Irregular thin-wall part machining method

Abstract

The invention relates to the technical field of thin-wall structural part machining, in particular to a machining method for an irregular thin-wall part. The irregular thin-walled part machining method comprises the steps that a sand mold machined part is obtained, a groove defined by rib plates is formed in one end of the sand mold machined part, and at least part of the rib plates are provided with positioning bosses; the whole surface of the sand mold machined part is sequentially subjected to rough machining and semi-finish machining, and a semi-finish machined part is obtained; first finish machining is carried out on the part, except the positioning boss, of the semi-finish machining part to obtain a first finish machining part, and a rib plate of the semi-finish machining part is provided with a communicating hole; a simulation load piece is installed in at least part of the groove of the first finish machining piece; and in the state that the first finish machining part is provided with the simulation load part, second finish machining is conducted on the positioning boss to obtain a second finish machining part, and the positioning boss of the second finish machining part is provided with a positioning hole. In this way, the problem that when an existing large-size thin-wall part is machined, the flatness of the surface of the top of the thin-wall part is low easily is solved.

Description

Technical Field

[0001] This invention relates to the field of thin-walled structural component processing technology, and more specifically, to a method for processing irregular thin-walled parts. Background Technology

[0002] Currently, satellites are arranged in a stacked configuration within the rocket body. This efficiently utilizes the rocket's space, enabling multiple satellite launches with a single rocket, thus reducing launch costs. These stackable satellites employ a flat-panel design, with their main structure being a single, highly integrated, and structurally complex aluminum alloy main plate. This main plate consists of a frame composed of multiple intersecting horizontal and vertical side panels and diagonal bracing panels. One side features an integrated base plate with a thickness of only 1mm, while the side panels are 2-3mm thick. The main plate is over 2.5m long and over 1.4m wide, making it a typical large-size, thin-walled structural component. Because satellites are precision equipment, high precision is required for the main plate's machining, with a maximum dimensional accuracy of ±0.05mm and a maximum positional accuracy of ±0.02mm. Such flat, thin-walled structural components have relatively weak structural rigidity, resulting in poor resistance to cutting forces during machining. This leads to vibration and deformation during processing, making it difficult to guarantee machining accuracy. The complex structure and poor panel rigidity also present significant challenges for pre-machining clamping and securing. Summary of the Invention

[0003] To address the problem of low surface flatness on the top surface of large, thin-walled parts during existing machining processes, this invention provides a method for machining irregular thin-walled parts, comprising the following steps:

[0004] A sand mold is obtained, wherein one end of the sand mold has M first grooves formed by N first ribs, and at least some of the ribs are provided with S first positioning bosses, and the sand mold has a first machining allowance, wherein N, M and S are natural numbers, and N, M > S > 1;

[0005] The entire surface of the sand mold is sequentially roughed and semi-finished to obtain a semi-finished part. The semi-finished part has a second machining allowance, the first groove forms a second groove, and the first positioning boss forms a second positioning boss.

[0006] A first finished part is obtained by performing a first finishing process on the part other than the second positioning boss of the semi-finished part. The second positioning boss has the second machining allowance, the second groove forms a third groove, and at least part of the second rib of the third groove has a connecting hole.

[0007] The simulated load element is installed within at least a portion of the third groove;

[0008] With the simulated load member present in the first finished part, the second positioning boss is subjected to a second finishing process to obtain a second finished part. The second positioning boss forms a third positioning boss. The second positioning boss and the third positioning boss have positioning holes, or the third positioning boss has positioning holes.

[0009] According to one embodiment of the present invention, a reference surface of the sand mold part is obtained;

[0010] The machining reference center of the sand mold is obtained based on the reference surface of the sand mold.

[0011] The entire surface of the sand mold is rough-machined based on the machining reference center to obtain a rough-machined part, wherein the rough-machined part has a third machining allowance.

[0012] The semi-finished part is obtained by semi-finishing the entire surface of the rough-machined part based on the machining reference center.

[0013] According to one embodiment of the present invention, the roughing, semi-finishing, and first finishing processes include:

[0014] The surface of the workpiece is machined around the machining reference center and in a direction away from the machining reference center;

[0015] Alternatively, the surface of the workpiece is divided into T processing regions based on the processing reference center, and the T processing regions are processed respectively along the processing reference center, where T is a natural number and T≥2.

[0016] According to one embodiment of the present invention, when a single groove in a single processing region has the following condition, the entire surface of the single groove in the single processing region is processed:

[0017] The surface area of ​​a single groove located within a single processing area is greater than or equal to 1 / 2 of the surface area of ​​a single independent groove.

[0018] According to one embodiment of the present invention, the roughing process further includes a first stabilization treatment, the first stabilization treatment comprising:

[0019] The rough-machined part is subjected to a first heat treatment and a first cold treatment, wherein the first cold treatment time is greater than the first heat treatment time.

[0020] According to one embodiment of the present invention, the semi-finishing further includes a second stabilization treatment, the second stabilization treatment comprising:

[0021] The precision-machined part is subjected to a second heat treatment and a second cold treatment, wherein the second cold treatment time is greater than the second heat treatment time.

[0022] According to one embodiment of the present invention, the ratio of the first machining allowance, the third machining allowance and the second machining allowance is 6~10:1.5~3:0.5~1.

