A large-size complex thin-walled butt joint end frame additive and subtractive automatic composite machining method

Abstract

The application discloses a kind of big size complex thin-walled butt joint end frame additive-subtractive automatic composite machining methods, comprising: the butt joint end frame is divided into several structure intervals in height;Design arc additive and numerical control subtractive composite alternation processing times;Plan the path of arc additive;Design numerical control subtractive path planning and tool selection;Design modularized inside bracing shape tooling;Through multiple additive-subtractive composite alternation, complete complex thin-walled butt joint end frame additive-subtractive automatic composite machining;Complex thin-walled butt joint end frame finish machining is shaped.The application utilizes the respective advantages of arc additive, numerical control subtractive, designs additive-subtractive automatic composite machining process, reasonably designs the path planning of arc additive and numerical control subtractive, designs modularized inside bracing shape tooling and other technical means, realizes the rapid, low-cost, high-precision manufacturing of the large complex thin-walled butt joint end frame, and greatly shortens the manufacturing cycle.

Description

Technical Field

[0001] This invention belongs to the field of machining and 3D printing technology, specifically relating to an automated composite processing method for additive and subtractive materials of large-size complex thin-walled docking end frames. Background Technology

[0002] Currently, in the aerospace field, as various aircraft, propulsion systems, and fuel tanks place increasingly higher demands on maneuverability, load capacity, and maximum capacity, their structures also face greater requirements for lightweighting and high strength. Most structures require all internal cavities to be machined to achieve maximum weight reduction. Meanwhile, for some large end frames and hulls, traditional manufacturing methods (such as casting and forging) are time-consuming and costly due to the need for initial mold investment. Therefore, the rapid, low-cost, and high-precision manufacturing of such large-size, complex, thin-walled docking end frames has been a persistent challenge to their large-scale application in the aerospace industry. Summary of the Invention

[0003] This invention addresses the need for rapid, low-cost, and high-precision manufacturing of large-sized, complex, thin-walled mating end frames. The technical solution of this invention provides an automated composite processing method for additive and subtractive manufacturing of such large-sized, complex, thin-walled mating end frames. This method effectively avoids the quality problems such as deformation and shrinkage caused by the previous welding manufacturing methods for these large, complex mating end frames. It also saves the time and cost of molds required for casting blanks, and can more easily achieve full machining of the product's internal cavity, effectively solving the problem of rapid, low-cost, and high-precision manufacturing of such large-sized, complex, thin-walled mating end frames.

[0004] The present invention provides an automated composite processing method for additive and subtractive materials of complex thin-walled butt joint frames, comprising:

[0005] Step 1: Based on the structural characteristics and distribution of the thin-walled butt joint frame, divide the butt joint frame into several structural intervals in terms of height;

[0006] Step 2: Based on the structural intervals divided into several sections of the docking end frame and the distribution of structural features within the intervals, design the number of alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing.

[0007] Step 3: Based on the structural characteristics and distribution within each structural section of the docking end frame, design the path planning for arc additive manufacturing;

[0008] Step 4: Based on the structural characteristics formed after arc additive manufacturing, and combined with the effective stroke of the additive / subtractive manufacturing equipment, design the path planning and tool selection for CNC subtractive manufacturing.

[0009] Step 5: Based on the specific structure and dimensions formed after adding or subtracting materials in each structural section, design modular internal support fixtures that are suitable for each structural section.

[0010] Step 6: Following the designed electric arc additive manufacturing path, CNC subtractive manufacturing path, and alternating addition and subtraction processing times, complete the automated addition and subtraction composite processing of complex thin-walled butt joint frames through multiple alternating addition and subtraction processes.

[0011] Step 7: Using an automated composite processing equipment for additive and subtractive manufacturing, the complex thin-walled docking end frame is finished, and the substrate is cut off to obtain the complete final docking end frame.

[0012] In step one, dividing the docking end frame into several structural intervals in height according to the structural features and distribution of the thin-walled docking end frame includes: dividing the docking end into several structural intervals in height according to the positional distribution and continuity of the protruding structures and suspended partitions on the thin-walled docking end frame.

[0013] In step two, the step of designing the number of alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing based on the structural intervals divided by the docking end frame includes: the number of structural intervals corresponds to the number of alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing.

[0014] In step three, the path planning for arc additive manufacturing based on the structural characteristics and distribution within each structural section of the docking end frame includes: adopting a path planning method that combines circular motion and short linear reciprocating motion. Specifically, the arc additive spindle head performs short linear reciprocating motion while the rotating worktable performs circular motion simultaneously, and the two motions combine to form the final path of the arc additive manufacturing.

