Titanium alloy, high-temperature alloy and duplex stainless steel material thread ultrasonic drilling rigid tapping machining method

Abstract

The invention discloses a thread ultrasonic drilling rigid tapping machining method for titanium alloy, high-temperature alloy and duplex stainless steel materials, and particularly relates to the technical field of thread tapping. The method comprises the steps of S1, machining center ultrasonic system integration and intelligent monitoring construction, S2, ultrasonic frequency precise allocation and strength precise detection, S3, ultrasonic-assisted efficient pre-drilling and intelligent cutting control, and S4, machining center ultrasonic system integration and intelligent monitoring construction. S4, tapping parameters are intelligently optimized, and multi-factor cooperative machining is carried out; and S5, rigid tapping cooling lubrication dynamic synergistic guarantee is carried out. The machining efficiency can be effectively improved by 9-15 times, the perpendicularity and smoothness of threads are better guaranteed, the thread machining quality is greatly improved, and meanwhile due to the ultrasonic machining mechanism, the service life of the tool is greatly prolonged by 3-5 times.

Description

Technical Field

[0001] The invention relates to the technical field of rigid thread tapping, and more specifically to a method for processing threads of titanium alloy, high-temperature alloy and duplex stainless steel using ultrasonic drilling rigid tapping. Background Art

[0002] At present, in modern manufacturing, titanium alloys, nickel-based high-temperature alloys, duplex stainless steel and other materials have been widely used in aerospace, energy, chemical and other fields due to their excellent properties, such as high strength, high temperature resistance, corrosion resistance, etc. However, these materials are extremely difficult to process, especially in thread processing, which faces many challenges, such as:

[0003] 1. Traditionally, manual tapping and thread milling are mainly used for the processing of M3 to M30 titanium alloy, nickel-based high-temperature alloy and duplex stainless steel threaded holes. Manual tapping is extremely labor-intensive, operators need to consume a lot of physical strength and the processing efficiency is extremely low. During the processing, it is difficult to ensure the verticality and stability of the tap, resulting in the inability to ensure the verticality of the thread, which is prone to large errors during assembly. In addition, the surface quality and finish of the manually processed threads are poor, the precision is insufficient, and the scrap rate is high. When producing threads in large quantities, it is impossible to meet production needs and becomes a serious bottleneck in the production process;

[0004] 2. Although thread milling has improved efficiency, labor intensity and quality compared to manual tapping, it still has significant defects: due to the special material properties of titanium alloy and high-temperature alloy, such as the small deformation coefficient of titanium alloy, material springback and high-temperature alloy work hardening, the quality of threads processed by thread milling is poor, the surface is relatively rough, and it is difficult to meet high-precision processing requirements. At the same time, the manufacturing process of thread milling cutters is complicated, the price is expensive, the service life is short, and the tool needs to be replaced frequently, which not only increases the tool cost, but also increases the equipment downtime due to tool changing operations, further reducing production efficiency. In actual processing, under normal circumstances, each threaded hole needs to be milled at least three times with a thread milling cutter, each time taking three minutes, and a total of at least 9 minutes to process a threaded hole, and the quality cannot be stably guaranteed. Sometimes it even needs to be milled five times, which takes up to fifteen minutes, greatly affecting the production schedule and cost control.

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

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

[0007] To achieve the above object, the present invention provides the following technical solution: a method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy, and duplex stainless steel material threads, which is used for rigid tapping of titanium alloy, nickel-based high temperature alloy, and duplex stainless steel material M3 to M30, comprising the following steps:

[0008] S1. Integration of ultrasonic system and intelligent monitoring of machining center. Technical transformation of machining center machine tools. Installation of ultrasonic generators, receivers, transducers, ultrasonic tool holders and related connection lines.

[0009] The ultrasonic generator adopts 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 process, ensuring that the ultrasonic energy is always in the best transmission state;

[0010] The ultrasonic toolholder is internally integrated with a high-precision vibration sensor, which can monitor the vibration of the tap in real time and feed the data back to the control system to achieve accurate monitoring and adjustment of the machining process;

[0011] S2. Accurately adjust the ultrasonic frequency and detect the strength. According to the carbide coated taps used for threads of different materials, apertures and depths, combined with the big data analysis of the material's microstructure and mechanical properties, adjust different ultrasonic frequency parameters, convert ultrasonic waves into mechanical energy and transmit them to the taps through an ultrasonic device, and use an ultrasonic monitoring system 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 control system of the machining center to achieve automatic detection and data recording;

[0012] S3, ultrasonic-assisted efficient pre-drilling and intelligent chip control, using ultrasonic-assisted pre-drilling of bottom holes, with a rotation speed of 1000-1600r / min and a feed of 100-250mm / min. During the pre-drilling process, the chips are finely broken by the vibration of ultrasonic waves, and the chips are discharged in time by a high-pressure water outlet device to avoid the influence 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 the discharge situation;

[0013] S4, intelligent optimization of tapping parameters and multi-factor collaborative processing. The machining center sets the machining parameters according to different materials, hole diameters, and depths of threads, and performs rigid tapping on pre-drilled bottom holes. The setting of machining parameters uses 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 machining parameters.

