High-efficiency processing technology for thin-walled structural member
By combining conformal support fixtures and sensor monitoring, the depth of cut and feed rate are adjusted, solving the vibration and deformation problems in the machining of thin-walled structural parts, improving machining quality and pass rate, and applicable to both planar and curved surface support.
Patent Information
- Application Number
- CN202511263366.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-05
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2045-09-05
AI Technical Summary
Thin-walled structural parts are prone to deformation during machining, especially during rough machining, where the vibration amplitude is too large due to the constant depth of cut and feed rate, which affects the machining quality and pass rate. Furthermore, the lack of bottom support when using rigid fixtures exacerbates the vibration.
The workpiece is fixed by conformal support fixtures combined with rigid clamps. Vibration and force sensors monitor the vibration amplitude and cutting force during the machining process, and the depth of cut and feed rate are adjusted. The machining is carried out by combining helical milling and plunge milling to adapt to the stress distribution in different areas.
It effectively controls vibration and deformation during processing, improves the processing quality and pass rate of thin-walled structural parts, and adapts to the support requirements of different planes and curved surfaces.
Smart Images
Figure CN120755394B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of machining technology, specifically relating to an efficient machining process for thin-walled structural components. Background Technology
[0002] Thin-walled structural components, due to their lightweight and high strength, are widely used in high-precision products. Their machining requires the processing of end faces and cavities. The machining process typically begins with roughing, milling the end faces and cavities, followed by finish machining according to precision requirements. During the roughing process, when milling layer by layer, the depth of cut and feed rate remain constant for each layer. If the vibration amplitude caused by residual stress during machining is too large, it can lead to deformation and reduce the pass rate of the machined component. Furthermore, before machining the end faces and cavities on the machine tool, thin-walled structural components are usually fixed at both ends using rigid fixtures. Because the bottom end lacks support, vibration is exacerbated during machining, leading to deformation and affecting the machining quality. Summary of the Invention
[0003] To address the problems of easy deformation and low pass rate in the machining of thin-walled structural parts caused by existing machining processes and the use of rigid fixtures, this invention provides an efficient machining process for thin-walled structural parts.
[0004] A high-efficiency processing technology for thin-walled structural components includes the following steps:
[0005] Step 1: Use conformal support fixtures to support the workpiece blank above the machine tool table. The two ends of the workpiece blank are fixed by rigid clamps, with the end face to be processed facing upwards.
[0006] Step 2: Arrange several vibration sensors on the back side of the end face to be processed of the workpiece blank, with the density of vibration sensors in high-stress areas being greater than that in other areas.
[0007] The vibration sensor communicates with the machine tool control system, and the machine tool control system acquires the position of the vibration sensor and the monitored vibration amplitude signal.
[0008] Step 3: Use the unequal-distance layer cutting method to perform rough milling on the upward end face. During the machining process, the machine tool control system adjusts the feed rate by monitoring the cutting force through the force sensor on the end face machining tool holder and adjusts the depth of cut by monitoring the vibration amplitude through the vibration sensor closest to the end face machining tool.
[0009] Step 4: The cavity on the end face is rough milled sequentially using a combination of helical milling and plunge milling. During the machining of each cavity, the machine tool control system adjusts the feed rate by monitoring the cutting force through the force sensor on the tool holder of the cavity machining tool, and adjusts the depth of cut by monitoring the vibration amplitude through the vibration sensor closest to the cavity machining tool.
[0010] Step 5: Perform precision machining on the end face and cavity according to the accuracy requirements.
[0011] Preferably, in step 2, the high-stress region refers to the corresponding region on the workpiece blank of a thin-walled structural component with a wall thickness of less than 2 mm or a radius of curvature of less than 10 mm.
[0012] Preferably, step 3 includes the following sub-steps:
[0013] Step 31: Based on the thickness that needs to be rough-milled off the end face to be processed, determine the cutting depth of each layer and the number of milling layers by gradually increasing the cutting depth.
[0014] Step 32, perform layer-by-layer milling. The milling process for each layer is as follows:
[0015] Step 321: The end face machining tool moves along an S-shaped tool path for milling.
[0016] Step 322, let i=1, where i represents the sequence number of the monitoring time during end face processing;
[0017] Step 323: The force sensor on the end face machining tool holder monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the i-th monitoring moment to the machine tool control system;
[0018] Step 324: When the vibration amplitude monitored by the vibration sensor closest to the end face machining tool at the i-th monitoring moment is greater than the amplitude threshold, the cutting depth of the end face machining tool is reduced by 5%; otherwise, the cutting depth remains unchanged.
