A processing method of a multi-groove structure complex thin-wall special-shaped cavity part

Abstract

The present application relates to a kind of machining methods of multi-rib complex thin-walled special-shaped cavity class parts, solve the precision machining problem of the inner cavity rib groove of large complex thin-walled cavity, outer wall rib groove root angle, thin-walled uniform thickness difficult to realize in prior art.It includes:1) electrode design;2) tooling design;3) workpiece pretreatment and clamping;4) electrode installation;5) machining track verification;6) machining parameter selection;7) machining process detection and evaluation.The present application is aimed at thin-walled parts and the processing of the parts with high uniformity requirement of wall thickness, uses the scheme of electric spark machining technology combined with combined electrode, has the beneficial effects of high-precision machining, reducing deformation or damage, good accessibility, etc.

Description

Technical Field

[0001] This patent relates to a processing method for complex thin-walled irregular cavity parts with multi-ribbed groove structure, belonging to the field of processing technology for complex thin-walled cavity parts. Background Technology

[0002] With the rapid development of additive manufacturing technology, its application in the design and manufacturing of large, thin-walled, complex structural parts is becoming increasingly widespread. Additive manufacturing technology, with its unique additive forming method, offers advantages for integral manufacturing and thin-walled manufacturing, making it possible to process complex structural parts that are difficult to machine. However, as the complexity of parts increases, additive manufacturing struggles to meet design requirements in terms of thin-wall thickness uniformity, surface finish, and dimensional accuracy, posing numerous challenges to subsequent precision machining. This is especially true for large-sized, multi-ribbed, complex, irregularly shaped, thin-walled cavity parts, which are bulky, have complex rib and groove layouts, and require high precision in terms of rib and groove root fillets and wall thickness uniformity after machining. These parts are widely used in high-end manufacturing fields such as aerospace, aviation, and automotive, but their manufacturing difficulty is also relatively high. Due to the confined space inside or outside the cavity, traditional machining methods have poor accessibility and cannot complete the machining. Summary of the Invention

[0003] This invention provides a machining method for complex thin-walled irregular cavity parts with multi-ribbed grooves, solving the problem of precision machining of the inner cavity ribs, the root angle of the outer wall ribs, and the uniform thickness of the thin wall of large complex thin-walled cavities that is difficult to achieve in the prior art.

[0004] This invention is achieved through the following technical solutions:

[0005] A method for machining complex thin-walled irregular cavity parts with multi-ribbed grooves includes:

[0006] 1) Electrode design: Based on the 3D model of the multi-ribbed thin-walled structure, the processing area and size of each rib structure are selected, and a dedicated electrode unit is designed for each rib structure. The shape of the electrode unit matches the rib structure to ensure the overlapping relationship between the separate electrodes. The electrode unit is made of materials with good conductivity, such as copper or graphite. The processing trajectory of each electrode is simulated to effectively avoid obstacles and design the processing accessibility.

[0007] 2) Tooling design: Multiple electrodes use the same type of electrode tooling. The tooling design principle should avoid the part body to prevent interference between the machine tool spindle and the part;

[0008] The electrodes are installed by connecting them to the tooling with screws. The tooling is connected to the machine tool via the machine tool's reference quick-change fixture. After installation, each electrode is positioned accurately relative to the XYZ axes of the machine tool by pulling the electrode reference surface.

[0009] 3) Processing technology flow

[0010] a) Workpiece pretreatment and clamping: Clean and wipe the additively manufactured parts to ensure the cleanliness and flatness of the machined surface and to ensure that the bottom reference surface is clean; at the same time, clean the machine tool worktable, comprehensively consider the processing range, select a reasonable position, align according to the part reference, and use tooling to clamp the part.

[0011] b) Electrode installation: Install the designed electrode units on the electrode fixture in a predetermined order and orientation. Use the electrode reference surface for precise positioning to ensure the relative positional accuracy between the electrode and the part. Place the reference for electrode wear detection on the machine tool table.

[0012] c) Machining trajectory verification: Using the electrode trajectory simulated by computer, a machining program is compiled. After the machine tool is positioned, actual no-load machining is performed to verify the accuracy and feasibility of the program trajectory.

[0013] d) Machining parameter selection: Based on the part material, thickness, and machining accuracy requirements, optimize the machining parameters of the EDM machine tool, including discharge pulse width, pulse interval, voltage, current, machining speed, etc., to ultimately achieve machining.

