Process for machining a 7075 aluminum alloy polyhedral part

Abstract

The application discloses a 7075 aluminum alloy polyhedral part machining process and relates to the technical field of precision machining. The process is processed by a three-axis numerical control machine tool, clamped by a vice, and the aluminum alloy part is clamped through a clamping process. The outer shape and the inner hole are coarsely milled. After rough machining, four corners are reserved as a clamping process platform. After semi-fine milling, only non-functional areas are removed. In the finishing process, the process platform is removed, so that the deformation is reduced. Meanwhile, the vibration suppression effect is achieved by dispensing glue in the staggered groove. Quick-drying glue is pre-dispensed at the opening of the 1.5mm groove, and after solidification, a temporary rigid support is formed to suppress cutting vibration and elastic deformation. Finally, the tooling is converted, each tolerance size is fine-milled, the clamping time is reduced, and the machining precision is improved.

Description

Technical Field

[0001] This invention relates to the field of precision machining technology, specifically to a machining process for 7075 aluminum alloy polyhedral parts. Background Technology

[0002] 7075 aluminum alloy is a high-strength, heat-treatable aluminum-zinc-magnesium-copper alloy. It is one of the most widely used hard aluminum alloys in the aerospace industry and is suitable for manufacturing high-precision and complex parts in aerospace, optical instruments and other fields. With its excellent strength-to-weight ratio and heat-treatable strengthening ability, 7075 aluminum alloy has become the preferred material in high-end engineering fields, especially in scenarios that require lightweight and high load-bearing capacity.

[0003] When machining existing 7075 aluminum alloy, stress deformation is easily generated, affecting dimensional stability. After machining the 1.5mm notches on both sides, a thin-walled structure (only 1mm thick) is formed in the local part. Material removal causes a sharp drop in rigidity, making it susceptible to cutting force, residual stress and clamping pressure, which can lead to torsion or springback deformation. At the same time, the positional accuracy and parallelism requirements of the multi-hole positions are high, and traditional machining methods are difficult to guarantee the accuracy. Existing technologies mostly rely on complex fixtures or multiple adjustments, which are inefficient and costly. Summary of the Invention

[0004] The purpose of this invention is to provide a machining process for 7075 aluminum alloy polyhedral parts, in order to solve the problems of easy deformation and high cost and low efficiency in the machining of 7075 aluminum alloy in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a machining process for 7075 aluminum alloy polyhedral parts, comprising the following steps:

[0006] Process 1: Using a three-axis CNC machine tool, the aluminum alloy part is clamped using a vise. The outer shape and inner hole are rough milled to obtain the irregular hole inside the aluminum alloy part.

[0007] Furthermore, four corners are reserved as process tables, and the remaining parts are rough milled to a single-sided allowance of 0.3mm;

[0008] Step 2: Clamp and fix the aluminum alloy part with a vise, leaving a 5mm irregular hole on the part;

[0009] Step 3: Clamp the object with a vise and fix it on the irregular hole. Perform semi-finishing of the shape and process handle, leaving a 0.15mm allowance on each side. Remove a small amount of material. Drill four angled clamping process holes and machine several stress relief grooves along the bevel.

[0010] Step 4: Clamp and fix the aluminum alloy parts with a vise, and perform semi-finish milling of the thickness, leaving a allowance of 0.15mm on one side;

[0011] Step 5: Clamp and fix the aluminum alloy parts with a vise, leaving a margin for the outer shape, and rough mill the frustum and round hole, leaving a margin of 0.15mm on one side;

[0012] Step 6: Clamp and fix the aluminum alloy parts with a vise, rough mill the square platform and tolerance holes, leaving a allowance of 0.15mm on one side;

[0013] Step 7: Use a vise to clamp and fix the aluminum alloy parts, and machine two misaligned grooves and screw holes to the required dimensions;

[0014] Step 8: Fix the aluminum alloy part with a vise and machine the misalignment groove on the other side of the aluminum alloy part to the required dimensions;

[0015] Step 9: Fix by applying a few drops of glue in the misalignment groove, and mill the reference surface. Before processing, apply a small amount of glue to fix the four openings.

