A method for controlling and correcting the position deviation of a notch on a frame plate part for aerospace

Abstract

The application discloses a method for controlling and correcting notch position deviation of frame plate parts for spaceflight, which binds the ring-shaped parts on a heat treatment quenching tool by metal wires in the shape of U or in the shape of upside-down U, the metal wires and the ring-shaped parts are made of the same material, the binding points are not less than six, and the positioning holes, the notching and the heat treatment are selected according to the material of the ring-shaped parts and the processing sequence of the heat treatment, and the notch deviation of the parts after the heat treatment is manually corrected. The production efficiency is improved by nearly 5 times, the one-time inspection qualified rate of the forming quality reaches 98%, the cracking and scrapping risk is reduced, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of machining, and more specifically to a method for controlling and correcting the offset of notch positions on aerospace frame plate-type parts. Background Technology

[0002] Frame rings are structural components of launch vehicles, forming the rocket body along with stringers, skin, and other parts. They are crucial radial load-bearing components. Frame rings are annular members with "Z" or "L" shaped cross-sections, machined from sheet metal. Common materials are LC9-M ultra-hard aluminum alloy or LY12-M hard aluminum alloy, with a material thickness of 2mm, widely used in aerospace products. The maximum radius of curvature for these parts is approximately R1670mm, with notches of varying shapes and sizes distributed along the generatrix to allow stringers to pass through. These parts can be categorized by name as frame rings, frame plates, and half-frame rings, with most having arc lengths of 90 degrees and 180 degrees. Due to the high requirements for form and position tolerances, the surface accuracy, flatness, and especially the positional accuracy of the stringer notches, can lead to deviations in the final product specifications and even interfere with the normal assembly of stringer components. Therefore, component accuracy is critical to the final dimensions of the final product.

[0003] For the positional inspection of stringer notches in frame ring, half-frame, and semi-frame ring parts, the industry standard method is to use a standard cutting and drilling template for comparison. When using this template, issues such as length deviation (i.e., the overall notch's relative position along the arc direction is longer or shorter than the standard position on the template) often occur at the far ends of the parts. For stringer notches, positioning holes are drilled using a dedicated cutting and drilling template, and the notch is then punched using a punching process. Finally, after heat treatment, manual correction is used to meet design requirements, achieving a deviation of no more than 1mm from the cutting and drilling template inspection.

[0004] In the traditional notch forming process for frame-type parts, technicians did not consider the impact of heat treatment on the stringer notches, nor did they specify clear requirements for the binding method and timing of heat treatment in the furnace, or control the length changes of parts made of different materials during heat treatment. Regardless of the material or specifications, the notches were machined first, followed by free binding heat treatment, and repeated rolling on a six-axis roller combined with manual correction to meet design requirements. For a long time, parts have suffered severe deformation after solution heat treatment. Since the arc length of some parts can reach up to 6 meters, there are more than 30 stringer notches. The more times the parts are repeatedly rolled on the six-axis roller, the more the material is compressed and deformed, resulting in significant displacement of the far-end notches. Therefore, correction is difficult, time-consuming, and labor-intensive, with a first-pass yield rate typically less than 60%. The problem of stringer notch position deviations has become a bottleneck restricting the final assembly schedule, and has remained unresolved for a long time. Summary of the Invention

[0005] The purpose of this invention is to address, based on existing technology, the problems of low processing efficiency, high labor intensity, low first-pass yield, and out-of-tolerance string notch position in frame plate-type parts. Simultaneously, it improves the efficiency of shape correction by nearly 5 times, achieving a first-pass yield of 98%.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for controlling and correcting the position offset of notches on aerospace frame plate-like parts includes the following steps:

[0008] S1: The ring-shaped part is bound to the heat treatment quenching fixture with metal wire in a U-shape or U-shape. The metal wire and the ring-shaped part are made of the same material, and there are no less than six binding points.

[0009] S2: Select the order of processing steps for positioning holes, punching notches, and heat treatment based on the material of the ring-shaped part;

[0010] S3: Manually correct the notch offset on the heat-treated part.