[0019] When the cutting force monitored by the force sensor on the end face machining tool holder is greater than the critical value of the cutting force at the i-th monitoring moment, the feed rate of the end face machining tool is reduced by 5%; otherwise, the feed rate remains unchanged.
[0020] Step 325, let i = i + 1;
[0021] The end face machining tool follows an S-shaped tool path and mills to the i-th monitoring moment based on the adjusted depth of cut and feed rate, and then proceeds to step 323.
[0022] Preferably, in step 4, the processing of each cavity includes the following sub-steps:
[0023] Step 41: Based on the thickness that needs to be removed by rough milling of the cavity to be machined compared to the rough-machined end face, the depth of cut for each layer and the number of spiral milling layers are determined by either increasing the depth of cut layer by layer or having a consistent depth of cut layer by layer for spiral milling. The depth of cut for each layer and the number of spiral milling layers are determined by either having a consistent depth of cut layer by layer for plunge milling.
[0024] Step 42: Drill a clearance hole in the center of the cavity in the rough-machined end face. The drilling depth of the clearance hole is the thickness of the cavity to be machined relative to the rough-machined end face that needs to be milled away.
[0025] The milling cutter for cavity machining enters the clearance hole;
[0026] Step 43: Perform helical milling layer by layer on the middle area of the cavity to be machined;
[0027] Step 44: Perform layer-by-layer insert milling at the four corners of the cavity to be machined.
[0028] Preferably, in step 43, when performing layer-by-layer helical milling on the middle area of the cavity to be machined, the milling process for each layer is as follows:
[0029] Step 431: The cavity machining milling cutter moves along the Archimedean spiral trajectory to perform side milling.
[0030] Step 432, let j=1, where j represents the sequence number of the monitoring time during the processing of the middle region of the cavity;
[0031] Step 433: The force sensor on the milling cutter bar for cavity machining monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the j-th monitoring moment to the machine tool control system;
[0032] Step 434: When the vibration amplitude monitored by the vibration sensor closest to the cavity milling cutter at the j-th monitoring time is greater than the amplitude threshold, the cutting depth of the cavity milling cutter is reduced by 5%; otherwise, the cutting depth remains unchanged.
[0033] When the cutting force monitored by the force sensor on the cavity milling cutter bar at the j-th monitoring time is greater than the critical value of the cutting force, the feed rate of the cavity milling cutter is reduced by 5%; otherwise, the feed rate remains unchanged.
[0034] Step 435, let j = j + 1;
[0035] The cavity machining milling cutter moves along the Archimedes spiral trajectory based on the adjusted depth of cut and feed rate to the j-th monitoring moment, and then proceeds to step 433.
[0036] Preferably, in step 44, when performing layer-by-layer milling at the four corners of the cavity to be machined, the milling process for each corner and each layer is as follows:
[0037] Step 441: Determine the movement path of the cavity machining cutter.
[0038] Starting from one end of the arc-shaped edge in each corner region, the cavity machining end mill moves along the arc-shaped trajectory to the other end, forming a new arc-shaped edge;
[0039] Afterwards, the cavity machining end mill resets and moves to one end of the new arc edge, and the above process is repeated;
[0040] In the above process, the cavity machining cutter moves along the arc trajectory one tool position at a time and performs a downward milling operation, and then lifts the cutter to move to the next tool position;
[0041] Step 442, let k=1, where k represents the sequence number of the monitoring time during the processing of the four corner areas of the cavity;
[0042] Step 443: The force sensor on the cutter bar of the cavity machining milling cutter monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the kth monitoring time to the machine tool control system;
[0043] Step 444: When the vibration amplitude monitored by the vibration sensor closest to the cavity milling cutter at the kth monitoring time is greater than the amplitude threshold, the depth of cut of the cavity milling cutter is reduced by 5%; otherwise, the depth of cut remains unchanged.
[0044] When the cutting force monitored by the force sensor on the cavity milling cutter bar at the kth monitoring time is greater than the critical value of the cutting force, the feed rate of the cavity milling cutter is reduced by 5%; otherwise, the feed rate remains unchanged.
[0045] Step 445, let k = k + 1;
[0046] The cavity machining milling cutter follows the tool path in step 441, based on the adjusted depth of cut and feed rate, and proceeds to the kth monitoring moment, after which it enters step 443.
