Machining and manufacturing method of special-shaped thin-wall shell

Abstract

The invention discloses a processing and manufacturing method of a special-shaped thin-wall shell, which comprises the following steps of: performing integral additive manufacturing on a special-shaped thin-wall shell blank by adopting a laser additive manufacturing method, reducing a shell inner cavity processing area and a processing allowance, and firstly processing characteristics such as a large end face, a large end face positioning hole, an inner cavity mounting plane, a butt-joint circulating hole and a groove; through the technical means of adjustable modular tooling and the like, the problems that a thin-wall shell product is difficult to clamp, fix and align are effectively solved, so that the profile precision is effectively controlled, the difficulty of clamping alignment and reference transmission is reduced, gaps during assembly are reduced, the production efficiency is improved, and the production cost is reduced. And high-efficiency machining of special-shaped thin-wall shell products is achieved.

Description

Technical Field

[0001] This invention relates to a method for processing and manufacturing an irregularly shaped thin-walled shell, belonging to the field of machining technology. Background Technology

[0002] Currently, various products in aerospace and other fields have higher requirements for lightweighting, and large, complex, irregularly shaped, thin-walled structural parts are widely used. These parts are characterized by open structures, complex curved surfaces, thin walls, complex structures, low rigidity, and susceptibility to deformation. These characteristics make them difficult to clamp and position during manufacturing, resulting in low processing efficiency, long cycles, and difficulty in ensuring the relative position of some features to the overall product after assembly.

[0003] At present, most parts are closed rotary structures, using traditional casting and machining methods. These methods result in large casting allowances and deformations, large machining removals, poor production efficiency, and poor shell assembly accuracy, which seriously affect product performance and overall product progress. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a method for processing and manufacturing irregularly shaped thin-walled shells.

[0005] The technical solution adopted in this invention is: a method for processing and manufacturing an irregularly shaped thin-walled shell, comprising: The additive blank for the irregular thin-walled shell is designed based on the structure, processing area, and processing allowance distribution of the irregular thin-walled shell. Draw horizontal reference lines, symmetrical reference lines, and axial end face lines on the additive manufacturing blank; Alignment is achieved based on the horizontal and symmetrical reference lines, and the large end face, positioning holes, docking circulation holes, and bevels on the additive blank are machined. Machining the holes on the inner cavity mounting boss and the large end mounting plane; Based on the machining datum of the large end face of the additive blank, the through threaded hole on the mounting boss of the inner cavity is machined from the outer wall surface inward. Based on the positioning holes on the large end face, clamp and position the large end face, machine the small end face and the outer wall of the small end, and machine the inner cavity mounting surface and the threaded holes on the inner cavity mounting surface of the small end.

[0006] Furthermore, a laser additive manufacturing method is used to integrally additive manufacture the irregular thin-walled shell to obtain an additive blank, while the non-processed areas of the inner cavity are directly additively formed without leaving any allowance.

[0007] Furthermore, the additive blank outer skin has no allowance, and the large end face, small end face, inner stop, mounting plane and side wall all have an allowance of 2~3mm.

[0008] Furthermore, process bosses are reserved on both the large end face and the small end face of the additive blank.

[0009] Furthermore, the step of marking horizontal and symmetrical reference lines and axial end face lines on the additive blank includes: Alignment is performed based on the process boss, and horizontal and symmetrical baselines are drawn. The end face lines of both ends are determined and drawn along the axial direction based on the non-machined features of the inner cavity of the thin-walled shell.

[0010] Furthermore, the holes on the machining inner cavity mounting boss and the large end mounting plane include: The internal mounting boss is machined using a round nose milling cutter, with a cutting depth not exceeding 0.3mm; A right-angle head tool is used to machine the large end mounting plane near the port and the holes on the large end mounting plane.

[0011] Furthermore, the step of machining a through threaded hole on the inner cavity mounting plane from the outer wall surface inward according to the machining datum of the large end face of the additive blank includes: The additive blank is vertically clamped, and the end face of the additive blank and the process boss are used as references. A five-axis swing shaft is used to machine the through threaded hole on the inner cavity mounting boss from the outer surface inward.

[0012] The advantages of this invention compared to the prior art are: (1) The present invention uses laser additive manufacturing method to integrally additive manufacture irregular thin-walled shells from blanks. The non-processed areas of the inner cavity are directly additively formed without leaving any allowance, thereby reducing the processing area and processing allowance as a whole.

[0013] (2) The present invention first performs feature processing on the large end, such as the large end face, end docking circulation hole, axial docking hole and bevel, and then performs machining on the small end, such as docking outer stop and docking end face, thereby effectively controlling the surface accuracy, reducing the difficulty of clamping and alignment and datum transfer, reducing the gap during assembly, and realizing high-precision machining and assembly of the shell.