[0023] According to one embodiment of the present invention, when performing the roughing, semi-finishing and first finishing, the end having the groove is first machined, and the peripheral side of the workpiece is machined.

[0024] According to one embodiment of the present invention, when machining one end of the workpiece having the groove, the internal structure of the groove is machined first, and then the top of the rib forming the groove is machined.

[0025] According to one embodiment of the present invention, the first groove includes R load mounting grooves and L first weight reduction grooves, the L first weight reduction grooves form a figure-eight-shaped structure, and the area of ​​the load mounting groove with the smallest area among the R load mounting grooves is greater than or equal to the area of ​​the first weight reduction groove with the largest area among the L first weight reduction grooves, wherein R and L are natural numbers, and R, L > 1.

[0026] According to one embodiment of the present invention, the first finishing process further includes machining a first threaded hole having at least three regions on the peripheral side of the first finished part, wherein the spacing between the three regions having the first threaded hole is consistent or inconsistent.

[0027] According to one embodiment of the present invention, the first finishing process further includes anodizing the first finished part.

[0028] According to one embodiment of the present invention, during the first finishing process, a second weight-reducing groove is machined on the outer peripheral side of the semi-finished part; during the second finishing process, a third weight-reducing groove is machined on the third positioning boss.

[0029] According to one embodiment of the present invention, the second positioning boss surface has the second machining allowance;

[0030] With the simulated load member present in the first finished part and the first finished part suspended in the air, the second positioning boss surface is subjected to a second finishing process.

[0031] According to one embodiment of the present invention, a process chuck is integrally formed on the side of the sand mold part, or a process chuck is connected to the side of the sand mold part. The process chuck is used for positioning the part during processing, and the process chuck is removed after the processing of the part is completed.

[0032] To address the problem of low surface flatness on the top surface of large, thin-walled parts during existing machining processes, this invention offers the following advantages:

[0033] 1. The present invention ensures that the thin-walled parts obtained by the present invention meet the requirements by installing a simulated load component in the groove during the second finishing process to simulate whether the obtained thin-walled parts meet the conditions of installing load components in actual application.

[0034] 2. The present invention obtains the third positioning boss by machining the second positioning boss under the condition of installing a simulated load component. This ensures that all the third positioning boss surfaces on the second finished part are coplanar. This avoids the problem of machining the third positioning boss first and then subjecting the second finished part to a simulated load. The simulated load component itself has a certain weight, and the weight exerted by the simulated load component on the second finished part can easily cause deformation (such as bending, tilting, etc.) or non-coplanarity of all the third positioning boss surfaces on the second finished part, which would affect the subsequent installation of the battery panel on the positioning boss.

[0035] 3. Compared with traditional honeycomb panel material assembly process and multi-part assembly process, the thin-walled parts prepared by the method of the present invention have the advantages of good internal quality, light weight, high degree of integration and stable dimensional accuracy. Attached Figure Description

[0036] Figure 1 A process flow diagram of the machining method for irregular thin-walled parts is shown;

[0037] Figure 2 A top view of the structure of a sand-molded part is shown;

[0038] Figure 3 It shows Figure 2 A front view structural diagram of a sand-molded part;

[0039] Figure 4 A schematic diagram of a sand-molded part with a process chuck is shown.

[0040] Figure 5 The first heat treatment process curve is shown;

[0041] Figure 6 The first cold treatment process curve is shown;

[0042] Figure 7 The second heat treatment process curve is shown;

[0043] Figure 8 The second cold treatment process curve is shown;

[0044] Figure 9 A schematic diagram of the structure in which a simulated load component is mounted on the first finished part is shown;

[0045] Figure 10 A schematic diagram of the structure of the second finished part is shown.

[0046] Reference numerals: A - Machining reference center; 10 - Sand molded part; 11 - First rib; 12 - First groove; 121 - Load mounting groove; 122 - First weight reduction groove; 13 - First positioning boss; 14 - Process chuck; 20 - First finished part; 21 - Third groove; 22 - Second rib; 23 - Second positioning boss; 24 - Connecting hole; 25 - Opening; 26 - Second weight reduction groove; 30 - Simulated load part; 40 - Second finished part; 41 - Third positioning boss; 42 - Positioning hole; 43 - Third weight reduction groove. Detailed Implementation

[0047] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0048] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0049] This embodiment discloses a method for processing irregular thin-walled parts, such as... Figure 1 As shown, it includes the following steps:

[0050] A sand mold part 10 is obtained. One end of the sand mold part 10 has M first grooves 12 surrounded by N first ribs 11. At least some of the ribs are provided with S first positioning bosses 13. The sand mold part 10 has a first machining allowance. N, M and S are natural numbers, and N, M > S > 1.

[0051] The entire surface of the sand mold 10 is sequentially roughed and semi-finished to obtain a semi-finished part. The semi-finished part has a second machining allowance. The first groove 12 forms a second groove, and the first positioning boss 13 forms a second positioning boss 23.

[0052] A first finishing part 20 is obtained by performing a first finishing process on the part other than the second positioning boss 23 of the semi-finished part. The second positioning boss 23 has the second machining allowance, and the second groove forms a third groove 21. At least a portion of the second rib 22 of the third groove 21 has a connecting hole 24.

