Ultrasonic vibration-assisted mechanical iron cutting combined electrochemical discharge machining
Tong Hao, Luo Yuge, Liu Guodong, Li Yong, NAWAZ Shan Ali (Department of Mechanical Engineering, Tsinghua University, State Key Laboratory of Tribology, Beijing 100084)
Abstract
Abstract: Traditional mechanical processing can easily cause surface micro-crack damage and side wall chipping and overcutting of insulating hard and brittle materials such as quartz glass. Electrochemical discharge machining can achieve damage-free processing of quartz glass and the processing accuracy can reach micron level, but it is difficult to solve the contradiction between damage-free processing accuracy and processing efficiency. With the goal of high-efficiency processing of quartz glass without surface damage, a new method of ultrasonic vibration-assisted mechanical milling and composite electrochemical discharge machining was proposed, and the mechanism of the method was analyzed; a high-speed pneumatic spindle was used to achieve pulse electrical conduction at high speeds. It solves the two technical problems of high-speed rotating brush disturbance and pulse electrical signal introduction of traditional spindles. Based on a high-speed camera, the microscopic instantaneous electrolysis generation bubble/gas film process under the conditions of this method was studied, and the process rules were obtained based on basic experiments. It was also verified through narrow groove structure processing that this method can effectively improve the damage-free processing efficiency of quartz glass.
Keywords: discharge-assisted chemical machining; electrochemical discharge machining; mechanical iron cutting; ultrasonic vibration; quartz glass; narrow groove
CLC classification number: TG66 Document code: A Article number: 1009-279X(2022)S1-0054-05
Ultrasonic Vibration Assisted Hybrid Process of Mechanical Milling and Electrochemical Discharge Machining
TONG Hao,LUO Yuge, LIU Guodong, LI Yong, NAWAZ Shan Ali
(State Key Laboratory of Tribology, Department of Mechanical Engineering,
Tsinghua University, Beijing 100084, China )
Abstract
Traditional processes of mechanical machining are easy to cause surface micro-crack damage and side-wall overcutting of hard and brittle insulating materials such as quartz glass. Spark assisted chemical engraving (SACE) has the feasibility of non-damage processing of quartz glass, and the processing accuracy can even reach micron level. However, in SACE the contradiction between non-damage processing accuracy and high processing efficiency is difficult to solve. In this paper, a novel hybrid process of ultrasonic vibration assisted mechanical milling and SACE is proposed to efficiently machine quartz glass without surface damage, considering the analysis of the process mechanism. A pneumatic spindle is used to realize high rotation speed and the conduction of pulsed electricity, which solves the technical problems of brush disturbance and pulsed signal introduction . The process of bubble/film generation from micro instantaneous electrolysis is observed by a high speed camera. The process rules are obtained from basic machining experiments. It is verified that the proposed process can improve the processing efficiency of quartz glass without surface damage.
Quartz glass has excellent properties such as good transparency, high hardness, biocompatibility and corrosion resistance, and has important application value in semiconductors, optical devices, sensors and other fields. For example, because of its unique
Due to the piezoelectric effect, quartz glass can be used as a crystal resonant device and has been used in acceleration, pressure, and light-sensitive sensors. As the requirements for small integration and strong overload capability of such sensors continue to increase, quartz crystal resonant devices need to be processed into tuning fork beams or thin sheet structures with micron-level processing accuracy. ^([1]){ }^{[1]} . For quartz glass hard and brittle materials, traditional mechanical processing is prone to surface micro-crack damage and side wall chipping and over-cutting, making it difficult to meet the requirements of fine and precise processing. and
The use of photolithography-based MEMS processes is not only costly and prone to high scrap rates, but also a single process is only suitable for processing two-dimensional structures.