[0015] In step four, based on the structural characteristics formed after arc additive manufacturing and combined with the effective stroke of the additive / subtractive manufacturing equipment, the path planning and tool selection for CNC subtraction are designed, including: using alternating clockwise and counterclockwise semicircular cutting to perform full-circumference path cutting, and employing a large-neck multi-faceted end mill (see structure). Figure 6 The cutting is completed; the ratio of the cutter head diameter to the cutter shank diameter of the large necked multi-faceted end mill is greater than 5:1; the circumferential side, upper surface and lower surface of the cutter head are all ground with cutting edges, and the tool can simultaneously have cutting capabilities in three directions: circumferential side, upper surface and lower surface.

[0016] In step five, the step of designing modular internal support fixtures adapted to each structural section based on the specific structure and dimensions formed after adding or subtracting materials from the electric arc in each structural section includes:

[0017] The internal support shaped tooling is a detachable multi-layer structure, and each layer of the internal support shaped tooling is adapted to the corresponding structural section.

[0018] After completing the electric arc additive manufacturing and CNC subtractive manufacturing in a structural section, the corresponding internal support shape tooling for that structural section is installed inside, until the internal support shape tooling for each structural section is installed in sequence.

[0019] Step seven, before removing the substrate, also includes: heat treatment of the mating end frame.

[0020] The complex thin-walled docking end frame can be made of aluminum alloy, titanium alloy, or other materials.

[0021] The outer diameter of the large end of the complex thin-walled mating frame can reach 2000-2500 mm.

[0022] The main wall thickness of the complex thin-walled docking end frame is only 2 to 3 mm.

[0023] The beneficial effects of this invention are:

[0024] To address the need for rapid, low-cost, and high-precision manufacturing of such large-sized, complex, thin-walled docking end frames, this invention provides an automated composite processing method for additive and subtractive manufacturing of such large-sized, complex, thin-walled docking end frames. This method effectively avoids the quality problems such as deformation and shrinkage caused by the previous welding manufacturing methods for such large and complex docking end frames. At the same time, it saves the cycle and cost of molds required for casting blanks, and can more easily achieve full machining of the product's internal cavity, effectively solving the need for rapid, low-cost, and high-precision manufacturing of such large-sized, complex, thin-walled docking end frames. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of a large, complex, thin-walled docking end frame.

[0026] Figure 2 This is a schematic diagram of a critical state structure for alternating additive and subtractive materials in an electric arc process.

[0027] Figure 3 This is a schematic diagram of the electric arc additive manufacturing path planning.

[0028] Figure 4 This is a schematic diagram of the clockwise and counterclockwise alternating cutting path for five-axis CNC subtractive material processing.

[0029] Figure 5 This is a simplified structural diagram of a modular internal support formwork.

[0030] Figure 6 This is a schematic diagram of a large necking multi-faceted end mill. Detailed Implementation

[0031] The selected test part is a large docking end frame of a certain type of aircraft in the aerospace field. The docking end frame is made of 5A06 aluminum alloy. The product has a rotating structure, with different bosses on the inner and outer walls. The main body wall thickness ranges from 2-3mm, and the outer diameter reaches [missing information]. The height is approximately 300mm, and the specific implementation method is as follows:

[0032] (1) Based on the specific structure and dimensions of the required large, complex, thin-walled mating end frame, design the process flow and scheme for automated composite processing of the mating end frame. The overall designed process scheme is as follows:

[0033] Substrate blanking - Arc welding of additive and subtractive materials - Heat treatment - X-ray inspection - Substrate removal - Subtractive finishing - Inspection.

[0034] Based on the structural characteristics and distribution of the thin-walled docking end frame, the docking end frame is divided into several structural intervals in terms of height; specifically: based on the positional distribution and continuity of the protruding structures and suspended partitions on the thin-walled docking end frame, the docking end is divided into several structural intervals in terms of height.

[0035] (2) Based on the structural intervals divided into several sections and the distribution of structural features within each section, design the number of alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing. Specifically: the number of structural intervals corresponds to the number of alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing; alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing are performed within the height of each structural interval.

[0036] Based on the structure and location of the internal bosses and suspended partitions of the docking end frame, a composite alternating arc-assisted addition and subtraction machining scheme is designed. This scheme includes three alternating addition and subtraction machining steps to achieve complete machining of the internal cavity and rough machining of the external shape. The first alternating addition and subtraction step is located at the first boss from bottom to top within the internal cavity. The second alternating addition and subtraction step is located above the suspended partition within the internal cavity. The third addition step completes the entire product's addition process, followed by subtraction machining. (Details are as follows...) Figure 2 As shown. Simultaneously, to compensate for shrinkage between adjacent additive manufacturing processes, through multiple experiments, a shrinkage allowance of 0.5–0.8 mm was reserved in the height direction after each additive / subtractive machining transition. In this example, 0.5–0.8 mm of shrinkage was reserved in the height direction at the first and second additive / subtractive machining transition positions; the third stage involved additive manufacturing up to the highest point of the part, followed by subtractive machining.

