Method for machining thin plate high temperature alloy with small diameter inclined hole multi-bulge features

Abstract

The present application belongs to the field of sheet high-temperature alloy processing and manufacturing, and relates to a sheet high-temperature alloy processing method with small-diameter inclined hole multi-bulge characteristics. The present application improves the processing efficiency and quality of sheet high-temperature alloy, determines the hole making position on the developed pattern by using hole axis positioning method, adopts non-contact laser cutting to complete the manufacturing of two-dimensional developed raw material contour, characteristic small hole and process positioning hole on the component base material sheet, uses local step forming method for the raw material, firstly performs integral profile die forming by positioning with the process positioning hole, then forms the bulge characteristics of the part one by one through the bending die with local profile, and finally clamps the part in the heat treatment clamp by positioning with the process positioning hole to realize accurate shape correction. The present application can flexibly adjust the normal direction of the bulge during the forming process, thereby ensuring the accuracy of the bulge.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of thin plate high-temperature alloy processing and manufacturing, and relates to a thin plate high-temperature alloy processing method with small-diameter inclined hole and multi-bulge characteristics. BACKGROUND

[0002] To adapt to the service environment and load working conditions of stress-thermal-acoustic-vibration combined action, especially to overcome new problems brought by high-temperature service environment conditions, commonly used titanium alloys and composite materials cannot meet the requirements. Therefore, more and more high-temperature alloy materials are applied to aircrafts. In addition to the iteration of part materials, many active cooling technologies are adopted in product structures, and the small-diameter inclined hole feature is a commonly used active cooling structure. Since the holes distributed on the entire surface of the thin plate part have a diameter of 2 mm and the central axis of the hole has a certain angle with the normal of the curved surface, drilling is the preferred method, but the poor machinability of high-temperature alloy, the large number of small-diameter inclined holes, and the need to ensure the angle between the central axis and the normal not only require special drill jigs and special high-temperature alloy steel drill bits, but also require a large amount of manual work. In addition, to meet the assembly requirements of such thin plate high-temperature alloy, a plurality of bulge structures for screw connection are present on the surface of the part. Such bulge structures are suitable for one-time forming by die pressing, which can accurately ensure the spatial position of each bulge. However, in fact, due to the constraints of part structure, negative angles are formed between the axes of the bulges, and die pressing cannot be completed at one time. At the same time, in order to eliminate the springback of the thin plate after die pressing, the part needs to be corrected twice, and the bulge will inevitably become a stumbling block for springback correction. In order to quickly, accurately and efficiently realize the forming of the thin plate high-temperature alloy with small-diameter inclined hole and multi-bulge characteristics, a suitable processing method is urgently needed. SUMMARY

[0003] In view of the above-mentioned problems of large number of small-diameter inclined holes, poor machinability, large amount of labor, and contradictions between the structure of the part with multi-bulge characteristics and the forming process, a thin plate high-temperature alloy processing method with small-diameter inclined hole and multi-bulge characteristics is provided, which improves the processing efficiency and quality of the thin plate high-temperature alloy. The hole axis positioning method is used to determine the hole making position on the developed drawing, the non-contact laser cutting is adopted to complete the manufacturing of the two-dimensional developed blank contour, the small hole and the process positioning hole on the component base plate, the blank is formed by the local step forming method, the overall profile is first formed by die pressing with the process positioning hole as the positioning, and then the bulge characteristics of the part are formed one by one by the bending die with a local profile. Finally, the part is clamped in the heat treatment fixture by the process positioning hole as the positioning, and the accurate correction is realized. The present application can flexibly adjust the normal direction of the bulge during the forming process, and ensures the accuracy of the bulge.

[0004] The technical scheme of the present application:

[0005] The method for processing thin plate high-temperature alloy with small-diameter inclined hole multi-bulge features includes the following steps: determining the position of a process positioning hole according to the shape of the thin plate high-temperature alloy part, determining the hole axis positioning method to determine the hole making position, and determining the two-dimensional manufacturing data set for part blanking, adopting a laser cutting process to complete the manufacturing of the raw material profile, the small hole features and the process positioning hole on the base plate, positioning by the process positioning hole in the bending process, bending the part profile, then clamping the part in the mold with the theoretical position of the bulge hole, drilling the bulge center hole, taking the bulge center hole as the positioning reference to form the bulge feature on the local bending die, and finally, taking the positioning hole as the processing reference to process the part clamped in the heat treatment tooling to realize accurate shape correction.