[0047] Preferably, the conformal support fixture includes a base plate, on which a support column is vertically movable, and a support head made of EAP material is fixedly provided at the top of the support column;
[0048] The support head is equipped with electrode plates, which form a closed loop with the power supply and voltage regulator.
[0049] Preferably, a silicone layer is adhered to the top of the support head.
[0050] Preferably, a piezoelectric sensor is provided at the position where the support head contacts the support column.
[0051] Preferably, a temperature sensor is installed at the position where the support head contacts the support column.
[0052] The beneficial effects of this invention are:
[0053] (1) In the roughing process of the end face and cavity, the feed rate is adjusted by the cutting force monitored by the force sensor on the corresponding tool holder, and the depth of cut is adjusted by the vibration amplitude monitored by the vibration sensor closest to the corresponding tool. This ensures that the amplitude of the vibration at the machining position and the machining force of the tool are within the corresponding critical values, preventing the vibration amplitude from being too large, thereby reducing the deformation caused by the machining process and improving the pass rate of the end face and cavity machining.
[0054] (2) In this invention, the workpiece blank is clamped by a combination of a rigid clamp to fix both ends and a conformal support fixture to support the bottom. The conformal support fixture reduces the vibration of the workpiece blank during processing, thereby reducing the deformation during processing and improving the processing quality.
[0055] (3) In the conformal support fixture of the present invention, the support column can be adjusted in height, so it can be adapted to support of planar surfaces and curved surfaces, and has a wide range of applications.
[0056] (4) In the conformal support fixture of the present invention, a support head is provided at the top of the support column. The support head is made of EAP material. After being electrically stimulated, it can produce a small deformation, thereby adjusting the support force with high adjustment accuracy. Attached Figure Description
[0057] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application.
[0058] Figure 1 This is a flowchart illustrating the efficient processing technology for thin-walled structural components according to the present invention;
[0059] Figure 2 This is a schematic diagram of the S-shaped tool path of the end face machining tool in this invention;
[0060] Figure 3 This is a schematic diagram of the Archimedean spiral trajectory of the cavity machining milling cutter in this invention;
[0061] Figure 4 This is a schematic diagram of the movement path of the milling cutter position in cavity machining in this invention;
[0062] Figure 5 This is a schematic diagram of the conformal support fixture supporting the plane in this invention;
[0063] Figure 6 This is a schematic diagram of the conformal support fixture supporting the curved surface in this invention;
[0064] Figure 7 This is a schematic diagram showing the assembly of the substrate, support column, and support head in this invention;
[0065] in:
[0066] 1. Substrate; 2. Support column; 3. Support head; 4. Electrode sheet; 5. Silicone layer; 6. Piezoelectric sensor; 7. Temperature sensor; 8. Nut. Detailed Implementation
[0067] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0068] Example 1:
[0069] like Figure 1 As shown, a high-efficiency processing technology for thin-walled structural components includes the following steps:
[0070] Step 1: Use conformal support fixtures to support the workpiece blank above the machine tool table. The two ends of the workpiece blank are fixed by rigid clamps, with the end face to be processed facing upwards.
[0071] Step 2: Arrange several vibration sensors on the back side of the end face to be processed of the workpiece blank, with the density of vibration sensors in high-stress areas being greater than that in other areas.
[0072] The vibration sensor communicates with the machine tool control system, and the machine tool control system acquires the position of the vibration sensor and the monitored vibration amplitude signal.
[0073] Step 3: Use the unequal-distance layer cutting method to perform rough milling on the upward end face. During the machining process, the machine tool control system adjusts the feed rate by monitoring the cutting force through the force sensor on the end face machining tool holder and adjusts the depth of cut by monitoring the vibration amplitude through the vibration sensor closest to the end face machining tool.
[0074] Step 4: The cavity on the end face is rough milled sequentially using a combination of helical milling and plunge milling. During the machining of each cavity, the machine tool control system adjusts the feed rate by monitoring the cutting force through the force sensor on the tool holder of the cavity machining tool, and adjusts the depth of cut by monitoring the vibration amplitude through the vibration sensor closest to the cavity machining tool.
[0075] Step 5: Perform precision machining on the end face and cavity according to the accuracy requirements.