Spark assisted chemical engraving (SACE), also known as electrochemical discharge machining, is a processing method suitable for insulating hard and brittle materials. Its basic principle is to use the formation of electrolytic bubbles on the surface of tool electrodes immersed in electrolyte. The gas film, as an insulating medium, breaks down spark discharge to generate high temperature and high pressure, and comprehensively removes the workpiece material through physical and chemical effects [2]. The SACE processing technology of quartz glass has been explored, and the processing accuracy recently studied can even reach the micron level. In 2018, Tang Weidong and Kang Xiaoming ^([3]){ }^{[3]} Use side wall insulated electrodes to 0.01mm//s0.01 \mathrm{~mm} / \mathrm{s} Processing at a scanning speed, the single depth of cut is 17.5 mum17.5 \mu \mathrm{~m} And have narrow grooves with good processing accuracy and quality. In 2019, LIU et al. ^([4]){ }^{[4]} use 0.002mm//s0.002 \mathrm{~mm} / \mathrm{s} At a feed speed of , the depth of cut obtained in a single scan is 70 mum70 \mu \mathrm{~m} of microchannels. At present, SACE mainly uses metal rods as tool electrodes when processing quartz glass. However, in order to achieve the requirements of higher precision, small overcutting amount and no micro-crack damage on the surface, it is necessary to limit the scanning speed and cutting depth to a minimum value. This requires It will cause low processing efficiency.
Ultrasonic vibration assistance has been proven to improve the process effects of mechanical cutting, electrical discharge machining, and electrochemical machining. Ultrasonic vibration-assisted cutting can reduce cutting force and cutting temperature, and improve the cutting performance of hard and brittle materials ^([5]){ }^{[5]} . Ultrasonic-assisted EDM can improve effective discharge rate and discharge stability ^([6]){ }^{[6]} . Ultrasound-assisted electrochemical processing can accelerate the discharge of electrolytic products through cavitation and liquid phase mass transfer effects. ^([7]){ }^{[7]} . Recently, domestic and foreign researchers have begun to explore ultrasonic-assisted SACE processing. Studies have shown that this process promotes uniform distribution of gas films and stable and active discharge on the electrode surface, and can improve SACE perforation efficiency. ^([8-9]){ }^{[8-9]} .
In order to achieve damage-free and efficient processing of quartz glass, this paper proposes a new method of ultrasonic vibration-assisted mechanical iron cutting and composite electrochemical discharge machining, and analyzes the mechanism of the composite processing method, using a high-speed pneumatic spindle to solve the problem of high spindle speeds. The technical problem of conducting pulse electricity to the tool electrode (end mill) is to observe the microscopic instantaneous process of the bubble film generated by electrolysis through high-speed cameras, to study the influence of key parameters of the composite process through basic experiments, and to propose a processing method through narrow groove structure processing verification. effectiveness.
1 Ultrasonic vibration-assisted mechanical iron cutting composite electrochemical discharge
Processing mechanism analysis
Ultrasonic vibration-assisted mechanical iron cutting combined electrochemical discharge machining is a processing method that combines mechanical iron cutting, SACE erosion and ultrasonic vibration. An analysis of its mechanism is shown in Figure 1. During the machining process, the iron knife serves as a tool electrode, and the lateral grooves on the milling cutter are beneficial to accelerating electrolyte flow renewal and timely removal of processing products (Figure 1a). The high temperature and high pressure generated by SACE spark discharge (Figure 1b) not only achieves material removal, but also changes the mechanical properties of quartz glass, making it
It softens and reduces the hardness and brittleness of the material, which is conducive to the transformation of the mechanical iron cutting process from brittle processing to plastic processing, so that the material can be better removed simultaneously under the action of discharge, thereby overall improving the shape and size accuracy and surface quality. and processing efficiency. Assisted ultrasonic longitudinal vibration can promote the influx of electrolyte into the tiny machining gap and timely update of the electrolyte, which is beneficial to increasing the generation rate of SACE bubbles and air films, reducing the thickness of the air film, making it easier for SACE to generate discharges, and ultrasonic vibration can also clean the tool electrode surface , which can prevent the adhesion and accumulation of processing products from affecting the SACE discharge effect (Figure 1c). The combined effect of the iron knife grooves, rotational motion and ultrasonic vibration on the electrolyte and processed products can avoid damage to the processed surface caused by excessive high temperature and high pressure of SACE discharge.
Figure 1 Analysis of the mechanism of ultrasonic vibration-assisted composite electrochemical discharge machining in iron cutting
2 Experimental system and research methods
2.1 Introduction to experimental system
Figure 2 shows the schematic diagram and physical diagram of the experimental system. The experimental system consists of pulse power supply, X//Y//ZX / Y / Z It consists of an axis motion platform, a high-speed rotating pneumatic spindle, an electrolyte circulation system, an open CNC system and an ultrasonic vibration module. The minimum pulse width of the pulse power supply is 1mus1 \mu \mathrm{~s} , the cathode is connected to the milling cutter tool electrode, and the anode is connected to the graphite auxiliary electrode; X、YX 、 Y The axis positioning accuracy is +-2mum,Z\pm 2 \mu \mathrm{~m}, Z The axis positioning accuracy is +-0.2 mum\pm 0.2 \mu \mathrm{~m} ;The pneumatic spindle is installed on ZZ On the shaft platform, the internal metal alloy mechanical structure can conduct pulse electricity to the tool electrode, thereby solving the interference problem of pulse electricity introduced by conventional electric spindles and the high-speed rotation dynamic balance problem caused by attaching brushes to the tool electrode; electrolyte The circulation system can regulate consistent immersion depth; the open CNC system consists of an industrial computer and a programmable multi-axis controller to control the machining process; the ultrasonic vibration module can output a vibration frequency of 80 kHz and a vibration amplitude range of 0∼5mum0 \sim 5 \mu \mathrm{~m} , the quartz glass workpiece is firmly bonded to the end of the ultrasonic transducer through a gasket, which facilitates the effective transmission of ultrasonic vibration to the workpiece.
2.2 Experimental research methods
Figure 3 is a schematic diagram of the experimental research process of ultrasonic vibration-assisted mechanical iron cutting and composite electrochemical discharge machining. The experiments include a given immersion depth, bubble/air film high-speed camera observation experiment, quartz glass adding
Figure 2 Schematic diagram of the experimental system and actual photos
work. The process parameters used in the experiment are shown in Table 1. Tool electrode adopts diameter 500 mum500 \mu \mathrm{~m} Diaogang micro milling cutter (Figure 3b), which has the characteristics of low resistivity, high melting point and high hardness; the workpiece adopts the size 30mmxx30 \mathrm{~mm} \times30mmxx4mm30 \mathrm{~mm} \times 4 \mathrm{~mm} of quartz glass. Figure 3a illustrates the method for setting the immersion depth. The end of the tool electrode is electrically contacted with a metal sheet of standard thickness to set the tool. The relative position between the end of the tool electrode and the surface of the workpiece is determined, and then it is lifted to the given immersion depth. position, inject electrolyte up to the end of the tool electrode to achieve a given immersion depth, and stabilize the immersion depth by maintaining a balance between the amount of electrolyte injected and outflowed during machining. Figure 3b shows the experimental situation of bubble/air film high-speed camera observation. When the tool electrode is only immersed in the electrolyte to a certain depth, the microscopic instantaneous bubbles at the end of the tool electrode are observed at different spindle speeds and different ultrasonic amplitudes. /// Air film formation process and morphological characteristics. The processing experiment shown in Figure 3c was to study the narrow groove processing effect of quartz glass by changing the auxiliary vibration amplitude, spindle speed and scanning speed (each set of experiments was repeated 2 times), and used an optical microscope, white light interference topography, and scanning The electron microscope evaluates the shape, dimensional accuracy and surface quality of the workpiece, and the material removal rate is obtained by calculating the volume of material removed and the processing time.
3 Experimental results and analysis
3.1 Bubbles /// Air film high-speed camera observation experiment
Step 1: Power Step 2: Mark Step 3: Note Step 4: Move
Figure 3 Schematic diagram of the experimental research process
The formation process and morphology of bubbles/air films during SACE processing have an important impact on the spark discharge process. Ultrasonic vibration-assisted mechanical milling combined SACE processing is a new process method under the joint action of ultrasonic vibration, mechanical milling and SACE. In the bubble/air film observation experiment, this paper designed four groups of experiments respectively: SACE, milling composite SACE, ultrasonic vibration-assisted SACE, and ultrasonic vibration-assisted iron cutting composite SACE.
