Ultrasonic drilling and rigid tapping methods for threading titanium alloys, high-temperature alloys, and duplex stainless steel materials

Abstract

This invention discloses a method for ultrasonic drilling and rigid tapping of threads in titanium alloys, high-temperature alloys, and duplex stainless steel. Specifically, it relates to the field of thread tapping technology, including: S1, integration and intelligent monitoring of a machining center ultrasonic system; S2, precise adjustment of ultrasonic frequency and accurate strength detection; S3, ultrasonic-assisted efficient pre-drilling and intelligent chip management; S4, intelligent optimization of tapping parameters and multi-factor collaborative processing; and S5, dynamic enhancement of cooling and lubrication for rigid tapping. This invention can effectively improve processing efficiency by 9-15 times, better ensure thread perpendicularity and surface finish, significantly improve thread processing quality, and, due to the ultrasonic processing mechanism, greatly increase tool life by 3-5 times.

Description

Technical Field

[0001] This invention relates to the field of rigid tapping technology for threaded steel, and more specifically, to a method for rigid tapping of threads in titanium alloys, high-temperature alloys, and duplex stainless steel using ultrasonic drilling. Background Technology

[0002] Currently, in modern manufacturing, materials such as titanium alloys, nickel-based superalloys, and duplex stainless steel are widely used in aerospace, energy, and chemical industries due to their excellent properties, such as high strength, high temperature resistance, and corrosion resistance. However, these materials are extremely difficult to process, especially in thread machining, which presents numerous challenges, such as:

[0003] 1. Traditionally, for machining threaded holes in titanium alloy and nickel-based high-temperature alloy duplex stainless steel of M3 to M30, manual tapping and thread milling are the two main methods. Manual tapping is extremely labor-intensive, requiring operators to expend a lot of physical strength and has extremely low processing efficiency. During the machining process, it is difficult to ensure the perpendicularity and stability of the tap, which leads to the inability to guarantee the perpendicularity of the thread, resulting in large errors during assembly. Furthermore, the surface quality and smoothness of manually machined threads are poor, the precision is insufficient, and the scrap rate is high. When mass-producing threads, it is impossible to meet production needs, becoming a serious bottleneck in the production process.

[0004] 2. Although thread milling improves upon manual tapping in terms of efficiency, labor intensity, and quality, it still has significant drawbacks. Due to the special material properties of titanium alloys and high-temperature alloys, such as the small deformation coefficient and springback of titanium alloys, and the work hardening of high-temperature alloys, the thread quality produced by thread milling is poor, with a rough surface, making it difficult to meet high-precision machining requirements. Furthermore, thread milling cutters are complex to manufacture, expensive, and have a short lifespan, requiring frequent tool replacements. This not only increases tool costs but also leads to increased equipment downtime due to tool changes, further reducing production efficiency. In actual machining, each threaded hole typically requires at least three passes with a thread milling cutter, each pass taking three minutes, totaling at least nine minutes per threaded hole, and the quality cannot be consistently guaranteed. Sometimes, it may even require five passes, consuming up to fifteen minutes, significantly impacting production schedules and cost control.

[0005] In view of the above situation, the present invention provides a method for rigid tapping of threads by ultrasonic drilling in titanium alloys, high-temperature alloys and duplex stainless steel materials. Summary of the Invention

[0006] In order to overcome the above-mentioned defects of the prior art, the present invention provides a method for rigid tapping of threads in titanium alloys, high-temperature alloys and duplex stainless steel materials by ultrasonic drilling, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for rigid tapping threads in titanium alloys, high-temperature alloys, and duplex stainless steel using ultrasonic drilling, for rigid tapping M3 to M30 threads in titanium alloys, nickel-based high-temperature alloys, and duplex stainless steel, comprising the following steps:

[0008] S1. Integration and intelligent monitoring of ultrasonic system for machining center: Technical modification of machining center machine tools, including the installation of ultrasonic generators, receivers, transducers, ultrasonic-specific tool holders, and related connecting lines.

[0009] The ultrasonic generator uses an intelligent frequency adaptive adjustment module, which can dynamically adjust the output frequency in real time according to the changes in material properties during the processing, ensuring that the ultrasonic energy is always in the best transmission state.

[0010] The ultrasonic tool holder integrates a high-precision vibration sensor, which can monitor the tap vibration in real time and feed the data back to the control system, enabling precise monitoring and adjustment of the machining process.

[0011] S2. Precise adjustment of ultrasonic frequency and accurate strength detection: Based on the carbide-coated taps used for threads of different materials, hole diameters, and depths, and combined with big data analysis of the microstructure and mechanical properties of the materials, different ultrasonic frequency parameters are adjusted. Ultrasonic waves are converted into mechanical energy and transmitted to the tap through an ultrasonic device. An ultrasonic monitoring system is used to accurately check the ultrasonic vibration intensity to ensure that the vibration intensity is within the preset optimal range. The ultrasonic monitoring system is connected to the machining center control system to realize automatic detection and data recording.

[0012] S3. Ultrasonic-assisted high-efficiency pre-drilling and intelligent chip control: Ultrasonic-assisted pre-drilling of the bottom hole is adopted, with a rotation speed of 1000-1600 r / min and a feed of 100-250 mm / min. During the pre-drilling process, the ultrasonic vibration causes the chips to be fine and broken. The high-pressure water outlet device is used to discharge the chips in time, avoiding the impact of chip accumulation on the machining accuracy. The pressure of the high-pressure water outlet device can be automatically adjusted according to the amount of chips generated and discharged.

[0013] S4. Intelligent optimization of tapping parameters and multi-factor collaborative processing: The machining center sets processing parameters according to different materials, hole diameters, and thread depths, and performs rigid tapping on pre-drilled bottom holes. The setting of processing parameters adopts an intelligent algorithm optimization model, which comprehensively considers multiple factors such as material properties, tool performance, and machine tool performance to achieve automatic matching and optimization of processing parameters.