[0006] First step: process positioning hole setting

[0007] The positioning hole serves as the processing reference for each processing procedure in the part manufacturing process and runs through the entire process of processing the thin plate high-temperature alloy part. In order to reduce the calculation deviation and reduce the number of positioning holes, the positioning holes are attached to the ear pieces on the same edge where the curvature changes little, and the number of positioning holes is selected to be 2-3. In order to better constrain the degrees of freedom of the part, the spacing between the positioning holes is not less than 200 mm, and the diameter of the positioning hole is selected to be 2.7-5.2 mm.

[0008] Second step: two-dimensional development data set and development raw material making

[0009] The two-dimensional development data set is the flattening of the theoretical profile of the part, and the important data for generating the laser cutting track is the three-dimensional data set of the part with positioning ear pieces and positioning holes, including small-diameter inclined holes, bulges and all features, which is expanded by the CATIA data expansion module at the same ratio;

[0010] The hole axis positioning method extracts the intersection of the inclined hole axis and the upper surface of the part in the digital model of the part, and projects the point to the pre-expanded surface. The expansion function is used to expand the selected expansion surface along with the center point, positioning hole, bulge center and other features to form a two-dimensional development data set.

[0011] The laser cutting machine generates the processing code of the two-dimensional development data set, the angle between the laser and the thin plate is the same as the inclined hole, and the small-diameter inclined hole, the positioning hole and the part features are cut on the thin plate to realize the processing of the development raw material;

[0012] Third step: bending part forming

[0013] The bending part forming is to clamp the bending die upper and lower dies which are consistent with the part surface on the center of the upper and lower platforms of the hydraulic machine by bolts, and to preform the unfolded blank by laser impact forming technology according to the part surface characteristics, so that the positioning hole can be consistent with the positioning pin on the bending die to realize effective positioning.

[0014] Fourth step: convex hull feature processing

[0015] The convex hulls are uniformly distributed on the surface of the whole part. In order to determine the theoretical position of the convex hull, a tire with the theoretical position of the convex hull is designed. The tire surface is consistent with the part surface, and the positioning pin A position is also set on the tire body to coordinate with the blank positioning hole. A drilling mechanism is set on the tire cover at the center position of the convex hull. The drilling mechanism is inlaid with a drill sleeve, and the axis thereof coincides with the center line of the convex hull. In order to facilitate drilling, the thickness of the tire cover is thinned in the part of the drilling mechanism.

[0016] The corresponding tire body part is set to avoid;

[0017] The formed blank is clamped in the tire with the positioning hole as the positioning reference and is pressed tightly, so that the blank tends to the theoretical position in the tire. A hand drill penetrates the drill sleeve on the tire cover to form a bottom hole on the part. Due to the poor cutting performance of high-temperature alloy sheet, a punch can also be used to print a center hole on the part through the drilling mechanism. Then the part is taken out and placed on a bench drill to finally complete the drilling of the bottom hole.

[0018] A local bending die is designed with the bottom hole of each convex hull as the positioning reference. The surface of the local bending die is proportional to the surface of the convex hull, and the convex and concave dies are installed on a common punch. A cylindrical positioning pin A is arranged at the center of the convex and concave dies, and the diameter thereof is the same as that of the bottom hole of the convex hull. The local bending die surface is aligned with the convex and concave die surface and the cylindrical positioning pin A, so that no separate guide mechanism is needed to guide the convex and concave dies, avoiding interference with the blank during the convex hull process.

[0019] The local bending die is installed on the punch and the mating surfaces are aligned. The blank is held by hand, the direction of the convex hull is identified, the bottom hole of the convex hull is sleeved into the cylindrical positioning pin A, and the curved surface normal at this position is kept parallel to the vertical direction, that is, the normal of the bottom hole of the convex hull is parallel to the vertical direction. Start the punch to complete the convex hull forming. Repeat the above actions to complete the forming of all convex hulls.

[0020] After the convex hull forming, the bottom hole of the convex hull is expanded by drawing. A punching die is designed with the expanded bottom hole as the positioning reference, and the final processing of the upper hole of the convex hull is completed by punching.

