Spaceflight profile frame multi-point stretch bending forming deviation measurement method and sample plate used thereby

Abstract

The application discloses a kind of aerospace profile frame multi-point stretch bending forming deviation measurement method and the sample plate used, belong to aerospace profile frame class part forming technical field, the present application is in view of the low precision of traditional sample plate comparison method, the high cost of non-contact laser measurement, design special sample plate and measurement process: sample plate is engraved with concentric theoretical circular arc line (including less than the arc line of smallest applicable radius of die, greater than the arc line of maximum applicable radius of die), symmetric radiation line (with die T-shaped groove axis coincides), is provided with the rectangular measurement datum gap of the intersection of radiation line and circular arc line and the pin hole (inserts cylindrical pin positioning part) consistent with circular arc line in number;Measurement method is through part positioning, selects datum arc line by positive and negative deviation, caliper actual measurement, deviation conversion and symmetric average, realize the accurate measurement of no special equipment.The present application is low in cost, high in efficiency, can directly provide data for die springback compensation and shape adjustment, form "forming-measurement-correction" technical closed loop.

Description

Technical Field

[0001] This invention relates to a method for measuring the deviation of multi-point bending forming of aerospace profile frames and the template used therein. Background Technology

[0002] Currently, most profile frame parts in the aerospace field have a large 180° central angle structure, and their forming process mainly adopts stretch bending and roll bending methods. Due to factors such as material springback and mold precision, the actual shape of the formed parts often deviates from the theoretical shape, and deviation measurement and correction are required to ensure that the parts meet assembly requirements.

[0003] In existing profile frame forming processes, multi-point stretch bending has become the mainstream choice due to its adjustable die surface, good forming consistency, and high production efficiency. However, the springback compensation after multi-point stretch bending requires precise acquisition of the surface deviation "along the shaping direction," i.e., "the radial direction of the die T-slot." Traditional measurement methods have significant shortcomings. Traditional template comparison method: can only obtain a rough deviation of a certain segment by placing the template against the part, cannot accurately measure the deviation value of discrete points, and has difficulty distinguishing between positive deviation (part outside the theoretical range) and negative deviation (part inside the theoretical range). Non-contact 3D laser measurement method: requires specialized and expensive equipment, and the automatic registration strategy is complex, GD&T (geometric dimensions and tolerances) items are difficult to formulate, and it is impossible to efficiently obtain the deviation value of the adjustment direction.

[0004] Therefore, there is an urgent need for an economical, fast, and accurate deviation measurement solution to meet the springback compensation and mold adjustment requirements of multi-point bending processes. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for measuring the multi-point bending forming deviation of aerospace profile frames, as well as a template for this purpose. This enables accurate measurement of the positive and negative deviations of the parts.

[0006] To achieve the above objectives, the present invention employs the following technical solutions: A template for measuring the deviation of multi-point bending forming of aerospace profile frames is provided. The template is engraved with several concentric theoretical arc lines and several symmetrically distributed radial lines. The theoretical arc lines intersect with the radial lines, and the radial lines coincide with the central axis of the T-groove of the multi-point bending mold. The template has a measurement reference notch located at the intersection of the radiation line and the theoretical arc line, which serves as a positioning reference for the measuring tool. The template also has several pin holes, and the cylindrical pins are tangent to the corresponding theoretical arc lines.

[0007] The present invention has the following advantages: It can accurately and quickly measure the positive and negative deviations of profile frames in a specific direction without the need for special equipment and instruments, and can cover a certain radius range. It is suitable for use in frame parts of various specifications. It eliminates the need to customize special templates for frame parts of multiple specifications, saving template materials and the storage space occupied by templates. It is especially suitable for multi-point bending springback compensation and mold adjustment of frame parts. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of a multi-point bending die structure.

[0009] Figure 2 This is a schematic diagram of a template structure used for measuring the deviation of multi-point bending forming of aerospace profile frames.

[0010] Figure 3 This is a magnified view of a part of a template used for measuring the deviation of multi-point bending forming of aerospace profile frames.

[0011] In the diagram: 5-template, 51-theoretical arc, 52-radiation line, 53-measuring reference notch, 531-left end face of notch, 532-front end face of notch, 533-right end face of notch, 54-pin hole, 6-depth vernier caliper, 61-front end of caliper base, 62-right end of caliper base, 63-fastening screw, 64-caliper body, 65-left end of caliper base, 641-left end of measuring surface, 642-right end of measuring surface, 7-part. Detailed Implementation

[0012] The present invention will now be described in detail with reference to the accompanying drawings.