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

[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 is the adjusted frequency, f init is the initial set frequency, k is the frequency adjustment coefficient, the value range is between 0.1-0.5, 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 conditions.

[0017] Preferably, in step S4, the intelligent algorithm optimization model is based on a neural network algorithm, and its input layer parameters include the material hardness H, elastic modulus E, hole diameter D and thread depth L, and the output layer is the speed n, feed rate f and ultrasonic frequency f ultra , the neural network is trained by a large amount of sample data so that the output processing parameters can achieve the optimal processing effect.

[0018] Preferably, in step S1, the high-precision vibration sensor has a measurement accuracy of nanometers, and is used to accurately capture tiny vibration deviations of the tap under high-frequency vibration, and timely transmit the data to the numerical control system of the machining center for processing.

[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 monitors the pressure changes in the chip removal pipeline in real time through the numerical control system, and the intelligent controller automatically adjusts the pressure or vacuum pump power in combination with the chip flow monitoring data to ensure smooth discharge of chips.

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

[0022] Preferably, in step S5, the integrated cooling and lubrication droplet injection system adopts piezoelectric drive technology, which can accurately control the injection frequency and particle size of the droplets. The injection frequency can be adjusted in the range of 100Hz-1000Hz, and the droplet particle size can be accurately controlled between 10μm-100μm, thereby achieving precise cooling and lubrication of the processing area.

[0023] Technical effects and advantages of the present invention:

[0024] 1. The present invention subverts the traditional processing technology through technical means such as intelligent frequency adaptive adjustment module and intelligent algorithm optimization model, and can effectively solve the thread processing problems of difficult-to-process materials such as titanium alloy, high-temperature alloy, duplex stainless steel, etc., greatly improve the processing efficiency, and the efficiency is increased by 9-15 times compared with the traditional thread milling processing method. At the same time, with the assistance of high-precision sensors and advanced detection equipment, the verticality and smoothness of the thread are better guaranteed, and the scrap rate is close to zero, which effectively improves the thread processing quality, meets the high-precision production requirements, reduces the rework and scrap losses caused by processing quality problems, and improves production efficiency;

[0025] 2. In the process of machining, the high-frequency vibration of ultrasound causes the coolant to be instantly atomized to take away the heat, and the actual contact time between the tool and the workpiece is only one-third of that of the traditional machining method. Combined with innovative technologies such as the cooling and lubrication integrated droplet injection system, the tool wear is greatly reduced. Compared with the traditional machining method, the tool life can be increased by 3-5 times, which significantly reduces 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 the present invention adjusts the ultrasonic frequency in real time according to the changes in material properties. The intelligent algorithm optimization model automatically matches the processing parameters based on multiple factors. The high-precision vibration sensor, pressure sensor, chip flow sensor and the like work closely with the control system of the machining center to realize all-round intelligent monitoring and adjustment of the machining process. It can respond to various abnormal situations in the machining process in a timely manner, ensure that the machining process is stable and reliable, effectively reduce the labor intensity and technical requirements of operators, improve the consistency and repeatability of the production process, and provide a strong guarantee for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the overall flow chart of the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1,

[0030] The embodiment of the present invention provides a method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread, which is as follows:

[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 methods are as follows:

[0036] 1. Select Suzhou Newway CNC gantry machining center, model PM1520HA for transformation, install ultrasonic generator, receiver, transducer and ultrasonic special tool holder according to S1 step, and connect relevant lines. Among them, the initial frequency of the intelligent frequency adaptive adjustment module of the ultrasonic generator is set to 20kHz based on the past experience of similar material processing, and the frequency adjustment coefficient is 0.3. The high-precision sensor integrated in the ultrasonic special tool holder is professionally calibrated before installation to ensure that the measurement accuracy reaches the nanometer level. After installation, it is stably connected with the CNC system of the machining center to realize real-time data transmission, providing guarantee for subsequent processing process monitoring;