[0014] S5. Dynamic enhancement of cooling and lubrication for rigid tapping: The rigid tapping speed is 40-60 r / min. During the tapping process, the integrated cooling and lubrication micro-droplet injection system is used to precisely spray the cooling and lubricating agent into the processing area in the form of micro-droplets. The size of the micro-droplets can be dynamically adjusted according to the processing conditions to improve the cooling and lubrication effect, further reduce tool wear and improve the quality of thread processing.

[0015] Preferably, in step S1, the intelligent frequency adaptive adjustment module calculates and adjusts the output frequency according to the following formula: Among them, f new For the adjusted frequency, f init The initial set frequency is given by k, which is the frequency adjustment coefficient, ranging from 0.1 to 0.5. ΔZ is the change in acoustic impedance of the material during processing, and Z0 is the initial acoustic impedance of the material.

[0016] Preferably, in step S3, the pressure of the high-pressure water outlet device can be automatically adjusted according to the amount of chips generated and the discharge situation.

[0017] Preferably, in step S4, the intelligent algorithm optimization model is based on a neural network algorithm. Its input layer parameters include the material hardness H, elastic modulus E, pore diameter D, and thread depth L. The output layer parameters are rotational speed n, feed rate f, and ultrasonic frequency f. ultra By training a neural network with a large amount of sample data, the output processing parameters can achieve the optimal processing effect.

[0018] Preferably, in step S1, the high-precision vibration sensor, with a measurement accuracy down to the nanometer level, is used to accurately capture the minute vibration deviations of the tap under high-frequency vibration and transmit the data to the CNC system of the machining center for processing in a timely manner.

[0019] Preferably, in step S2, the ultrasonic monitoring system uses high-frequency ultrasonic vibration technology, which is not affected by interference factors such as light and mechanical vibration, and achieves high-precision measurement of ultrasonic vibration intensity with a measurement error of <0.1‰.

[0020] Preferably, in step S3, the pressure regulation of the high-pressure water outlet device is achieved by real-time monitoring of pressure changes in the chip discharge pipe through a numerical control system. Combined with data from chip flow monitoring, the intelligent controller automatically adjusts the pressure or vacuum pump power to ensure smooth chip discharge.

[0021] Preferably, in step S4, the intelligent algorithm optimization model is based on a genetic algorithm or a neural network algorithm. By learning and analyzing a large amount of historical processing data, it establishes an optimal matching relationship library of material-tool-machine tool processing parameters, and performs rapid retrieval and optimization adjustment according to real-time working conditions during actual processing.

[0022] Preferably, in step S5, the integrated cooling and lubrication microdroplet injection system adopts piezoelectric drive technology, which can precisely control the injection frequency and particle size of the microdroplets. The injection frequency can be adjusted in the range of 100Hz-1000Hz, and the microdroplet particle size can be precisely controlled between 10μm-100μm, so as to achieve precise cooling and lubrication of the processing area.

[0023] The technical effects and advantages of this invention are as follows:

[0024] 1. This invention, through intelligent frequency adaptive adjustment modules, intelligent algorithm optimization models, and other technical means, revolutionizes traditional processing techniques. It can efficiently solve the thread processing problems of difficult-to-machine materials such as titanium alloys, high-temperature alloys, and duplex stainless steel, significantly improving processing efficiency. Compared with traditional thread milling methods, the efficiency is increased by 9-15 times. At the same time, with the assistance of high-precision sensors and advanced detection equipment, the perpendicularity and surface finish of the threads are better guaranteed, the scrap rate is close to zero, effectively improving the quality of thread processing, meeting the requirements of high-precision production, reducing rework and scrap losses caused by processing quality problems, and improving production efficiency.

[0025] 2. In the processing of this invention, the high-frequency vibration of the ultrasonic wave causes the coolant to atomize instantly and carry away the heat. The actual contact time between the tool and the workpiece is only one-third of that in traditional processing methods. Combined with innovative technologies such as the integrated cooling and lubrication micro-droplet injection system, tool wear is greatly reduced. Compared with traditional processing methods, tool life can be increased by 3-5 times, significantly reducing the frequency and cost of tool replacement. This not only helps to reduce production costs, but also reduces equipment downtime caused by frequent tool replacement, and improves the utilization rate of production equipment and overall production efficiency.

[0026] 3. The intelligent frequency adaptive adjustment module of this invention adjusts the ultrasonic frequency in real time according to changes in material properties. The intelligent algorithm optimization model automatically matches processing parameters by integrating multiple factors. In addition, the close cooperation between high-precision vibration sensors, pressure sensors, chip flow sensors and other components with the machining center control system enables comprehensive intelligent monitoring and adjustment of the processing process. It can respond to various abnormal situations in the processing process in a timely manner, ensuring the stability and reliability of the processing process. It effectively reduces the labor intensity and technical requirements of operators, improves the consistency and repeatability of the production process, and provides a strong guarantee for large-scale industrial production. Attached Figure Description

[0027] Figure 1 This is the overall flowchart of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] This invention provides a method for rigid tapping threads using ultrasonic drilling in titanium alloys, high-temperature alloys, and duplex stainless steel, as detailed below:

[0031] Material: Titanium alloy Ti-6Al-4V;

[0032] Thread specification: M20, pitch 2.5mm

[0033] Aperture: 17.5mm;

[0034] Hole depth: 35mm.

[0035] The specific processing method is as follows:

[0036] 1. A Suzhou Neway CNC gantry machining center, model PM1520HA, was selected for modification. Following step S1, the ultrasonic generator, receiver, transducer, and ultrasonic-specific tool holder were installed and connected to the relevant wiring. The intelligent frequency adaptive adjustment module of the ultrasonic generator was initially set to 20kHz based on past experience processing similar materials, with a frequency adjustment coefficient of 0.3. The high-precision sensor integrated into the ultrasonic-specific tool holder underwent professional calibration before installation to ensure nanometer-level measurement accuracy. After installation, it was stably connected to the CNC system of the machining center, enabling real-time data transmission and providing support for monitoring subsequent processing.