[0076] In this application, the rough machining of the end face and cavity has already removed most of the excess material from the workpiece blank compared to the formed thin-walled structural part. For example, compared to the formed thin-walled structural part, the thickness of the excess material to be milled on a certain end face of the workpiece blank is 5.2 mm. During rough milling, the thickness is 5 mm, and the remaining 0.2 mm of excess material is milled through finishing. Finishing can be achieved using existing technology, and the specific machining process will not be described in detail. The same applies to the cavity. After rough machining, the remaining small-sized excess material is milled using existing finishing processes. In addition, in this application, during the layer-by-layer rough milling of the end face and cavity, the depth of cut is adjusted based on the monitoring of amplitude and cutting force. Therefore, there are unevennesses on the end face and the bottom surface of the cavity after rough milling. These unevennesses can be eliminated in the finishing stage using existing finishing processes based on the accuracy requirements.
[0077] Preferably, in step 2, the high-stress region refers to the corresponding region on the workpiece blank of a thin-walled structural component with a wall thickness of less than 2 mm or a radius of curvature of less than 10 mm.
[0078] Preferably, step 3 includes the following sub-steps:
[0079] Step 31: Based on the thickness that needs to be rough-milled off the end face to be processed, determine the cutting depth of each layer and the number of milling layers by gradually increasing the cutting depth.
[0080] For example, if the thickness to be rough-milled off the end face to be processed is 5mm, the milling depth of the first layer is 0.8mm, and the range of increasing milling depth between adjacent layers is 0.1~0.3mm. When the milling depth between adjacent layers increases by 0.1mm, the milling depth of the second layer is determined to be 0.9mm, the milling depth of the third layer is 1.0mm, the milling depth of the fourth layer is 1.1mm, and the milling depth of the fifth layer is 1.2mm.
[0081] Step 32, perform layer-by-layer milling. The milling process for each layer is as follows:
[0082] Step 321, as follows Figure 2 As shown, the end face machining tool travels along an S-shaped tool path for milling.
[0083] Step 322, let i=1, where i represents the sequence number of the monitoring time during end face processing;
[0084] Step 323: The force sensor on the end face machining tool holder monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the i-th monitoring moment to the machine tool control system;
[0085] Step 324: When the vibration amplitude monitored by the vibration sensor closest to the end face machining tool at the i-th monitoring moment is greater than the amplitude threshold, the cutting depth of the end face machining tool is reduced by 5%; otherwise, the cutting depth remains unchanged.
[0086] When the cutting force monitored by the force sensor on the end face machining tool holder is greater than the critical value of the cutting force at the i-th monitoring moment, the feed rate of the end face machining tool is reduced by 5%; otherwise, the feed rate remains unchanged.
[0087] Specifically, the critical value for amplitude is 0.15 m / s², and the critical value for cutting force is 600 N;
[0088] Step 325, let i = i + 1;
[0089] The end face machining tool follows an S-shaped tool path and mills to the i-th monitoring moment based on the adjusted depth of cut and feed rate, and then proceeds to step 323.
[0090] In this application, the milling depth is adjusted by monitoring the vibration amplitude of the vibration sensor closest to the end face machining tool, and the feed rate is adjusted by monitoring the cutting force of the force sensor on the end face machining tool holder. This ensures that the vibration amplitude at the machining position and the machining force of the tool are both within the corresponding critical values during the machining process, preventing excessive vibration amplitude, thereby reducing deformation caused by the machining process and improving the pass rate of end face machining.
[0091] Preferably, in step 4, the processing of each cavity includes the following sub-steps:
[0092] Step 41: Based on the thickness that needs to be removed by rough milling of the cavity to be machined compared to the rough-machined end face, the depth of cut for each layer and the number of spiral milling layers are determined by either increasing the depth of cut layer by layer or having a consistent depth of cut layer by layer for spiral milling. The depth of cut for each layer and the number of spiral milling layers are determined by either having a consistent depth of cut layer by layer for plunge milling.
[0093] For example, if the thickness of the cavity to be machined needs to be removed by rough milling compared to the rough-machined end face, the middle part of the cavity to be machined is helically milled in three layers. When the depth of cut increases layer by layer, the depth of cut for the first layer of helical milling is 0.8mm, with the depth of cut between adjacent layers increasing by 0.2mm. The depth of cut for the second layer is determined to be 1.0mm, and the depth of cut for the third layer is 1.2mm. When the depth of cut for each layer is consistent, the depth of cut for each layer of helical milling is 1.0mm. The four corners of the cavity to be machined are plunge milled in two layers, with the depth of cut for each layer being 1.5mm.