[0037] 2. According to step S2, for titanium alloy Ti-6Al-4V material and M20 thread specification, combined with the material's microstructure and mechanical properties big data analysis, by querying the professional material database established within the company (the database covers the detailed crystal structure, hardness, elastic modulus and other parameters of various titanium alloy materials and the corresponding relationship with the ultrasonic frequency), the ultrasonic frequency is preliminarily determined to be 21kHz. Subsequently, the ultrasonic vibration intensity is accurately checked using an ultrasonic monitoring device. During the detection process, if it is found that the vibration intensity is not within the preset optimal range (the amplitude is set to 10-15μm in this embodiment), the intelligent frequency adaptive adjustment module of the ultrasonic generator is started for adjustment. During the adjustment, according to the formula Assuming that the material sample is tested before processing and the change in material acoustic impedance ΔZ is 3% (relative to the initial acoustic impedance Z0), substitute it into the formula to calculate the new frequency f new, and set it in the ultrasonic generator, and use the ultrasonic monitoring system to check the vibration intensity again until it meets the requirements. At the same time, the ultrasonic monitoring system automatically records the detection data into the machining center control system to facilitate subsequent process analysis and optimization;

[0038] 3. According to step S3, ultrasonic-assisted pre-drilling of a 17.5 mm diameter bottom hole is performed. The rotation speed is set to 1300 r / min, the feed rate is set to 160 mm / min, and the high-pressure central water outlet device is started. 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 of the workpiece in real time, and the chip flow sensor synchronously detects the chip generation and discharge. If it is found that the chips have a tendency to accumulate, for example, the chip flow rate Q reaches 4 g / min, (assuming α is 25, b is 1, according to the relationship between impact pressure and chip flow F = α × Q b ) The intelligent controller automatically adjusts the center water outlet pressure vacuum pump power, increases the center water outlet pressure, ensures the timely discharge of chips, and uses the ultrasonic vibration to make the chips appear fine and broken, effectively avoiding the influence of chips on processing accuracy, laying a good foundation for the subsequent tapping process;

[0039] 4. According to step S4, the intelligent algorithm optimization model is used to set the rigid tapping parameters. The material hardness (about 330HB), elastic modulus (about 110GPa), hole diameter 17.5mm and thread depth 35mm are input. The output speed is 50r / min, the feed rate is 0.12mm / r, and the ultrasonic frequency is 23kHz. After these parameters are accurately set to the machining center, the rigid tapping operation is started. During the tapping process, the machining center control system pays close attention to the data feedback from the high-precision vibration sensor in the ultrasonic special tool holder. The sensor can accurately capture the tiny vibration deviation of the tap under high-frequency vibration. Once abnormal vibration or excessive cutting force occurs, the control system immediately adjusts the processing parameters according to the sensor feedback to ensure the stability and efficiency of the processing process and the quality of thread processing.

[0040] 5. According to step S5, the integrated cooling and lubrication droplet injection system is started during the tapping process. The piezoelectric drive technology is used. The initial injection frequency is set to 400 Hz and the droplet size is set to 40 μm. During the processing, the temperature change is monitored in real time by a temperature sensor installed near the processing area. At the same time, the tool wear condition is comprehensively judged based on the preset tool wear threshold (which can be determined through experiments or experience) and the actual processing time.

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

[0042] This embodiment was tested:

[0043] 1. Thread accuracy detection: Use a high-precision thread plug gauge to perform a pass / stop test on the processed thread to ensure that the basic size of the thread meets the requirements. Then, use a universal tool microscope to measure the median and minor diameter of the thread. Select three measurement sections evenly along the length of the thread, measure each section twice, take the average value as the measurement result, and compare it with the standard value. The allowable deviation of the median diameter is ±0.05mm, and the allowable deviation of the minor diameter is ±0.03mm.

[0044] 2. Surface roughness test: Use a roughness meter to test the thread surface. Select 5 measuring points evenly along the spiral direction on the thread side. Measure each point 3 times and take the average value as the surface roughness R of the point. a Value, to ensure the measurement results are accurate and reliable, compared with the surface roughness ≤6.3μm specified in the standard;

[0045] 3. Tool wear detection: After the tapping is completed, carefully remove the tap, observe the wear of the tap cutting edge under the ultra-depth microscope, use image analysis software to measure the wear width of the tap back face, select 3 measurement positions evenly on the cutting edge, take the average value as the wear width value, and judge it as qualified if the wear width is less than 0.1mm. At the same time, record the wear morphology and characteristics of the tool to provide a reference for subsequent tool life analysis and process improvement. Continuously rigidly tap 12 holes, the tap coating is not worn, the plug gauge test is all qualified, and the 12 holes thread processing time is a total of 10 minutes.

[0046] The specific test table data is as follows:

[0047]

[0048] Embodiment 2,

[0049] The embodiment of the present invention provides a method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread, which is as follows:

[0050] Material: Nickel-based high temperature alloy Inconel718;

[0051] Thread specification: M16, pitch 2mm

[0052] Aperture: 14mm;

[0053] Hole depth: 30mm.