[0021] Fifth step: accurate shape correction

[0022] The precision correction is still based on the positioning hole as a machining reference, the part is installed on a stable heat treatment fixture through a positioning pin, and the surface rebound and internal stress generated in the forming process are eliminated by heating and holding in the clamped state;

[0023] The heat treatment fixture has high temperature resistance, the area of the clamping surface is set according to the rebound state of the part, the convex feature on the surface is set to avoid, in order to improve the use efficiency of the heat treatment furnace, the upper surface of the heat treatment fixture is processed into a plane, can be stacked and placed, the thin plate high-temperature alloy part is precisely corrected by heat treatment, the rebound and internal stress are completely eliminated, and the forming precision is further improved;

[0024] Through the above-mentioned accurate calculation of the simplified part before forming, the discrete machining thinking and the unchanged machining reference in the forming, and the precise correction of the stable heat treatment after forming, the thin plate high-temperature alloy with small diameter inclined hole and multiple convex features is realized.

[0025] The beneficial effects of the present application are:

[0026] (1) The hole shaft positioning method is proposed, the hole making position is accurately determined through the conversion between the three-dimensional model and the two-dimensional drawing, and the manufacturing quality and precision of the product are improved;

[0027] (2) The manufacturing precision of the component is improved by adopting the step forming method, the step forming is formed by adopting a unified theoretical positioning reference, and the error caused by repeated positioning is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The positioning hole and the ear piece are selected for the schematic diagram;

[0029] Figure 2 It is a two-dimensional expansion schematic diagram;

[0030] Figure 3 It is a bending die schematic diagram;

[0031] Figure 4 It is a tire schematic diagram;

[0032] Figure 5 It is a convex die concave die and processing state schematic diagram;

[0033] Figure 6 It is a heat treatment fixture schematic diagram.

[0034] Among them: 1 positioning hole, 2 ear piece, 3 small curvature change edge, 4 bending die lower die, 5 positioning pin, 6 tire cover, 7 drilling mechanism, 8 positioning pin A, 9 convex. DETAILED DESCRIPTION

[0035] The present application will be explained below in combination with figures and examples, so as to be more easily understood.

[0036] 1. Positioning hole setting

[0037] The positioning hole 1 runs through the entire process of sheet high-temperature alloy part processing, serving as the processing reference of each processing procedure. In order to reduce the calculation deviation and facilitate positioning during forming, the positioning hole 1 is attached to the lug 2 on the same edge 3 with small curvature variation, the number of positioning holes 1 is selected as two, in order to better constrain the degree of freedom of the part, the distance between the positioning holes 1 is not less than 200 mm, and the diameter of the positioning hole 1 is selected as 5.2 mm. As shown in Figure 1 .

[0038] 2. Two-dimensional development data set and development blank manufacturing

[0039] The two-dimensional development data set is the flattening of the theoretical surface of the part, which is the proportional development of the three-dimensional data set of the part with the positioning hole 1, including small-diameter inclined holes, convex hulls 9 and all other features, with the selected reference surface as the development reference. The two-dimensional development data set and the three-dimensional data set are reversible, that is, the three-dimensional data set can be developed into a two-dimensional development data set through CATIA software, and at the same time, the two-dimensional development data set can realize the three-dimensional data set state after forming. The two-dimensional development data set is an important data for generating laser cutting tracks. The laser cutting machine generates processing codes from the two-dimensional development data set, and the angle between the laser and the sheet is the same as the inclined hole, which cuts small-diameter inclined holes, positioning holes 1 and part features such as shape on the sheet material, realizing the processing of the development blank. As shown in Figure 2 .

[0040] 3. Bending part forming

[0041] The bending part forming is a bending die that is consistent with the part surface, and the upper die is not shown, which is clamped on the center of the upper and lower platforms of the hydraulic machine through bolts. According to the characteristics of the part surface, the laser impact forming technology is used to pre-form the development blank, so that the positioning hole 1 can be coordinated with the positioning pin 5 on the bending die to achieve effective positioning. After the pre-formed development blank is stably positioned on the lower die, the upper die is slowly lowered to realize effective closing of the upper and lower dies and pressure preservation, and the bending forming of the part is completed. As shown in Figure 3 .

[0042] 4. Convex hull feature processing

[0043] The convex 9 is evenly distributed on the surface of the part, in order to determine the theoretical position of the convex 9, the design has the convex 9 theoretical position of the tire, the tire surface is consistent with the part surface, and the positioning pin position is also set on the tire body. The drill mechanism 7 is provided on the tire cover 6 at the center position of the convex 9, the drill mechanism 7 is inlaid with a drill sleeve, the axis of which coincides with the center line of the convex 9, in order to facilitate drilling, the thickness of part of the tire cover 6 is thinned. The corresponding tire body part is set to avoid.