[0053] The simulated load element 30 is installed in at least a portion of the third groove 21;

[0054] With the simulated load member 30 in the state of the first precision-machined part 20, the second positioning boss 23 is subjected to a second precision-machined process to obtain the second precision-machined part 40. The second positioning boss 23 forms a third positioning boss 41. The second positioning boss 23 and the third positioning boss 41 have positioning holes, or the third positioning boss 41 has a positioning hole 42.

[0055] In this embodiment, M grooves are for mounting load components, and S positioning bosses are for mounting the battery panel. At least a portion of the second rib 22 of the third groove 21 also has an opening 25. The opening 25 and the connecting hole 24 are for wire routing. By installing simulated load components 30 in at least a portion of the third groove 21 during the second finishing process, the suitability of the obtained thin-walled part for mounting load components in actual applications is simulated, ensuring that the thin-walled part obtained in this embodiment meets the requirements. The third positioning boss 41 is obtained by machining the second positioning boss 23 under the condition of installing the simulated load component 30. This ensures that all the third positioning bosses 41 on the second finished part 40 are coplanar. This avoids machining the third positioning bosses 41 first and then simulating the load on the second finished part 40. Since the simulated load component 30 itself has a certain weight, the weight exerted by the simulated load component 30 on the second finished part 40 can easily cause deformation (such as bending, tilting, etc.) or non-coplanarity of all the third positioning bosses 41 on the second finished part 40, affecting the subsequent installation of the solar panel on the positioning boss. Since the simulated load component 30 simulates the load component in actual application, as long as the weight of the simulated load component 30 is similar to that of the load component in actual application, the simulated load component 30 can be installed in some of the third grooves 21. Compared with the traditional honeycomb panel material assembly process and multi-part assembly process, the thin-walled part prepared by the method of this embodiment has the advantages of good internal quality, light weight, high degree of integration, and stable dimensional accuracy.

[0056] Preferably, the number of third grooves 21 with simulated load components 30 installed is greater than the number of third grooves 21 without simulated load components 30 installed, further ensuring the reliability of simulated load on the workpiece.

[0057] Preferably, the third positioning boss 41 has a positioning hole 42, that is, the positioning hole 42 is machined after the second finishing process. Since the positioning boss has a small structural size, this processing method ensures the strength of the positioning boss. If the positioning hole 42 is machined first, the positioning boss is prone to deformation when other surfaces of the positioning boss are machined. On the other hand, it ensures that the positioning hole 42 is not affected by other processing and is not deformed.

[0058] Preferably, the connecting hole 24 includes a circular hole and / or a rectangular hole to meet more usage needs.

[0059] Preferably, during the first finishing process, the workpiece is fixed using vacuum adsorption. Vacuum adsorption solves the problems of clamping thin-walled semi-finished workpieces, which is difficult, and the vibrations that easily occur during the first finishing process, thus affecting the machining process and the accuracy of the workpiece.

[0060] According to one embodiment of the present invention, such as Figure 2 As shown, the reference surface of the sand mold 10 is obtained;

[0061] The machining reference center A of the sand mold 10 is obtained based on the reference surface of the sand mold 10;

[0062] Based on the machining reference center A, the entire surface of the sand mold 10 is rough-machined to obtain a rough-machined part, wherein the rough-machined part has a third machining allowance;

[0063] Based on the machining reference center A, the entire surface of the rough-machined part is semi-finished to obtain a semi-finished part.

[0064] In this embodiment, the second machining allowance < the third machining allowance < the first machining allowance. Obtaining the reference surface facilitates the identification of the machining reference center A and easily guides the roughing, semi-finishing, and first finishing processes.

[0065] According to one embodiment of the present invention, the roughing, semi-finishing, and first finishing processes include:

[0066] The surface of the workpiece is machined around the machining reference center A and in a direction away from the machining reference center A;

[0067] Alternatively, the surface of the workpiece is divided into T processing regions based on the processing reference center A, and the T processing regions are processed respectively along the processing reference center A, where T is a natural number and T≥2.

[0068] In this embodiment, by machining the surface of the workpiece around the machining reference center A and in a direction away from the machining reference center A, i.e., machining from the middle of the workpiece first, and dividing the surface of the workpiece into T machining areas based on the machining reference center A, and machining each of the T machining areas along the machining reference center A, the method of machining from one end of the workpiece to the other end, which is farthest from it, is avoided, as machining from one end of the workpiece to the other end, can easily cause machining stress accumulation and affect the machining quality at the far end.

[0069] According to one embodiment of the present invention, when a single groove in a single processing region has the following condition, the entire surface of the single groove in the single processing region is processed:

[0070] The surface area of ​​a single groove located within a single processing area is greater than or equal to 1 / 2 of the surface area of ​​a single independent groove.

[0071] In this embodiment, the surface area of ​​a single groove within a single processing area is greater than or equal to half the surface area of ​​a single independent groove. This should be understood as follows: when multiple grooves are divided into a single processing area, two situations arise: first, the entire single groove is located within the single processing area; second, a portion of a single groove is located within the single processing area, while another portion is located outside the single processing area. In the second situation, if the surface area of ​​the groove within the single processing area is greater than or equal to half its area, the portion of the single groove located outside the single processing area is processed, even if only a portion of the single groove is outside the single processing area. This embodiment avoids the problems of intermittent processing and frequent tool path movements when processing single grooves, such as groove sidewalls or bottoms, thereby ensuring both workpiece quality and processing speed.