[0016] When the part is placed on a precision plate (flatness 0.002mm), the part is stable in its natural state (without external force). The parts are fixed by glue on the plate in their natural state, and the flatness of the reference surface is 0.005mm.

[0017] Step 10: Secure the aluminum alloy parts to the four corners using simple tooling and screws from the connecting holes. Then, precision mill the other side of the aluminum alloy parts to ensure that the two sides are parallel by 0.015mm.

[0018] Step 11: Using a five-axis machine tool, make a support fixture, and fasten the four corners of the aluminum alloy part to the support fixture with screws through the connecting holes. Precision mill the process handle inside the aluminum alloy part and the outer surface of the part, as well as the holes around the aluminum alloy part to the required dimensions, to ensure the tolerance requirements of each position.

[0019] Step 12: Place a contour block in the middle of the top of the aluminum alloy part and tighten it with a screw through a threaded hole in the middle of the contour block. Remove the screws in the connecting holes at the four corners of the aluminum alloy part, fine mill the four bevels of the aluminum alloy part, and finally remove the support fixture.

[0020] Furthermore, the semi-finishing process involves milling the main body of the aluminum alloy part to a thickness of 25.2mm; the semi-finishing process also includes milling the middle section of the aluminum alloy part and the outer shape of the aluminum alloy part, with a single-sided allowance of 0.1mm.

[0021] Furthermore, when machining the misalignment groove, a vise is used to clamp the aluminum alloy part in the thickness direction to mill the misalignment groove to the required dimensions.

[0022] Compared with the prior art, the present invention provides a machining process for 7075 aluminum alloy polyhedral parts. In the machining of 7075 aluminum alloy, after rough machining, the four corners are retained as clamping process tables. After semi-finish milling, only non-functional areas are cut off. During finish machining, the process tables are removed to reduce deformation. At the same time, adhesive is applied to the misalignment groove to achieve vibration suppression. Quick-drying adhesive is pre-applied at the 1.5mm groove opening, which forms a temporary rigid support after curing to suppress cutting vibration and elastic deformation. Finally, tooling conversion is used to finish mill the various tolerance dimensions, reducing assembly time and improving machining accuracy. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0024] Figure 1 This is a schematic diagram of the process one provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the second process provided in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the three-stage process provided in an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the fourth process step provided in an embodiment of the present invention;

[0028] Figure 5 A schematic diagram of process five provided in an embodiment of the present invention;

[0029] Figure 6 A schematic diagram of process six provided in an embodiment of the present invention;

[0030] Figure 7 A schematic diagram of the structure of process seven provided in an embodiment of the present invention;

[0031] Figure 8 A schematic diagram of the eight-step process provided in an embodiment of the present invention;

[0032] Figure 9 A schematic diagram of the structure of process nine provided in an embodiment of the present invention;

[0033] Figure 10 A schematic diagram of the process ten structure provided in an embodiment of the present invention;

[0034] Figure 11 A schematic diagram of process eleven provided in an embodiment of the present invention;

[0035] Figure 12 This is a schematic diagram of the twelve-step process provided in an embodiment of the present invention;

[0036] Figure 13 This is a schematic diagram of the structure of the finished product provided in an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Aluminum alloy parts; 2. Irregular holes; 3. Process handles; 4. Unloading grooves; 5. Connecting holes; 6. Misalignment grooves; 7. Adhesive; 8. Support fixtures; 9. Threaded holes; 10. Contouring pressure blocks. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0040] As attached Figure 1 To be continued Figure 13 As shown:

[0041] Example:

[0042] This invention provides a machining process for 7075 aluminum alloy polyhedral parts, including the following steps:

[0043] Step 1: Reference Figure 1 The three-axis CNC machine tool is used for processing. A vise is used for clamping. Three pairs of aluminum alloy parts 1 are clamped by clamping process. The outer shape and inner hole are rough milled to obtain the irregular hole 2 inside the aluminum alloy parts 1.