[0094] Step 42: Drill a clearance hole in the center position of the cavity in the rough-machined end face. The drilling depth of the clearance hole is the thickness of the cavity to be machined relative to the rough-machined end face that needs to be milled away. The diameter of the clearance hole is larger than the diameter of the cavity machining milling cutter.
[0095] The milling cutter for cavity machining enters the clearance hole;
[0096] Step 43: Perform helical milling layer by layer on the middle area of the cavity to be machined;
[0097] Step 44: Perform layer-by-layer insert milling at the four corners of the cavity to be machined.
[0098] Preferably, in step 43, when performing layer-by-layer helical milling on the middle area of the cavity to be machined, the milling process for each layer is as follows:
[0099] Step 431, as Figure 3 As shown, the cavity machining milling cutter moves along the Archimedean spiral trajectory to perform side milling;
[0100] Step 432, let j=1, where j represents the sequence number of the monitoring time during the processing of the middle region of the cavity;
[0101] Step 433: The force sensor on the milling cutter bar for cavity machining monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the j-th monitoring moment to the machine tool control system;
[0102] Step 434: When the vibration amplitude monitored by the vibration sensor closest to the cavity milling cutter at the j-th monitoring time is greater than the amplitude threshold, the cutting depth of the cavity milling cutter is reduced by 5%; otherwise, the cutting depth remains unchanged.
[0103] When the cutting force monitored by the force sensor on the cavity milling cutter bar at the j-th monitoring time is greater than the critical value of the cutting force, the feed rate of the cavity milling cutter is reduced by 5%; otherwise, the feed rate remains unchanged.
[0104] Specifically, the critical value for amplitude is 0.15 m / s², and the critical value for cutting force is 600 N;
[0105] Step 435, let j = j + 1;
[0106] The cavity machining milling cutter moves along the Archimedes spiral trajectory based on the adjusted depth of cut and feed rate to the j-th monitoring moment, and then proceeds to step 433.
[0107] In this application, the depth of cut during helical milling of the middle area of the cavity is adjusted by monitoring the vibration amplitude of the vibration sensor closest to the cavity milling cutter, and the feed rate is adjusted by monitoring the cutting force of the force sensor on the cutter shank of the cavity milling cutter. This ensures that the amplitude of the vibration at the machining position and the machining force of the tool are both within the corresponding critical values during the machining process, preventing excessive vibration amplitude, thereby reducing deformation caused by the machining process and improving the pass rate of end face cavity machining.
[0108] Preferably, in step 44, when performing layer-by-layer milling at the four corners of the cavity to be machined, the milling process for each corner and each layer is as follows:
[0109] Step 441: Determine the movement path of the cavity machining cutter.
[0110] like Figure 4 As shown, starting from one end of the arc edge in each corner region, the cavity machining end mill moves along the arc trajectory to the other end to form a new arc edge;
[0111] Afterwards, the cavity machining end mill resets and moves to one end of the new arc edge, and the above process is repeated;
[0112] In the above process, the cavity machining cutter moves along the arc trajectory one tool position at a time and performs a downward milling operation. Then the cutter is lifted and moved to the next tool position. The distance between two adjacent tool positions is 0.2~1mm.
[0113] Step 442, let k=1, where k represents the sequence number of the monitoring time during the processing of the four corner areas of the cavity;
[0114] Step 443: The force sensor on the cutter bar of the cavity machining milling cutter monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the kth monitoring time to the machine tool control system;
[0115] Step 444: When the vibration amplitude monitored by the vibration sensor closest to the cavity milling cutter at the kth monitoring time is greater than the amplitude threshold, the depth of cut of the cavity milling cutter is reduced by 5%; otherwise, the depth of cut remains unchanged.
[0116] When the cutting force monitored by the force sensor on the cavity milling cutter bar at the kth monitoring time is greater than the critical value of the cutting force, the feed rate of the cavity milling cutter is reduced by 5%; otherwise, the feed rate remains unchanged; here the feed rate of the cavity milling cutter refers to the downward milling speed;
[0117] Specifically, the critical value for amplitude is 0.15 m / s², and the critical value for cutting force is 600 N;
[0118] Step 445, let k = k + 1;
[0119] The cavity machining milling cutter follows the tool path in step 441, based on the adjusted depth of cut and feed rate, and proceeds to the kth monitoring moment, after which it enters step 443.