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0014] Example 1: like Figures 1-3 As shown, A template 5 for measuring the deviation of multi-point bending forming of aerospace profile frames is provided. The template 5 has several concentric theoretical arc lines 51 and several symmetrically distributed radial lines 52 engraved on it. The theoretical arc lines 51 and radial lines 52 intersect, and the radial lines 52 coincide with the central axis of the T-shaped groove on the multi-point bending die base (e.g., the multi-point bending die...). Figure 1 As shown, its structure and function can be found in the "A Flexible Multi-Point Bending Die for Aerospace Profile Frames" submitted on the same day, which is used for the "radiation direction" for positioning deviation measurement to ensure that the measurement direction is consistent with the die adjustment direction; The template 5 has a measurement reference notch 53 located at the intersection of the radiation line 52 and the theoretical arc line 51, which serves as the positioning reference for the measuring tool (depth vernier caliper 6). The template 5 also has several pin holes 54, and the cylindrical pins (i.e., the positioning pins 4 of the template 5) inserted into the pin holes 54 are tangent to the corresponding theoretical arc line 51. The pin holes 54 are used to insert the cylindrical pins to achieve the positioning of the aerospace profile frame part 7 on the template 5.

[0015] The theoretical arc 51 contains at least one arc with a radius smaller than the minimum applicable radius of the multi-point bending die, and at least one arc with a radius larger than the maximum applicable radius of the die; several arcs 51 are concentrically distributed, covering the range from "smaller than the minimum applicable radius of the die" to "larger than the maximum applicable radius of the die" (designed according to the maximum springback of part 7), ensuring that parts 7 with different springback amounts can find a matching baseline.

[0016] The measurement reference notch 53 is a rectangular structure and is symmetrical about the corresponding radiation line 52. The length direction of the notch 53 is perpendicular to the radiation line 52. The midpoint of the front end face of the measurement reference notch 53 (i.e., the front end face 532 of the measurement reference notch) coincides with the intersection of the radiation line 52 and the theoretical arc line 51, ensuring that the measured data is accurate.

[0017] The length of the measuring reference notch 53 satisfies: (1) When the front end 61 of the depth vernier caliper 6 is against the front end face 532 of the notch and the left end 65 of the caliper 6 is against the left end face 531 of the notch, the right end 642 of the measuring surface of the caliper 6 is located on the radiation line 52. (2) When the front end 61 of the depth vernier caliper 6 is close to the front end face 532 of the notch and the right end 62 of the caliper 6 is close to the right end face 533 of the notch, the left end 641 of the measuring surface of the caliper 6 is located on the radial line 52. This ensures that no matter which side of the measuring part 7 is deviated, the measuring point of the caliper 6 in contact with the part 7 is accurately locked on the mold adjustment direction (radial line 52), avoiding deviation of the measuring direction and data failure due to improper length.

[0018] The number of pin holes 54 is consistent with the number of theoretical arc lines 51, which can be adapted to profile frame parts 7 with different radii. There is no need to make a separate template 5 for each part 7, saving material costs and storage space.

[0019] In this embodiment, the template 5 can be precisely adapted to the multi-point bending mold, providing a stable benchmark for the deviation measurement of part 7 without the need for special equipment, while covering the measurement needs of parts of various specifications, taking into account both accuracy and versatility.

[0020] Example 2: A method for measuring the multi-point bending forming deviation of aerospace profile frames includes the following steps: S1: Part positioning: Based on the forming radius of the part 7 to be measured, select the corresponding target theoretical arc line in the concentric theoretical arc line 51 of the template 5; insert a cylindrical pin (template 5 positioning pin 4) into the pin hole 54 corresponding to the target theoretical arc line 51, place the inner side (design datum surface) of part 7 against the cylindrical pin, and move part 7 left and right to ensure that the deviations on both sides of part 7 are symmetrical. S2: Deviation measurement.