[0014] e) Process inspection and evaluation: After each electrode is processed, the reference quick-change fixture is replaced, and the wall thickness is detected by a standard ball to determine whether the processing is in place. The processing is judged based on the amount of allowance.

[0015] This invention addresses the machining of thin-walled parts with high requirements for wall thickness uniformity. It employs an electrical discharge machining (EDM) technique combined with a combination electrode, which offers advantages such as high-precision machining, reduced deformation or damage, and good accessibility. Attached Figure Description

[0016] Figure 1 This is an isometric view of the combined electrode design of the present invention;

[0017] Figure 2 This is a disassembled diagram of the electrodes according to a specific embodiment of the present invention. The serial numbers in the diagram represent 22 different electrodes.

[0018] Figure 3 This is a schematic diagram of the electrode processing of the present invention;

[0019] Figure 4 This is a diagram showing the installation of the electrodes and tooling of this invention. Detailed Implementation

[0020] This invention addresses the challenge of low rigidity and high machining accuracy in complex, thin-walled, ribbed parts manufactured using additive manufacturing. It proposes a non-contact, macroscopically force-free precision electrical discharge machining method, effectively solving the problem of cutting deformation during machining.

[0021] To address the challenges of limited space, rounded corners, uniform wall thickness, and poor machinability in rib grooves, a tooling and multiple separate electrodes were designed. The machining of each poorly accessible rib groove was accomplished through the separate electrode method and ingenious trajectory motion.

[0022] This complex, thin-walled, irregularly shaped cavity part with multiple ribs and grooves is an additively manufactured component. It has a large overall volume and consists of numerous ribs and grooves and thin walls. The thickness of the thin walls after additive manufacturing is uneven, and the radius of the rib roots varies, failing to meet design accuracy requirements. Due to the narrow location of the ribs and the weak rigidity of the thin walls, machining accessibility is poor. Therefore, using a combination of multiple separate electrodes or localized fillet electrodes can meet the requirements.

[0023] The invention will be further described below with reference to the accompanying drawings:

[0024] like Figure 1-4 As shown, this invention relates to a method for processing complex thin-walled irregular cavity parts with multi-ribbed groove structures, specifically including:

[0025] 1) Electrode Design. Based on the 3D model of the multi-ribbed thin-walled structure, the machining area and dimensions for each rib are selected. A dedicated electrode unit is designed for each rib, ensuring not only that the shape of the electrode unit matches the rib structure, but also that the overlap relationship between the individual electrodes is maintained. Figure 1 , Figure 2 The electrode units are mostly made of materials with good electrical conductivity, such as copper or graphite. Considering the distribution and processing sequence of the groove structure on this part, a total of 11 pairs (22 individual) separate electrodes were designed. Figure 2 It simulates the processing trajectory of each electrode, effectively avoids obstacles, and ensures that all electrodes are accessible for processing.

[0026] 2) Tooling Design. The workpiece is placed on the worktable of a four-axis EDM machine, with its bottom surface as the reference. A clamping plate holds the center of the workpiece for stable clamping. For ease of use, multiple electrodes utilize the same type of electrode tooling. Figure 3 , Figure 4 The tooling design principle should avoid the part itself to prevent interference between the machine tool spindle and the part;

[0027] The electrodes are installed by connecting them to the tooling with screws. The tooling is then connected to the machine tool using the machine tool's reference quick-change fixture. After each electrode is installed, the electrode reference surface must be pulled to ensure accurate relative position with the XYZ axes of the machine tool.

[0028] 3) Processing technology flow

[0029] a) Workpiece pretreatment and clamping: Perform necessary pretreatment work such as cleaning and wiping on the additively manufactured parts to ensure the cleanliness and flatness of the machined surfaces and to ensure that the bottom reference surface is clean. At the same time, clean the machine tool worktable, comprehensively consider the machining range, select a reasonable position, align it according to the part reference, and use tooling to clamp the part.

[0030] b) Electrode Installation: Install the designed electrode units onto the electrode fixture according to the predetermined sequence and orientation. Precise positioning using the electrode reference surface ensures the relative positional accuracy between the electrode and the workpiece. A reference for electrode wear detection is placed on the machine tool table.