[0120] In this application, the depth of cut during milling at the four corners of the cavity is adjusted by monitoring the vibration amplitude of the vibration sensor closest to the cavity milling cutter, and the feed rate is adjusted by monitoring the cutting force of the force sensor on the cutter shank. This ensures that the vibration amplitude at the machining position and the machining force of the tool are both within the corresponding critical values during the machining process, preventing excessive vibration amplitude, thereby reducing deformation caused by the machining process and improving the pass rate of end face cavity machining.
[0121] Example 2:
[0122] Based on Example 1, the conformal support fixture includes a base plate 1, on which a support column 2 is vertically movable. A support head 3 made of EAP material is fixedly mounted at the top of the support column 2. EAP material is an electroactive polymer material with special electrical and mechanical properties; it deforms upon electrical stimulation and has good shock resistance. The fitting relationship between the base plate 1, support column 2, and support head 3 is as follows: Figure 7 As shown;
[0123] The support head 3 is provided with an electrode plate 4 inside, and the electrode plate 4 forms a closed loop with the power supply and voltage regulator.
[0124] Electrode 4 is made of copper foil, has a square structure, is 0.1 mm thick, and has a side length of 5 mm. The wire between electrode 4 and voltage regulator is made of copper core, has a diameter of 1 mm, and has an insulation layer thickness of 0.5 mm. The output range of voltage regulator is 50~200V.
[0125] The substrate 1 of this application has several through vertical holes for mounting support columns 2. The bottom end of the vertical holes has a countersunk hole for mounting nuts 8. Nuts 8 are fixedly mounted in the countersunk hole. The outer wall of the support column 2 has an external thread that mates with the nuts 8. After the support column 2 extends downward into the vertical holes, it engages with the nuts 8 through the thread. The lifting and lowering adjustment of the support column 2 can be achieved by rotating the support column 2.
[0126] Preferably, a silicone layer 5 is bonded to the top of the support head 3. The silicone layer 5 is in direct contact with the workpiece blank, increasing contact flexibility and reducing surface scratches on the workpiece blank through flexible contact.
[0127] Preferably, a piezoelectric sensor 6 is provided at the position where the support head 3 contacts the support column 2. The piezoelectric sensor 6 is used to monitor the supporting force on the workpiece blank.
[0128] Preferably, a temperature sensor 7 is provided at the position where the support head 3 contacts the support column 2, and the temperature sensor 7 is used to monitor the temperature of the support head 3.
[0129] The support column 2 has a through hole in the middle for the connecting wires of the electrode plate 4, the transmission line of the piezoelectric sensor 6, and the transmission line of the temperature sensor 7 to pass through.
[0130] In Example 2, when the conformal support fixture is used:
[0131] First, the substrate 1 is placed on the machine tool table and fixed. The curvature of the surface to be supported in the workpiece blank is measured using a vernier caliper to determine the initial height of each support column 2. Then, the workpiece blank is supported on each support column 2, and the two ends of the workpiece blank are fixed with rigid clamps. The magnitude of the support force is monitored by each piezoelectric sensor 6. When the support force is less than the minimum value in the set range, the output voltage of the voltage regulator connected to the electrode plate 4 in the corresponding support head 3 is adjusted, causing the support head 3 to deform and push upward against the workpiece blank, increasing the support force until it is within the set range. When the support force is greater than the maximum value in the set range, the output voltage of the voltage regulator connected to the electrode plate 4 in the corresponding support head 3 is adjusted, causing the support head 3 to deform and retract downward, decreasing the support force until it is within the set range. When the magnitude of the support force monitored by all piezoelectric sensors 6 is within the set range, the support adjustment of the conformal support fixture for the workpiece blank is completed, and subsequent milling processing can be performed.
[0132] During the process of supporting the workpiece blank by the conformal support fixture, the electrode plate 4 heats up, causing the temperature of the support head 3 to rise. When the temperature of the support head 3 is too high, thermal deformation will occur, which will affect the supporting effect of the support head 3 on the workpiece blank, and thus affect the processing effect. Therefore, in this application, the temperature of the support head 3 is monitored by the temperature sensor 7. When the temperature of the support head 3 is too high, the power to the corresponding electrode plate 4 is cut off to reduce the impact of thermal deformation on the support of the workpiece blank.