[0054] The specific processing methods are as follows:

[0055] 1. Select Suzhou Newway CNC gantry machining center, model PM1520HA, for transformation, install ultrasonic related equipment according to S1 steps, and set the initial frequency of the intelligent frequency adaptive adjustment module of the ultrasonic generator to 25kHz to ensure that it can be effectively adjusted according to the changes in material properties in the subsequent processing process. The piezoelectric sensor in the ultrasonic special tool handle is strictly calibrated and connected to the CNC system to ensure the accuracy and timeliness of tap vibration monitoring;

[0056] 2. According to step S2, combined with the material properties of nickel-based high-temperature alloy Inconel718 and M16 thread specifications, through in-depth analysis of a large amount of material microstructure and mechanical properties data accumulated by the company, the ultrasonic frequency is adjusted to 26kHz, and a high-precision ultrasonic monitor (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 is used according to the formula Adjustments are made. For example, the material sample is tested before processing to obtain a material acoustic impedance change ΔZ of 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 to the ultrasonic generator until the vibration intensity meets the requirements, and the ultrasonic detector simultaneously records the data to the control system of the machining center;

[0057] 3. Perform ultrasonic assisted pre-drilling of the bottom hole according to step S3, set the rotation speed to 1400r / min, set the feed rate to 250mm / min, start the high-pressure water outlet device, and set the initial pressure to 2kg based on experience. During the pre-drilling process, the pressure sensor and the chip flow sensor work in real time. When the chip flow Q reaches 5g / min, (assuming α is 30, 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 discharge of chips, while using ultrasonic vibration to refine the chips and improve processing accuracy;

[0058] 4. According to step S4, the intelligent algorithm optimization model is used to set the rigid tapping parameters. The material hardness (about 400HB), elastic modulus (about 200Pa), hole diameter 14mm and thread depth 30mm are input. The output speed is 45r / min, the feed rate is 0.16mm / r, and the ultrasonic frequency is 28kHz after the neural network is calculated. After setting these parameters in the machining center, rigid tapping begins. During the machining process, the CNC system adjusts the machining parameters in time according to the feedback data of the high-precision vibration sensor in the ultrasonic special tool holder to ensure machining stability and thread quality.

[0059] 5. According to step S5, the integrated cooling and lubrication droplet injection system is started during the tapping process. The piezoelectric drive technology is used, the initial injection frequency is set to 500 Hz, and the droplet size is set to 50 μm. During the processing, the temperature of the processing area and the tool wear are monitored in real time through the temperature sensor and the tool wear monitoring system. When the temperature rises above 100 ° C or the tool cutting force increases significantly, the control system automatically adjusts the injection frequency to 700 Hz and reduces the droplet size to 40 μm, thereby enhancing the cooling and lubrication effect, reducing tool wear, and ensuring the processing quality.

[0060] This embodiment was tested:

[0061] 1. Comprehensive inspection of thread accuracy. Use thread plug gauge to conduct through-and-stop inspection on the processed thread to ensure that the basic size of the thread is qualified. Then, use three-coordinate measuring machine to measure the major diameter and middle diameter of the thread. Select 4 measuring 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 of the major diameter is ±0.06mm, and the allowable deviation of the middle diameter is ±0.04mm.

[0062] 2. Multi-point surface roughness detection: Use a roughness meter to detect the thread surface. Select 3 measurement points at the top, side and bottom of the thread. Measure each point 3 times and take the average value as the surface roughness R of the point. a value, ensuring that the measurement results fully reflect the thread surface quality and are compared with the surface roughness ≤6.3μm specified in the standard;

[0063] 3. Detailed inspection of tool wear: After tapping, place the tap under a microscope to observe the wear of the cutting edge. Use image analysis software to measure the wear length of the tap cutting edge. Select 4 measurement positions evenly on the cutting edge and take the average value as the wear length value. The wear length is less than 0.12mm and is considered qualified. At the same time, the position, shape and characteristics of tool wear are recorded in detail to provide a strong basis for tool maintenance and process improvement. Continuously rigidly tap 11 holes, and the tap coating is not worn.

[0064] The specific test table data is as follows:

[0065]

[0066]

[0067] Embodiment 3,

[0068] The embodiment of the present invention provides a method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread, which is as follows:

[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 methods are as follows:

[0074] 1. The Neway PM3560SL gantry machining center was selected as the basis for the transformation. The ultrasonic generator, receiver, transducer, ultrasonic tool holder and other equipment were installed according to step S1, and the lines were connected. The initial frequency of the ultrasonic generator's intelligent frequency adaptive adjustment module was set to 21kHz, and the frequency adjustment coefficient was set to 0.4. The MEMS micro-electromechanical sensor in the ultrasonic tool holder was calibrated and connected to the CNC system to ensure accurate monitoring of the tap vibration;

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

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

[0077] 4. According to step S4, the intelligent algorithm optimization model is used to set the rigid tapping parameters. The material hardness (about 350HB), elastic modulus (about 120Pa), hole diameter 27.5mm and thread depth 30mm are input. The output speed is 48r / min, the feed rate is 0.18mm / r, and the ultrasonic frequency is 24kHz after the neural network is calculated. After setting these parameters in the machining center, the rigid tapping is started. During the machining process, the CNC system adjusts the machining parameters in time according to the feedback data of the high-precision vibration sensor in the ultrasonic special tool holder to ensure the stability of the machining process.

