The history of human understanding and use of drill bits can be traced back to prehistoric times. The stone drill used by the deaf person to "fire the wood" can be regarded as the most primitive drill bit. The twist drill (commonly known as the drill bit) widely used in modern industrial processing is a complex workpiece machining tool with a complex shape, which was born more than 100 years ago. Today, hundreds of millions of drill bits are consumed every year in the world. According to statistics, in the US automobile manufacturing industry, the proportion of drilling processes in mechanical processing accounts for about 50%; in the aircraft industry, the proportion of drilling processes is even higher. