A precision machining method for a thin-wall beryllium-aluminum alloy support part

Abstract

The embodiment of the present application provides a kind of thin-walled beryllium aluminum alloy support part precision machining method, the method comprises the following steps: step 1: the outer circle of beryllium aluminum alloy part blank is turned, the balance 0.1-0.15 millimeter, establishes rough reference;Step 2: rough reference is positioned and clamped to workbench, and milling processes top surface groove to size;Step 3: milling processes lateral curved surface, reinforcing rib to size.Step 1 only turns the outer circle of beryllium aluminum alloy part blank, does not process inner hole, therefore, the inside support strength of part is greater, so that the processing surface of part blank is without tremor.Step 3 only processes the lateral curved surface of part blank, reinforcing rib, does not process sectorial inner cavity, so that the surface quality of thin-walled beryllium aluminum alloy support part prepared by the above processing method is better, and the part yield is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of parts processing methods, and in particular to a precision machining method for thin-walled beryllium aluminum alloy bracket parts. Background Technology

[0002] Beryllium-aluminum alloys possess advantages such as light weight, high specific strength, high specific stiffness, good thermal stability, high toughness, and corrosion resistance. Combining the low density of beryllium with the easy machinability of aluminum, they have become an increasingly important new material. With the continuous development of my country's industry and the increasing demand, the structures and types of parts are becoming more diverse, complex, thin-walled, and lightweight, placing higher demands on the machining of cast beryllium-aluminum alloy mechanical parts.

[0003] Precision casting is an important method for preparing beryllium-aluminum alloys, which can significantly reduce production costs. Subsequent precision machining is crucial for ensuring the final product meets application requirements. (See also...) Figure 1 This is a thin-walled beryllium aluminum alloy bracket part, which is a rotationally symmetric complex thin-walled cast aluminum alloy part, including multiple thin-walled curved surfaces, multiple weight-reducing grooves, and multiple reinforcing ribs. Specifically, the thin-walled curved surfaces (wall thickness ≤ 1 mm), the reinforcing ribs (thickness 2-4 mm), and the weight-reducing grooves (wall thickness ≤ 1 mm) are all part of this component. Currently, the field of precision machining technology for rotationally symmetric, complex thin-walled parts is still in its early stages, especially in the exploratory phase for precision machining of rotationally symmetric, complex thin-walled, and high-precision cast beryllium aluminum alloy parts.

[0004] A method for machining thin-walled beryllium aluminum alloy bracket parts in the prior art includes the following steps: obtaining a part blank, rough positioning and clamping it onto a worktable, milling a weight-reducing groove, and machining pin holes on the bottom surface. The process flow is as follows:

[0005] 1) Machin the outer diameter and inner diameter of the part blank, with a allowance of 0.1-0.3mm, and establish a rough datum;

[0006] 2) Mill the top surface groove to the required dimensions;

[0007] 3) Milling the triangular sector-shaped inner cavity to the required dimensions, with a tool extension length L≥65mm, resulted in significant machining chatter and obvious chatter marks;

[0008] 4) Milling of lateral curved surfaces and ribs to dimensions, with the machining toolpath being a circular motion from the outside in;

[0009] 5) Mill the reverse groove to the required dimensions;

[0010] 6) Time-sensitive processing;

[0011] 7) Finish-machine the outer diameter and inner hole to the required dimensions;

[0012] 8) Grind the reference surface;

[0013] 9) Finish milling the end face.

[0014] The existing precision machining method, which involves milling a weight-reducing groove in a machining center, milling an external weight-reducing groove, milling a lateral thin-walled curved surface, turning an internal hole, and wire cutting a fan-shaped thin-walled curved surface, results in a poor finished product qualification rate. Summary of the Invention

[0015] To address the aforementioned technical problems, this invention proposes a precision machining method for thin-walled beryllium aluminum alloy bracket parts, aiming to improve the finished product qualification rate.

[0016] A method for precision machining of thin-walled beryllium aluminum alloy bracket parts includes the following steps:

[0017] Step 1: Machine the outer diameter of the beryllium aluminum alloy part blank, leaving a allowance of 0.1-0.15 mm, and establish a rough datum;

[0018] Step 2: Fix the rough datum positioning clamp of the part onto the worktable, and mill the top surface groove to the dimension marked on the part;

[0019] Step 3: Mill the side curved surfaces and reinforcing ribs of the part to the dimensions indicated on the part's label;

[0020] Step 4: Mill the bottom groove of the part to the specified dimensions;

[0021] Step 5: Perform aging treatment on the parts.

[0022] After step 4 and before step 5, the following step is included: Step 50: Use wire EDM to machine the triangular sector-shaped inner cavity to the dimensions marked on the part.