[0037] 2. Following step S2, for the Ti-6Al-4V titanium alloy material and M20 thread specification, and combining the material's microstructure and mechanical properties with big data analysis, by querying the company's internal professional material database (which covers the detailed crystal structure, hardness, elastic modulus, and other parameters of various titanium alloy materials and their correspondence with ultrasonic frequency), the ultrasonic frequency was initially determined to be 21kHz. Subsequently, an ultrasonic monitoring device was used to precisely check the ultrasonic vibration intensity. During the detection process, if the vibration intensity was found to be outside the preset optimal range (set to 10-15μm amplitude in this embodiment), the intelligent frequency adaptive adjustment module of the ultrasonic generator was activated for adjustment. During adjustment, the formula was used... Assuming that the change in acoustic impedance ΔZ of the material sample is 3% (relative to the initial acoustic impedance Z0) before processing, substitute this value into the formula to calculate the new frequency f. newThe ultrasonic generator is then set up, and the ultrasonic monitoring system is used again to check the vibration intensity until it meets the requirements. At the same time, the ultrasonic monitoring system automatically records the detection data to the machining center control system for easy subsequent process analysis and optimization.

[0038] 3. Perform ultrasonic-assisted pre-drilling of a 17.5mm diameter pilot hole according to step S3. Set the rotation speed to 1300 r / min and the feed rate to 160 mm / min. Start the high-pressure center water outlet device. The initial pressure is estimated to be 2 kg based on experience and material properties. During the pre-drilling process, the pressure sensor monitors the pressure change required for chip removal in real time, and the chip flow sensor simultaneously detects the amount of chips generated and the discharge status. If a chip accumulation trend is detected, for example, if the chip flow rate Q reaches 4 g / min (assuming α is 25 and b is 1, based on the relationship between impact pressure and chip flow rate F = α × Q), b The intelligent controller automatically adjusts the power of the vacuum pump at the center outlet water pressure to increase the center outlet water pressure and ensure that the chips are discharged in time. At the same time, the ultrasonic vibration makes the chips into small fragments, effectively avoiding the impact of chips on the machining accuracy and laying a good foundation for the subsequent tapping process.

[0039] 4. Following step S4, the rigid tapping parameters are set using an intelligent algorithm optimization model. Input parameters such as material hardness (approximately 330 HB), elastic modulus (approximately 110 GPa), hole diameter 17.5 mm, and thread depth 35 mm. The neural network calculates and outputs a rotational speed of 50 r / min, a feed rate of 0.12 mm / r, and an ultrasonic frequency of 23 kHz. After accurately setting these parameters on the machining center, the rigid tapping operation is initiated. During the tapping process, the machining center control system closely monitors the data from the high-precision vibration sensor inside the ultrasonic tool holder. This sensor accurately captures minute vibration deviations of the tap under high-frequency vibration. If abnormal vibration or excessive cutting force occurs, the control system immediately adjusts the machining parameters based on the sensor feedback to ensure a stable and efficient machining process and guarantee thread quality.

[0040] 5. Following step S5, start the integrated cooling and lubrication micro-droplet injection system during the tapping process. Using piezoelectric drive technology, initially set the injection frequency to 400Hz and the micro-droplet size to 40μm. During the processing, the temperature changes are monitored in real time by a temperature sensor installed near the processing area. At the same time, the tool wear condition is judged based on the preset tool wear threshold (which can be determined by experiment or experience) and the actual processing time.

[0041] For example, when the temperature rises above 90°C or the processing time reaches a certain duration and the cutting force of the tool shows a significant upward trend, the control system automatically adjusts the spray frequency to 600Hz and reduces the droplet size to 30μm to enhance the cooling and lubrication effect, further reduce tool wear, and ensure machining accuracy and surface quality.

[0042] This embodiment will be tested:

[0043] 1. Thread accuracy inspection: Use a high-precision thread plug gauge to check the go / no-go of the machined thread to ensure that the basic dimensions of the thread meet the requirements. Then, use a universal tool microscope to measure the pitch diameter and minor diameter of the thread. Select three measurement sections evenly along the thread length, measure each section twice, take the average value as the measurement result, and compare it with the standard value. The allowable deviation for the pitch diameter is ±0.05mm, and the allowable deviation for the minor diameter is ±0.03mm.

[0044] 2. Surface roughness inspection: A roughness tester is used to inspect the threaded surface. Five measurement points are evenly selected along the helical direction on the side of the thread. Each point is measured three times, and the average value is taken as the surface roughness R of that point. a The value is used to ensure the accuracy and reliability of the measurement results, and is compared with the surface roughness specified in the standard as ≤6.3μm;

[0045] 3. Tool Wear Inspection: After tapping, the tap is carefully removed, and the wear of the tap's cutting edge is observed under a super depth-of-field microscope. Image analysis software is used to measure the wear width of the tap's flank face. Three measurement positions are evenly selected on the cutting edge, and the average value is taken as the wear width value. A wear width of less than 0.1mm is considered acceptable. The wear morphology and characteristics of the tool are recorded to provide a reference for subsequent tool life analysis and process improvement. Twelve holes were continuously and rigidly tapped, with no wear on the tap coating. All plug gauge tests were passed. The total processing time for the twelve holes was 10 minutes.

[0046] The specific test data is as follows:

[0047]

[0048] Example 2

[0049] This invention provides a method for rigid tapping threads using ultrasonic drilling in titanium alloys, high-temperature alloys, and duplex stainless steel, as detailed below:

[0050] Material: Nickel-based superalloy Inconel 718;

[0051] Thread specification: M16, pitch 2mm

[0052] Aperture: 14mm;

[0053] Hole depth: 30mm.

[0054] The specific processing method is as follows:

[0055] 1. Suzhou Neway CNC gantry machining center, model PM1520HA, was selected for modification. Ultrasonic equipment was installed according to step S1. The initial frequency of the intelligent frequency adaptive adjustment module of the ultrasonic generator was set to 25kHz to ensure that it can be effectively adjusted according to the changes in material properties during subsequent processing. The piezoelectric sensor in the ultrasonic special tool holder was strictly calibrated and then connected to the CNC system to ensure the accuracy and timeliness of tap vibration monitoring.

