Methods, apparatus, electronic equipment, readable media, and products for drawing precision standard images for projection measurement.

Abstract

This invention discloses a method, apparatus, electronic device, readable medium, and product for drawing precision standard images for projection measurement. The drawing method includes: S1, acquiring contour data; S2, controlling the contour tolerance zone; S3, formulating a drawing strategy for contour lines; S4, fixing the standard image and adjusting the pen tip; S5, compiling the contour drawing program and sending instructions; S6, dynamically adjusting the line type and ink marks during the drawing process; and S7, detecting the standard image. The drawing apparatus of this invention includes a polyester film for drawing, an aluminum alloy pad with tiny adsorption holes, an L-shaped base, a pen tip, a pen tip limiting block, a first integral tool holder, a limiting seat, and a ring-shaped pen disk. This invention solves the problem of the inability to draw high-precision tolerances using standard images for projection measurement through structural improvements, ensuring that the distance between the maximum and minimum contours is ≤0.01mm, overcoming the problem of discontinuous ink marks in the standard image, and improving the recognizability of contour lines.

Description

Technical Field

[0001] This invention belongs to the field of geometric inspection technology for aero-engine components, specifically relating to a method, device, electronic equipment, readable medium, and product for drawing high-precision standard images based on reflective ink marks and dynamic linewidth. Background Technology

[0002] The rotor disc and blades of an aero-engine are connected by a tenon-groove structure to form the core power transmission unit, which is a critical stress-bearing component under high-speed engine rotation. The surfaces of the tenons and grooves in this connection structure are mostly complex curved surfaces. Dimensional deviations and surface defects of these parts directly affect the stability of the mating connection between the disc and blades, thereby threatening the safe operation of the engine. Therefore, high-precision and high-efficiency inspection of the critical curved surfaces is required.

[0003] The profiles of blade tenons are mostly complex curved surfaces, characterized by high dimensional accuracy requirements, strict surface quality requirements, and asymmetrical structures. Coordinate measuring machines (CMMs) cannot allow their probes to enter specific structures, and scanning is prone to distortion. Traditional methods have significant limitations: contact measurement is inefficient and lacks continuous measurement capability for curved profiles; visual inspection is easily affected by lighting and metal reflections. For the measurement of the profiles and surface shapes of precision parts such as wheel hub tenons, blade teeth, gears, and profile templates in aero-engines, standard images are often projected for comparative measurement.

[0004] Chinese invention patent (application number: CN201711367744.7) discloses a method for drawing standard images on a projector based on a coordinate measuring machine. However, the drawn images can only be placed horizontally on the platform, resulting in poor stability during the drawing process and an inability to meet high-precision requirements. CN201110023538.0 discloses a method for measuring the contour of a tenon groove on a projector, but its operability is poor.

[0005] To address the issues of severe visual interference, low inspection accuracy, and inadequacy to meet the requirements of mass production in existing technologies for inspecting tenon joints of aero-engine blades, there is an urgent need for a method and device for drawing high-precision standard images. Summary of the Invention