[0023] Step 50 includes: clamping the part using a wire EDM fixture; the wire EDM fixture includes a fixture body, the top surface of the fixture body is provided with a step that is recessed inward toward the bottom surface, the step is an inner slot hole limiting part, and a positioning and directional pin hole is formed on the inner slot hole limiting part along the axial direction; the inner slot hole limiting part cooperates with the rough reference; the part and the wire EDM fixture are fixedly connected by the positioning pin.

[0024] Step 5 is followed by:

[0025] Step 6: Perform precision machining on the outer diameter and inner diameter of the aged parts to the dimensions indicated on the parts.

[0026] Step 7: Grind the rough reference;

[0027] Step 8: Finish mill the top and bottom surfaces of the part.

[0028] The side of the fixture body is provided with a directional finding face. When the wire cutting fixture is installed on the worktable, the directional finding face is used to determine the positive face in the X direction.

[0029] The positioning and orientation pin holes include two, which are evenly distributed on the circumference, and the plane containing the center line of the two positioning and orientation pin holes is perpendicular to the plane containing the orientation and orientation face.

[0030] A pressure plate is provided on the top surface of the fixture body. When the part is assembled with the wire cutting fixture, the pressure plate presses the rough reference firmly.

[0031] The pressure plate is provided with fastening screws, which connect and press the pressure plate to the coarse reference. There are two pressure plates arranged opposite each other.

[0032] Step 8 includes: clamping the part with a precision machining fixture, and then precision milling the top and bottom surfaces of the part;

[0033] The finishing fixture includes: a positioning plane and a clamping plate;

[0034] The positioning plane has a planar accuracy greater than 0 and less than or equal to 0.003 mm, and a surface roughness less than or equal to Ra0.4;

[0035] The clamping plate is a hollow circular plate, and the shape of the hollow part matches the external shape of the part;

[0036] Through holes are provided on the clamping plate and the positioning plane for bolts to be inserted to connect the part to the positioning plane and the clamping plate;

[0037] When milling the top surface of the part, the bottom surface of the part is aligned with the positioning plane of the finishing fixture, the hollow part of the clamping plate is clamped to the outer wall of the part, and the part is connected and fixed to the positioning plane and the clamping plate by bolts.

[0038] The precision machining method for thin-walled beryllium aluminum alloy bracket parts provided in this embodiment of the invention involves machining only the outer circle of the beryllium aluminum alloy part blank in step 1, without machining the inner hole. Therefore, the inner support strength of the part is relatively high, resulting in a smooth machining surface free of chatter marks. In step 3, only the lateral curved surfaces and reinforcing ribs of the part blank are machined, without machining the fan-shaped inner cavity. This results in a better surface quality for the thin-walled beryllium aluminum alloy bracket parts produced by the above machining method, and a significantly improved part yield. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of a thin-walled beryllium aluminum alloy support component in the prior art;

[0040] Figure 2This is a schematic diagram of the rough reference for the pin hole of a thin-walled beryllium aluminum alloy bracket part provided in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of a wire cutting fixture provided in an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram illustrating the assembly of a part with a wire EDM fixture according to an embodiment of the present invention;

[0043] Figure 5 This is a schematic diagram of the positioning plane provided in an embodiment of the present invention;

[0044] Figure 6 This is a schematic diagram of the structure of the clamping plate provided in an embodiment of the present invention;

[0045] Figure 7 This is a schematic diagram of the positioning plane, parts, and clamping plate assembly provided in an embodiment of the present invention. Detailed Implementation

[0046] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0047] This invention provides a method for precision machining of thin-walled beryllium aluminum alloy bracket parts, the method comprising the following steps:

[0048] Step 1: Machine the outer diameter of the beryllium aluminum alloy part blank, leaving a allowance of 0.1-0.15 mm, and establish a rough datum;

[0049] Step 2: Fix the rough datum positioning clamp onto the worktable and mill the top surface groove to the dimensions marked on the part;

[0050] Step 3: Mill the side curved surfaces and reinforcing ribs to the dimensions marked on the part;

[0051] Step 4: Mill the bottom groove to the dimensions marked on the part;

[0052] Step 5: Aging the parts. Then, proceed with the following treatments according to existing technology:

[0053] Step 6: Perform precision machining on the outer diameter and inner diameter of the aged parts to the required dimensions;

[0054] Step 7: Grind the rough reference;

[0055] Step 8: Finish mill the end face of the part.