[0021] S21: Select the measurement reference arc. If the part 7 at the measurement point has a positive deviation (part 7 is located outside the target theoretical arc 51 and does not obstruct the target theoretical arc 51), then the target theoretical arc 51 is selected as the measurement reference arc; if the part 7 at the measurement point has a negative deviation (part 7 is located inside the target theoretical arc 51 and obstructs the target theoretical arc 51), then a smaller theoretical arc 51 with a radius smaller than the target theoretical arc 51 is selected as the measurement reference arc. S22: Specific deviation measurement; When measuring the deviation on the left side of part 7, place the front end 61 of the depth vernier caliper 6 against the front end face 532 of the measuring reference notch, and the left end 65 of the caliper 6 against the left end face 531 of the measuring reference notch. Push the caliper body 64 so that the right end 642 of the measuring surface abuts against the side wall of part 7. Tighten the fastening screw 63 and then read the deviation value. When measuring the deviation on the right side of part 7, place the front end 61 of the depth vernier caliper 6 against the front end face 532 of the measuring reference notch, and the right end 62 of the caliper 6 against the right end face 533 of the measuring reference notch. Push the caliper body 64 so that the left end 641 of the measuring surface abuts against the side wall of part 7. Tighten the fastening screw 63 and then read the deviation value. S3: Deviation processing performs a baseline conversion on the negative deviation value: subtract the distance between the smaller theoretical arc 51 and the target theoretical arc 51 from the measured value of the negative deviation to obtain the negative deviation value based on the target theoretical arc 51; take the average value of the deviation values ​​at the symmetrical positions of part 7 and retain the positive and negative signs to ignore the influence of the non-uniformity of the part 7's structure.

[0022] In this embodiment, the method, in collaboration with the template 5, can accurately obtain the positive and negative deviations of the part 7 using only the depth vernier caliper 6. The data can be directly used for mold adjustment, taking into account both ease of operation and measurement accuracy.

[0023] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A template for measuring the multi-point bending forming deviation of aerospace profile frames, characterized in that: The template is engraved with several concentric theoretical arc lines and several symmetrically distributed radial lines, and the theoretical arc lines and the radial lines are intersected. The radial lines coincide with the central axis of the T-groove of the multi-point bending die. The template has a rectangular measurement reference notch located at the intersection of the radiation line and the theoretical arc line, which serves as the positioning reference for the measuring tool. The template also has several pin holes, and the cylindrical pins inserted into the pin holes are tangent to the corresponding theoretical arc lines for positioning the parts to be measured. The measurement reference notch is rectangular and symmetrical about the corresponding radial line. The length direction of the measurement reference notch is perpendicular to the radial line. The midpoint of the front face of the measurement reference notch coincides with the intersection of the radial line and the theoretical arc. The length of the measurement reference notch must meet the following conditions: (1) When the front end of the depth vernier caliper is against the front end face of the notch and the left end of the caliper is against the left end face of the notch, the right end of the measuring surface of the caliper is located on the radial line. (2) When the front end of the depth vernier caliper is against the front end face of the notch and the right end of the caliper is against the right end face of the notch, the left end of the measuring surface of the caliper is located on the radial line.

2. A method for measuring the multi-point bending forming deviation of aerospace profile frames based on the template described in claim 1, characterized in that, Includes the following steps: S1: Part positioning: Based on the forming radius of the part to be measured, select the corresponding target theoretical arc line in the concentric theoretical arc line of the template; insert a cylindrical pin into the pin hole corresponding to the target theoretical arc line, place the inner side of the part against the cylindrical pin, and move the part left and right to ensure that the deviations on both sides of the part are symmetrical. S2: Deviation Measurement S21: Select the measurement reference arc: If the part at the measurement point has a positive deviation, then select the target theoretical arc as the measurement reference arc; if the part at the measurement point has a negative deviation, then select a smaller theoretical arc with a radius smaller than the target theoretical arc as the measurement reference arc. S22: Specific deviation measurement; When measuring the deviation on the left side of the part, place the front end of the depth vernier caliper base against the front face of the measuring reference notch, and the left end of the base against the left end face of the measuring reference notch. Push the caliper body so that the right end of the measuring surface abuts against the side wall of the part. Tighten the fastening screw and then read the deviation value. When measuring the deviation on the right side of the part, place the front end of the depth vernier caliper base against the front face of the measuring reference notch, and the right end of the base against the right end face of the measuring reference notch. Push the caliper body so that the left end of the measuring surface abuts against the side wall of the part. Tighten the fastening screw and then read the deviation value. S3: Deviation processing performs a baseline conversion on the negative deviation value: subtract the distance between the smaller theoretical arc and the target theoretical arc from the measured value of the negative deviation to obtain the negative deviation value based on the target theoretical arc; take the average value of the deviation values ​​of the symmetrical positions of the parts and retain the positive and negative signs.

3. The template for measuring the multi-point bending forming deviation of aerospace profile frames according to claim 1, characterized in that: The theoretical arc line includes at least one arc line with a radius smaller than the minimum applicable radius of the multi-point bending die, and at least one arc line with a radius larger than the maximum applicable radius of the die.

4. The template for measuring the multi-point bending forming deviation of aerospace profile frames according to claim 1, characterized in that: The number of pin holes is consistent with the number of theoretical arc lines.

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