[0072] According to one embodiment of the present invention, such as Figure 5 and Figure 6 As shown, the roughing process further includes a first stabilization treatment, which includes:

[0073] The rough-machined part is subjected to a first heat treatment and a first cold treatment, wherein the first cold treatment time is greater than the first heat treatment time.

[0074] In this embodiment, the rough-machined parts are placed into the furnace for cooling after heat treatment, avoiding stress deformation caused by rapid cooling. This hot-and-cold treatment process releases the internal stress generated during machining, preventing part deformation.

[0075] Preferably, the temperature of the first heat treatment is 110℃~130℃, the heating rate is ≤50℃ / h, the holding time is 4~6h, and the cooling method is furnace cooling to room temperature. A first cold treatment is performed within 24 hours after the first heat treatment. Setting the heating rate to ≤50℃ / h avoids excessively rapid heating that could cause stress deformation, while too slow a rate would affect the heating efficiency. The furnace cooling to room temperature method avoids rapid cooling that could cause stress deformation.

[0076] Preferably, the temperature of the first cold treatment is -60℃ to -90℃, the cooling rate is ≤50℃ / h, the holding time is 11 to 16h, and after the holding time is completed, the temperature is raised to room temperature at a rate of ≤50℃ / h.

[0077] According to one embodiment of the present invention, such as Figure 7 and Figure 8 As shown, the semi-finishing process further includes a second stabilization treatment, which includes:

[0078] The precision-machined part is subjected to a second heat treatment and a second cold treatment, wherein the second cold treatment time is greater than the second heat treatment time.

[0079] In this embodiment, the semi-finished parts are placed into the furnace for cooling after heat treatment to avoid stress deformation caused by rapid cooling. This hot-and-cold treatment process releases the internal stress generated during machining, preventing part deformation.

[0080] Preferably, the temperature of the second heat treatment is 110℃~130℃, the heating rate is ≤50℃ / h, the holding time is 2~4h, and the cooling method is furnace cooling to room temperature. The second cooling treatment is performed within 24 hours after the first heat treatment. By setting the heating rate to ≤50℃ / h, excessively rapid heating can easily cause stress deformation, while too slow heating will affect the rate. Furnace cooling to room temperature avoids rapid cooling that can easily cause stress deformation.

[0081] Preferably, the temperature of the second cold treatment is -60℃ to -90℃, the cooling rate is ≤50℃ / h, the holding time is 6 to 10h, and after the holding time is completed, the temperature is raised to room temperature at a rate of ≤50℃ / h.

[0082] According to one embodiment of the present invention, the ratio of the first machining allowance, the third machining allowance and the second machining allowance is 6~10:1.5~3:0:0.5~1.

[0083] In this embodiment, by setting a reasonable ratio between the first machining allowance, the third machining allowance, and the second machining allowance, the machining accuracy of each operation is guaranteed, and the internal stress of the workpiece obtained after the last machining process is avoided, which would affect the quality of the workpiece. At the same time, the process of eliminating the internal stress of the workpiece is avoided, reducing the number of machining processes. This embodiment has the characteristics of improving machining efficiency and reducing production costs.

[0084] According to one embodiment of the present invention, when performing the roughing, semi-finishing and first finishing, the end having the groove is first machined, and the peripheral side of the workpiece is machined.

[0085] In this embodiment, by processing the end of the workpiece with the groove first, it is convenient to process the other end (bottom) of the workpiece after confirming that the groove processing meets the requirements. This avoids the situation where the groove does not meet the requirements when processing the bottom of the workpiece first and then processing the groove end of the workpiece, in which case the workpiece cannot be used and the time spent processing the bottom of the workpiece is wasted.

[0086] According to one embodiment of the present invention, when machining one end of the workpiece having the groove, the internal structure of the groove is machined first, and then the top of the rib forming the groove is machined.

[0087] In this embodiment, due to the requirements of the finished product, there is a high requirement for the coplanarity of the end face of the part with the groove structure. By first processing the internal structure of the groove and then processing the top of the rib plate that forms the groove, the coplanarity of the end face of the part with the groove structure is ensured.

[0088] Preferably, when machining one end of the workpiece having the groove, the sidewall of the rib forming the groove, the bottom of the groove, and the top of the rib are machined. This further ensures that the bottom of the groove is also coplanar.

[0089] Preferably, when performing the first finishing process and machining one end of the semi-finished part with the groove, the internal structure of the groove is machined first, and then the top of the rib forming the groove is machined. This ensures that the obtained machined part has a coplanar end face with the groove, while also maintaining the machining rate.

[0090] According to one embodiment of the present invention, such as Figure 2 As shown, the first groove 12 includes R load mounting grooves 121 and L first weight reduction grooves 122. The L first weight reduction grooves 122 form a figure-eight-shaped structure. The area of ​​the load mounting groove 121 with the smallest area among the R load mounting grooves 121 is greater than or equal to the area of ​​the first weight reduction groove 122 with the largest area among the L first weight reduction grooves 122. Here, R and L are natural numbers, and R and L > 1.