Figure 4 shows the bubble/gas film formation process and morphology as the electrolysis time changes. From the horizontal time axis, it can be seen that 0mus0 \mu \mathrm{~s} When applying pulse voltage, 100 mus100 \mu \mathrm{~s} When the tool electrode side wall has generated electrolytic bubbles, 200 400 mus400 \mu \mathrm{~s} When the electrolysis bubbles gradually increase, 500 mus\mu \mathrm{s} When the insulating gas film is formed; longitudinal comparison of electrolytic bubbles in different process groups /// The formation process and shape of the air film can be seen. With the assistance of ultrasonic vibration, SACE processing generates
The air film is generally thin. This is because the movement of electrolytic microbubbles on the surface of the tool electrode is affected by the driving force of ultrasonic vibration and buoyancy at the same time, causing the bubbles to tend to adhere along the side wall of the tool electrode. ^([8]){ }^{[8]} . When the tool electrode is rotated at a high speed (iron cutting combined with SACE), the air film forms a "mushroom cloud" shape with bubbles accumulated on the upper part of the tool electrode and a dense air film at the end due to the combined action of centrifugal force and buoyancy, and ultrasonic vibration assists iron cutting. Cutting composite SACE can obtain a thinner air film at the end of the tool electrode.
Figure 4 Bubble/gas film formation process and morphology in different process groups as the electrolysis time changes
The statistical gas film thickness increasing with the electrolysis time is shown in Figure 5. It can be seen that the thickness of the air film increases with the increase of electrolysis time. Among them, the thickness of the air film generated by conventional SACE electrolysis is the largest, while the thickness of the end air film during ultrasonic vibration-assisted milling combined SACE electrolysis is the smallest, which is conducive to discharging SACE. Constrained to the tool electrode end, thereby reducing lateral discharge energy loss and overcutting machining errors.
Figure 5 The thickness of the gas film as the electrolysis time increases
The scanning speeds are 0.01、0.15、0.30mm//s0.01 、 0.15 、 0.30 \mathrm{~mm} / \mathrm{s} In the case of , the narrow grooves processed by a single pass (single scan) are shown in Figures 6 to 8 respectively. The statistics of the processed groove width and groove depth are shown in Figure 9.
According to the scanning speed shown in Figure 6 0.01mm//s0.01 \mathrm{~mm} / \mathrm{s} The result: The discharge high-temperature and high-pressure erosion in conventional SACE processing (no rotation of the milling cutter) causes a large number of micro-cracks and micro-pits to appear on the rough surface of the groove bottom (Figure 6a); ultrasonic vibration-assisted SACE processing can achieve a greater
At the same time, ultrasonic vibration promotes the renewal and cooling effect of the electrolyte, eliminating some thermal damage micro-cracks, but a large number of micro-pits still appear (Figure 6b); milling composite SACE can effectively eliminate micro-cracks and micro-pits The pit surface is damaged, but there are continuous meniscus cuts on the machined surface (Figure 6c); ultrasonic vibration-assisted milling composite SACE can process a smooth surface of the groove (Figure 6d).
Figure 7 Scanning speed 0.15mm//s0.15 \mathrm{~mm} / \mathrm{s} Narrow slots machined in a single pass
According to the scanning speed shown in Figure 8 0.30mm//s0.30 \mathrm{~mm} / \mathrm{s} The result when:
As the scanning speed further increases, the surface microcrack damage of conventional SACE processing and ultrasonic vibration-assisted SACE processing is further reduced (Figure 8a and Figure 8b); an obvious brittle removal effect appears during milling combined SACE processing, that is, a brittle removal effect is produced at the edge of the groove. Large-area chipping and overcutting (Fig. 8c); micro-edge chipping and overcutting also occurs during ultrasonic vibration-assisted milling composite SACE processing (Fig. 8d), which causes the machined surface to begin to deteriorate and produce tool marks.
According to the statistical results of groove depth and groove width shown in Figure 9, it can be seen that the groove depth and groove width processed by SACE and ultrasonic vibration-assisted SACE will decrease as the scanning speed increases. This is because the increase in scanning speed will cause the unit scan to decrease. Reduced discharge energy distributed over the area, resulting in lower material removal; Milling Composite SACE and Ultrasonic Vibration Assisted Milling Composite SACE Because of the cutting process, the groove depth and groove width are basically not affected by the scanning speed. However, it is worth noting that as the scanning speed increases, the brittle cutting effect becomes obvious, that is, brittle peeling occurs at the bottom of the groove and brittleness appears at the edge of the groove. collapse (Fig. 8), resulting in a slight increase in groove depth and overwidth. (d) Ultrasonic vibration-assisted iron cutting composite SACE
Figure 8 Scanning speed 0.30mm//s0.30 \mathrm{~mm} / \mathrm{s} Narrow slot machined in a single pass
Figure 9 Effect of scanning speed on groove width and groove depth
Electric discharge machining method, the typical width of processing on quartz glass is 500 mum500 \mu \mathrm{~m} Microfluidic narrow groove structure (Figure 10), using the process parameters shown in Table 1, the scanning speed is 0.15mm//s0.15 \mathrm{~mm} / \mathrm{s} , the cutting depth is 100 mum100 \mu \mathrm{~m} Under the condition of using a single trajectory and a single scan, the processing results show that this method can achieve narrow groove processing with no surface damage, smooth bottom surface and regular side walls, and the processing efficiency reaches 7.5 xx10^(6)mum^(3)//s7.5 \times 10^{6} \mu \mathrm{~m}^{3} / \mathrm{s} .