[0056] 2. Following step S2, and considering the material properties of the nickel-based superalloy Inconel 718 and the M16 thread specification, a thorough analysis of the company's extensive data on material microstructure and mechanical properties is conducted. The ultrasonic frequency is set to 26kHz. A high-precision ultrasonic monitoring instrument (measurement error <0.1‰) is used to check the ultrasonic vibration intensity. If it is not within the preset optimal amplitude range of 12-16μm, the intelligent frequency adaptive adjustment module adjusts according to the formula... Adjustments are made, for example, before processing, the material sample is tested and the change in acoustic impedance ΔZ is 4% (relative to the initial acoustic impedance Z0). The frequency adjustment coefficient k is taken as 0.35. The new frequency is calculated and set in the ultrasonic generator until the vibration intensity meets the requirements. At the same time, the ultrasonic detector records the data to the processing center control system.

[0057] 3. Perform ultrasonic-assisted pre-drilling of the pilot hole according to step S3. Set the rotation speed to 1400 r / min and the feed rate to 250 mm / min. Start the high-pressure water outlet device. The initial pressure is set to 2 kg based on experience. During the pre-drilling process, the pressure sensor and chip flow sensor work in real time. When the chip flow rate Q reaches 5 g / min (assuming α is 30 and b is 1.2, according to the formula F = α × Q), b The intelligent controller automatically adjusts the central water outlet pressure or vacuum pump power to ensure smooth chip discharge, while using ultrasonic vibration to refine the chips and improve processing accuracy.

[0058] 4. Following step S4, the rigid tapping parameters are set using an intelligent algorithm optimization model. Input parameters such as material hardness (approximately 400HB), elastic modulus (approximately 200Pa), hole diameter 14mm, and thread depth 30mm. The neural network calculates and outputs a rotation speed of 45r / min, a feed rate of 0.16mm / r, and an ultrasonic frequency of 28kHz. After setting these parameters on the machining center, rigid tapping begins. During the machining process, the CNC system adjusts the machining parameters in a timely manner based on feedback data from the high-precision vibration sensor inside the ultrasonic tool holder to ensure machining stability and thread quality.

[0059] 5. Following step S5, activate the integrated cooling and lubrication micro-droplet injection system during the tapping process. Employing piezoelectric drive technology, the initial injection frequency is set to 500Hz, and the micro-droplet size is set to 50μm. During processing, the temperature of the processing area and the tool wear are monitored in real time by a temperature sensor and a tool wear monitoring system. When the temperature rises above 100℃ or the tool cutting force increases significantly, the control system automatically adjusts the injection frequency to 700Hz and reduces the micro-droplet size to 40μm to enhance the cooling and lubrication effect, reduce tool wear, and ensure processing quality.

[0060] This embodiment will be tested:

[0061] 1. Comprehensive thread accuracy inspection: Use thread plug gauges to check the go / no-go of the machined thread to ensure that the basic thread dimensions are qualified. Then, use a coordinate measuring machine to measure the major diameter and pitch diameter of the thread. Select 4 measurement points evenly in the circumferential direction of the thread, measure each point twice, take the average value as the measurement result, and compare it with the standard value. The allowable deviation for the major diameter is ±0.06mm, and the allowable deviation for the pitch diameter is ±0.04mm.

[0062] 2. Multi-point surface roughness inspection: A roughness tester is used to inspect the thread surface. Three measurement points are selected at the thread crest, flank, and root. Each point is measured three times, and the average value is taken as the surface roughness R at that point. a The value is used to ensure that the measurement results fully reflect the surface quality of the thread and are compared with the surface roughness specified in the standard as ≤6.3μm.

[0063] 3. Detailed inspection of tool wear: After tapping, the tap is placed under a microscope to observe the wear of the cutting edge. Image analysis software is used to measure the wear length of the tap's cutting edge. Four measurement positions are evenly selected on the cutting edge, and the average value is taken as the wear length value. A wear length less than 0.12mm is considered acceptable. The location, shape, and characteristics of tool wear are recorded in detail to provide a strong basis for tool maintenance and process improvement. Eleven holes were continuously and rigidly tapped, and the tap coating showed no wear.

[0064] The specific test data is as follows:

[0065]

[0066]

[0067] Example 3

[0068] This invention provides a method for rigid tapping threads using ultrasonic drilling in titanium alloys, high-temperature alloys, and duplex stainless steel, as detailed below:

[0069] Material: Titanium alloy Ti-5Al-2.5Sn

[0070] Thread specification: M30, pitch 3.5mm

[0071] Aperture: 27.5mm;

[0072] Hole depth: 30mm.

[0073] The specific processing method is as follows:

[0074] 1. Based on the Neway PM3560SL gantry machining center, the ultrasonic generator, receiver, transducer, and ultrasonic-specific tool holder were installed according to step S1, and the wiring was connected. The initial frequency of the intelligent frequency adaptive adjustment module of the ultrasonic generator was set to 21kHz, and the frequency adjustment coefficient was set to 0.4. After calibration, the MEMS microelectromechanical sensor in the ultrasonic-specific tool holder was connected to the CNC system to ensure accurate monitoring of tap vibration.

[0075] 2. Following step S2, for the titanium alloy Ti-5Al-2.5Sn material and M30 thread specification, the ultrasonic frequency is determined to be 22kHz based on material database analysis. An ultrasonic monitoring instrument (measurement error <0.1‰) is used to check the ultrasonic vibration intensity. If it is not within the preset optimal amplitude range of 13-17μm, the intelligent frequency adaptive adjustment module adjusts it according to the formula... Adjustments are made, assuming that the change in acoustic impedance of the material is detected to be 5% (relative to the initial acoustic impedance Z0) during the processing, a new frequency is calculated and set in the ultrasonic generator until the vibration intensity meets the requirements. At the same time, the ultrasonic monitoring instrument records the data to the processing center control system.