[0078] 5. According to step S5, the integrated cooling and lubrication droplet injection system is started during the tapping process. The piezoelectric drive technology is used, the initial injection frequency is set to 600 Hz, and the droplet size is set to 45 μm. During the processing, the temperature of the processing area and the tool wear are monitored in real time through the temperature sensor and the tool wear monitoring system. When the temperature rises above 110 ° C or the tool cutting force increases significantly, the control system automatically adjusts the injection frequency to 800 Hz and reduces the droplet size to 35 μm, thereby enhancing the cooling and lubrication effect, reducing tool wear, and ensuring the processing quality.

[0079] This embodiment was tested:

[0080] 1. Comprehensive detection of thread accuracy. Use thread plug gauge to detect the thread after processing to ensure that the basic size of the thread is qualified. Then use three-coordinate measurement to detect the major diameter and middle diameter of the thread. Select 4 measurement sections evenly along the length of the thread. Each section is measured 3 times. The average value is taken as the measurement result and compared with the standard tolerance zone. The major diameter and middle diameter tolerance is ±0.07mm. At the same time, check whether the parameters such as thread angle and pitch meet the standard requirements.

[0081] 2. Detailed surface roughness test: Use a roughness meter to select 8 measuring 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 of the point. a Value, to ensure that the thread surface quality is fully reflected, and compared with the surface roughness ≤6.3μm specified in the standard;

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

[0083] The specific test table data is as follows: The following should quote M30 data

[0084]

[0085] Embodiment 4,

[0086] The embodiment of the present invention provides a method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread, which is as follows:

[0087] Material: Nickel-based high temperature alloy Inconel625

[0088] Thread specification: M30, pitch 3.5mm

[0089] Aperture: 27.5mm;

[0090] Hole depth: 30mm.

[0091] The specific processing methods are as follows:

[0092] 1. Choose Neway gantry machining center PM3560SL for transformation. According to the S1 step, accurately install the ultrasonic generator, receiver, transducer and ultrasonic special tool holder, and connect the relevant lines. The initial frequency of the intelligent frequency adaptive adjustment module of the ultrasonic generator is set to 26kHz to ensure that it has good frequency adjustment performance. The high-precision sensor in the ultrasonic special tool holder undergoes a strict calibration procedure before installation to ensure that its measurement accuracy reaches the nanometer level. After installation, it is stably connected with 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 subsequent machining processes;

[0093] 2. According to step S2, for the nickel-based high-temperature alloy Inconel625 and M30 thread specifications, combined with the company's accumulated rich material microstructure and mechanical properties big data, after in-depth analysis, the ultrasonic frequency is adjusted to 27kHz, and the high-precision ultrasonic monitoring technology is used. The measurement error is less than 0.1‰, and the ultrasonic vibration intensity is carefully checked. If the vibration intensity is not within the preset optimal amplitude range of 14-18μm, the intelligent frequency adaptive adjustment module of the ultrasonic generator is immediately started for adjustment. The adjustment process is based on the formula Assume that during the processing, the material acoustic impedance change ΔZ is detected by advanced material acoustic impedance monitoring equipment to be 6% (relative to the initial acoustic impedance Z0), and the frequency adjustment coefficient k is 0.4, and the new frequency f is quickly calculated. new And set it in the ultrasonic generator, and use the ultrasonic monitor to check the vibration intensity again until it meets the requirements. At the same time, the ultrasonic monitor automatically records the test data in full to the control system of the machining center, providing detailed basis for subsequent process analysis and quality traceability;

[0094] 3. Perform ultrasonic-assisted pre-drilling of the bottom hole according to step S3, set the rotation speed to 1450r / min, the feed rate to 145mm / min, start the high-pressure central water outlet device, and set its initial pressure to 3kg based on material properties and empirical values. During the pre-drilling process, the pressure sensor and the chip flow sensor work closely together to monitor the pressure change and chip generation and discharge during chip removal in real time. When the chip flow rate Q reaches 7g / min, (assuming α is 40, 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 discharge of chips. At the same time, the high-frequency vibration of ultrasound is used to make the chips appear small and evenly broken, effectively avoiding the adverse effects of chip accumulation on machining accuracy and creating good machining conditions for subsequent rigid tapping processes;