[0091] In this embodiment, by setting the V-shaped groove of the plate, it is ensured that a groove for the installation of load-bearing components is reserved, and that the ribs forming the V-shaped groove provide support strength for the workpiece. In addition, the setting of the first weight-reducing groove 122 can also reduce the weight of the workpiece and provide a lightweight effect for the workpiece.

[0092] Preferably, the figure-eight structure has two ends located on one side of the workpiece and close to the middle region of that side, and the other two ends of the figure-eight structure extend to the middle region located on the other side of the workpiece and away from that side. This further ensures the reliability of the figure-eight first weight-reducing groove 122 in providing support strength to the workpiece.

[0093] Preferably, the stiffening rib having at least partially formed the first weight-reducing groove 122 has a positioning boss. Since the positioning boss is for mounting the solar panel, setting the positioning boss for mounting the solar panel on the stiffening rib having partially formed the first weight-reducing groove 122 ensures the stability of the structure.

[0094] According to an embodiment of the present invention (not shown in the figure), the first finishing process further includes machining a first threaded hole having at least three regions on the circumferential side of the first finished part 20, wherein the spacing between the three regions having the first threaded hole is consistent or inconsistent.

[0095] In this embodiment, by machining at least three regions of a first threaded hole on the circumferential side of the first finished part 20, the first threaded hole is used for mounting and positioning the first finished part 20 during the second finishing process. This ensures that the first finished part 20 is suspended during the second finishing process, thereby ensuring that the weight of the simulated load 30 on the first finished part 20 after it is mounted is more consistent with the weight of the load 30 on the workpiece in actual application. The method of machining the end face of the positioning boss after the simulated load 30 is mounted on the first finished part 20 further ensures that the multiple positioning boss surfaces are coplanar.

[0096] Preferably, the first threaded holes are machined on two adjacent corners or near two adjacent corners of the first finished part 20, and on the side of the first finished part 20 away from the two corners. The regions with the first threaded holes are connected end to end to form a triangular structure to ensure the reliability of the installation and positioning of the first finished part 20 during the second finishing process.

[0097] Preferably, the spacing between the three regions having the first threaded hole is inconsistent.

[0098] Preferably, the first finishing process further includes machining a second threaded hole near the first threaded hole at least a portion of the bottom of the first finishing part 20, and the second threaded hole is near the edge of the first finishing part 20. The first threaded hole and the second threaded hole cooperate to provide machining positioning for the first finishing part 20 during the second finishing process, thereby improving the reliability of the installation positioning of the first finishing part 20 during the second finishing process.

[0099] Preferably, the first finishing process further includes anodizing the first finished part 20.

[0100] In this embodiment, the chemical properties of the first finished part 20, such as corrosion resistance, wear resistance, weather resistance, and insulation, are improved by anodizing the first finished part 20.

[0101] Preferably, the anodizing process is performed after the threaded hole is machined.

[0102] According to one embodiment of the present invention, such as Figure 9 and Figure 10 As shown, during the first finishing process, a second weight-reducing groove 26 is machined on the outer peripheral side of the semi-finished part; during the second finishing process, a third weight-reducing groove 43 is machined on the third positioning boss 41.

[0103] In this embodiment, the lightweighting effect of the workpiece is further improved by setting the second weight-reducing groove 26 and the third weight-reducing groove 43.

[0104] According to one embodiment of the present invention, the second positioning boss 23 has the second machining allowance on its surface;

[0105] When the first precision-machined part 20 has the simulated load part 30 and the first precision-machined part 20 is in a suspended state, the second positioning boss 23 surface is subjected to a second precision-machined process.

[0106] In this embodiment, the solar panel is installed by multiple positioning bosses on the machined part. Since the positioning boss surface is the contact surface with the solar panel, any deformation, bending, or tilting of any positioning boss surface will cause it to be non-coplanar with the others, affecting subsequent solar panel installation. By machining only the positioning boss surface during the second finishing process, processing efficiency is improved while ensuring that all positioning boss surfaces are coplanar. Furthermore, the first finishing part 20 is suspended, ensuring that the weight of the simulated load 30 on the first finishing part 20 more closely reflects the actual weight impact on the machined part during application. Machining the positioning boss end faces while the simulated load 30 is installed on the first finishing part 20 further ensures that all positioning boss surfaces are coplanar.

[0107] Preferably, the top surface of the semi-finished part with the groove and the part other than the platform of the second positioning boss 23 are subjected to a first finishing process to obtain a first finished part 20, and the top surface of the semi-finished part with the groove and the platform of the second positioning boss 23 have a second machining allowance.

[0108] With the first finished part 20 having the simulated load part 30, the top surface of the semi-finished part having the groove side and the platform of the second positioning boss 23 are subjected to a second finishing process to obtain the second finished part 40.

[0109] In this way, it is further ensured that the top surface of the second precision-machined part 40 with the groove side is coplanar and the table surface of all the third positioning bosses 41 on the second precision-machined part 40 is coplanar.

[0110] According to one embodiment of the present invention, such as Figure 4 As shown, the sand mold 10 has a process chuck 14 integrally formed on its side, or the process chuck 14 is connected to the side of the sand mold 10. The process chuck 14 is used to position the workpiece during processing, and the process chuck 14 is removed after the workpiece is processed.