Figure 10 Typical narrow slot structure
4 Conclusion
In order to improve the processing effect of quartz glass, this paper proposes a new method of ultrasonic vibration-assisted mechanical iron cutting combined electrochemical discharge machining (SACE). The mechanism of the combined processing method is analyzed. SACE, milling combined SACE, and milling combined SACE are carried out respectively. Ultrasonic vibration-assisted SACE, ultrasonic vibration-assisted milling combined with SACE bubbles /// High-speed camera observation experiments and quartz glass narrow groove processing experiments during the air film formation process have led to the following conclusions:
(1) Due to the high-speed rotation of the milling cutter tool electrode and the buoyancy of the bubbles, an air film similar to the characteristics of a "mushroom cloud" is formed during the milling composite SACE and ultrasonic vibration-assisted iron cutting composite SACE, and the ultrasonic vibration-assisted milling composite SACE can A thinner gas film is obtained at the end of the tool electrode, which is beneficial to discharge breakdown and the discharge is more concentrated at the end of the tool electrode.
(2) Milling composite SACE and ultrasonic vibration-assisted iron cutting composite SACE can significantly improve SACE machining accuracy and surface quality; there is an optimal value for the scanning speed (feed rate). If it is lower than the optimal value, SACE thermal damage will be the main cause. If it is higher than the optimal value, the damage will be mainly removed by brittleness.
(3) Narrow groove processing has verified that ultrasonic vibration-assisted mechanical milling combined with SACE processing has significantly improved the quartz glass processing process. Through the analysis of the processing mechanism, it is believed that the process improvement is the transformation from brittle processing to plastic processing during the processing, and electrolysis in the tiny processing gap. The comprehensive effect of liquid renewal, increased generation rate of bubbles and air films, easier breakdown discharge of the air film at the end of the tool electrode, and ultrasonic cleaning of the tool electrode surface.
3.3 Typical narrow groove processing experiments
This article uses ultrasonic vibration-assisted mechanical iron cutting composite electrochemistry
(3) The Taylor bath abrasive flow method can not only effectively remove edge burrs of micro-hole arrays on complex cylindrical thin-walled parts, but also effectively reduce surface roughness values and improve surface quality. This paper preliminarily verifies the feasibility of this method from the aspects of principle methods, theoretical analysis and experimental research, laying a good foundation for subsequent research. However, due to the complex geometric structure of the rotary thin-walled parts, in-depth research in modeling analysis and experimental research is still required in the later stage to further optimize the process plan and processing equipment to complete efficient and high-quality burr removal.
References:
[1] Zeng Chun, Chen Sitao, Dou Haifeng. Techniques for deburring aviation precision parts in machining centers [J]. Modern Manufacturing Engineering, 2016(8):77-82.
[2] PRAMANIK A, BASAK AK, PRAKASH C, et al. Burr formation and its treatments -a review [J]. International Journal of Advanced Manufacturing Technology, 2020, 107(2)2189-2210.
[3] PANG XQ, ZENG YN, ZHANG J, et al. Analytical model and experimental verification of poisson burr formation in ductile metal machining [J]. Journal of Materials Processing Technology, 2021,290:116966.
[4] Li Huang, Xu Zhilong, Pi Jun. Simulation study of Poisson burrs and chip morphology in V-shaped groove micro cutting [J]. Mechanical Design and Manufacturing, 2020 (11): 175-178.
[5] Fan Yihang, Lu Zequn, Hao Zhaopeng. Research on factors affecting burr under high-speed cutting of nickel-based superalloy [J]. Mechanical Engineering and Technology, 2020, 9 (2): 89-99.