[0095] 4. According to step S4, the rigid tapping parameters are set using the intelligent algorithm optimization model (based on the neural network algorithm). The hardness of the material (about 420HB), elastic modulus (about 210GPa), hole diameter 26.5mm and thread depth 30mm are input. The well-trained neural network quickly calculates the output speed to be 42r / min, the feed rate to be 0.1mm / r, and the ultrasonic frequency to be 29kHz. After these precisely calculated parameters are accurately set to the machining center, the rigid tapping operation is started. During the tapping process, the control system of the machining center continues to pay close attention to the data feedback from the high-precision vibration sensor in the ultrasonic special tool holder. The sensor can keenly capture the tiny vibration deviation of the tap under high-frequency vibration. Once abnormal vibration, excessive cutting force fluctuation or other unstable processing conditions occur, the control system immediately adjusts the processing parameters according to the sensor feedback to ensure that the processing process remains stable and efficient at all times, effectively ensuring the high-quality completion of thread processing.

[0096] 5. According to step S5, the integrated cooling and lubrication droplet injection system is started during the tapping process. Advanced piezoelectric drive technology is used. The initial injection frequency is set to 550 Hz and the droplet size is set to 55 μm. During the processing, the temperature changes are monitored in real time by high-precision temperature sensors installed at key positions in the processing area. At the same time, the tool wear condition is comprehensively judged by combining the preset tool wear threshold model (this model comprehensively considers factors such as tool material, processing parameters and material properties) and actual processing time, cutting force changes and other factors.

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

[0098] This embodiment was tested:

[0099] 1. Comprehensive detection of thread accuracy. Use a high-resolution image measuring instrument to measure the processed threads comprehensively, accurately measure the major diameter, middle diameter, minor diameter, thread angle, pitch and other parameters of the threads, and make detailed comparisons with the standard values. The middle diameter tolerance is controlled within the range of ±0.08mm to ensure that the geometric accuracy of the threads fully meets the design requirements. During the measurement process, each parameter is measured multiple times at different positions of the threads (e.g., 6 measurement points are evenly selected in the circumferential direction of the threads, 3 measurement sections are selected in the length direction of the threads, and each section is measured 3 times for each parameter). The average value is taken as the final measurement result to ensure the accuracy and reliability of the measurement data.

[0100] 2. Surface roughness fine detection: Use advanced roughness meter to conduct detailed detection of thread surface. Select 6 measurement points evenly distributed on the circumference of different cross sections of the thread. Each point is measured multiple times in different directions (such as measuring each point 4 times). The average value is taken as the surface roughness R of the point. a The measured value is strictly compared with the surface roughness ≤6.3μm specified in the standard to determine whether the thread surface quality is qualified.

[0101] 3. Tool wear depth and area detection: After tapping is completed, carefully remove the tap and carefully observe the wear of the tap cutting edge under an ultra-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 area of ​​the tap cutting edge. Select multiple measurement positions evenly on the cutting edge (such as 5 measurement positions) for measurement, and take the average value as the final measurement result. The wear area ratio is less than 5% and is considered qualified. At the same time, record the specific position, morphological characteristics and wear law of the tool wear in detail to provide a strong reference for subsequent tool life analysis, tool optimization design and processing technology improvement.

[0102] The specific test table data is as follows:

[0103]

[0104] Embodiment 5,

[0105] The embodiment of the present invention provides a method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread, which is as follows:

[0106] Material: Nickel-based high temperature alloy Incone1625

[0107] Thread specification: M3, pitch 0.5mm

[0108] Aperture: 2.5mm;

[0109] Hole depth: 10mm.

[0110] The specific processing methods are as follows:

[0111] 1. Choose Neway gantry machining center PM3560SL for transformation, carefully install ultrasonic generator, receiver, transducer and ultrasonic tool holder according to S1 step, and ensure that the relevant line connections are accurate. The initial frequency of the intelligent frequency adaptive adjustment module of the ultrasonic generator is set to 22kHz according to material characteristics and past experience, and the frequency adjustment coefficient is set to 0.35 to ensure that it can effectively adapt to material changes and adjust the frequency during the machining process. The high-precision MEMS micro-electromechanical sensor in the ultrasonic tool holder undergoes a professional calibration and testing process before installation to ensure that its measurement accuracy reaches the nanometer level. After installation, it can achieve stable and efficient connection with the CNC system of the machining center, transmit tap vibration data in real time, and lay the foundation for precise control of the machining process;