[0044] Furthermore, four corners are reserved as process tables, and the remaining parts are rough milled to a single-sided allowance of 0.3mm. The purpose is to remove excess material and release stress.

[0045] Step 2: Reference Figure 2 The aluminum alloy part 1 is clamped and fixed by a vise, and a 5mm irregular hole 2 is left on the aluminum alloy part 1 to facilitate secondary clamping.

[0046] Step 3: Reference Figure 3 The aluminum alloy part 1 is clamped and fixed on the irregular hole 2 by a vise, and the shape and process handle 3 are semi-finished. The single-sided allowance is 0.15mm, and the amount removed is small to prevent the aluminum alloy part 1 from being deformed during clamping. The clamping process holes are drilled at four angles, and several stress relief grooves 4 are machined along the bevel. The machining of stress relief grooves 4 can reduce stress concentration during the subsequent removal of residual material and prevent deformation caused by the later removal of residual material.

[0047] Step 4: Reference Figure 4 The aluminum alloy part 1 is clamped and fixed with a vise, and the thickness is semi-finished with a single-sided allowance of 0.15mm. Attention should be paid to the clamping force to prevent the aluminum alloy part 1 from being deformed during clamping.

[0048] Step 5: Reference Figure 5 Aluminum alloy part 1 is clamped and fixed with a vise, with a rough milling of the truncated cone and the round hole, leaving a 0.15mm allowance on one side.

[0049] Step Six: Reference Figure 6 Aluminum alloy part 1 is clamped and fixed with a vise, and the square platform and tolerance hole are rough milled, leaving a allowance of 0.15mm on one side;

[0050] Step 7: Reference Figure 7 The aluminum alloy part 1 is clamped and fixed with a vise, and two misaligned grooves 6 and screw holes are machined to the required dimensions.

[0051] Step 8: Reference Figure 8 Aluminum alloy part 1 is clamped and fixed by vise, and misalignment groove 6 on the other side of aluminum alloy part 1 is machined to the required size.

[0052] Step Nine: Reference Figure 9 Fixing is achieved by applying several glue 7s in the misalignment groove 6 and precision milling the reference surface. Before processing, a small amount of glue should be applied to fix the four openings.

[0053] To solve the problem of thin-walled structure deformation, after machining the 1.5mm misalignment grooves 6 on both sides of the aluminum alloy part 1, a thin-walled area with a thickness of only 1mm is formed. During subsequent cutting, due to the difference in material removal rate, the internal residual stress is redistributed. With the periodic action of the cutting force, it is easy to produce torsional deformation with a maximum value of 0.2mm. Moreover, the springback increases with the extension of the machining interval. Traditional clamping methods cannot effectively suppress this type of deformation. However, applying several glues 7 to the misalignment grooves 6 can effectively prevent deformation from occurring.

[0054] When the part is placed on a precision plate (flatness 0.002mm), the part is stable in its natural state (without external force). The parts are fixed by glue on the plate in their natural state, and the flatness of the reference surface is 0.005mm.

[0055] Step 10: Reference Figure 10 The aluminum alloy part 1 is fixed by screws at the four corners of the connecting hole 5 using simple tooling. The other side of the aluminum alloy part 1 is precision milled to ensure that the two sides are parallel by 0.015mm.

[0056] Step Eleven: Reference Figure 11 Using a five-axis machine tool, support fixture 8 is made. The four corners of aluminum alloy part 1 are fastened to support fixture 8 through connecting holes 5 and screws. The process of precision milling the aluminum alloy part 1 is to ensure the dimensions of the inner surface 3 and the outer surface of the aluminum alloy part 1, as well as the holes around the aluminum alloy part 1, to ensure the tolerance requirements of each position.