[0056] In the above processing method of this invention embodiment, only the outer circle of the beryllium aluminum alloy part blank is machined in step 1, and the inner hole is not machined. Therefore, the inner support strength of the part is relatively large, so that the machined surface of the part blank is free of chatter marks. In step 3, only the lateral curved surface and reinforcing ribs of the part blank are machined, and the fan-shaped inner cavity is not machined. This results in better surface quality of the thin-walled beryllium aluminum alloy bracket part obtained by the above processing method, and the part yield is greatly improved. Furthermore, when machining the lateral thin-walled curved surface, in order to avoid cracking of the curved surface during machining, according to the outer curved surface cavity structure, the tool path of the lateral thin-walled curved surface is designed as follows: from top to bottom (to ensure bottom support), traveling milling (to ensure downward cutting force), end milling tool (to reduce tool cutting resistance), and finally outer corner clearing machining (the reinforcing rib 2 and the upper and lower end faces can provide sufficient support).

[0057] In the above embodiment, after step 4 and before step 5, there is also step 50: using wire EDM to process the triangular sector-shaped inner cavity to the required size.

[0058] In existing technologies, thin-walled beryllium aluminum alloy bracket parts have multiple reinforcing ribs inside, and the cavity formed between two adjacent reinforcing ribs is a triangular sector-shaped inner cavity. By using tooling to clamp the blank of the thin-walled beryllium aluminum alloy bracket part and machining the triangular sector-shaped inner cavity using wire electrical discharge machining, the precision of the finished part is guaranteed to a certain extent. This process involves no cutting force and has low cutting stress, thus ensuring high machining quality.

[0059] See Figure 2 In the above embodiment, step 50 includes: clamping the part with a wire EDM fixture; the wire EDM fixture includes a fixture body, the top surface of the fixture body is provided with a step that is recessed inward toward the bottom surface, the step is an inner slot hole limiting part, and a positioning and orientation pin hole is formed on the inner slot hole limiting part along the axial direction; the inner slot hole limiting part cooperates with the rough reference of the part, and a pin hole can be formed on the rough reference, the positioning and orientation pin hole corresponds to the pin hole on the rough reference, and the part and the wire EDM fixture are fixedly connected by the positioning pin.

[0060] When the part is clamped onto the wire EDM fixture, the rough reference of the part mates with the step of the wire EDM fixture, i.e., the inner groove hole limiting part. Then, the reference surface and the wire EDM fixture are connected by the positioning pin, thereby realizing the fixed connection between the wire EDM fixture and the part.

[0061] See Figure 3 In the above embodiments, the side of the fixture body is provided with a directional finding face. When the wire cutting fixture is installed on the worktable, the directional finding face is used to determine the X-direction plane.

[0062] After clamping the part into the wire EDM fixture, and then installing the wire EDM fixture onto the worktable, it is necessary to perform alignment of the positive plane in the X direction in order to improve machining accuracy. An directional alignment surface is provided on the side of the fixture body to facilitate alignment of the positive plane in the X direction, thereby improving the machining accuracy of the part and thus improving the yield of the finished product.

[0063] See Figure 3 In the above embodiment, the positioning and orientation pin holes include two, which are evenly distributed on the circumference, and the plane containing the center line of the two positioning and orientation pin holes is perpendicular to the plane containing the orientation and orientation face.

[0064] To ensure precise positioning of the parts, while enhancing positioning accuracy, it is also necessary to prevent displacement during processing. The plane containing the center lines of the two positioning and directional pin holes is perpendicular to the plane containing the directional facing face. This ensures accurate positioning of the parts and also prevents displacement of the wire cutting fixture to a certain extent, thereby ensuring precise processing accuracy and improving the yield of finished products.

[0065] See Figure 3 and Figure 4 In the above embodiment, a pressure plate is provided on the upper top surface of the fixture body. When the part is assembled with the wire cutting fixture, the rough reference is pressed by the pressure plate.

[0066] The part is assembled with the wire EDM fixture by using a pressure plate, which further fixes the part to the fixture, ensuring more accurate positioning of the part and preventing displacement. The pressure plate can be fixedly set on the top surface of the fixture body, and then the rough reference can be inserted into the pressure plate, or other clamping devices can be used to clamp and fix the pressure plate and the rough reference.

[0067] In the above embodiments, the pressure plate is provided with fastening screws, which connect and press the pressure plate to the coarse reference.

[0068] After fixing the pressure plate to the rough reference position, use fastening screws to position and tighten the pressure plate to the rough reference, ensuring reliable connection and easy disassembly.

[0069] In the above embodiments, the pressure plates include two plates arranged opposite each other to further improve the reliability of fastening. Of course, the number of pressure plates can be multiple, and can be freely selected according to the actual situation.

[0070] See Figure 5 , Figure 6 and Figure 7In the above embodiment, step 8 includes: clamping the part with a precision machining fixture, and then precision milling the top and bottom surfaces of the part; the precision machining fixture includes: a positioning plane and a clamping plate; the positioning plane has a plane accuracy greater than 0 and less than or equal to 0.003 mm, and a surface roughness less than or equal to Ra0.4; the clamping plate is a hollow circular plate, and the shape of the hollow part matches the external shape of the part; through holes are opened on the clamping plate and the positioning plane for bolts to connect the part to the positioning plane and the clamping plate.