[0006] In order to overcome the defects of the existing technology, the present invention aims to provide a method, device, electronic device, readable medium, and product for drawing precision standard images for projection measurement, so as to solve the technical problems of standard images for projection measurement, such as the inability to draw high-precision tolerances (maximum contour - minimum contour ≤ 0.01mm), poor wear resistance, discontinuous ink marks, and poor recognizability.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for drawing precise standard images for projection measurements, employing the following apparatus for drawing precise standard images for projection measurements, the apparatus comprising: A drawing film, wherein the drawing surface of the drawing film is a sandblasted surface that has undergone sandblasting treatment; An aluminum alloy pad with micro-adsorption holes, wherein the surface of the aluminum alloy pad with micro-adsorption holes includes a vertical plane for placing a drawing film, the plane is provided with micro-adsorption holes and a limiting structure, the drawing film is adsorbed by the airflow in the micro-adsorption holes and constrained between the plane and the limiting structure. L-shaped base, the vertical edge of which is attached to an aluminum alloy pad with tiny adsorption holes; The pen refills include ordinary ink refills with different line widths, and fluorescent ink refills or reflective ink refills with different line widths. The pen refill limiting block includes a rounded quadrangular prism structure. The side of the quadrangular prism structure has a pen refill limiting hole, and the bottom of the quadrangular prism structure has a pen refill insertion hole. A pen refill is inserted into the pen refill insertion hole. The shape of the pen refill insertion hole is the same as the shape of the pen refill, so that there is a surface contact between the pen refill and the pen refill insertion hole. The first integral tool holder and the limiting seat, the pen refill limiting block is installed in the first integral tool holder and fixed in the first integral tool holder by the limiting seat; A ring-shaped pen disk with multiple pen refill limit blocks vertically mounted on the same side end face of the same ring-shaped pen disk via a first integral tool holder and a limit seat. The middle hole of the ring-shaped pen disk is connected to the machine tool. The rotation drive mechanism of the machine tool drives the ring-shaped pen disk to rotate. The line width of the pen refills in different pen refill limit blocks of the same ring-shaped pen disk is different. The method for drawing precise standard images for projection measurement includes the following steps: S1. Obtain contour data: Obtain the contour geometry data of the part to be measured, and draw the projection measurement contour diagram of the part to be measured in its original proportion. The contour diagram includes the maximum contour and the minimum contour. S2, Controlling the profile tolerance zone: Based on the processing requirements, usage requirements, or assembly requirements of the part to be tested, for some dimensions of the part to be tested, compress the profile tolerance of that part, while keeping the profile tolerance of the remaining dimensions unchanged, and update the profile diagram in S1. S3. Develop a strategy for drawing outline lines: For the updated contour map in S2, adjust the line width of the maximum and minimum contours at different positions, select different line widths according to the contour tolerance at different positions, and finally determine the line widths to ensure that the lines corresponding to the maximum contour and the lines corresponding to the minimum contour do not overlap and the interval between them is clear. S4. Standard image fixing and pen tip adjustment: Fix the L-shaped base to the machine tool workbench, and connect the L-shaped base and the aluminum alloy pad with tiny suction holes by bolts. Lay the drawing film flat on the plane of the aluminum alloy pad with tiny suction holes, with the sandblasted side of the drawing film facing outwards. Ensure that the drawing film and the aluminum alloy pad with tiny suction holes are tightly fitted without gaps or wrinkles. Insert the pen refill corresponding to the line width finally determined in S3 into the pen refill limiting block and fix it by the limiting seat. S5. Contour drawing program development and command transmission: According to the magnification ratio requirements, the updated outline in S2 is drawn as an enlarged CAD format drawing, the drawing is converted into an NC program, different pen core line widths are selected, and the data is transmitted to the CNC machine tool. S6. Dynamically adjustable line width and ink flow during the drawing process: In the CNC machine tool, the NC program in S5 is executed as the drawing program. When it is necessary to switch to different drawing line widths, rotate the ring pen disk to the pen core of the corresponding drawing line width. The machine tool spindle moves and clamps the pen core, and then resets to continue executing the drawing program. When drawing the smallest outline, rotate the ring pen disk to the pen core using fluorescent ink or reflective ink. The machine tool spindle moves and clamps the pen core, and then resets to continue executing the drawing program. S7, Standard Image Detection: After the drawing process in S6 is completed, the size, line continuity, whether the lines in key areas interfere with each other, and the recognition of fluorescent / reflective ink marks of the obtained standard image are detected. If the detection is qualified, it is used for the projection contour comparison detection of the part to be tested.

[0008] As one option, the drawing film is a polyester film or a polyimide film.