[0057] Step Twelve: Reference Figure 12By placing a contouring block 10 in the middle of the top of the aluminum alloy part 1 and fastening it with a screw by threaded hole 9 in the middle of the contouring block 10, removing the screws in the four corner connecting holes 5 of the aluminum alloy part 1, precision milling the four bevels of the aluminum alloy part 1, and finally removing the support fixture 8.

[0058] refer to Figure 13 The final finished aluminum alloy part 1 is obtained.

[0059] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A machining process for a 7075 aluminum alloy polyhedral part, comprising the following steps: Process 1: Using a three-axis CNC machine tool for processing, a vise is used for clamping. The aluminum alloy part (1) is clamped by (3) through the clamping process. The outer shape and inner hole are rough milled to obtain the irregular hole (2) inside the aluminum alloy part (1). Furthermore, four corners are reserved as process tables, and the remaining parts are rough milled to a single-sided allowance of 0.3mm; Step 2: Clamp and fix the aluminum alloy part (1) with a vise, leaving a 5mm irregular hole (2). Step 3: Clamp the object with a vise and fix it on the irregular hole (2). Perform semi-finishing of the shape and process handle (3). Leave a single-sided allowance of 0.15mm. Remove a small amount. Drill process holes at four angles and process several stress relief grooves (4) along the bevel. Step 4: Fix the aluminum alloy part (1) with a vise and perform semi-finish milling of the thickness, leaving a allowance of 0.15mm on one side; Step 5: Fix the aluminum alloy part (1) with a vise, deviate the outer shape allowance, rough mill the frustum and the round hole, and leave a single-sided allowance of 0.15mm; Step 6: Fix the aluminum alloy part (1) with a vise, rough mill the square platform and tolerance hole, leaving a single-sided allowance of 0.15mm; Step 7: Fix the aluminum alloy part (1) with a vise, and machine two misaligned grooves (6) and screw holes to the required dimensions; Step 8: Fix the aluminum alloy part (1) with a vise, and process the misalignment groove (6) on the other side of the aluminum alloy part (1) to the required size; Step 9: Fix by applying several glues (7) in the misaligned groove (6), and mill the reference surface. Before processing, apply a small amount of glue to fix the four openings. When the part is placed on a precision plate with a flatness of 0.002mm, the part is stable in its natural state. The parts are fixed by glue on the plate in their natural state, and the flatness of the reference surface is 0.005mm. Step 10: Fix the aluminum alloy part (1) at the four corners with screws from the connecting holes (5) using simple tooling, and mill the other side of the aluminum alloy part (1) to ensure that the two sides are parallel by 0.015mm. Process 11: Using a five-axis machine tool, make a support fixture (8), and fasten the four corners of the aluminum alloy part (1) to the support fixture (8) with screws through the connecting holes (5). Mill the process tool (3) inside the aluminum alloy part (1) and the outer surface of each side, as well as the holes around the aluminum alloy part (1) to the required dimensions, and ensure the tolerance requirements of each position. Step 12: By placing a contour block (10) in the middle of the top of the aluminum alloy part (1) and fastening it with screws through the threaded hole (9) in the middle of the contour block (10), remove the screws in the four corner connecting holes (5) of the aluminum alloy part (1), finely mill the four bevels of the aluminum alloy part (1), and finally remove the support fixture (8).

2. The machining process for a 7075 aluminum alloy polyhedral part according to claim 1, characterized in that, Semi-finished aluminum alloy parts (1) with a main body thickness of 25.2 mm; The process handle (3) in the middle of the semi-finish milled aluminum alloy part (1) and the shape of the aluminum alloy part (1) are left with a single-sided allowance of 0.1mm.

3. The machining process for a 7075 aluminum alloy polyhedral part according to claim 1, characterized in that, When machining the misaligned groove (6), a vise is used to clamp the aluminum alloy part (1) in the thickness direction to mill the misaligned groove (6) to the required size.

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