[0112] 2. According to step S2, for the nickel-based high-temperature alloy Incone1625 and M3 thread specifications, combined with the detailed material microstructure and mechanical properties big data analysis within the company, the ultrasonic frequency is determined to be 23kHz, and the ultrasonic vibration intensity is carefully checked using a high-precision ultrasonic monitor (measurement error <0.1‰). If the vibration intensity is not within the preset optimal amplitude range of 15-20μm, the intelligent frequency adaptive adjustment module of the ultrasonic generator is quickly started for adjustment. The adjustment is based on the formula Assuming that the acoustic impedance change ΔZ of the material detected during the processing is 7% (relative to the initial acoustic impedance Z0), the new frequency f is calculated. new And set it in the ultrasonic generator, and use the ultrasonic monitor to check the vibration intensity again until it meets the requirements. At the same time, the ultrasonic detector automatically records the test data in full to the control system of the machining center, providing detailed basis for subsequent process analysis and quality traceability;

[0113] 3. Perform ultrasonic-assisted pre-drilling of the bottom hole according to step S3, set the rotation speed to 1600r / min, the feed rate to 0.1mm / r, and start the central water outlet device, which is estimated to be 2kg based on material properties and experience. During the pre-drilling process, the pressure sensor and the chip flow sensor work together to monitor the pressure changes in the chip removal pipeline and the chip generation and discharge in real time. When the chip flow rate Q reaches 8g / min, (assuming α is 45, b is 1.5, according to the formula F = α × Q b ), the intelligent controller automatically adjusts the center water outlet pressure or vacuum pump power in time to ensure smooth discharge of chips, and uses ultrasonic vibration to refine the chips, improve processing accuracy, and create favorable conditions for subsequent rigid tapping processes;

[0114] 4. According to step S4, the rigid tapping parameters are set using the intelligent algorithm optimization model (based on the neural network algorithm). The material hardness (about 480HB), elastic modulus (about 210GPa), hole diameter 2.5mm and thread depth 10mm are input. The neural network quickly calculates the output speed of 40r / min, the feed rate of 0.22mm / r, and the ultrasonic frequency of 25kHz. After these parameters are accurately set to the machining center, the rigid tapping operation is started. During the tapping process, the machining center control system closely monitors the data fed back by the high-precision vibration sensor in the ultrasonic special tool holder. Once abnormal vibration or excessive cutting force occurs, the machining parameters are immediately adjusted according to the sensor feedback to ensure a stable and efficient machining process and ensure the quality of thread machining.

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

[0116] This embodiment was tested:

[0117] 1. Comprehensive detection of thread accuracy. Comprehensively use high-precision thread gauges and professional measuring tools to conduct comprehensive detection of the processed threads. Use thread plug gauges and ring gauges for pass / stop detection to ensure that the basic dimensions of the threads are qualified. Then use universal tool microscopes and three-coordinate measuring machines and other equipment to measure the thread's median diameter, minor diameter, thread angle, pitch and other parameters. Perform multiple measurements at different positions of the thread (e.g. select 8 measurement points evenly in the thread circumferential direction, select 4 measurement sections in the thread length direction, and measure each parameter 3 times in each section). Take the average value as the final measurement result and compare it with the standard value. The median diameter tolerance is controlled within the range of ±0.09mm to ensure that the thread accuracy meets the requirements.

[0118] 2. Comprehensive surface roughness test: Use a high-precision roughness tester to conduct a comprehensive test on the thread surface. Select 10 measurement points at the key parts of the thread (such as the thread crest, flank, and root, etc.). Perform multiple measurements on each point in different directions (such as measuring each point 5 times). Take the average value as the surface roughness R of the point. a The measured value is strictly compared with the surface roughness ≤6.3μm specified in the standard to determine whether the thread surface quality is qualified;

[0119] 3. Tool wear depth and fillet radius detection. After tapping is completed, carefully remove the tap, carefully observe the wear of the tap cutting edge under an ultra-depth of field microscope, use professional measuring tools to measure the tap cutting edge fillet radius increment and cutting edge wear depth, select multiple measurement positions evenly on the cutting edge (such as selecting 6 measurement positions) for measurement, and take the average value as the final measurement result. The edge fillet radius increment less than 0.05mm is judged to be qualified. At the same time, the specific location, morphological characteristics and wear rules of the tool wear are recorded in detail to provide a strong reference basis for subsequent tool life analysis, tool optimization design and processing technology improvement.

[0120] The specific test table data is as follows:

[0121]

[0122] The ultrasonic rigid tapping principle of the present invention is:

[0123] The electric energy is converted into ultrasonic energy through the ultrasonic generator, and the ultrasonic energy is converted into vibration mechanical energy through the ultrasonic receiver and transducer, and then 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 to achieve rigid tapping of difficult-to-process materials such as titanium alloy, high-temperature alloy, and duplex stainless steel. During the processing, the high-frequency vibration of the tap can instantly atomize the coolant, quickly taking away the processing heat. The actual processing condition is invisible intermittent cutting, and the contact time between the tool and the workpiece is only one-third of that of the traditional processing method.