[0037] (3) Based on the structural characteristics and distribution within each structural section of the docking end frame, plan the path of electric arc additive manufacturing.

[0038] Arc additive manufacturing employs a multi-parallel overlapping path planning method. Since the part is a circular compartment structure, short, straight circular paths are suitable for planning. By utilizing a vertical turntable to rotate along these short, straight paths, additive manufacturing with arbitrary wall thickness and compartment characteristics can be achieved. Path planning for a single-layer cross-section is as follows... Figure 3 As shown.

[0039] The path planning method adopts a combination of circular motion and short linear reciprocating motion. Specifically, the arc additive manufacturing spindle head performs short linear reciprocating motion, while the rotary table performs circular motion simultaneously. The combination of the two motions forms the final path of the arc additive manufacturing process.

[0040] (4) Based on the structural characteristics formed after electric arc additive manufacturing, and combined with the effective stroke of the additive and subtractive manufacturing equipment, design the path planning and tool selection for CNC subtractive manufacturing.

[0041] Due to the product's outer diameter reaching Furthermore, the crossbeam of the additive and subtractive manufacturing composite equipment is equipped with both a five-axis milling and subtractive manufacturing unit and an arc additive manufacturing unit, which limits the stroke of the five-axis milling and subtractive manufacturing unit, making it unable to fully cover the area. The circumference is limited, so a path cutting method is adopted to cut the entire circumference by alternating clockwise and counterclockwise semicircles, machining 180° of semicircle at a time, supplemented by the rotation of the worktable to complete the circumference cutting. Simultaneously, due to the interference from the internal bosses and suspended partitions of the product, a large-neck multi-faceted wheel milling cutter is required. "Large neck" specifically refers to the ratio of the cutter head diameter to the cutter shank diameter being greater than 5:1; "multi-faceted" specifically means that the cutter head has cutting edges ground on its circumferential side, upper surface, and lower surface. This cutter can simultaneously possess cutting capabilities in three directions: circumferential side, upper surface, and lower surface. See the specific structure for details. Figure 6 To complete the cutting. Specifically, as follows... Figure 4 As shown.

[0042] (5) Based on the specific structure and dimensions formed by adding or subtracting materials after the electric arc in each structural section, design modular internal support fixtures that are suitable for each structural section.

[0043] The internal support shaping fixture includes multiple layers of internal support shaping units. Each layer of internal support shaping unit includes a positioning base, multiple sets of internal support claws, and multiple sets of telescopic positioning components. The multiple sets of telescopic positioning components are circumferentially symmetrically mounted on the positioning base like cylinders. The telescopic ends of the telescopic positioning components are connected to the internal support claws. The arc-shaped surface of the far end of the internal support claws is attached to the inner wall of the docking end frame after cutting. This describes the structure of the internal support and the shaping docking end frame.

[0044] like Figure 5 The schematic diagram of the modular internal support frame tooling shown shows that the overall structure of the tooling is modular, which is easy to assemble and disassemble. The overall structure is three-layered, corresponding to the three structural sections of the thin-walled butt joint frame. After the material addition and subtraction processing of each structural section is completed, the internal support frame tooling of the corresponding layer is installed.

[0045] (6) Through three alternating electric arc addition and subtraction composite processes, the addition and subtraction composite processing of complex thin-walled butt joint frames is completed automatically.

[0046] During each alternating process of adding and subtracting materials, the inner cavity is fully machined, while the outer surface has a 1mm allowance on each side. After all the alternating processes of adding and subtracting materials are completed, the outer surface is finally finished.

[0047] (7) Use automated composite processing equipment for additive and subtractive materials to complete the fine machining of the complex thin-walled docking end frame and cut off the substrate.

[0048] This invention provides an automated composite processing method for adding or subtracting materials for large, complex, thin-walled docking end frames. This method can effectively avoid the quality problems such as deformation and shrinkage caused by the previous welding manufacturing method for such large, complex docking end frames. At the same time, it saves the cycle and cost of molds required for casting blanks, and can more easily realize the full machining of the product's internal cavity. It effectively solves the needs for fast, low-cost, and high-precision manufacturing of such large-size, complex, thin-walled docking end frames.

[0049] This intellectual property has solved many problems in actual production and has a wide range of applications, showing great promise for future use.

