the coordinates of all the parts to be measured can be measured by dial gauge in one clamping, without the need to clamp repeatedly for different positioning references, thus improving the efficiency of the inspection.

[0018] 3. In this solution, a unique clamping datum is determined by the first, second, and third locating pins. The coordinates of all positions to be measured are transformed into a single clamping datum, which can reduce clamping errors caused by multiple clamping operations and improve detection accuracy.

[0019] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 This is a schematic diagram of the structure of a coordinate measuring tool according to a preferred embodiment of the present invention;

[0022] Figure 2 yes Figure 1 Enlarged view of point A in the middle;

[0023] Figure 3 This is a schematic diagram of the feeding device according to a preferred embodiment of the present invention.

[0024] Legend:

[0025] 1. Base; 2. First clamping seat; 3. Second clamping seat; 4. Third clamping seat; 5. Clamping component; 51. Clamping sleeve; 52. Clamping rod; 53. Clamping block; 54. Guide groove; 55. Guide block; 6. Guide rail; 7. Positioning hole; 8. Positioning pin; 91. Support base plate; 92. Support bracket; 93. Support platform; 94. Longitudinal slide groove; 95. Transverse slide groove; 96. Vertical slide groove; 10. Material cart chassis assembly; 11. Material cart lifting assembly; 12. Material cart upper base plate assembly. Detailed Implementation

[0026] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0027] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0028] This application discloses a coordinate measuring machine tool and a testing method.

[0029] Reference Figure 1 The coordinate measuring machine tooling includes a base 1, a first clamping seat 2, a second clamping seat 3, and a third clamping seat 4;

[0030] The base 1 is used to place on the worktable of the coordinate measuring machine. The base 1 is provided with a positioning surface for cooperating with the positioning reference of the worktable of the coordinate measuring machine. The first clamping seat 2 is fixed on the base 1. The first clamping seat 2 has a first positioning end face. The first positioning end face is provided with a first positioning pin 8 and a clamping member 5 that cooperates with the first positioning pin 8. The second clamping seat 3 is slidably engaged with the base 1. The sliding direction is parallel to the first positioning end face. The second clamping seat 3 has a second positioning end face that is coplanar with the first positioning end face. The second positioning end face is provided with a second positioning pin 8 that is parallel to the first positioning pin 8 and a clamping member 5 that cooperates with the second positioning pin 8. The third clamping seat 4 is disposed on the base 1. The third clamping seat 4 is provided with a third positioning pin 8 that is parallel to the first positioning pin 8 and a clamping member 5 that cooperates with the third positioning pin 8.

[0031] In this embodiment, a positioning reference is provided on the worktable of the coordinate measuring machine. Specifically, the positioning reference consists of an L-shaped positioning reference plate placed on the worktable. The right-angled interior angles of the positioning reference plate form longitudinal and transverse references, and the upper surface of the worktable forms a vertical reference. The cooperation between the positioning surface on the base 1 and the positioning reference of the coordinate measuring machine ensures that the base 1 can be accurately and repeatably positioned on the worktable of the coordinate measuring machine, which is the basis for accurate measurement. Accurate positioning means consistency of the measurement starting point, thereby ensuring the reliability and consistency of the measurement data. Secondly, this mechanical positioning reduces errors caused by human operation and improves the overall accuracy of the measurement process. In addition, it simplifies the measurement preparation work, effectively saves the time for setting up and adjusting the tooling, and improves work efficiency. The cooperation of the first positioning pin 8, the second positioning pin 8, and the third positioning pin 8 can accurately position the part. At the same time, the cooperation with the clamping part 5 can fully support the part, allowing the part to be removed from the worktable of the coordinate measuring machine. In this way, during inspection, the coordinates of all parts to be measured can be measured in one clamping without repeated clamping for different positioning references, thus improving the efficiency of inspection.

[0032] A guide rail 6 is provided on the horizontal side of the base 1. The second clamping seat 3 and the third clamping seat 4 are slidably engaged with the guide rail 6. Several positioning holes 7 are arranged on the guide rail 6 along the length direction. Positioning pins 8 that are engaged with positioning are provided on the second clamping seat 3 and the third clamping seat 4.