[0011] In the above technical solution, when the material of the annular part is 2A12-O, the annular part is bound in a ∩ shape, and when the material of the annular part is 7A09-O, the annular part is bound in a ∪ shape.

[0012] In the above technical solution, when the material of the ring-shaped part is 2A12-O, after heat treatment, the ring-shaped part is then drilled with positioning holes and punched with notches. When the material of the ring-shaped part is 7A09-O, after drilling positioning holes and punching with notches, the ring-shaped part is then heat treated.

[0013] In the above technical solution, the metal wire used to bind the ring-shaped parts is aluminum wire.

[0014] In the above technical solution, when the notch is offset outward compared to the test template, the overall width of the part is reduced while ensuring the width of the web plate, so that the arc length of the entire part is shortened and the notch returns to the correct position. When the notch is offset inward compared to the test template, the overall width of the part is increased while ensuring the width of the web plate, so that the arc length of the entire part is lengthened and the notch returns to the correct position.

[0015] In the above technical solution, when the notch is offset outward compared to the test template, the height of the small bend of the fencing is increased by adjusting the root of the small bend of the fencing, thereby reducing the width of the web. When the notch is offset inward compared to the test template, the height of the small bend of the fencing is decreased by adjusting the upper edge of the small bend of the fencing, thereby increasing the width of the web.

[0016] The proposed modification method is based on three reasons:

[0017] Firstly, traditional methods of binding parts during heat treatment often result in deformation due to improper binding. This invention employs a ∪-shaped or ∩-shaped binding, minimizing the contact area between the part and the quenching medium surface during furnace loading (reducing deformation caused by resistance when the part enters the 470°C–500°C high-temperature liquid medium). The binding wire is made of aluminum wire, the same material as the part, which solves the problem of parts with different coefficients of thermal expansion being unable to stretch in the quenching medium, leading to severe localized deformation. Increasing the binding positions increases the support of the tooling for the part, reducing deformation caused by the part's own weight and the movement of the quenching support when it is in a soft state at high temperatures. Based on the deformation length of the stringer notch of different raw materials, ∪-shaped or ∩-shaped binding is used (previously, binding was free and without clear requirements; operators arbitrarily chose ∪-shaped or ∩-shaped binding without considering material factors). That is, when loading the part into the furnace, both ends are fixed to the quenching tooling with the ends facing upwards or downwards. During quenching, due to the weight of the part itself, a U-shaped binding will make the quenched part longer, while a U-shaped binding will make the quenched part shorter, and the stringer notch will become longer or shorter accordingly.

[0018] The deformation length of the stringer notch varies depending on the raw material. The appropriate binding method is either ∪-shaped or ∩-shaped (current technology uses free binding without clear requirements; operators arbitrarily choose ∪-shaped or ∩-shaped binding without considering material factors). This means that when the parts are loaded into the furnace, both ends are fixed to the quenching fixture with the ends facing upwards or downwards. During quenching, due to the weight of the parts themselves, ∪-shaped binding will cause the quenched parts to lengthen, while ∩-shaped binding will cause them to shorten, thus affecting the length of the stringer notch. It is determined that ∩-shaped binding quenching should be used for all 2A12-O (LY12-M) parts because the parts will generally lengthen during repeated reshaping on the rolling mill after heat treatment (this material is naturally aged and will not shorten without subsequent artificial aging processes). For frame plate parts made of 7A09-O (LC9-M) material, the parts will shorten after quenching and artificial aging; using ∪-shaped binding quenching can help to lengthen them.

[0019] Secondly, the timing of heat treatment.