[0076] 3. Perform ultrasonic-assisted pre-drilling of the pilot hole according to step S3, setting the rotation speed to 1500 r / min and the feed rate to 150 mm / min. Start the high-pressure water outlet device, setting the initial pressure to 3 kg. During the pre-drilling process, monitor the chip removal status in real time using a pressure sensor and a chip flow sensor. When the chip flow rate Q reaches 6 g / min (assuming α is 35 and b is 1.3, according to the formula F = α × Q), b The intelligent controller automatically adjusts the high-pressure center outlet water pressure or vacuum pump power to ensure smooth chip discharge, while using ultrasonic vibration to refine the chips and improve processing accuracy.

[0077] 4. Following step S4, the rigid tapping parameters are set using an intelligent algorithm optimization model. Input parameters such as material hardness (approximately 350 HB), elastic modulus (approximately 120 Pa), hole diameter 27.5 mm, and thread depth 30 mm. The neural network calculates and outputs a rotational speed of 48 r / min, a feed rate of 0.18 mm / r, and an ultrasonic frequency of 24 kHz. After setting these parameters in the machining center, rigid tapping is started. During the machining process, the CNC system adjusts the machining parameters in a timely manner based on feedback data from the high-precision vibration sensor inside the ultrasonic tool holder to ensure a stable machining process.

[0078] 5. Following step S5, activate the integrated cooling and lubrication micro-droplet injection system during the tapping process. Employing piezoelectric drive technology, the initial injection frequency is set to 600Hz, and the micro-droplet size is set to 45μm. During processing, the temperature of the processing area and the tool wear are monitored in real time by a temperature sensor and a tool wear monitoring system. When the temperature rises above 110℃ or the tool cutting force increases significantly, the control system automatically adjusts the injection frequency to 800Hz and reduces the micro-droplet size to 35μm to enhance the cooling and lubrication effect, reduce tool wear, and ensure processing quality.

[0079] This embodiment will be tested:

[0080] 1. Comprehensive thread accuracy inspection: The thread plug gauge is used to check the go and stop of the machined thread to ensure that the basic thread size is qualified. Then, the major diameter and pitch diameter of the thread are measured by a three-coordinate measuring machine. Four measurement sections are evenly selected along the thread length, and each section is measured three times. The average value is taken as the measurement result and compared with the standard tolerance zone. The major diameter and pitch diameter tolerance is ±0.07mm. At the same time, the thread profile angle, pitch and other parameters are checked to see if they meet the standard requirements.

[0081] 2. Detailed surface roughness inspection: Using a roughness tester, select 8 measurement points at intervals along the entire length of the thread. Measure each point 3 times and take the average value as the surface roughness R at that point. a The value is used to ensure a comprehensive reflection of the thread surface quality, and is compared with the surface roughness specified in the standard as ≤6.3μm.

[0082] 3. Tool wear depth detection: After tapping is completed, observe the wear condition of the tap rake face under a microscope. Use a measuring tool to measure the wear depth of the tap rake face. Select three measurement positions evenly on the cutting edge and take the average value as the wear depth value. A wear depth of less than 0.08mm is considered qualified. At the same time, record the characteristics and patterns of tool wear to provide a reference for tool management and process optimization.

[0083] The specific test data is as follows: The following should reference M30 data.

[0084]

[0085] Example 4

[0086] This invention provides a method for rigid tapping threads using ultrasonic drilling in titanium alloys, high-temperature alloys, and duplex stainless steel, as detailed below:

[0087] Material: Inconel 625, a nickel-based superalloy

[0088] Thread specification: M30, pitch 3.5mm

[0089] Aperture: 27.5mm;

[0090] Hole depth: 30mm.

[0091] The specific processing method is as follows:

[0092] 1. A Neway gantry machining center PM3560SL was selected for modification. The ultrasonic generator, receiver, transducer, and ultrasonic-specific tool holder were precisely installed according to step S1, and the relevant lines were connected. The intelligent frequency adaptive adjustment module of the ultrasonic generator was initially set to 26kHz to ensure good frequency adjustment performance. The high-precision sensor in the ultrasonic-specific tool holder underwent a strict calibration procedure before installation to ensure that its measurement accuracy reached the nanometer level. After installation, it was stably connected to the CNC system of the machining center to realize the real-time and accurate transmission of tap vibration data, providing key support for the precise control of the subsequent machining process.

[0093] 2. Following step S2, for the nickel-based superalloy Inconel 625 and M30 thread specifications, and combining the company's extensive data on material microstructure and mechanical properties, an in-depth analysis was conducted, and the ultrasonic frequency was set to 27kHz. Using high-precision ultrasonic monitoring technology, with a measurement error <0.1‰, the ultrasonic vibration intensity was carefully checked. If the vibration intensity was not within the preset optimal amplitude range of 14-18μm, the intelligent frequency adaptive adjustment module of the ultrasonic generator was immediately activated for adjustment. The adjustment process followed the formula... Assuming that during processing, an advanced material acoustic impedance monitoring device detects a change in material acoustic impedance ΔZ of 6% (relative to the initial acoustic impedance Z0), and the frequency adjustment coefficient k is taken as 0.4, the new frequency f is quickly calculated. new The vibration intensity is then set into the ultrasonic generator and checked again using an ultrasonic monitor until it meets the requirements. At the same time, the ultrasonic monitor automatically records the detection data to the machining center control system, providing detailed information for subsequent process analysis and quality traceability.

[0094] 3. Perform ultrasonic-assisted pre-drilling of the pilot hole according to step S3. Set the rotation speed to 1450 r / min and the feed rate to 145 mm / min. Start the high-pressure center water outlet device, with its initial pressure set to 3 kg based on material properties and empirical values. During the pre-drilling process, the pressure sensor and chip flow sensor work closely together to monitor the pressure changes, chip generation, and discharge status in real time. When the chip flow rate Q reaches 7 g / min (assuming α is 40 and b is 1.4, according to the formula F = α × Q), b The intelligent controller quickly and automatically adjusts the central water outlet pressure or vacuum pump power to ensure timely and smooth chip discharge. At the same time, the high-frequency vibration of the ultrasonic waves makes the chips appear as small and uniform fragments, effectively avoiding the adverse effects of chip accumulation on machining accuracy and creating good machining conditions for the subsequent rigid tapping process.