[0111] In this embodiment, the process chuck 14 facilitates the assembly and fixation of the workpiece during processing.

[0112] Preferably, there are at least three process chucks 14. More preferably, there are three to ten process chucks 14. The number of process chucks 14 can be set according to the size of the workpiece.

[0113] Preferably, a single process chuck 14 provides two layers: the lower layer is for positioning fixtures such as pressure plates to press down, and the upper layer is for positioning the pressure plates in the vertical direction, thereby increasing the reliability of installing and fixing the workpiece.

[0114] Preferably, the process chuck 14 is removed after the semi-finished part is completed.

[0115] Preferably, a first threaded hole is machined on the side of the first finished part 20 after the process chuck 14 is removed.

[0116] Example 1

[0117] A method for processing a flat, thin-walled aluminum alloy structural component with a complex structure, such as... Figure 1 As shown, it includes the following steps:

[0118] Step 1: Prepare the part blank:

[0119] The motherboard component blanks are manufactured using sand casting low-pressure casting process. The component blanks (sand-cast part 10) are as follows: Figure 2 As shown, the blank material is aluminum alloy, and the sand mold is prepared using 3D printing. The machining allowance on one side of the blank is designed to be 5mm. The blank material is as follows: Figure 2 As shown, one side of the part blank has grooves formed by multiple ribs. A portion of these grooves, forming a V-shape, has a smaller area than the other parts. These V-shaped grooves are the first weight-reducing groove 122, while the remaining grooves are load mounting grooves 121 for mounting load components. Some ribs have positioning bosses for mounting battery panels. After cleaning, the surface of the part blank undergoes X-ray inspection to analyze for internal defects such as porosity, inclusions, or cold shuts. If defects exceed the standard, they are repaired by welding. Before machining the part blank, it is usually heat-treated, including solution treatment and artificial aging. The repair method and heat treatment of this sand-cast part described above are existing technologies and will not be elaborated upon here.

[0120] Step 2: Set up the process chuck:

[0121] Three process chucks 14 are welded to the outside of the part blank. The part blank with the process chucks 14 is as follows: Figure 4 As shown, two adjacent process chucks 14 are located at two adjacent corners of the part blank, and the corner surfaces of the part blank where the process chucks 14 are located have a chamfered structure, such as... Figure 4 As shown, the process chuck 14 is made of the same material as the workpiece blank and is welded using TIG or MIG welding. The three process chucks 14 are arranged in a triangle, with each process chuck 14 consisting of upper and lower layers. The gap between the upper and lower layers is used for connecting the pressure plate fixture on the worktable.

[0122] Step 3: Draw the outline of the part blank:

[0123] Using manual scribing, the outline of the part blank's outer frame around its perimeter and top is drawn, that is, the outline of the part blank's outer frame in three directions: length (X-axis), width (Y-axis), and thickness (Z-axis). The scribing position is adjusted according to the actual machining allowance of each part's structure. Figure 2 and Figure 3 As shown.

[0124] Step 4: Fix the blank part:

[0125] Before clamping the process chuck 14, align it according to the contour line and clamp the pressure plate after determining the position of the part. On the worktable of the vertical CNC machine tool, use one end of the pressure plate fixture to extend into the gap between the two layers of the process chuck 14 to clamp the lower process chuck 14, so that the part blank is fixed on the worktable.

[0126] Step 5: Locate the datum plane and datum center:

[0127] Based on the outline of the part blank, offset outwards by 5mm according to the theoretical single-sided machining allowance, and machine the datum surfaces through end milling and side milling. The datum surfaces are the surfaces of the part blank in the X-axis, Y-axis and Z-axis directions, respectively. Find the machining datum center A of the part blank based on the peripheral outline of the part blank.

[0128] Step Six: Rough Machining

[0129] All surfaces of the part blank (including the clamping surface of the machining process chuck 14) are rough machined using end milling and side milling. First, the side of the part blank tool with the groove structure is machined. While machining this side, the outer peripheral side of the part blank is also machined. Then, the part blank is flipped over and the bottom plane side is machined, leaving a 2mm machining allowance on each side to obtain the rough machined part.

[0130] Specifically, starting from the reference center, machining is first performed towards the left side of the part blank. After machining is completed, machining is then performed towards the right side starting from the reference center. Carbide end mills are used for end milling and side milling. Cutting parameters: spindle speed 1000~2000 r / min, feed rate 800~1000 mm / min, depth of cut 1~2 mm.

[0131] In this process, a T-slot milling cutter is used to side-mill the rib plate below the positioning boss. The T-slot milling cutter has a shank diameter of 12~20mm, a shank length of 180~220mm, and a cutter head thickness of 5~10mm. The cutter head diameter is determined based on the farthest distance between the positioning boss and the rib plate.

[0132] Step 7: Perform the first stabilization treatment:

[0133] First heat treatment: Place the rough-machined part from step six into a box-type resistance furnace at room temperature and heat it at a heating rate of 40℃ / h. When the temperature reaches 120±10℃, hold it at that temperature for 6 hours. Then stop heating, hold it at that temperature, and cool it to room temperature with the furnace. The process curve is as follows. Figure 6 As shown.