[0031] c) Machining trajectory verification: Using the electrode trajectory simulated by computer, a machining program is compiled. After the machine tool is positioned, the machining is carried out in actual no-load operation to verify the accuracy and feasibility of the program trajectory.

[0032] d) Selection of machining parameters: Based on the requirements of the aluminum alloy material, thickness, and machining accuracy of the part, the machining parameters of the EDM machine tool were optimized, including discharge pulse width, pulse interval, voltage, current, and machining speed, and the machining was finally achieved.

[0033] e) Process inspection and evaluation: After each electrode is processed, the reference quick-change fixture is replaced, and the wall thickness is detected by a standard ball to determine whether the processing is in place. The processing is judged based on the allowance size.

[0034] This invention addresses the machining of thin-walled parts with high requirements for wall thickness uniformity. It employs an electrical discharge machining (EDM) technique combined with a combination electrode, which offers the following advantages:

[0035] 1) Precision machining of the root of the rib groove in a narrow space

[0036] Electrical discharge machining (EDM) technology is characterized by high precision. By optimizing pulse power supply parameters and using a precision control system for precise discharge control, it can ensure good uniformity of wall thickness.

[0037] 2) Reduce deformation and damage

[0038] Compared with traditional machining methods, electrical discharge machining (EDM) has no macroscopic cutting force, which helps to reduce deformation or damage to thin-walled parts during machining and maintain their shape and dimensional stability.

[0039] 3) Flexibility and accessibility solve the inaccessibility issues of traditional processing

[0040] The separate electrode design offers greater flexibility and accessibility, enabling the machining of complex shapes and hard-to-reach areas. For thin-walled parts, this means that more complex shapes and structures can be achieved while maintaining high precision.

[0041] These advantages make this solution a promising candidate for application and have significant market potential in the high-end aerospace manufacturing sector for complex thin-walled, multi-ribbed parts.

Claims

1. A method for machining complex thin-walled irregular cavity parts with multi-ribbed groove structure, characterized by: include: 1) Electrode design: Based on the 3D model of the multi-ribbed thin-walled structure, the processing area and size of each ribbed structure are selected, and a dedicated electrode unit is designed for each ribbed structure. The shape of the electrode unit matches the ribbed structure to ensure the overlapping relationship between the separate electrodes. Simulate the machining trajectory of each electrode to design effective obstacle avoidance and machining accessibility. 2) Tooling design: Multiple electrodes use the same type of electrode tooling. The tooling design principle should avoid the part body to prevent interference between the machine tool spindle and the part; The electrodes are installed by connecting them to the tooling with screws. The tooling is connected to the machine tool via the machine tool's reference quick-change fixture. After installation, each electrode is positioned accurately relative to the XYZ axes of the machine tool by pulling the electrode reference surface. 3) Processing technology flow a) Workpiece pretreatment and clamping: Clean and wipe the additively manufactured parts to ensure the cleanliness and flatness of the machined surface and to ensure that the bottom reference surface is clean; at the same time, clean the machine tool worktable, comprehensively consider the processing range, select a reasonable position, align according to the part reference, and use tooling to clamp the part. b) Electrode installation: Install the designed electrode units on the electrode fixture in a predetermined order and orientation. Use the electrode reference surface for precise positioning to ensure the relative positional accuracy between the electrode and the part. Place the reference for electrode wear detection on the machine tool table. c) Machining trajectory verification: Using the electrode trajectory simulated by computer, a machining program is compiled. After the machine tool is positioned, actual no-load machining is performed to verify the accuracy and feasibility of the program trajectory. d) Machining parameter selection: Based on the part material, thickness, and machining accuracy requirements, optimize the machining parameters of the EDM machine tool to ultimately achieve the machining; e) Process inspection and evaluation: After each electrode is processed, the reference quick-change fixture is replaced, and the wall thickness is detected by a standard ball to determine whether the processing is in place. The processing is judged based on the amount of allowance.

2. The processing method for a complex thin-walled irregular cavity part with a multi-ribbed groove structure according to claim 1, characterized in that: The electrode unit is made of copper or graphite.

3. The processing method for a complex thin-walled irregular cavity part with a multi-ribbed groove structure according to claim 1, characterized in that: Optimizing the machining parameters of an electrical discharge machining (EDM) machine tool includes adjusting the discharge pulse width, pulse interval, voltage, current, and machining speed.

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