[0020] Depending on the material and specifications, the heat treatment process can be scheduled before or after drilling positioning holes and punching notches. When the part material is 2A12-O (LY12-M) and the part's curvature is 90° (for longer parts with 180° notches, drilling positioning holes, punching notches, and corrections cannot be completed within two hours; only ∩-shaped binding can reduce the offset), the punching notch process should be performed within two hours after heat treatment and quenching (this is the optimal correction time for the material; beyond this time, the material structure will gradually harden, increasing the difficulty of correction and posing a risk of cracking). The significance lies in the fact that the notch is not machined on the part before heat treatment. After taking it out of the furnace, there is no need to control the number of rolling adjustments. The notch is machined only after the rolling adjustment is completed to meet the requirements. At this time, the material structure is basically stable, and no further rolling adjustment is needed. The possibility of displacement is greatly reduced, thus effectively controlling the position of the notch. When the part material is 7A09-O (LC9-M), the drilling of positioning holes and punching of notches should be carried out before heat treatment quenching and artificial aging. This is because when the part is in a soft state at high temperature, its own gravity can cause the part to lengthen slightly. This helps to control the problem of the part shortening after artificial aging and the notch shifting inward by using the heat treatment U-shaped quenching method.

[0021] Third, even after the first two control measures, the parts still have problems with out-of-tolerance gap offset. Due to the uneven material structure, the amount of heat treatment deformation varies from part to part, and the number of rolling corrections is also different, which makes control difficult. Therefore, the manual method of this invention can only be used for correction.

[0022] The corrective principle of this invention is as follows:

[0023] When the notch is offset outwards and longer compared to the inspection template, reducing the part width by 1mm within the tolerance range is equivalent to reducing the radius by 1mm. That is, the part's surface radius of curvature decreases from R1670 to R1669. Calculations show that the total 180° arc shortens by more than 3mm. The notch on the part naturally shrinks inwards with the change in arc length, thus returning to the correct position and meeting the template inspection requirements. Conversely, when the notch is offset inwards and shorter compared to the inspection template, increasing the part width by 1mm within the tolerance range is equivalent to increasing the radius by 1mm. That is, increasing from R1670 to R1671, the total 180° arc increases by more than 3mm. The notch on the part naturally extends outwards with the change in arc length, thus returning to the correct position and meeting the template inspection requirements. In other words, by manually correcting the width of the web plate, we can change the template's position forward or backward by 1mm relative to the part's initial non-conforming state. The change in the overall arc length resulting from this correction of the notch on the part allows for a 3mm adjustment space inwards or outwards.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] 1. Improved production efficiency: Previously, it took 2 to 3 hours to process one product after heat treatment, but now it only takes 30 to 40 minutes, increasing production efficiency by nearly 5 times.

[0026] 2. Improved forming quality: Parts formed by this method achieve a first-pass yield of 98%.

[0027] 3. Reduced production costs: Reduced risk of cracking and scrapping, increased efficiency and reduced production costs. Attached Figure Description

[0028] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0029] Figure 1 This is a schematic diagram of a 180° frame plate part;

[0030] Figure 2 This is a diagram of the web width. Figure 1 ;

[0031] Figure 3 This is a map showing the location of the school.

[0032] Figure 4 This is a diagram of the web width. Figure 2 ;

[0033] Figure 5 This is a diagram showing the location of the school. Detailed Implementation

[0034] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0035] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0036] This embodiment uses frame plate parts made of two materials, 7A09-O (LC9-M) and 2A12-O (LY12-M), as follows: Figure 1 The comparison will be illustrated below.

[0037] When the part material is 7A09-O (LC9-M), this embodiment uses U-shaped binding quenching. The U-shaped binding will make the quenched part longer. Therefore, the part at the rear end of the binding is first drilled with positioning holes and punched with notches, and then subjected to heat treatment quenching. The reason for choosing this process is that when the part is in a soft state at high temperature, its own weight can make the part slightly longer overall. This is beneficial to control the problem of the part becoming shorter after artificial aging and the notch shifting inward by using the U-shaped binding quenching method.

[0038] When the part material is 2A12-O (LY12-M), this embodiment uses ∩-shaped binding quenching. ∩-shaped binding shortens the quenched part because the part lengthens during repeated shaping on the rolling press after heat treatment. Longer parts with more notches cannot complete drilling positioning holes, punching notches, and correction within 2 hours; ∩-shaped binding is necessary to reduce offset. The notch punching process is performed within 2 hours after heat treatment and quenching (the optimal correction time for the material; beyond this time, the material structure gradually hardens, increasing the difficulty of correction and posing a risk of cracking). Because the notch is not machined on the part during heat treatment, there is no need to control the number of rolling adjustments after removal from the furnace. The notch is machined only after the rolling adjustment meets the requirements. At this point, the material structure is nearly stable, and further rolling adjustments are unnecessary, greatly reducing the possibility of offset and effectively controlling the notch position. Therefore, the part is heat-treated and quenched before drilling positioning holes and punching notches.