[0033] A guide rail 6 is provided laterally on the base 1, providing a sliding path for the second and third clamping seats 4. The second and third clamping seats 4 can slide along the guide rail 6, allowing them to adjust their position laterally on the base 1. Several positioning holes 7 are arranged along the length of the guide rail 6. Through the cooperation of the positioning holes 7 and positioning pins 8, the clamping seats can be precisely positioned and fixed, ensuring stability and repeatability during the measurement process. Compared to completely manual adjustment, this design allows for quick and accurate positioning and fixing of the clamping seats, improving efficiency while ensuring the stability of the clamping seats during measurement, thus contributing to improved accuracy and reliability of the measurement results. By sliding the second clamping seat 3, the distance between the first and second positioning pins 8 can be adjusted, thereby accommodating and fixing parts of different sizes and shapes, providing great flexibility and adaptability.

[0034] The base 1 includes an air cushion plate and a movable plate disposed on the air cushion plate. The air cushion plate is provided with an air inlet for connecting an air source, and the air inlet extends to the bottom surface of the air cushion plate.

[0035] With the above solution, when the air source is connected to the air inlet on the air cushion plate, air is guided to the bottom surface of the air cushion plate. This air forms an air cushion layer between the air cushion plate and the moving plate. Due to the flow and pressure of the gas, this air cushion can reduce the direct contact between the moving plate and the air cushion plate, reduce the friction between the air cushion plate and the worktable, reduce physical wear, and extend the service life of the equipment; it also reduces the force required for movement, making it easy to move even heavy objects, thereby improving work efficiency; for sensitive parts that require precision handling or positioning, the air cushion plate can reduce the pressure and damage to the parts during handling.

[0036] Reference Figure 1 and Figure 2 The clamping component 5 includes a clamping sleeve 51, a clamping rod 52, and a clamping block 53. The clamping sleeve 51 is used to be fixedly connected to the first clamping seat 2, the second clamping seat 3, or the third clamping seat 4. The clamping rod 52 passes through the clamping sleeve 51 and slides axially with the clamping sleeve 51. One end of the clamping rod 52 is fixedly connected to the clamping block 53, and the other end of the clamping rod 52 is threaded with a locking component.

[0037] Through the above scheme, the clamping sleeve 51 is fixedly connected to the first, second, or third clamping seat 4, providing a foundation and stability for the entire clamping mechanism; the clamping rod 52 passes through the clamping sleeve 51 and slides axially with the clamping sleeve 51. This design allows the clamping rod 52 to move along the axial direction to accommodate parts of different specifications or adjust the clamping position; one end of the clamping rod 52 is fixedly connected to the clamping block 53, which directly contacts the part to be measured and is responsible for fixing and positioning the part; the other end of the clamping rod 52 is connected to a locking element through a thread to fix the position of the clamping rod 52 and ensure the stability of the part during the measurement process.

[0038] Optionally, a rubber pad is provided on the clamping block 53. The rubber pad effectively prevents the hard clamping block 53 from directly contacting and potentially damaging the surface of the part being measured; at the same time, rubber has good frictional properties, which can increase the frictional force between the clamping block 53 and the part being measured, ensuring the stability of the part during the measurement process and preventing slippage or displacement.

[0039] The outer wall of the clamping rod 52 is provided with a guide groove 54 along the axial direction, and a guide block 55 that mates with the guide groove 54 is fixed on the clamping sleeve 51. With the above scheme, when the clamping rod 52 moves in the clamping sleeve 51, the guide block 55 slides along the guide groove 54, thereby guiding the axial movement of the clamping rod 52, while restricting movement in other directions, so that the guide rod will not rotate with the rotation of the locking element, and the clamping block 53 can move axially with the guide rod and thus be smoothly pressed onto the workpiece.

[0040] The coordinate measuring fixture also includes a support base set on the base 1. The support base has a support surface that matches the outer contour of the part. The support base and the base 1 are movably matched so that the position of the support surface relative to the base 1 can be adjusted.

[0041] By using a support base on the base 1, and forming a support surface on the support base that matches the outer contour of the part, the appropriate support base can be selected according to the shape and size of different parts during use, so that the support surface fits tightly with the outer contour of the part. The support surface that matches the outer contour of the part can provide specialized support for parts of different shapes and sizes, ensuring their stability.