[0134] First cold treatment: Within 18 hours after heat treatment, the parts are transferred to a freezer and cooled at a rate of 30℃ / h. When the temperature reaches -70±10℃, it is held for 16 hours, and then heated to room temperature at a rate of 30℃ / h. The process curves for the first heat treatment and the first cold treatment are as follows: Figure 5 and Figure 6 As shown.

[0135] Step 8, Semi-finishing:

[0136] All surfaces of the roughed part obtained in step seven (including the clamping surface of the process chuck 14) are semi-finished using end milling and side milling. First, the side of the roughed part with the groove structure is machined. While machining this side, the outer peripheral side of the roughed part is also machined. Then, the bottom plane side of the roughed part is machined, leaving a machining allowance of 0.5mm on each side to obtain the semi-finished part.

[0137] Specifically, during semi-finishing, machining begins from the reference center and proceeds towards the left side of the roughed workpiece. After this, machining resumes from the reference center and proceeds towards the right side of the roughed workpiece. Carbide end mills are used for end milling and side milling, with the following cutting parameters: spindle speed 500~1000 r / min, feed rate 600~800 mm / min, and depth of cut 0.5~1 mm. A T-slot end mill is used for side milling of the rib plate below the locating boss. Finally, the locating pin holes on the process chuck 14 are machined by milling.

[0138] Step 9: Perform a second stabilization treatment.

[0139] Second heat treatment: Place the semi-finished part from step eight into a box-type resistance furnace at room temperature and heat it at a heating rate of 40℃ / h. When the temperature reaches 120±10℃, hold it at that temperature for 3 hours. Then stop heating, hold it at that temperature, and cool it to room temperature with the furnace. The process curve is as follows. Figure 8 As shown.

[0140] Second cold treatment: Within 18 hours after heat treatment, the semi-finished parts are transferred to a freezer and cooled at a rate of 30℃ / h. When the temperature reaches -70±10℃, it is held for 8 hours, and then heated to room temperature at a rate of 30℃ / h. The process curves for the second heat treatment and the second cold treatment are as follows: Figure 9 As shown.

[0141] Step 10, First Finishing Process:

[0142] Before processing, the vacuum adsorption fixture is fixed on the worktable using a pressure plate fixture. Positioning pins are used to position and install the process chuck 14 onto the vacuum adsorption fixture. The vacuum system is activated to firmly adsorb the semi-finished part obtained in step nine onto the vacuum adsorption fixture. The first finishing process is performed using end milling and side milling. All surfaces of the semi-finished part are machined except for the positioning boss surface (battery panel mounting surface) and the positioning hole 42 on the positioning boss. The side of the rough-machined part with the groove structure is machined first, and the opening 25 and connecting hole 24 structure on the internal rib of the machined part are machined. While machining this side, the outer peripheral side of the semi-finished part is also machined, and a second weight-reducing groove 26 is machined on the outer peripheral sidewall of the semi-finished part. Then, the bottom plane side of the semi-finished part is machined. While machining the outer peripheral sidewall of the semi-finished part, the three process chucks 14 are simultaneously removed to obtain the first finished part 20. The first finished part is as follows: Figure 9 As shown.

[0143] Specifically, starting from the reference center, machining is first performed towards the left side of the semi-finished part, and after machining is completed, machining is then performed towards the right side of the roughed part starting from the reference center.

[0144] End milling and side milling are performed using carbide end mills with the following cutting parameters: spindle speed 200~400 r / min, feed rate 300~500 mm / min, and depth of cut 0.1~0.2 mm. A T-slot end mill is used for side milling of the rib plate below the positioning boss. A right-angle milling head is used to mill the second weight-reducing groove and the opening 25 and connecting hole 24 on the internal rib plate of the workpiece.

[0145] Step 11: Machining the threaded hole in the workpiece:

[0146] On the bottom of the first finished part 20 and the side after removing the process chuck 14, all the assembly threaded holes of the first finished part 20 obtained in step eleven are machined by drilling, and then the threads are tapped by hand to obtain the first finished part 20 with threaded holes.

[0147] Step 12, Oxidation Treatment:

[0148] The first finished part 20 with threaded holes obtained in step eleven is subjected to anodizing treatment.

[0149] Step Thirteen, Second Finishing Process:

[0150] A simulated load 30 is installed on the first finished part 20 obtained by anodizing in step twelfth. The first finished part 20 after installing the simulated load 30 is as follows: Figure 9 As shown.

[0151] The first precision-machined part 20 is mounted on the assembly fixture on the worktable. The second threaded hole at the bottom and the first threaded hole on the side of the first precision-machined part 20 are connected to the assembly fixture by bolts, keeping the bottom of the first precision-machined part 20 in a suspended state. Specifically, the gap between the bottom of the first precision-machined part 20 and the assembly fixture is kept ≤0.02mm. After confirming that the first precision-machined part 20 is fixed, the first precision-machined part 20, with the simulated load part 30 installed throughout the process, is subjected to a second precision machining of the positioning boss surface by end milling. After the positioning boss surface is machined, the positioning boss is machined with a third weight-reducing groove 43 structure by end milling. The end milling uses a carbide end mill, with a spindle speed of 500~1000 r / min, a feed rate of 200~300 mm / min, and a depth of cut of 0.05~0.10 mm. Finally, using a drilling-then-boring method, the positioning holes 42 on the positioning boss surface are machined to obtain the second finished part 40, which is the thin-walled aluminum alloy structural part. The second finished part 40 is as follows: Figure 10 As shown.