[0009] As one solution: the limiting structure is a U-shaped protrusion that extends vertically along the surface of an aluminum alloy pad with tiny adsorption holes for placing a drawing film. The U-shaped protrusion has a U-shaped groove on its surface to restrict the movement of the drawing film, and the drawing film is placed in the U-shaped groove.

[0010] As one solution: a spring is provided at one end of the pen refill limiting block corresponding to the first integral handle to ensure stable contact between the pen refill and the drawing film and to counteract vibration interference.

[0011] As one possible approach: In S1, the contour data is a dataset of coordinate points, or dimensions and dimensional tolerances.

[0012] As one approach: In S2, the spacing between the line corresponding to the maximum contour and the line corresponding to the minimum contour is ≤0.01mm.

[0013] As one solution: In S3, the drawing size accuracy is 0.002 to 0.005 mm, which is the deviation range between the actual size of the outline and the theoretical design size. In S3, the maximum contour and the minimum contour include three regions with different line widths: the first contour precision line width A is 0.01 to 0.06 mm, the second contour precision line width B is 0.07 to 0.10 mm, and the third contour precision line width C is 0.11 to 0.20 mm. In step S5, different magnification ratios can be selected, including magnification of 5 times, magnification of 20 times, magnification of 30 times, or magnification of 50 times; In step S7, a high-precision five-coordinate measuring instrument is selected to inspect the standard image.

[0014] A computer-readable medium having a computer program stored thereon, wherein when the computer program is executed by a processor, steps S1 to S7 of the aforementioned method for drawing precise standard images for projection measurement are executed sequentially.

[0015] A computer program product includes computer-readable code, or a non-volatile computer-readable storage medium carrying the computer-readable code, wherein when the computer-readable code is run in a processor of an electronic device, the processor in the electronic device performs steps S1 to S7 of the aforementioned method for drawing a precision standard image for projection measurement.

[0016] An electronic device includes a memory and a processor. The memory stores a computer program that can be executed by the processor. When the computer program is executed by the processor, it implements steps S1 to S7 of the aforementioned method for drawing precise standard images for projection measurement.

[0017] Compared with the prior art, the method, apparatus, electronic device, readable medium, and product for drawing precise standard images for projection measurement of the present invention have the following characteristics: 1. Significantly improved line drawing quality: By using the surface contact constraint of the square-headed pen clip in the shape of a quadrangular prism to restrict the degree of rotation, the problem of line interference and breakpoints caused by insufficient constraint in traditional cylindrical pen clips is solved, ensuring the continuous and complete lines of complex curved contours; at the same time, the combination of sandblasting treatment of the drawing film and vertical fixing method solves the problem of poor ink adhesion and easy smudging, improving the clarity of lines.

[0018] 2. Functional optimization to adapt to testing scenarios: The circular pen disk enables automatic switching between reflective / fluorescent ink and different line widths, eliminating the need for manual pen replacement and shortening pen change time; the reflective / fluorescent ink can effectively improve the recognizability of the standard image outline during the testing process, prevent leaf reflection interference, and different line widths can clearly distinguish different tolerance zones, providing support for accurate comparative testing.

[0019] 3. Guarantee of drawing accuracy and stability: The high-precision flatness of the aluminum alloy pad with tiny adsorption holes, combined with the tight fixing effect of the drawing film adsorption and fixing structure, avoids deformation and displacement during the drawing process, thus ensuring the dimensional accuracy of the standard drawing.