[0044] The formed blank is clamped in the tire with the positioning hole 1 as the positioning reference and is pressed tightly, so that the blank tends to the theoretical position in the tire. The hand drill penetrates the drill sleeve on the tire cover 6 to form a bottom hole on the part. Due to the poor cutting performance of the high-temperature alloy sheet, a center hole can also be printed on the part by punching through the drill mechanism 7, and then the part is taken out and placed on a bench drill to finally complete the drilling of the bottom hole. As shown in Figure 4 .

[0045] The bottom hole of each convex 9 is used as a positioning reference to design a local bending die. The surface of the local bending die is proportional to the surface of the convex 9, and the convex and concave dies are installed on a common punch. A cylindrical positioning pin 8 is arranged at the center of the convex and concave dies, and the diameter of the cylindrical positioning pin 8 is the same as that of the bottom hole of the convex 9. The fitting relationship of the local bending die surface is adjusted through the convex and concave die surfaces and the cylindrical positioning pin 8, without the need to additionally set a guide mechanism for guiding the convex and concave dies, thereby avoiding interference between the convex 9 and the blank during the process.

[0046] The local bending die is installed on the punch and the fitting surface is adjusted. The blank is held in hand, the direction of the convex 9 is identified, the bottom hole of the convex 9 is sleeved into the cylindrical positioning pin 8, and the curved surface normal at this position is kept parallel to the vertical direction, that is, the normal of the hole of the convex 9 is parallel to the vertical direction. Start the punch to complete the forming of the convex 9. Repeat the above actions to complete the forming of all convexes 9. As shown in Figure 5 .

[0047] After the convex 9 is formed, the bottom hole of the convex 9 is expanded. A punching die is designed using the expanded bottom hole as a positioning reference, and the final processing of the hole on the convex 9 is completed by punching.

[0048] 5、Precise correction

[0049] The precision correction is still based on the positioning hole 1 as the machining reference, the part is installed on the stable heat treatment fixture through the positioning pin 8, and the surface rebound and internal stress generated in the forming process are eliminated by heating and holding in the clamped state. The heat treatment fixture has high temperature resistance, the area of the clamping surface is set according to the rebound state of the part, and the convex 9 features on the surface are set to avoid. In order to improve the use efficiency of the heat treatment furnace, the upper surface of the heat treatment fixture is processed into a plane, which can be stacked and placed. Through the heat treatment precision correction of the thin plate high-temperature alloy part, the rebound and internal stress are completely eliminated, and the forming precision is further improved. As shown in Figure 6

[0050] Through the above-mentioned accurate calculation of the simplified part before forming, the discrete machining thinking and the unchanged machining reference in the forming, and the precision correction of the stable heat treatment after forming, the thin plate high-temperature alloy machining forming with small diameter inclined hole and multiple convex 9 features is realized.​