[6] Shi Ming, Qiu Yi, Cai Yaojie, et al. Mechanism and experimental study of ultrasonic strengthening of soft abrasive flow [J]. Chinese Journal of Mechanical Engineering, 2014, 50(7): 84-93.
[7] ZHAN SD,ZHAO Y H. Plasma-assisted electrochemical machining of microtools and microstructures [J]. International Journal of Machine Tools and Manufacture, 2020, 156:103596.
[8] Gu Shengyu, Zhang Dan, Zhu Yongcheng, et al. Design of ultrasonic-assisted abrasive jet horn [J]. Mechanical Design, 2019, 36(12): 21-27.
[9] Deng Qianfa, Zheng Tao, Yuan Julong, et al. Electrode morphology in abrasive flow polishing with dielectrophoretic effect [J]. Chinese Mechanical Engineering, 2020, 31(23): 2822-2828.
[10] Li Junye, Lu Hui, Su Ningning, et al. Research on quality control of abrasive flow precision machining nozzles using large eddy simulation Smagorinsky model [J]. Chinese Mechanical Engineering, 2020, 31(10): 1169-1174.
[11] ZHANG TQ,WANG ZX,YU TB,et al. Modeling and prediction of generated local surface profile for ultrasonic vibration -assisted polishing of optical glass BK7 [J]. Journal of Materials Processing Technology, 2021,289: 116933.
[12] Li Baoguo, Qiang Junhua. Deburring tools and methods suitable for machining centers [J]. Modern Manufacturing Engineering, 2014 (4): 57-59.
[13] BEOM JK, KIM YG,KIM KJ,et al. Study on the deburring of intersecting holes with abrasive flow machining [J]. Journal of the Korean Society for Precision Engineering, 2019, 36(2): 163-168. (Continued from page 58)
References:
[1] Gao Yang, Lei Qiang, Zhao Junwu, et al. Research status and development trends of micromechanical resonant accelerometers [J]. Intense Laser and Particle Beam, 2017, 29 (8): 080201-1-080201-14 .
[2] HE SQ,TONG H,LIU G. Spark assisted chemical engraving (SACE) mechanism on ZrO_(2)\mathrm{ZrO}_{2} ceramics by analyzing processed products [J]. Ceramics International, 2018,44(7):7967-7971.
[3] Tang Weidong, Kang Xiaoming. Research on the characteristics of micro-groove electrochemical discharge machining of side wall insulated electrodes [J]. Electrical Machining and Mold, 2018(4):35-39.
[4] LIU Y, ZHANG C, LI SS, et al. Experimental study of micro electrochemical discharge machining of ultra-clear glass with a rotating helical tool [J]. Processes, 2019,7 (4): 195.
[5] Zhou Hongwei, Gu Meilin, Wei Zhi, et al. Research on milling force of ultrasonic vibration-assisted micro-iron cutting of quartz glass [J]. Tool Technology, 2014, 48(5): 32-35.
[6] Xu Minggang, Wu Zhiwei, Zhang Qinjian, et al. Research on motion error model of spindle rotation-ultrasonic vibration-assisted electric discharge machining machine tool [J]. Journal of Applied Basic and Engineering Sciences, 2020, 28(5): 1248-1258.
[7] Ma Yucai, Yin Yingyue, Huo Jinxing, et al. Research on ultrasonic-assisted electrolytic grinding of GH625 micro holes [J]. Electrical Machining and Mold, 2021 (1): 43-49.
[8] HAN MS,MIN BK,LEE S J. Geometric improvement of electrochemical discharge micro -drilling using an ultrasonic -vibrated electrolyte [J]. Journal of Micromechanics and Microengineering, 2009, 19:065004.
[9] ELHAMI S,RAZFAR M R. Effect of ultrasonic vibration on the single discharge of electrochemical discharge machining [J]. Materials and Manufacturing Processes, 2018, 33:444-451.
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Postcode: 215011 Tel: 0512-67274541
Received date: 2022-01-07
Fund project: National Natural Science Foundation of China (51675302); independent research project of the State Key Laboratory of Tribology (SKLT2019B04)
Brief introduction of the first author: Tong Hao, male, born in 1978, associate researcher.