[0020] 4. High versatility: In addition to being compatible with standard drawings for blade tenon contour inspection, it can also adjust contour trajectory files, pen specifications, and ink types according to the geometric inspection requirements of different parts, making it suitable for high-precision standard image drawing of other complex curved surface parts. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method for drawing a precision standard image for projection measurement according to the present invention; Figure 2 This is a schematic diagram of the combination of the aluminum alloy pad with tiny adsorption holes, the limiting structure, and the L-shaped base in this invention. Figure 3 This is a schematic diagram of the four-prism pen clip structure, pen disk structure, and main shaft assembly state in this invention. Figure 4 This is a schematic diagram of the quadrangular prism pen clip structure in this invention; Figure 5 These are tenon outlines with different line widths drawn using the precision standard image drawing method for projection measurement in this invention. In the diagram: 1-Aluminum alloy pad with tiny suction holes, 2-Title suction holes, 3-Limiting structure, 4-L-shaped base, 5-Pen refill, 6-Pen refill limiting block, 7-First integral tool holder, 8-Limiting seat, 9-Annular pen disk, 10-Second integral tool holder, 11-Pen disk positioning hole, 12-Pen refill limiting hole, 13-Limiting seat bolt hole, 14-Annular pen disk center hole, 15-Drawing polyester film, 16-Sandblasted surface of drawing polyester film, A-First contour accuracy line width area (line width: 0.01~0.06mm), B-Second contour accuracy line width area (line width: 0.07~0.10mm), C-Third contour accuracy line width area (line width: 0.11~0.20mm). Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0023] like Figures 1-5As shown, this invention designs a method for drawing precise standard images for projection measurement, comprising: S1. Obtain contour data: Obtain the contour geometry data (coordinate point dataset, or dimensions and dimensional tolerances) of the part to be measured, and draw the original scale projection measurement contour diagram of the part to be measured, including the maximum contour and the minimum contour. S2. Control the profile tolerance zone: Based on the machining requirements and usage (assembly) requirements of the part to be measured, for some dimensions of the part to be measured, the profile tolerance needs to be compressed in order to ensure the machining consistency and assembly accuracy of the part to be measured. The remaining profile tolerances remain unchanged, and the profile drawing is redrawn. S3. Develop a strategy for drawing the outline lines: For the outline drawing in step S1, according to the tolerances in step S2, select different line widths based on different outline tolerances (e.g., ...). Figure 5 The maximum and minimum contours of the tenon are divided into three regions, A, B, and C, based on different contour tolerances. Each region has a different line width: the first contour line width is 0.01–0.06 mm, the second contour line width is 0.07–0.10 mm, and the third contour line width is 0.11–0.20 mm. Since the "minimum contour" of the standard image is obscured by the machined part during measurement, making it difficult to observe, the "minimum contour" is drawn using lines with fluorescent or reflective ink. The drawing size accuracy is 0.002–0.005 mm (here, the drawing size accuracy of 0.002–0.005 mm refers to the deviation range between the actual size of the contour lines and the theoretical design size when drawing the standard image; it is the core indicator for measuring the accuracy of contour drawing. Lines that are too wide will occupy the already very precise and small contour area).

[0024] S4. Standard Image Fixing and Pen Lead Adjustment: The drawing surface of the standard image is sandblasted (e.g., ...). Figure 5The drawing surface of the polyester film 15 is sandblasted to obtain a sandblasted surface 16, enhancing its writability. The treated standard image is then vertically laid flat on an aluminum alloy pad 1 with micro-adsorption holes. The micro-adsorption holes 2 on the surface of the aluminum alloy pad 1 (the position of the micro-adsorption holes 2 is adjustable to avoid the drawing outline) can flatten and adsorb the standard image, preventing displacement and protrusion. The drawing polyester film 15 and the aluminum alloy pad 1 with micro-adsorption holes are tightly fitted without gaps. The aluminum alloy pad 1 with micro-adsorption holes is fixed to the L-shaped base 4 and the limiting structure 3, which serves as a support device, by bolts. Pen refills 5, loaded with fluorescent ink, ordinary ink, and different line widths, are respectively installed on a multi-station rotating ring pen disk 9. The clamping force of the square-headed pen refill limiting block 6 is adjusted to ensure the pen refills 5 are securely clamped. The annular pen disk 9 is the core component of the multi-station rotary pen disk device. It is an annular part and connects to the rotary drive mechanism through the central hole 14. According to program requirements, the rotary drive mechanism changes angles to replace pen refills 5 at different positions, enabling a rotary pen-changing function. The pen refill 5 is installed within the pen refill limiting block 6. The square-headed quadrangular prism design of the pen refill limiting block 6 is its core clamping feature. As a detachable modular structure, adjusting the pen refill limiting hole 12 on the pen refill limiting block 6 allows for the replacement of pen refills 5 of different specifications and sizes without replacing the entire pen refill limiting block 6, improving the device's adaptability. The pen refill limiting block 6 is clamped by the first integral handle 7, which is mounted on the annular pen disk 9 through the pen disk positioning hole 11.