Claims

1. A method of machining a thin plate high temperature alloy having a small diameter slant hole multi-bulge feature, characterized by, The steps are as follows: Step 1: Process positioning hole setting The positioning hole (1) serves as the machining reference for each machining process during component manufacturing, and is used throughout the entire process of machining the thin plate high-temperature alloy part. In order to reduce calculation deviation and reduce, the positioning hole (1) is attached to the lug (2) on the same edge where the curvature of the part changes little; Step 2: Two-dimensional development data set and development blank making The two-dimensional development data set is the flattening of the theoretical surface of the part. As important data for generating laser cutting tracks, the part with the added positioning lug (2) and positioning hole (1) contains a three-dimensional data set of all features such as small diameter inclined holes and convex hulls (9), which is proportionally developed through a CATIA data development module; The hole axis positioning method extracts the intersection of the inclined hole axis and the upper surface of the component in the digital model of the component, and projects the point to the pre-developed surface. The developed surface is developed along with features such as the center point, positioning hole (1), and convex hull (9) center by using the development function, forming a two-dimensional development data set; Step 3: Bending part forming The bending part forming uses upper and lower dies of a bending die that is consistent with the part surface. The upper and lower dies are respectively clamped in the center of the upper and lower platforms of a hydraulic machine through bolts. According to the characteristics of the part surface, the developed blank is pre-formed using laser impact forming technology, so that the positioning hole (1) can be in coordination with the positioning pin (5) on the bending die, achieving effective positioning. After the pre-formed developed blank is stably positioned on the lower die, the upper die is slowly lowered to achieve effective closing and pressure maintaining of the upper and lower dies, and the bending forming of the part is completed; Step 4: Convex hull feature processing The convex hulls (9) are evenly distributed on the surface of the entire part. The convex hull (9) is consistent with the part surface in terms of the tire surface profile. The positioning pin A (8) is also provided on the tire body to coordinate with the blank positioning hole (1). A drilling mechanism (7) is provided on the tire cover (6) at the center of the convex hull (9); The formed blank is clamped in the tire body with the positioning hole (1) as the positioning reference and is pressed tightly, so that the blank tends to be in the theoretical position in the tire body; A handheld electric drill penetrates the drill sleeve on the tire cover (6) to form a bottom hole on the part; With the bottom hole of each convex hull (9) as the positioning reference, a local bending die is designed. The surface of the local bending die is proportional to the surface of the convex hull (9) and has a convex and concave die form, which is installed on a common punch; The local bending die is installed on the punch and is aligned with the mating surface. The blank is held by hand, the direction of the convex hull (9) is identified, the bottom hole of the convex hull (9) is sleeved into the cylindrical positioning pin A (8), and the curved surface normal at this position is kept parallel to the vertical direction, i.e. the normal of the convex hull (9) hole is parallel to the vertical direction. Start the punch to complete the forming of the convex hull (9). Repeat the above actions to complete the forming of all convex hulls (9); After the convex hull (9) is formed, the bottom hole of the convex hull (9) is expanded. With the expanded bottom hole as the positioning reference, a punching die is designed, and the final processing of the upper hole of the convex hull (9) is completed by punching; Step 5: Precision shaping The precision correction is still based on the positioning hole (1) as the machining reference, the part is installed on the stable heat treatment fixture through the positioning pin (8), and the surface rebound and internal stress generated in the forming process are eliminated by heating and holding in the clamped state; The heat treatment fixture has high temperature resistance, the area of the clamping surface is set according to the rebound state of the part, the convex (9) features on the surface are set to avoid, and the upper surface of the heat treatment fixture is machined into a plane; The discrete machining thinking in forming and the precision correction of stable heat treatment after forming realize the machining and forming of the thin plate high-temperature alloy with small diameter inclined hole and multiple convex (9) features.

2. The method of claim 1, wherein the method further comprises: The number of positioning holes (1) is selected to be 2-3, the distance between the positioning holes (1) is not less than 200mm, and the diameter of the positioning hole (1) is selected to be 2.7-5.2mm.

3. The method of claim 1 or 2, wherein the method further comprises, In the second step, the laser cutting machine generates the machining code of the two-dimensional expanded data set, the included angle between the laser and the thin plate is the same as the inclined hole, and the small diameter inclined hole, the positioning hole (1) and the part contour feature are cut on the thin plate material, realizing the machining of the expanded blank.

4. The method of claim 1 or 2, wherein the method further comprises, The drilling mechanism (7) is inlaid with a drill sleeve, the axis of which coincides with the center line of the convex (9), and the thickness of the part of the cap (6) of the drilling mechanism (7) is thinned.

5. The method of claim 3 wherein the thin plate superalloy is processed to have small diameter angled hole multi-bulge features. The drilling mechanism (7) is inlaid with a drill sleeve, the axis of which coincides with the center line of the convex (9), and the thickness of the part of the cap (6) of the drilling mechanism (7) is thinned.

6. The method of claim 1 or 2 or 5, wherein the thin plate superalloy is processed to have a small-diameter inclined hole multi-protrusion feature, and The center of the convex and concave die is provided with a cylindrical positioning pin A (8), the diameter of which is the same as that of the bottom hole of the convex (9); the local curved die surface is aligned through the convex and concave die surface and the cylindrical positioning pin A (8).

7. The method of claim 3 wherein the thin plate superalloy is processed to have small diameter, angled hole, multi-bulge features. The center of the convex and concave die is provided with a cylindrical positioning pin A (8), the diameter of which is the same as that of the bottom hole of the convex (9); the local curved die surface is aligned through the convex and concave die surface and the cylindrical positioning pin A (8).

8. The method of claim 4 wherein the thin plate superalloy is processed to have small diameter, angled hole, multi-bulge features. The center of the convex and concave die is provided with a cylindrical positioning pin A (8), the diameter of which is the same as that of the bottom hole of the convex (9); the local curved die surface is aligned through the convex and concave die surface and the cylindrical positioning pin A (8).

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