[0095] 4. Following step S4, the rigid tapping parameters are set using an intelligent algorithm optimization model (based on a neural network algorithm). Input parameters such as material hardness (approximately 420 HB), elastic modulus (approximately 210 GPa), hole diameter 26.5 mm, and thread depth 30 mm. The trained neural network quickly calculates and outputs a rotational speed of 42 r / min, a feed rate of 0.1 mm / r, and an ultrasonic frequency of 29 kHz. After accurately setting these precisely calculated parameters to the machining center, the rigid tapping operation is initiated. During the tapping process, the machining center's control system continuously and closely monitors the data fed back by the high-precision vibration sensor inside the ultrasonic tool holder. This sensor can sensitively capture minute vibration deviations of the tap under high-frequency vibration. If abnormal vibration, excessive cutting force fluctuations, or other unstable machining conditions occur, the control system immediately adjusts the machining parameters based on the sensor feedback, ensuring that the machining process remains stable and efficient, effectively guaranteeing the high-quality completion of thread machining.

[0096] 5. Following step S5, activate the integrated cooling and lubrication micro-droplet injection system during the tapping process. Employing advanced piezoelectric drive technology, initially set the injection frequency to 550Hz and the micro-droplet size to 55μm. During the machining process, monitor temperature changes in real time using high-precision temperature sensors installed at key locations in the machining area. Simultaneously, combine the preset tool wear threshold model (which comprehensively considers factors such as tool material, machining parameters, and material properties) with multiple factors such as actual machining time and cutting force changes to comprehensively determine the tool wear condition.

[0097] For example, when the temperature rises above 120°C or the cutting force of the tool shows a significant upward trend in a short period of time and continues for a certain period of time, the control system automatically adjusts the spray frequency to 750Hz and reduces the droplet size to 45μm to significantly enhance the cooling and lubrication effect, further reduce tool wear, and effectively ensure that the machining accuracy and surface quality always meet high standards.

[0098] This embodiment will be tested:

[0099] 1. Comprehensive thread accuracy inspection: A high-resolution image measuring instrument is used to comprehensively measure the machined thread, accurately measuring various parameters such as the major diameter, pitch diameter, minor diameter, thread angle, and pitch, and comparing them in detail with standard values. The pitch diameter tolerance is controlled within ±0.08mm to ensure that the geometric accuracy of the thread fully meets the design requirements. During the measurement process, each parameter is measured multiple times at different positions on the thread (e.g., 6 measurement points are evenly selected in the circumferential direction of the thread, and 3 measurement sections are selected in the length direction of the thread, with each parameter measured 3 times in each section). The average value is taken as the final measurement result to ensure the accuracy and reliability of the measurement data.

[0100] 2. Fine surface roughness inspection: An advanced roughness tester is used to perform detailed inspection of the thread surface. Six measurement points are evenly distributed on the circumference of different cross-sections of the thread. Multiple measurements are taken at each point in different directions (e.g., four measurements at each point), and the average value is taken as the surface roughness R at that point. a The measured value is used to ensure a comprehensive and accurate reflection of the thread surface quality. The measured value is strictly compared with the surface roughness specified in the standard as ≤6.3μm to determine whether the thread surface quality is qualified.

[0101] 3. Tool wear depth and area inspection: After tapping, carefully remove the tap and carefully observe the wear of the tap's cutting edge under a super depth-of-field microscope. Use professional image analysis software to accurately measure the wear length, width, and proportion of the wear area to the total cutting edge area. Select multiple measurement positions evenly on the cutting edge (e.g., select 5 measurement positions) for measurement, and take the average value as the final measurement result. The wear area ratio is less than 5%, which is considered qualified. At the same time, record the specific location, morphological characteristics, and wear pattern of the tool wear in detail to provide a strong reference for subsequent tool life analysis, tool optimization design, and machining process improvement.

[0102] The specific test data is as follows:

[0103]

[0104] Example 5

[0105] This invention provides a method for rigid tapping threads using ultrasonic drilling in titanium alloys, high-temperature alloys, and duplex stainless steel, as detailed below:

[0106] Material: Nickel-based superalloy Incone 1625

[0107] Thread specification: M3, pitch 0.5mm

[0108] Aperture: 2.5mm;

[0109] Hole depth: 10mm.

[0110] The specific processing method is as follows:

[0111] 1. A Neway gantry machining center PM3560SL was selected for modification. The ultrasonic generator, receiver, transducer, and ultrasonic-specific tool holder were carefully installed according to step S1, and the relevant wiring connections were ensured to be accurate. The initial frequency of the intelligent frequency adaptive adjustment module of the ultrasonic generator was set to 22kHz based on material characteristics and past experience, and the frequency adjustment coefficient was set to 0.35 to ensure that it can effectively adapt to changes in material and adjust the frequency during the machining process. The high-precision MEMS microelectromechanical sensor in the ultrasonic-specific tool holder underwent a professional calibration and testing process before installation to ensure that its measurement accuracy reaches the nanometer level. After installation, it achieves a stable and efficient connection with the CNC system of the machining center, transmitting tap vibration data in real time, laying the foundation for precise control of the machining process.

[0112] 2. Following step S2, and considering the nickel-based superalloy Incone1625 and M3 thread specifications, and based on detailed data analysis of the material's microstructure and mechanical properties, the ultrasonic frequency was determined to be 23kHz. A high-precision ultrasonic monitoring instrument (measurement error <0.1‰) was used to carefully check the ultrasonic vibration intensity. If the vibration intensity was outside the preset optimal amplitude range of 15-20μm, the intelligent frequency adaptive adjustment module of the ultrasonic generator was quickly activated for adjustment, based on the formula... Assuming that a 7% change in the material's acoustic impedance ΔZ is detected during processing (relative to the initial acoustic impedance Z0), calculate the new frequency f. new The vibration intensity is then set into the ultrasonic generator and checked again using an ultrasonic monitor until it meets the requirements. At the same time, the ultrasonic detector automatically records the detection data completely to the machining center control system, providing detailed information for subsequent process analysis and quality traceability.