[0014] (3) The present invention uses a reserved process boss for rough machining datum alignment. By designing tooling for effective positioning and datum transfer, the difficulty of clamping and alignment is reduced, the overall rigidity of the workpiece is improved, and the surface accuracy and wall thickness requirements are guaranteed. Attached Figure Description

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the thin-walled shell structure in an embodiment of the present invention; Figure 2 This is a diagram of the blank structure in an embodiment of the present invention.

[0016] Figure 3 This is a drawing of a thin-walled shell component in an embodiment of the present invention; Figure 4 This is a structural diagram of the large end of the thin-walled shell in an embodiment of the present invention. Detailed Implementation

[0017] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0018] This invention proposes a method for processing and manufacturing irregular thin-walled shells. The blank is processed using laser additive manufacturing, which reduces the processing area and processing allowance of the thin-walled shell. The large end is processed with features such as the large end face, end docking circulation hole, axial docking hole and beveling. Then the small end is processed with the docking outer stop and docking end face, thereby effectively controlling the surface accuracy, reducing the difficulty of clamping and alignment and datum transfer, reducing the gap during assembly, and realizing high-precision processing and assembly of the shell.

[0019] A method for processing and manufacturing an irregularly shaped thin-walled shell, comprising: 1. Design the additive blank 1 for the irregular thin-walled shell based on its structure, processing area, and processing allowance distribution; 2. Draw the horizontal reference line, the symmetrical reference line, and the axial end face line on the additive blank 1, including: Alignment is performed based on the process boss, and horizontal and symmetrical baselines are drawn. The end face lines of both ends are determined and drawn along the axial direction based on the non-machined features of the inner cavity of the thin-walled shell.

[0020] 3. Align the additive blank according to the horizontal and symmetrical reference lines, and machine the large end 5 end face, the positioning hole 2, the docking circulation hole and the bevel on the large end end face; 4. Machining the holes on the inner cavity mounting boss 6 and the large end mounting plane 3, including: The internal mounting boss is machined using a round nose milling cutter, with a cutting depth not exceeding 0.3mm; Using a right-angle head tool, machine the large end 5 near the port large end mounting plane 3 and the hole on the large end mounting plane 3.

[0021] 5. Based on the machining datum of the large end face of the additive blank, machine the through threaded hole 7 on the inner cavity mounting boss 6 from the outer wall surface inward, including: The additive blank 1 is vertically clamped, and the through threaded hole 7 on the inner cavity mounting boss is machined from the outer surface inward using a five-axis swing shaft, with the end face of the additive blank and the process boss as the reference.

[0022] 6. Based on the positioning hole 2 on the large end face, clamp and position the large end 5 end face, machine the small end 4 end face and the small end outer wall surface, and machine the threaded holes on the small end inner cavity mounting surface and the small end inner cavity mounting surface 8.

[0023] The irregular thin-walled shell is integrally additively manufactured using laser additive manufacturing method to obtain additive blank 1. The non-processed area of ​​the inner cavity is directly additively formed without leaving any allowance.

[0024] The additive blank 1 has no allowance for the outer skin, and a 2-3mm allowance is left for the large end face, small end face, inner stop, mounting plane and side wall; process bosses are reserved on the large end face and small end face of the additive blank 1.

[0025] Example The invention will be further illustrated below by means of embodiments. The test workpiece in the embodiments is an irregularly shaped thin-walled shell, such as... Figure 1 , Figure 3 As shown, the material of this part is TA15 titanium alloy. The blank is formed by laser additive manufacturing. The thin-walled shell has a thin-walled reinforcing rib structure. The long axis dimension is about 398mm, the short axis dimension is about 240mm, the height is about 410mm, and the thinnest wall thickness is 1.2mm. Mounting holes are distributed on the ends and inner surfaces of the thin-walled shell. The assembled thin-walled shell can be smoothly installed with other components.

[0026] The manufacturing method specifically includes: Step 1: Design the additive blank for the thin-walled shell based on its structure, machining area, and machining allowance distribution. Figure 2 As shown.

[0027] According to the technical requirements, the machining allowance is reasonably distributed. Non-fitting assembly surfaces are directly additively formed without setting allowances. The machining allowance is 2mm to minimize the machining cycle. The additive blank 1 of the thin-walled shell is a rib-reinforced structure to avoid the risk of deformation during additive manufacturing due to the excessive size of the thin-walled shell. At the same time, in order to facilitate the alignment of the machining datum in the later stage, process bosses are reserved on the front and rear end faces. Meanwhile, the additive model needs to be designed with ribs, dot matrix, etc. to prevent the workpiece from deforming too much during the additive manufacturing process.