[0042] The support base includes a support base plate 91, a support bracket 92, and a support platform 93. The base plate 1 has a longitudinal sliding groove 94 along the direction perpendicular to the first positioning end face. The support base plate 91 has a transverse sliding groove 95 parallel to the first positioning end face. The support bracket 92 has a vertical sliding groove 96 that is perpendicular to both the transverse sliding groove 95 and the longitudinal sliding groove 94. The support base plate 91 is provided with a longitudinal sliding rod that cooperates with the longitudinal sliding groove 94. The support bracket 92 is provided with a transverse sliding rod that cooperates with the transverse sliding groove 95. The support platform 93 is provided with a vertical sliding rod that cooperates with the vertical sliding groove 96.

[0043] The above design incorporates longitudinal, transverse, and vertical grooves and corresponding sliding rods, allowing for precise adjustment of the support in these three directions during use. Specifically, the longitudinal position of the support is adjusted longitudinally by moving the longitudinal sliding rod on the support base plate 91 along the longitudinal groove 94 of the base 1; the transverse position of the support is adjusted laterally by moving the transverse sliding rod on the support bracket 92 along the transverse groove 95 of the support base plate 91; and the vertical position of the support is adjusted vertically by moving the vertical sliding rod on the support platform 93 along the vertical groove 96 of the support bracket 92. This multi-directional adjustable design allows the support to adapt to various complex part shapes, providing stable support for different parts and improving measurement adaptability. Precise adjustment of the support position ensures the stability of the part during measurement, reducing measurement errors caused by improper part positioning and improving measurement accuracy.

[0044] There are two parallel support brackets 92. The vertical slide rods on the two support brackets 92 can slide simultaneously or independently. The vertical slide rods are threaded and locked with locking bolts after passing through the vertical slide grooves 96.

[0045] With the above scheme, when the two vertical slide rods slide simultaneously, the support platform 93 can be moved upward or downward. When only one vertical slide rod slides or when the sliding speeds of the two vertical slide rods are different, the support platform 93 will tilt to adjust the angle of the part. It can be understood that the width of the vertical slide groove 96 is greater than the diameter of the vertical slide rod, providing space for the two vertical slide rods to move independently.

[0046] Reference Figure 3 The coordinate measuring fixture also includes a loading device, which includes a material cart chassis assembly 10, a material cart lifting assembly 11, and a material cart upper base plate assembly 12. The material cart base 1 is provided with rollers. One end of the material cart lifting assembly 11 is connected to the material cart chassis assembly 10 and the other end is connected to the material cart upper base plate assembly 12 to adjust the distance between the material cart chassis assembly 10 and the material cart upper base plate assembly 12. The material cart upper base plate assembly 12 has a support surface for supporting the base 1.

[0047] Through the above scheme, the material cart chassis assembly 10 enables the entire loading device to be easily moved within the factory or warehouse; the material cart lifting assembly 11 is driven mechanically, hydraulically, or electronically, and the lifting assembly can adjust the distance between the chassis assembly and the upper base plate assembly; the material cart upper base plate assembly 12 is located on top of the material cart and is used to directly support the base 1 and the parts on the base 1. In use, the material cart upper base plate assembly 12 can be lowered by the material cart lifting assembly 11, so that the base 1 can be moved more easily onto the material cart upper base plate assembly 12, and then the loading device can be moved to transport the parts to the coordinate measuring machine area; then the material cart upper base plate assembly 12 can be raised by the material cart lifting assembly 11, so that the height of the material cart upper base plate assembly 12 is flush with the worktable of the coordinate measuring machine, and finally the base 1 can be moved to transfer the base 1 and the parts on the base 1 to the worktable.

[0048] The material cart lifting assembly 11 allows for adjustment of the height of the material cart's base plate according to different operational requirements, facilitating connection with other equipment or adapting to loads at varying heights. This reduces manual handling, lightens the workload for workers, and improves the efficiency and safety of material handling. The material cart lifting assembly 11 can be driven by a hydraulic system, a screw lifting system, or a gear and rack mechanism. In one embodiment, the material cart lifting assembly 11 includes a foot-operated hydraulic lifting lever, allowing for raising and lowering of the assembly by stepping on a foot pedal.

[0049] This embodiment also discloses a coordinate measuring machine (CMM) method, including the following steps:

[0050] Step S100: Set a reference baffle on the worktable and establish a preliminary detection coordinate system based on the reference baffle. The preliminary detection coordinate system includes the X-axis, Y-axis and Z-axis.