[0025] S5. Contour drawing program compilation and instruction sending: According to the drawing strategy of step S3, select different magnification ratios (such as magnification of 5 times, 20 times, 30 times, 50 times, etc.) for the contour drawing in step S2, formulate different pen cores 5 and drawing order in step S3, and send the processing instructions for precision standard images to the processing equipment (such as five-axis machining center, CNC boring machine, etc.) in the form of NC program (Numerical Control). After the program is imported into the drawing control system, calibrate the positioning consistency between the machine tool spindle (the machine tool spindle is equipped with a second integral tool holder 10, and the first integral tool holder 7 and the second integral tool holder 10 are both hydraulic tool holders) and the ring pen disk 9.

[0026] S6. Dynamically adjustable line type and ink marks during the drawing process: After the device is started, the machine tool spindle drives the currently held pen to draw according to the preset contour trajectory; when drawing to the area where the line width or ink mark needs to be switched, the machine tool spindle retracts to a safe distance, the rotary drive mechanism drives the ring pen disk 9 to rotate, rotates the pen of the corresponding specification or type to the drawing station and completes the positioning, and the machine tool spindle continues to draw according to the trajectory.

[0027] S7. Standard Image Inspection: After the drawing is completed, the size, line continuity, whether the lines in the key areas interfere with each other, and the recognizability of reflective ink marks of the standard image are inspected. After passing the inspection, it is used for the projection contour comparison inspection of the part to be tested.

[0028] The drawing method of the present invention can collect contour data, tolerance requirements, and line width / ink matching schemes of different aerospace parts (blades, tenons, gears, etc.) by building a drawing process database, and realize one-click retrieval of drawing parameters, thereby improving batch processing and drawing efficiency.

[0029] like Figures 1-4 As shown, based on the above drawing method, this invention designs a precision standard image drawing device for projection measurement, including a pen refill 5, a pen refill limiting block 6, a spring, a first integral handle 7, a limiting seat 8, and an annular pen disk 9. The spring is installed at the tail of the pen refill limiting block 6, and the pen refill 5 passes through the rear end of the pen refill limiting block 6 and protrudes outside the pen refill limiting block 6. Then, both are inserted into the first integral handle 7. At this time, the tail of the pen refill limiting block 6 compresses the spring, maintaining a certain elasticity. The pen refill limiting block 6 is fixed by the limiting seat 8, which has a limiting seat bolt hole 13. The limiting seat 8 is connected to the first integral handle 7 through bolts in the limiting seat bolt hole 13. Pen refills 5 of different specifications are assembled in the above manner and then placed in different positions on the annular pen disk 9.

[0030] The aluminum alloy pad 1 with micro-adsorption holes is made of 6061 aluminum alloy sheet, a precision sheet commonly used in aerospace, which has excellent flatness retention, strength, and wear resistance. The surface of the aluminum alloy pad 1 with micro-adsorption holes is subjected to hard anodizing treatment to improve surface hardness and prevent flatness deviation caused by long-term wear. When designing the aluminum alloy pad 11 with micro-adsorption holes, the processing of micro-adsorption holes 2 has been considered. The hole diameter is 0.211~0.297mm, and they are distributed in an array. At the same time, a removable silicone sealing gasket is designed to block the adsorption holes according to the contour shape and size, so that the micro-adsorption holes 2 avoid the drawn contour.