[0133] The conformal support fixture design of this application can support planar or curved surfaces, and has wide applicability. Among them, the support for planar surfaces is as follows: Figure 5 As shown, the support for the curved surface is as follows: Figure 6 As shown.
[0134] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, they are not intended to limit the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the protection scope of the present invention.
Claims
1. A high-efficiency processing technology for thin-walled structural components, characterized in that, Includes the following steps: Step 1: Use conformal support fixtures to support the workpiece blank above the machine tool table. The two ends of the workpiece blank are fixed by rigid clamps, with the end face to be processed facing upwards. Step 2: Arrange several vibration sensors on the back side of the end face to be processed of the workpiece blank, with the density of vibration sensors in high-stress areas being greater than that in other areas. The vibration sensor communicates with the machine tool control system, and the machine tool control system acquires the position of the vibration sensor and the monitored vibration amplitude signal. Step 3: Use the unequal-distance layer cutting method to perform rough milling on the upward end face. During the machining process, the machine tool control system adjusts the feed rate by monitoring the cutting force through the force sensor on the end face machining tool holder and adjusts the depth of cut by monitoring the vibration amplitude through the vibration sensor closest to the end face machining tool. Specifically: at each monitoring moment, if the vibration amplitude monitored by the vibration sensor closest to the end face machining tool is greater than the amplitude threshold, the depth of cut of the end face machining tool will be reduced by 5%; otherwise, the depth of cut will remain unchanged. If the cutting force monitored by the force sensor on the end face machining tool holder is greater than the cutting force threshold, the feed rate of the end face machining tool will be reduced by 5%; otherwise, the feed rate will remain unchanged. Step 4: The cavity on the end face is rough milled sequentially using a combination of helical milling and plunge milling. During the machining of each cavity, the machine tool control system adjusts the feed rate by monitoring the cutting force through the force sensor on the tool holder of the cavity machining tool, and adjusts the depth of cut by monitoring the vibration amplitude through the vibration sensor closest to the cavity machining tool. Specifically: at each monitoring moment, if the vibration amplitude monitored by the vibration sensor closest to the cavity machining tool is greater than the amplitude threshold, the depth of cut of the cavity machining tool will be reduced by 5%; otherwise, the depth of cut will remain unchanged. If the cutting force monitored by the force sensor on the tool holder of the cavity machining tool is greater than the cutting force threshold, the feed rate of the cavity machining tool will be reduced by 5%; otherwise, the feed rate will remain unchanged. Step 5: Perform precision machining on the end face and cavity according to the accuracy requirements.
2. The high-efficiency processing technology for thin-walled structural components as described in claim 1, characterized in that, In step 2, the high-stress area refers to the area on the workpiece blank corresponding to the area with a wall thickness of less than 2 mm or a radius of curvature of less than 10 mm in a thin-walled structural component.
3. The high-efficiency processing technology for thin-walled structural components as described in claim 1, characterized in that, Step 3 includes the following sub-steps: Step 31: Based on the thickness that needs to be rough-milled off the end face to be processed, determine the cutting depth of each layer and the number of milling layers by gradually increasing the cutting depth. Step 32, perform layer-by-layer milling. The milling process for each layer is as follows: Step 321: The end face machining tool moves along an S-shaped tool path for milling. Step 322, let i=1, where i represents the sequence number of the monitoring time during end face processing; Step 323: The force sensor on the end face machining tool holder monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the i-th monitoring moment to the machine tool control system; Step 324: When the vibration amplitude monitored by the vibration sensor closest to the end face machining tool at the i-th monitoring moment is greater than the amplitude threshold, the cutting depth of the end face machining tool is reduced by 5%; otherwise, the cutting depth remains unchanged. When the cutting force monitored by the force sensor on the end face machining tool holder is greater than the critical value of the cutting force at the i-th monitoring moment, the feed rate of the end face machining tool is reduced by 5%; otherwise, the feed rate remains unchanged. Step 325, let i = i + 1; The end face machining tool follows an S-shaped tool path and mills to the i-th monitoring moment based on the adjusted depth of cut and feed rate, and then proceeds to step 323.