[0051] Select a suitable reference baffle, which should have precise right-angled edges and known dimensions, and mount the reference baffle on the worktable. This typically involves fixing the baffle in a designated position on the worktable, ensuring it is stable and perpendicular to the worktable plane. Use one edge of the reference baffle as a reference line for the X-axis or Y-axis. The Z-axis is usually perpendicular to the worktable surface.

[0052] Step S200: Install the part to be inspected onto the coordinate measuring machine fixture.

[0053] First, place the part on the support base, then adjust the position of the support base so that the mounting hole of the part is aligned with the first positioning pin 8 and the second positioning pin 8; push the part to move so that the first positioning pin 8 and the second positioning pin 8 are inserted into the corresponding mounting holes on the part, thereby driving the clamping parts 5 on the first clamping base 2 and the second clamping base 3 to clamp the part; then push the third clamping base 4 to move so that the point positioning pin 8 is aligned with the mounting hole on the part, and finally lock the clamping parts 5 on the third clamping base 4.

[0054] Step 300: Install the coordinate measuring tooling fixture with parts on the workbench, make the coordinate measuring tooling fixture cooperate with the reference baffle, and obtain the coordinates of the fixture reference point in the preliminary detection coordinate system according to the dimensional relationship between the fixture reference point position on the fixture and the reference baffle.

[0055] Step S400: Obtain the positional relationship between the part's to-be-inspected position and the fixture reference point according to the assembly relationship between the part and the fixture, and combine the coordinates of the fixture reference point in the preliminary detection coordinate system to obtain the coordinates of the part's to-be-inspected position in the preliminary detection coordinate system.

[0056] Step S500: Perform dot detection on the part through the probe according to the coordinates of the part's to-be-inspected position in the preliminary detection coordinate system to obtain the measured coordinates of the part's to-be-inspected position.

[0057] Step S600: Fit and establish the measured coordinate system based on the measured coordinates of the part, and judge whether the machining dimensions of the part's to-be-inspected position are qualified according to the position of the measured coordinates of the part's to-be-inspected position in the measured coordinate system, combined with the theoretical position of the part in the measured coordinate system and the allowed tolerance.

[0058] Use a coordinate measuring machine to obtain the measured coordinate points of each to-be-inspected position of the part to ensure the accuracy of data collection. Select appropriate measured point positions (usually representative geometric features such as holes, bosses, edges, etc.) as reference points. Fit out the measured coordinate system through the measured coordinate points obtained by measurement, and compare the measured coordinates with the theoretical coordinates in the part drawing or CAD model; use the software of the coordinate measuring machine for comparative analysis to calculate the difference between the measured coordinates and the theoretical coordinates; determine the allowed tolerance range of the machining dimensions of the to-be-inspected position according to the design drawing or quality standard; compare the difference between the measured coordinates and the theoretical coordinates with the tolerance range to judge whether the machining dimensions are within the allowed tolerance range. If the difference is within the allowed tolerance range, it is judged as qualified; if it exceeds the tolerance range, it is marked as unqualified and the degree of unqualified is recorded.