[0031] The pen refill limiting block 6 adopts a four-sided prism pen clip structure. Its four outer walls and the inner wall of the limiting seat 8 form a surface-to-surface contact fit. By replacing the contact constraint of the traditional cylindrical structure in any direction with surface contact constraint, the pen's rotational freedom in the x and y directions is restricted, the vibration interference caused by the movement of the first integral handle 7 is offset, the pen is prevented from shaking irregularly, and the continuous and complete contour lines of the complex curved surface of the tenon are ensured.

[0032] A multi-station rotary pen tray device includes a rotary drive mechanism, a ring-shaped pen tray 9, and at least three pen refills 5 of different specifications. The ring-shaped pen tray 9 is fixedly connected to the output end of the rotary drive mechanism through a central hole 14. The multiple pen refills are evenly distributed around the circumference of the ring-shaped pen tray 9. At least one pen refill 5 is filled with reflective ink, while the remaining pen refills 5 are filled with ordinary ink. The pen refills 5 filled with ordinary ink have different line width specifications to adapt to different tolerance bands. When it is necessary to switch line widths or ink types during the drawing process, the machine tool spindle, carrying the second integral tool holder 10, retracts to a safe position in the vertical or horizontal direction. The rotary drive mechanism drives the ring-shaped pen tray 9 to rotate, accurately positioning the target pen refill 5 to the drawing station. After that, the machine tool spindle drives the second integral tool holder 10 to... Figure 3 Along the rightward direction, remove the pen refill limiting block 6 and pen refill 5 together from the first integral tool holder 7 (at this time, the first integral tool holder 7 is open) and complete the clamping. After the machine tool spindle is reset, continue drawing to achieve integrated drawing of reflective ink marks and different line widths. The rotary drive mechanism is a supporting power and transmission component that provides rotational power to the annular pen disk 9, and is not marked in the attached drawings of the instruction manual.

[0033] The precision standard image drawing device for projection measurement of the present invention has the following innovations: First, the structural innovation of the drawing device: The pen tip limiting block 6 adopts a surface contact clamping design with a four-sided prism pen clip structure, which replaces the line contact constraint of the traditional cylindrical pen clip, restricts the rotational freedom of the ink pen tip in the x / y direction, cancels the interference of the knife handle vibration, and solves the problems of line breakpoints and interference. It is the core structural improvement of precision drawing.

[0034] Second, the vertical adsorption aluminum pad design: the aluminum alloy pad 1 with tiny adsorption holes 2 combined with the U-shaped limiting structure 3 achieves the fixation of the standard image without displacement or gap. Compared with the horizontal placement method in the existing technology, it completely solves the problem of standard image deformation and displacement during the drawing process. Moreover, the position of the tiny adsorption holes 2 is adjustable and can avoid the drawing outline.

[0035] Third, the multi-station rotating pen tray structure: the ring-shaped pen tray 9 is equipped with pen refills 5 with different line widths and different ink types, realizing automatic switching of line width and fluorescent / reflective ink, eliminating the need for manual pen changing, improving drawing efficiency, and adapting to the needs of mass production.

[0036] Fourth, the standard image is sandblasted with polyester film: This solves the problems of poor ink adhesion and easy smudging, improves the clarity of lines and the abrasion resistance of the standard image, and is suitable for the long-term use needs of projection measurement.

[0037] The method for drawing precise standard images for projection measurement in this invention has the following innovations: First, the dynamic line width adjustment strategy: the line width area is divided according to the contour tolerance of different positions of the part, so that the maximum / minimum contour lines do not overlap and the intervals are clear, which solves the problem of difficult contour differentiation under high precision tolerance (≤0.01mm).

[0038] Second, the targeted application of fluorescent / reflective inks: the smallest outlines are drawn using fluorescent / reflective inks, which solves the problem of reflective interference during the inspection of aero-engine blades and improves the recognizability of the outlines.