[0113] 3. Perform ultrasonic-assisted pre-drilling of the pilot hole according to step S3. Set the rotation speed to 1600 r / min and the feed rate to 0.1 mm / r. Start the central water outlet device, which is estimated to be 2 kg based on material properties and experience. During the pre-drilling process, the pressure sensor and chip flow sensor work together to monitor the pressure changes in the chip discharge pipe and the amount and discharge of chips in real time. When the chip flow rate Q reaches 8 g / min (assuming α is 45 and b is 1.5, according to the formula F = α × Q), b The intelligent controller automatically adjusts the central water outlet pressure or vacuum pump power in a timely manner to ensure that the chips are discharged smoothly. At the same time, it uses ultrasonic vibration to refine the chips, improve the processing accuracy, and create favorable conditions for the subsequent rigid tapping process.

[0114] 4. Following step S4, the rigid tapping parameters are set using an intelligent algorithm optimization model (based on a neural network algorithm). Input parameters such as material hardness (approximately 480 HB), elastic modulus (approximately 210 GPa), hole diameter (2.5 mm), and thread depth (10 mm). The neural network quickly calculates and outputs a rotational speed of 40 r / min, a feed rate of 0.22 mm / r, and an ultrasonic frequency of 25 kHz. After accurately setting these parameters on the machining center, the rigid tapping operation is initiated. During the tapping process, the machining center control system closely monitors the data from the high-precision vibration sensor inside the ultrasonic tool holder. If abnormal vibration or excessive cutting force occurs, the machining parameters are immediately adjusted based on the sensor feedback to ensure a stable and efficient machining process and guarantee thread quality.

[0115] 5. Following step S5, activate the integrated cooling and lubrication micro-droplet injection system during the tapping process. Employing advanced piezoelectric drive technology, the initial injection frequency is set to 700Hz, and the micro-droplet size is set to 40μm. During processing, the temperature of the processing area and the tool wear are monitored in real time by a temperature sensor and a tool wear monitoring system. When the temperature rises above 130℃ or the tool cutting force increases significantly, the control system automatically adjusts the injection frequency to 900Hz and reduces the micro-droplet size to 30μm to enhance the cooling and lubrication effect, reduce tool wear, and ensure processing accuracy and surface quality.

[0116] This embodiment will be tested:

[0117] 1. Comprehensive thread accuracy inspection: High-precision thread gauges and professional measuring tools are used to comprehensively inspect the machined threads. Thread plug gauges and ring gauges are used to check for go and stop, ensuring that the basic thread dimensions are qualified. Then, universal tool microscopes and coordinate measuring machines are used to measure parameters such as the thread pitch diameter, minor diameter, thread angle, and pitch. Multiple measurements are taken at different positions on the thread (e.g., 8 measurement points are evenly selected in the thread circumference direction, and 4 measurement sections are selected in the thread length direction, with each parameter measured 3 times in each section). The average value is taken as the final measurement result and compared with the standard value. The pitch diameter tolerance is controlled within ±0.09mm to ensure that the thread accuracy meets the requirements.

[0118] 2. Comprehensive surface roughness inspection: A high-precision roughness tester is used to comprehensively inspect the thread surface. Ten measurement points are selected at key parts of the thread (such as the thread crest, flank, and root). Multiple measurements are taken at each point in different directions (e.g., 5 measurements per point), and the average value is taken as the surface roughness R at that point. a The measured value is used to ensure a comprehensive reflection of the thread surface quality. The measured value is strictly compared with the standard-specified surface roughness of ≤6.3μm to determine whether the thread surface quality is qualified.

[0119] 3. Tool wear depth and fillet radius inspection: After tapping, carefully remove the tap and observe the wear of the tap cutting edge under a super depth-of-field microscope. Use professional measuring tools to measure the increase in the fillet radius of the tap cutting edge and the wear depth of the cutting edge. Select multiple measurement positions evenly on the cutting edge (e.g., select 6 measurement positions) for measurement, and take the average value as the final measurement result. The fillet radius increase is considered qualified if it is less than 0.05mm. At the same time, record the specific location, morphological characteristics and wear pattern of the tool wear in detail to provide a strong reference for subsequent tool life analysis, tool optimization design and machining process improvement.

[0120] The specific test data is as follows:

[0121]

[0122] The principle of ultrasonic rigid tapping in this invention is as follows:

[0123] Electrical energy is converted into ultrasonic energy by an ultrasonic generator. The ultrasonic energy is then converted into vibrational mechanical energy by an ultrasonic receiver and transducer. This energy is transmitted to the tap through the ultrasonic tool holder. The tap vibrates at a high frequency of 20,000 to 40,000 times per second, enabling rigid tapping of difficult-to-machine materials such as titanium alloys, high-temperature alloys, and duplex stainless steel. During the machining process, the high-frequency vibration of the tap causes the coolant to atomize instantly, quickly carrying away the machining heat. The actual machining situation is an invisible intermittent cutting, and the contact time between the tool and the workpiece is only one-third of that of traditional machining methods.

[0124] It revolutionizes traditional processing techniques and solves the problem of rigid tapping of difficult-to-machine materials such as titanium alloys, high-temperature alloys, and duplex stainless steel, turning the impossible into possible, increasing efficiency by 9-15 times, significantly reducing labor intensity, and better ensuring thread perpendicularity, surface finish, and zero scrap rate.

[0125] Moreover, the tool life is greatly improved. Due to the rapid removal of processing heat and the reduction of the actual contact time between the tool and the workpiece, the tool life can be increased by 3-5 times compared with traditional processing methods, and the tool cost is greatly reduced.

[0126] In summary, the rigid tapping threads of this invention are all of qualified quality, with significantly improved surface finish. It demonstrates excellent performance in terms of thread machining accuracy, surface roughness, and tool wear control, effectively proving its advantages over traditional machining methods. It can meet the requirements of high-quality thread machining, improve production efficiency, and reduce costs.