4. The high-efficiency processing technology for thin-walled structural components as described in claim 1, characterized in that, In step 4, the processing of each cavity includes the following sub-steps: Step 41: Based on the thickness that needs to be removed by rough milling of the cavity to be machined compared to the rough-machined end face, the depth of cut for each layer and the number of spiral milling layers are determined by either increasing the depth of cut layer by layer or having a consistent depth of cut layer by layer for spiral milling. The depth of cut for each layer and the number of spiral milling layers are determined by either having a consistent depth of cut layer by layer for plunge milling. Step 42: Drill a clearance hole in the center of the cavity in the rough-machined end face. The drilling depth of the clearance hole is the thickness of the cavity to be machined relative to the rough-machined end face that needs to be milled away. The milling cutter for cavity machining enters the clearance hole; Step 43: Perform helical milling layer by layer on the middle area of the cavity to be machined; Step 44: Perform layer-by-layer insert milling at the four corners of the cavity to be machined.
5. The high-efficiency processing technology for thin-walled structural components as described in claim 4, characterized in that, In step 43, when performing layer-by-layer spiral milling on the middle area of the cavity to be machined, the milling process for each layer is as follows: Step 431: The cavity machining milling cutter moves along the Archimedean spiral trajectory to perform side milling. Step 432, let j=1, where j represents the sequence number of the monitoring time during the processing of the middle region of the cavity; Step 433: The force sensor on the milling cutter bar for cavity machining monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the j-th monitoring moment to the machine tool control system; Step 434: When the vibration amplitude monitored by the vibration sensor closest to the cavity milling cutter at the j-th monitoring time is greater than the amplitude threshold, the cutting depth of the cavity milling cutter is reduced by 5%; otherwise, the cutting depth remains unchanged. When the cutting force monitored by the force sensor on the cavity milling cutter bar at the j-th monitoring time is greater than the critical value of the cutting force, the feed rate of the cavity milling cutter is reduced by 5%; otherwise, the feed rate remains unchanged. Step 435, let j = j + 1; The cavity machining milling cutter moves along the Archimedes spiral trajectory based on the adjusted depth of cut and feed rate to the j-th monitoring moment, and then proceeds to step 433.
6. The high-efficiency processing technology for thin-walled structural components as described in claim 4, characterized in that, In step 44, when performing layer-by-layer milling at the four corners of the cavity to be machined, the milling process for each corner and each layer is as follows: Step 441: Determine the movement path of the cavity machining cutter. Starting from one end of the arc-shaped edge in each corner region, the cavity machining end mill moves along the arc-shaped trajectory to the other end, forming a new arc-shaped edge; Afterwards, the cavity machining end mill resets and moves to one end of the new arc edge, and the above process is repeated; In the above process, the cavity machining cutter moves along the arc trajectory one tool position at a time and performs a downward milling operation, and then lifts the cutter to move to the next tool position; Step 442, let k=1, where k represents the sequence number of the monitoring time during the processing of the four corner areas of the cavity; Step 443: The force sensor on the cavity machining milling cutter bar monitors the cutting force, and each vibration sensor monitors the vibration amplitude, and transmits the monitoring data at the kth monitoring time to the machine tool control system; Step 444: When the vibration amplitude monitored by the vibration sensor closest to the cavity milling cutter at the kth monitoring time is greater than the amplitude threshold, the depth of cut of the cavity milling cutter is reduced by 5%; otherwise, the depth of cut remains unchanged. When the cutting force monitored by the force sensor on the cavity machining cutter bar at the kth monitoring time is greater than the critical value of the cutting force, the feed rate of the cavity machining cutter is reduced by 5%; otherwise, the feed rate remains unchanged. Step 445, let k = k + 1; The cavity machining milling cutter follows the tool path in step 441, based on the adjusted depth of cut and feed rate, and proceeds to the kth monitoring moment, after which it enters step 443.
7. The high-efficiency processing technology for thin-walled structural components as described in claim 1, characterized in that, The conformal support fixture includes a base plate (1), on which a support column (2) is vertically movable, and a support head (3) made of EAP material is fixedly installed at the top of the support column (2). The support head (3) is provided with an electrode plate (4), which forms a closed loop with the power supply and voltage regulator.
8. The high-efficiency processing technology for thin-walled structural components as described in claim 7, characterized in that, The top of the support head (3) is bonded with a silicone layer (5).
9. The high-efficiency processing technology for thin-walled structural components as described in claim 7, characterized in that, A piezoelectric sensor (6) is installed at the position where the support head (3) contacts the support column (2).
10. The high-efficiency processing technology for thin-walled structural components as described in claim 7, characterized in that, A temperature sensor (7) is installed at the position where the support head (3) contacts the support column (2).
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