[0028] Step 2: Align the additive manufacturing pre-reserved process bosses and draw the horizontal reference line, symmetrical reference line, and axial end face line.

[0029] Step 3: Align the workpiece according to the marked baseline, and machine the large end 5 end face of the additive manufacturing blank, including the positioning holes 2 (located at both ends of the large end long shaft), the docking circulation holes, the 8 large end threaded holes 9, and the bevel, etc. Figure 4As shown.

[0030] Step 4: Using tooling for clamping and positioning, use a small-diameter round nose milling cutter to machine the inner boss 6 with a small depth of cut, with a cutting depth not exceeding 0.3mm to avoid excessive tool length causing tool chatter. Use a right-angle head tool to machine the mounting plane 3 near the inner wall at the large end and the hole on the mounting plane 3.

[0031] Step 5: Using tooling for positioning and alignment, a five-axis machining center is used to finish machining the through threaded hole 7 on the inner cavity boss 6 from the outer surface inward and several rows of through holes 10 distributed around the circumferential surface (each row includes several through holes 10). The end process positioning hole 2 ensures that the relative position between the outer surface of the thin-walled shell and the mating hole is more accurate.

[0032] Step 6: Turn the part over and use locating pins to position and align the large end of the irregular thin-walled shell. Use an adjustable pressure plate to firmly fix the thin-walled shell onto the tooling, so that the large end 5 of the thin-walled shell fits into the tooling surface. Use locating pins at both ends for precise positioning, and finish machine the small end 4 end face, the small end outer surface, the small end inner mounting surface, and the threaded holes on the mounting surface 8.

[0033] The embodiments described above are merely preferred embodiments of the present invention. Ordinary variations and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for processing and manufacturing an irregularly shaped thin-walled shell, characterized in that, include: The additive blank of the irregular thin-walled shell is designed according to the structure, processing area and processing allowance distribution of the irregular thin-walled shell (1). Draw a horizontal reference line, a symmetrical reference line and an axial end face line on the additive blank (1); Alignment is performed based on the horizontal and symmetrical reference lines, and the large end (5) face, positioning hole (2), docking circulation hole and bevel are machined on the large end face of the additive blank; Machining the holes on the inner cavity mounting boss (6) and the large end mounting plane (3); Based on the machining reference of the large end face of the additive blank, the through thread hole (7) on the inner cavity mounting boss (6) is machined from the outer wall to the inside. According to the positioning hole (2) on the large end face, clamp and position the large end (5) end face, process the small end (4) end face and the small end outer wall surface, and process the threaded holes on the small end inner cavity mounting surface and the small end inner cavity mounting surface (8).

2. The method for processing and manufacturing an irregularly shaped thin-walled shell according to claim 1, characterized in that, The irregular thin-walled shell is integrally additively manufactured using laser additive manufacturing method to obtain an additive blank (1). The non-processed area of ​​the inner cavity is directly additively formed without leaving any allowance.

3. The method for processing and manufacturing an irregularly shaped thin-walled shell according to claim 2, characterized in that, The additive blank (1) has no allowance for the outer skin, and a allowance of 2~3mm is left for the large end face, small end face, inner stop, mounting plane and side wall.

4. The method for processing and manufacturing an irregularly shaped thin-walled shell according to claim 3, characterized in that, Both the large and small end faces of the additive blank (1) are reserved with process bosses.

5. The method for processing and manufacturing an irregularly shaped thin-walled shell according to claim 4, characterized in that, The step of marking horizontal and symmetrical reference lines and axial end face lines on the additive manufacturing blank includes: Alignment is performed based on the process boss, and horizontal and symmetrical baselines are drawn. The end face lines of both ends are determined and drawn along the axial direction based on the non-machined features of the inner cavity of the thin-walled shell.

6. The method for processing and manufacturing an irregularly shaped thin-walled shell according to claim 5, characterized in that, The holes on the machining inner cavity mounting boss and the large end mounting plane (3) include: The internal mounting boss is machined using a round nose milling cutter, with a cutting depth not exceeding 0.3mm; Using a right-angle head tool, machine the large end (5) near the port large end mounting plane (3) and the hole on the large end mounting plane (3).

7. The method for processing and manufacturing an irregularly shaped thin-walled shell according to claim 6, characterized in that, The process of machining a through-threaded hole on the inner cavity mounting plane from the outer wall surface inward, based on the machining datum of the large end face of the additive blank, includes: The additive blank (1) is vertically clamped, and the through threaded hole (7) on the inner cavity mounting boss is machined from the outer surface inward using a five-axis swing shaft with the end face of the additive blank and the process boss as the reference.

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