[0127] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for rigid tapping threads in titanium alloys, high-temperature alloys, and duplex stainless steel using ultrasonic drilling, for rigid tapping of M3 to M30 threads in titanium alloys, nickel-based high-temperature alloys, and duplex stainless steel, characterized in that: Includes the following steps: S1. Integration and intelligent monitoring of ultrasonic system for machining center: Technical modification of machining center machine tools, including the installation of ultrasonic generators, receivers, transducers, ultrasonic-specific tool holders, and related connecting lines. The ultrasonic generator uses an intelligent frequency adaptive adjustment module, which can dynamically adjust the output frequency in real time according to the changes in material properties during the processing, ensuring that the ultrasonic energy is always in the best transmission state. The ultrasonic tool holder integrates a high-precision vibration sensor, which can monitor the tap vibration in real time and feed the data back to the control system, enabling precise monitoring and adjustment of the machining process. S2. Precise adjustment of ultrasonic frequency and accurate detection of strength: Based on the carbide-coated taps used for threads of different materials, hole diameters and depths, combined with big data analysis of the microstructure and mechanical properties of the materials, different ultrasonic frequency parameters are adjusted. Ultrasonic waves are converted into mechanical energy and transmitted to the tap through an ultrasonic device. The ultrasonic monitoring system is used to accurately check the ultrasonic vibration intensity to ensure that the vibration intensity is within the preset optimal range. The ultrasonic monitoring system is connected to the machining center control system to realize automatic detection and data recording. S3. Ultrasonic-assisted high-efficiency pre-drilling and intelligent chip control: Ultrasonic-assisted pre-drilling of the bottom hole is adopted, with a rotation speed of 1000-1600 r / min and a feed of 100-250 mm / min. During the pre-drilling process, the ultrasonic vibration causes the chips to be fine and broken. The high-pressure water outlet device is used to discharge the chips in time, avoiding the impact of chip accumulation on the machining accuracy. The pressure of the high-pressure water outlet device can be automatically adjusted according to the amount of chips generated and discharged. S4. Intelligent optimization of tapping parameters and multi-factor collaborative processing: The machining center sets processing parameters according to different materials, hole diameters, and thread depths, and performs rigid tapping on pre-drilled bottom holes. The setting of processing parameters adopts an intelligent algorithm optimization model, which comprehensively considers multiple factors such as material properties, tool performance, and machine tool performance to achieve automatic matching and optimization of processing parameters. S5. Dynamic enhancement of cooling and lubrication for rigid tapping: The rigid tapping speed is 40-60 r / min. During the tapping process, the integrated cooling and lubrication micro-droplet injection system is used to precisely spray the cooling and lubricating agent into the processing area in the form of micro-droplets. The size of the micro-droplets can be dynamically adjusted according to the processing conditions to improve the cooling and lubrication effect, further reduce tool wear and improve the quality of thread processing.

2. The method for rigid tapping ultrasonic drilling of threads in titanium alloys, high-temperature alloys, and duplex stainless steel materials according to claim 1, characterized in that: In step S1, the intelligent frequency adaptive adjustment module calculates and adjusts the output frequency according to the following formula: Among them, f new For the adjusted frequency, f init The initial set frequency is given by k, which is the frequency adjustment coefficient, ranging from 0.1 to 0.

5. ΔZ is the change in acoustic impedance of the material during processing, and Z0 is the initial acoustic impedance of the material.

3. The method for rigid tapping ultrasonic drilling of threads in titanium alloys, high-temperature alloys, and duplex stainless steel materials according to claim 1, characterized in that: In step S3, the high-pressure water outlet and micro-droplet jet lubrication system automatically adjusts according to the amount of chips generated and discharged.

4. The method for rigid tapping ultrasonic drilling of threads in titanium alloys, high-temperature alloys, and duplex stainless steel materials according to claim 1, characterized in that: In step S4, the intelligent algorithm optimization model is based on a neural network algorithm. Its input layer parameters include the material hardness H, elastic modulus E, pore size D, and thread depth L. The output layer parameters are rotational speed n, feed rate f, and ultrasonic frequency f. ultra By training a neural network with a large amount of sample data, the output processing parameters can achieve the optimal processing effect.

5. The method for rigid tapping ultrasonic drilling of threads in titanium alloys, high-temperature alloys, and duplex stainless steel materials according to claim 1, characterized in that: In step S1, the high-precision vibration sensor, with a measurement accuracy down to the nanometer level, is used to accurately capture the minute vibration deviations of the tap under high-frequency vibration and transmit the data to the CNC system of the machining center for processing in a timely manner.

6. The method for rigid tapping ultrasonic drilling of threads in titanium alloys, high-temperature alloys, and duplex stainless steel materials according to claim 1, characterized in that: In step S2, the ultrasonic monitoring system uses ultrasonic high-frequency vibration technology, which is not affected by ambient light and mechanical vibration, and achieves high-precision measurement of ultrasonic vibration intensity with a measurement error of <0.1‰.

7. The method for rigid tapping ultrasonic drilling of threads in titanium alloys, high-temperature alloys, and duplex stainless steel materials according to claim 1, characterized in that: In step S3, the pressure regulation of the high-pressure water outlet device is achieved by real-time monitoring of the pressure changes in the chip discharge pipe through the machine tool CNC system. Combined with data from chip flow sensors of different materials and apertures, the intelligent controller automatically adjusts the control pressure or vacuum pump power to ensure smooth chip discharge.

8. The method for rigid tapping ultrasonic drilling of threads in titanium alloys, high-temperature alloys, and duplex stainless steel materials according to claim 1, characterized in that: In step S4, the intelligent algorithm optimization model is based on genetic algorithm or neural network algorithm. By learning and analyzing a large amount of historical processing data, it establishes an optimal matching relationship library of material-tool-machine tool processing parameters, and performs rapid retrieval and optimization adjustment according to real-time working conditions in actual processing.

9. The method for rigid tapping ultrasonic drilling of threads in titanium alloys, high-temperature alloys, and duplex stainless steel materials according to claim 1, characterized in that: In step S5, the integrated cooling and lubrication microdroplet injection system adopts piezoelectric drive technology, which can precisely control the injection frequency and particle size of the microdroplets. The injection frequency can be adjusted in the range of 100Hz-1000Hz, and the microdroplet particle size can be precisely controlled between 10μm-100μm, so as to achieve precise cooling and lubrication of the processing area.

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