[0039] When performing manual corrections, if the notch shifts outward compared to the inspection template, it indicates that the arc length of the part is too long. While maintaining the web width dimension of 100±1 (or other dimensions), the web width of the entire part can be adjusted to 100~99mm (e.g., Figure 2 Correcting the range shortens the overall arc length of the part, returning the notch to its correct position. By adjusting the root of the small bend radius of the fender, the height of the small bend is reduced from 28mm to 29mm, thereby reducing the web width to 99mm. Figure 3 As shown.

[0040] When the notch shifts inward compared to the test template, it indicates that the arc length of the part is too short. Similarly, while ensuring the web width dimension is 100±1 (or other dimensions), simultaneously shift the web width of the entire part by 100~101mm (e.g., Figure 4 Correcting the arc length within the specified range will lengthen the entire part, returning the notch to its correct position. By adjusting the upper edge of the small bend of the fender, the height of the small bend is reduced from 28mm to 27mm, increasing the web width to 101mm. Through these manual corrections, the quality issue of the stringer notch misalignment can be resolved. Only the height of the small bend of the fender needs to be ensured to remain within tolerance. Figure 5 As shown.

[0041] In this embodiment, common tools are used, such as aluminum hammers, aluminum straight top blocks, and straightening molds. By controlling the heat treatment process in the first two points of this embodiment, the offset of the stringer notch position is controlled to the optimal state before manual correction. Then, by using traditional cold sheet metal manual forming tools in conjunction with the mold and operating according to the correction position and principle determined by the technical solution, the straightening process can be completed easily and quickly.

[0042] 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 method for controlling and correcting the positional offset of a notch on a ring-shaped aerospace component, characterized in that... Includes the following steps: S1: The ring-shaped part is bound to the heat treatment quenching fixture with metal wire in a U-shape or U-shape. The metal wire and the ring-shaped part are made of the same material, and there are no less than six binding points. S2: Select the order of drilling positioning holes, punching notches, and heat treatment based on the material of the ring-shaped part; S3: Manually correct the notch offset on the heat-treated part; When the material of the ring-shaped part is 2A12-O, the ring-shaped part is bound using a ∩-shaped binding method. When the material of the ring-shaped part is 7A09-O, the ring-shaped part is bound with a ∪-shaped binding. When the material of the ring-shaped part is 2A12-O, after heat treatment, the ring-shaped part is then drilled with positioning holes and punched with notches. When the material of the ring-shaped part is 7A09-O, after drilling positioning holes and punching notches on the ring-shaped part, the ring-shaped part is then heat-treated.

2. The method for controlling and correcting the position offset of a notch on a ring-shaped aerospace component according to claim 1, characterized in that: The metal wire used to bind the ring-shaped parts is aluminum wire.

3. The method for controlling and correcting the position offset of a notch on a ring-shaped aerospace component according to claim 1, characterized in that: When the notch shifts outward relative to the inspection template, the overall width of the part is reduced while ensuring the width of the web plate, thus shortening the arc length of the entire part and returning the notch to its correct position. When the notch shifts inward relative to the test template, the overall width of the part is increased to correct it while ensuring the width of the web plate, thus lengthening the arc length of the entire part and returning the notch to the correct position.

4. The method for controlling and correcting the position offset of a notch on a ring-shaped aerospace component according to claim 3, characterized in that: When the notch shifts outward relative to the test template, the root of the small bend in the welt is adjusted to increase its height and reduce the web width. When the notch shifts inward compared to the test template, the height of the small bend of the welt is reduced by adjusting the upper edge of the welt, thereby increasing the width of the web.

Images