[0152] When the threaded hole of the first precision-machined part 20 is connected to the assembly fixture via bolts, a wire thread insert is first installed on the threaded hole of the first precision-machined part 20 to facilitate the connection between the first precision-machined part and the assembly fixture. Since the workpiece is made of aluminum alloy in some embodiments, and aluminum alloy is relatively soft, resulting in low thread strength in the threaded hole of the workpiece, it is generally necessary to embed a wire thread insert in the threaded hole of the aluminum alloy workpiece. This allows the wire thread insert and the threaded structure of the assembly fixture to mesh with each other, thereby ensuring a high threaded connection strength between the workpiece and the assembly fixture.

[0153] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the scope of this disclosure.

Claims

1. An irregular thin-walled part machining method characterized by, The method comprises the following steps: obtaining a sand processing piece, the sand processing piece having M first grooves surrounded by N first ribs at one end, and at least part of the ribs being provided with S first positioning bosses, the sand processing piece having a first processing allowance, wherein N, M and S are natural numbers, N, M > S > 1; sequentially performing rough machining and semi-finishing machining on the entire surface of the sand processing piece to obtain a semi-finished piece, the semi-finished piece having a second processing allowance, the first grooves forming second grooves, and the first positioning bosses forming second positioning bosses; performing first finishing machining on the semi-finished piece except the second positioning bosses to obtain a first finished piece, the second positioning bosses having the second processing allowance, the second grooves forming third grooves, and at least part of the second ribs of the third grooves having communication holes; mounting a simulation load piece in at least part of the third grooves; performing second finishing machining on the second positioning bosses to obtain a second finished piece in the state that the first finished piece has the simulation load piece, the second positioning bosses forming third positioning bosses, the second positioning bosses and the third positioning bosses having positioning holes, or the third positioning bosses having positioning holes.

2. The method of claim 1, wherein obtaining a reference surface of the sand processing piece; obtaining a machining reference center of the sand processing piece based on the reference surface of the sand processing piece; performing rough machining on the entire surface of the sand processing piece based on the machining reference center to obtain a rough machining piece, wherein the rough machining piece has a third processing allowance; performing semi-finishing machining on the entire surface of the rough machining piece based on the machining reference center to obtain a semi-finished piece.

3. The method of claim 2, wherein The rough machining, semi-finishing machining and first finishing machining comprise: machining the surface of the machining piece around the machining reference center and in the direction away from the machining reference center; or dividing the surface of the machining piece into T machining regions based on the machining reference center, and machining the T machining regions respectively along the machining reference center, wherein T is a natural number, and T ≥ 2.

4. The method of claim 3, wherein When a single groove in a single machining region has the following conditions, the entire surface of the single groove in the single machining region is machined: the surface area of the single groove in the single machining region is greater than or equal to 1 / 2 of the surface area of the single groove alone.

5. The method of claim 2, wherein The rough machining further comprises a first stabilization treatment, and the first stabilization treatment comprises: performing first heat treatment and first cold treatment on the rough machining piece, and the first cold treatment time is greater than the first heat treatment time.

6. The method of claim 2, wherein The semi-finishing machining further comprises a second stabilization treatment, and the second stabilization treatment comprises: performing second heat treatment and second cold treatment on the semi-finished piece, and the second cold treatment time is greater than the second heat treatment time.

7. The method of claim 2, wherein The processing allowance ratio of the first processing allowance, the third processing allowance and the second processing allowance is 6-10:1.5-3:0.5-1.

8. The method of claim 1, wherein When the rough machining, semi-finishing machining and first finishing machining are performed, one end having the grooves is machined first, and the peripheral side of the machining piece is machined.

9. The method of claim 1, wherein When machining one end of the machining piece with the groove, the structure inside the groove is machined first, and then the top of the rib plate forming the groove is machined.

10. The method of claim 1, wherein The first groove comprises R load mounting grooves and L first weight reduction grooves, the L first weight reduction grooves form a similar eight-shaped structure, the area of the smallest load mounting groove among the R load mounting grooves is greater than or equal to the area of the largest first weight reduction groove among the L first weight reduction grooves, wherein R and L are natural numbers, R, L>1.

11. The method of claim 1, wherein The first finish machining further comprises machining a first threaded hole with at least three regions on the peripheral side of the first finish machining piece, the spacing between the three regions of the first threaded hole is consistent or inconsistent.

12. The method of claim 1, wherein When the first finish machining is performed, a second weight reduction groove is machined on the peripheral side of the semi-finish machining piece; when the second finish machining is performed, a third weight reduction groove is machined on the third positioning boss.

13. The method of claim 1, wherein The second positioning boss has the second machining allowance; When the first finish machining piece has the simulation load piece and the first finish machining piece is in a suspended state, the second positioning boss is subjected to second finish machining.

14. The method of claim 1, wherein The sand mold machining piece is integrally formed with a process chuck on the side thereof, or the process chuck is connected to the side of the sand mold machining piece, the process chuck is used for positioning when the machining piece is machined, and the process chuck is removed after the machining of the machining piece is completed.

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