[0039] Third, active compression of the profile tolerance zone: Combining the machining / assembly requirements of the parts, the tolerance of key dimensions is compressed while the other dimensions remain unchanged, taking into account both inspection accuracy and actual production, and adapting to the personalized inspection needs of aerospace parts.

[0040] In summary, the drawing device and method of this invention are not only suitable for the detection of tenon contours of aero-engine blades, but can also be applied to the standard image drawing of complex curved surface parts such as wheel mortises, gears, and profile templates by adjusting the contour trajectory, pen specifications, and ink type, thus overcoming the limitations of existing technologies. This invention can be applied to industrial control computers to realize hardware configuration (such as industrial motherboards and high-precision motion control cards) and software design.

[0041] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method for drawing precise standard images for projection measurement, characterized in that, The following apparatus for drawing precise standard images for projection measurement is used, and the apparatus includes: A drawing film, wherein the drawing surface of the drawing film is a sandblasted surface (16) that has undergone sandblasting treatment; An aluminum alloy pad (1) with micro-adsorption holes has a surface including a plane for placing a drawing film in a vertical state. The plane is provided with micro-adsorption holes (2) and a limiting structure (3). The drawing film is adsorbed by the airflow in the micro-adsorption holes (2) and constrained between the plane and the limiting structure (3). L-shaped base (4), the vertical edge of which is attached to an aluminum alloy pad (1) with tiny adsorption holes; The pen refill (5) includes ordinary ink pen refills with different line widths, and fluorescent ink pen refills or reflective ink pen refills with different line widths. The pen refill limiting block (6) includes a rounded quadrangular prism structure. The side of the quadrangular prism structure has a pen refill limiting hole (12), and the bottom surface of the quadrangular prism structure has a pen refill insertion hole. A pen refill (5) is inserted into the pen refill insertion hole. The shape of the pen refill insertion hole is the same as the shape of the pen refill (5), so that the pen refill (5) and the pen refill insertion hole are in surface contact. The first integral knife handle (7) and the limiting seat (8) are connected. The pen refill limiting block (6) is installed in the first integral knife handle (7) and fixed in the first integral knife handle (7) by the limiting seat (8). The annular pen disk (9) and multiple pen refill limit blocks (6) are vertically mounted on the same side end face of the same annular pen disk (9) through the first integral tool holder (7) and the limit seat (8). The middle hole (14) of the annular pen disk (9) is connected to the machine tool. The rotation drive mechanism of the machine tool drives the annular pen disk (9) to rotate. The line width of the pen refills (5) in different pen refill limit blocks (6) of the same annular pen disk (9) is different. The method for drawing precise standard images for projection measurement includes the following steps: S1. Obtain contour data: Obtain the contour geometry data of the part to be measured, and draw the projection measurement contour diagram of the part to be measured in its original proportion. The contour diagram includes the maximum contour and the minimum contour. S2, Controlling the profile tolerance zone: Based on the processing requirements, usage requirements, or assembly requirements of the part to be tested, for some dimensions of the part to be tested, compress the profile tolerance of that part, while keeping the profile tolerance of the remaining dimensions unchanged, and update the profile diagram in S1. S3. Develop a strategy for drawing the outline lines: For the updated contour map in S2, adjust the line width of the maximum and minimum contours at different positions, select different line widths according to the contour tolerance at different positions, and finally determine the line widths to ensure that the lines corresponding to the maximum contour and the lines corresponding to the minimum contour do not overlap and the interval between them is clear. S4. Standard image fixing and pen refill (5) adjustment: The L-shaped base (4) is fixed on the machine tool workbench. The L-shaped base (4) and the aluminum alloy pad (1) with tiny adsorption holes are connected by bolts. The drawing film is laid flat on the plane of the aluminum alloy pad (1) with tiny adsorption holes, with the sandblasting surface (16) of the drawing film facing outward. Ensure that the drawing film and the aluminum alloy pad (1) with tiny adsorption holes are tightly fitted without gaps or wrinkles. The pen refill (5) corresponding to the line width finally determined in S3 is inserted into the pen refill limiting block (6) and fixed by the limiting seat (8). S5. Contour drawing program development and command transmission: According to the magnification ratio requirements, the updated outline in S2 is drawn as an enlarged CAD format drawing, the drawing is converted into an NC program, different pen cores (5) line widths are selected, and the drawing is transmitted to the CNC machine tool. S6. Dynamically adjustable line width and ink flow during the drawing process: In the CNC machine tool, the NC program in S5 is executed as the drawing program. When it is necessary to switch to different drawing line widths, rotate the ring pen disk (9) to the pen core (5) of the corresponding drawing line width. The machine tool spindle moves and clamps the pen core (5). Then reset and continue to execute the drawing program. When drawing the smallest outline, rotate the ring pen disk (9) to the pen core (5) using fluorescent ink or reflective ink. The machine tool spindle moves and clamps the pen core (5). Then reset and continue to execute the drawing program. S7, Standard Image Detection: After the drawing process in S6 is completed, the size, line continuity, whether the lines in key areas interfere with each other, and the recognition of fluorescent / reflective ink marks of the obtained standard image are detected. If the detection is qualified, it is used for the projection contour comparison detection of the part to be tested.