[0071] Step 8 includes: when milling the top surface of the part, positioning the bottom surface of the part against the positioning plane of the finishing fixture, inserting the hollow portion of the clamping plate into the outer wall of the part, and connecting and fixing the part to the positioning plane and the clamping plate with bolts. After milling the top surface, if the flatness is less than that of the bottom surface, position the top surface of the part against the positioning plane of the finishing fixture, insert the hollow portion of the clamping plate into the outer wall of the part, and connect and fix the part to the positioning plane and the clamping plate with bolts. After milling the bottom surface, if the flatness is less than or equal to 0.01 mm, position the top surface of the part against the positioning plane of the finishing fixture, insert the hollow portion of the clamping plate into the outer wall of the part, and connect and fix the part to the positioning plane and the clamping plate with bolts.

[0072] It will be apparent to those skilled in the art that the embodiments of the present invention are not limited to the details of the exemplary embodiments described above, and that the embodiments of the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the embodiments of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the embodiments of the present invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be encompassed within the embodiments of the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims. Furthermore, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units, modules, or devices recited in the system, apparatus, or terminal claims may also be implemented by the same unit, module, or device through software or hardware.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and are not intended to limit them. Although the embodiments of the present invention have been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the embodiments of the present invention should not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for precision machining of thin-walled beryllium aluminum alloy bracket parts, wherein, The thin-walled beryllium aluminum alloy support component has multiple reinforcing ribs inside, and a triangular fan-shaped inner cavity is formed between two adjacent reinforcing ribs. Its characteristic is that the processing method includes the following steps: Step 1: Machine the outer diameter of the beryllium aluminum alloy part blank, leaving a allowance of 0.1-0.15 mm, and establish a rough datum; Step 2: Fix the rough datum positioning clamp of the part onto the worktable, and mill the top surface groove to the dimension marked on the part; Step 3: Mill the side curved surfaces and reinforcing ribs of the part to the dimensions indicated on the part's label; Step 4: Mill the bottom groove of the part to the dimensions marked on the part; Step 5: Perform aging treatment on the parts; In step 1, the inner hole was not machined; in step 3, the triangular sector-shaped inner cavity was not machined. The process includes the following steps after step 4 and before step 5: Step 50: Using wire EDM to machine the triangular sector-shaped inner cavity to the dimensions marked on the part. Step 50 includes: clamping the part using a wire EDM fixture; the wire EDM fixture includes a fixture body, the top surface of which has a step recessed inward toward the bottom surface, the step being an inner slot hole limiting part, and a positioning and orientation pin hole being formed on the inner slot hole limiting part along the axial direction; the inner slot hole limiting part mates with the rough reference; the part and the wire EDM fixture are fixedly connected by positioning pins; the side of the fixture body has an orientation finding face, which is used to determine the positive plane in the X direction when the wire EDM fixture is installed on the worktable; the positioning and orientation pin holes include two, evenly distributed on the circumference, and the plane containing the center line of the two positioning and orientation pin holes is perpendicular to the plane containing the orientation finding face.

2. The processing method according to claim 1, characterized in that, Step 5 is followed by: Step 6: Perform precision machining on the outer diameter and inner diameter of the aged parts to the dimensions indicated on the parts. Step 7: Grind the rough reference; Step 8: Finish mill the top and bottom surfaces of the part.

3. The processing method according to claim 2, characterized in that, Step 8 includes: clamping the part with a precision machining fixture, and then precision milling the top and bottom surfaces of the part; The finishing fixture includes: a positioning plane and a clamping plate; The positioning plane has a planar accuracy greater than 0 and less than or equal to 0.003 mm, and a surface roughness less than or equal to Ra0.4; The clamping plate is a hollow circular plate, and the shape of the hollow part matches the external shape of the part; Through holes are provided on the clamping plate and the positioning plane for bolts to be inserted to connect the part to the positioning plane and the clamping plate; When milling the top surface of the part, the bottom surface of the part is aligned with the positioning plane of the finishing fixture, the hollow part of the clamping plate is clamped to the outer wall of the part, and the part is connected and fixed to the positioning plane and the clamping plate by bolts.

4. The processing method according to claim 1, characterized in that, A pressure plate is provided on the top surface of the fixture body. When the part is assembled with the wire cutting fixture, the pressure plate presses the rough reference firmly.

5. The processing method according to claim 4, characterized in that, The pressure plate is provided with fastening screws, which connect and press the pressure plate to the coarse reference. There are two pressure plates arranged opposite each other.

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