[0050] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0051] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. An automated composite processing method for additive and subtractive materials of large-size complex thin-walled butt joint end frames, characterized in that, include: Based on the structural characteristics and distribution of the thin-walled docking end frame, the docking end frame is divided into several structural intervals in terms of height; Based on the structural sections divided by the docking end frame, design the number of alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing; Based on the structural characteristics and distribution within each structural section of the docking end frame, the path for arc additive manufacturing is planned; Based on the structural characteristics formed after arc additive manufacturing, and combined with the effective stroke of the additive and subtractive manufacturing equipment, the path planning and tool selection for CNC subtractive manufacturing are designed. Based on the specific structure and dimensions formed by adding or subtracting materials after the electric arc in each structural section, design modular internal support shape tooling adapted to each structural section. According to the designed electric arc additive manufacturing path, CNC subtractive manufacturing path, and the number of times of additive and subtractive compound processing are performed, the automated composite processing of complex thin-walled butt joint frames is completed through multiple alternating additive and subtractive manufacturing processes. An automated composite processing equipment for additive and subtractive manufacturing is used to complete the fine machining of the complex thin-walled docking end frame, and the substrate is cut off to obtain the complete final docking end frame; The path planning for arc additive manufacturing based on the structural characteristics and distribution within each structural section of the docking end frame includes: adopting a path planning method that combines circular motion and short linear reciprocating motion. Specifically, the arc additive spindle head performs short linear reciprocating motion while the rotary table performs circular motion simultaneously, and the two motions combine to form the final path of the arc additive manufacturing. Based on the structural characteristics formed after arc additive manufacturing, and combined with the effective stroke of the additive / subtractive manufacturing equipment, the path planning and tool selection for CNC subtractive manufacturing are designed, including: using alternating clockwise and counterclockwise semicircular paths for full-circumference cutting, and using a large-neck multi-faceted wheel milling cutter to complete the cutting, wherein: the ratio of the cutter head diameter to the cutter shank diameter of the large-neck multi-faceted wheel milling cutter is greater than 5:1; the circumferential side, upper surface, and lower surface of the cutter head are all ground with cutting edges.

2. The automated composite processing method for adding or subtracting materials of complex thin-walled butt joint frames according to claim 1, characterized in that: The method of dividing the thin-walled docking end frame into several structural intervals in height according to its structural features and distribution includes: dividing the docking end into several structural intervals in height according to the positional distribution and continuity of the protruding structures and suspended partitions on the thin-walled docking end frame.

3. The automated composite processing method for adding or subtracting materials of complex thin-walled butt joint frames according to claim 1, characterized in that: The design of the number of alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing based on the structural intervals divided by the docking end frame includes: the number of structural intervals corresponding to the number of alternating processes of electric arc additive manufacturing and CNC subtractive manufacturing.

4. The automated composite processing method for adding or subtracting materials of complex thin-walled butt joint frames according to claim 1, characterized in that: The modular internal support fixture, designed to fit each structural section based on the specific structure and dimensions formed after adding or subtracting materials from the electric arc in each structural section, includes: The internal support shaped tooling is a detachable multi-layer structure, and each layer of the internal support shaped tooling is adapted to the corresponding structural section. After completing the electric arc additive manufacturing and CNC subtractive manufacturing in a structural section, the corresponding internal support shape tooling for that structural section is installed inside, until the internal support shape tooling for each structural section is installed in sequence.

5. The automated composite processing method for adding or subtracting materials of complex thin-walled butt joint frames according to claim 4, characterized in that: The internal support shaping fixture includes multiple layers of internal support shaping units. Each layer of internal support shaping unit includes a positioning base, multiple sets of internal support claws, and multiple sets of telescopic positioning components. The multiple sets of telescopic positioning components are circumferentially symmetrically installed on the positioning base. The telescopic ends of the telescopic positioning components are connected to the internal support claws. The arc-shaped surface of the far end of the internal support claws is attached to the inner wall of the docking end frame after cutting. This describes the structure of the internal support and the shaping docking end frame.

6. The automated composite processing method for adding or subtracting materials of complex thin-walled butt joint frames according to claim 1, characterized in that: Before removing the substrate, the process also includes heat treatment of the mating end frame.

7. The automated composite processing method for adding or subtracting materials of complex thin-walled butt joint frames according to any one of claims 1-6, characterized in that: The outer diameter of the complex thin-walled docking end frame is 2000~2500mm.

8. The automated composite processing method for adding or subtracting materials of complex thin-walled butt joint frames according to any one of claims 1-6, characterized in that: The main wall thickness of the complex thin-walled docking end frame ranges from 2 to 3 mm.

Images