2. The method for drawing precise standard images for projection measurement according to claim 1, characterized in that: The drawing film is a polyester film or a polyimide film.

3. The method for drawing precise standard images for projection measurement according to claim 1, characterized in that: The limiting structure (3) is a U-shaped protrusion that extends vertically along the surface of the aluminum alloy pad (1) with tiny adsorption holes for placing a drawing film. The U-shaped protrusion has a U-shaped groove on its surface to restrict the movement of the drawing film, and the drawing film is placed in the U-shaped groove.

4. The method for drawing precise standard images for projection measurement according to claim 1, characterized in that: The pen refill limiting block (6) is provided with a spring at one end of the first integral knife handle (7). The spring ensures stable contact between the pen refill (5) and the drawing film, and counteracts vibration interference.

5. The method for drawing precise standard images for projection measurement according to claim 1, characterized in that: In S1, the contour data is a dataset of coordinate points, or dimensions and dimensional tolerances.

6. The method for drawing precise standard images for projection measurement according to claim 1, characterized in that: In S2, the gap width between the line corresponding to the maximum contour and the line corresponding to the minimum contour is ≤0.01mm.

7. The method for drawing precise standard images for projection measurement according to claim 1, characterized in that: In S3, the drawing size accuracy is 0.002 to 0.005 mm, which is the deviation range between the actual size of the outline and the theoretical design size. In S3, the maximum contour and the minimum contour include three regions with different line widths: the first contour precision line width A is 0.01 to 0.06 mm, the second contour precision line width B is 0.07 to 0.10 mm, and the third contour precision line width C is 0.11 to 0.20 mm. In step S5, different magnification ratios can be selected, including magnification of 5 times, magnification of 20 times, magnification of 30 times, or magnification of 50 times; In step S7, a high-precision five-coordinate measuring instrument is selected to inspect the standard image.

8. A computer-readable medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it sequentially implements steps S1 to S7 in the method for drawing precise standard images for projection measurement as described in any one of claims 1 to 7.

9. A computer program product comprising computer-readable code, or a non-volatile computer-readable storage medium carrying computer-readable code, characterized in that: When the computer-readable code is run in the processor of the electronic device, the processor in the electronic device performs steps S1 to S7 in the method for drawing a precision standard image for projection measurement as described in any one of claims 1 to 7.

10. An electronic device, comprising a memory and a processor, characterized in that: The memory stores a computer program that can be executed by the processor. When the computer program is executed by the processor, it implements steps S1 to S7 of the method for drawing a precision standard image for projection measurement as described in any one of claims 1 to 7.

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