[0059] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A three-coordinate measuring tool, characterized in that: comprising a base (1), a first clamping seat (2), a second clamping seat (3) and a third clamping seat (4); the base (1) is used to be placed on the workbench of a three-coordinate detector, and the base (1) is provided with a positioning surface used to cooperate with the positioning reference of the workbench of the three-coordinate detector; the first clamping seat (2) is fixed on the base (1), and a first positioning end surface is formed on the first clamping seat (2), and a first positioning pin and a clamping piece (5) matched with the first positioning pin are arranged on the first positioning end surface; the second clamping seat (3) is in sliding cooperation with the base (1), and the sliding direction is parallel to the first positioning end surface, and a second positioning end surface parallel to the first positioning end surface is formed on the second clamping seat (3), and a second positioning pin parallel to the first positioning pin and a clamping piece (5) matched with the second positioning pin are arranged on the second positioning end surface; the third clamping seat (4) is arranged on the base (1), and a third positioning pin parallel to the first positioning pin and a clamping piece (5) matched with the third positioning pin are arranged on the third clamping seat (4); the clamping piece (5) comprises a clamping sleeve (51), a clamping rod (52) and a clamping block (53); the clamping sleeve (51) is used to be fixedly connected with the first clamping seat (2), the second clamping seat (3) or the third clamping seat (4), the clamping rod (52) is arranged in the clamping sleeve (51) and is in axial sliding cooperation with the clamping sleeve (51), one end of the clamping rod (52) is fixedly connected with the clamping block (53), and the other end of the clamping rod (52) is threadedly connected with a locking piece. The three-coordinate measuring tool further comprises a feeding device, and the feeding device comprises a trolley chassis assembly (10), a trolley lifting assembly (11) and a trolley upper bottom plate assembly (12); a roller is arranged on the trolley base (1), one end of the trolley lifting assembly (11) is connected with the trolley chassis assembly (10), the other end of the trolley lifting assembly (11) is connected with the trolley upper bottom plate assembly (12) to adjust the distance between the trolley chassis assembly (10) and the trolley upper bottom plate assembly (12), and a supporting surface for supporting the base (1) is formed on the trolley upper bottom plate assembly (12). 2.The three-coordinate measuring tool according to claim 1, characterized in that: a guide groove (54) is formed on the outer wall of the clamping rod (52) in the axial direction, and a guide block (55) matched with the guide groove (54) is fixed on the clamping sleeve (51). 3.The three-coordinate measuring tool according to claim 2, characterized in that: a guide rail (6) is arranged on the base (1) in the transverse direction, the second clamping seat (3) and the third clamping seat (4) are in sliding cooperation with the guide rail (6), a plurality of positioning holes (7) are arranged on the guide rail (6) in the length direction, and a positioning pin matched with the positioning hole (7) is arranged on the second clamping seat (3) and the third clamping seat (4). 4.The three-coordinate measuring tool according to claim 3, characterized in that: the three-coordinate measuring tool further comprises a supporting seat arranged on the base (1), and a supporting surface matched with the outer contour of a part is formed on the supporting seat; the supporting seat is in movable cooperation with the base (1) so that the position of the supporting surface relative to the base (1) is adjustable. ​ ​ ​ ​ ​ ​ ​ ​ ​ 5. The three-coordinate measuring tool of claim 4, wherein: the support base comprises a support bottom plate (91), a support bracket (92) and a support table (93), the base (1) is provided with a longitudinal sliding groove (94) in the direction perpendicular to the first positioning end face, the support bottom plate (91) is provided with a transverse sliding groove (95) parallel to the first positioning end face, the support bracket (92) is provided with a vertical sliding groove (96) perpendicular to the transverse sliding groove (95) and the longitudinal sliding groove (94), the support bottom plate (91) is provided with a longitudinal sliding rod matched with the longitudinal sliding groove (94), the support bracket (92) is provided with a transverse sliding rod matched with the transverse sliding groove (95), and the support table (93) is provided with a vertical sliding rod matched with the vertical sliding groove (96).

6. The three-coordinate measuring tool of claim 5, wherein: the support bracket (92) is provided in parallel with two, the vertical sliding rods on the two support brackets (92) are simultaneously slid or independently slid, and the vertical sliding rods are threadedly connected with locking bolts after penetrating through the vertical sliding groove (96).

7. The three-coordinate measuring tool of claim 1, wherein: the base (1) comprises an air cushion plate and a moving plate arranged on the air cushion plate, the air cushion plate is provided with an air inlet for connecting an air source, and the air inlet extends to the bottom surface of the air cushion plate.

8. A method of three-dimensional measurement using the three-dimensional measurement tool of any one of claims 1 to 7, characterized by, comprising the following steps: setting a reference baffle on the workbench, establishing a preliminary detection coordinate system according to the reference baffle, and the preliminary detection coordinate system comprising an X axis, a Y axis and a Z axis; installing the three-coordinate measuring tool with the part on the workbench, making the three-coordinate measuring tool cooperate with the reference baffle, obtaining the coordinates of the fixture reference point in the preliminary detection coordinate system according to the size relationship between the fixture reference point on the fixture and the reference baffle; obtaining the position relationship between the part to be detected and the fixture reference point according to the assembly relationship between the part and the fixture, obtaining the coordinates of the part to be detected in the preliminary detection coordinate system in combination with the coordinates of the fixture reference point in the preliminary detection coordinate system; obtaining the measured coordinates of the part to be detected by the probe through the dot detection of the part according to the coordinates of the part to be detected in the preliminary detection coordinate system; fitting and establishing a measured coordinate system according to the measured coordinates of the part, judging whether the machining size of the part to be detected is qualified or not according to the position of the measured coordinates of the part to be detected in the measured coordinate system in combination with the theoretical position of the part in the measured coordinate system and the allowable tolerance.

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