[0124] It subverts the traditional processing technology and solves the problem of rigid tapping of difficult-to-process materials such as titanium alloy, high-temperature alloy, duplex stainless steel, etc., making the impossible possible, improving efficiency by 9-15 times, greatly reducing labor intensity, and better ensuring thread verticality, smoothness, 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. Compared with traditional processing methods, the tool life can be increased by 3-5 times and the tool cost is greatly reduced.

[0126] To sum up, the rigid tapping threads of the present invention have qualified quality, greatly improved smoothness, and excellent performance in thread processing accuracy, surface roughness and tool wear control, which effectively proves its advantages over traditional processing methods, can meet high-quality thread processing needs, improve production efficiency and reduce costs.

[0127] The above description is only 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Titanium alloy, high temperature alloy, duplex stainless steel material thread ultrasonic drilling rigid tapping processing method, used for titanium alloy, nickel-based high temperature alloy, duplex stainless steel M3 to M30 rigid tapping, characterized by: The following steps are involved: S1. Integration of ultrasonic system and intelligent monitoring of machining center. Technical transformation of machining center machine tools. Installation of ultrasonic generators, receivers, transducers, ultrasonic tool holders and related connection lines. The ultrasonic generator adopts 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 process, ensuring that the ultrasonic energy is always in the best transmission state; The ultrasonic toolholder is internally integrated with a high-precision vibration sensor, which can monitor the vibration of the tap in real time and feed the data back to the control system to achieve accurate monitoring and adjustment of the machining process; S2. Accurately adjust the ultrasonic frequency and detect the strength. According to the carbide coated taps used for threads of different materials, apertures and depths, combined with the big data analysis of the material's microstructure and mechanical properties, adjust different ultrasonic frequency parameters, convert ultrasonic waves into mechanical energy and transmit them to the taps through an ultrasonic device, and use an ultrasonic monitoring system 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 control system of the machining center to achieve automatic detection and data recording; S3, ultrasonic-assisted efficient pre-drilling and intelligent chip control, using ultrasonic-assisted pre-drilling of bottom holes, with a rotation speed of 1000-1600r / min and a feed of 100-250mm / min. During the pre-drilling process, the chips are finely broken by the vibration of ultrasonic waves, and the chips are discharged in time by the high-pressure central water outlet device to avoid the influence of chip accumulation on the processing accuracy. The pressure of the high-pressure water outlet device can be automatically adjusted according to the amount of chips generated and the discharge situation; S4, intelligent optimization of tapping parameters and multi-factor collaborative processing. The machining center sets the machining parameters according to different materials, hole diameters, and depths of threads, and performs rigid tapping on pre-drilled bottom holes. The setting of machining parameters uses 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 machining parameters. S5. Dynamic efficiency enhancement of rigid tapping cooling and lubrication. The rigid tapping speed is 40-60r / min. During the tapping process, the cooling and lubrication integrated droplet injection system is used to accurately spray the cooling lubricant into the processing area in the form of droplets. The droplet size can be dynamically adjusted according to the processing conditions to improve the cooling and lubrication effect, further reduce tool wear and improve thread processing quality.

2. The method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread 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 is the adjusted frequency, f init is the initial set frequency, k is the frequency adjustment coefficient, the value range is between 0.1-0.5, 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 ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread according to claim 1, characterized in that: In step S3, the high-pressure water outlet and micro-droplet jet lubrication system are automatically adjusted according to the amount of chip generation and discharge.

4. The method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread according to claim 1, characterized in that: In step S4, the intelligent algorithm optimization model is based on a neural network algorithm, whose input layer parameters include material hardness H, elastic modulus E, hole diameter D and thread depth L, and the output layer is speed n, feed rate f and ultrasonic frequency f ultra , the neural network is trained by a large amount of sample data so that the output processing parameters can achieve the optimal processing effect.

5. The method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread according to claim 1, characterized in that: In step S1, the high-precision vibration sensor has a measurement accuracy of nanometers and is used to accurately capture the tiny vibration deviation 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 ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread according to claim 1, characterized in that: In step S2, the ultrasonic monitoring system adopts ultrasonic high-frequency vibration technology, which is not affected by interference factors such as ambient light and mechanical vibration, and achieves high-precision measurement of ultrasonic vibration intensity with a measurement error of less than 0.1‰.

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

8. The method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread according to claim 1, characterized in that: 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 adjustments according to real-time working conditions in actual processing.

9. The method for ultrasonic drilling and rigid tapping of titanium alloy, high temperature alloy and duplex stainless steel thread according to claim 1, characterized in that: In step S5, the integrated cooling and lubrication droplet injection system adopts piezoelectric drive technology, which can accurately control the injection frequency and particle size of the droplets. The injection frequency can be adjusted in the range of 100Hz-1000Hz, and the droplet particle size can be accurately controlled between 10μm-100μm, thereby achieving precise cooling and lubrication of the processing area.

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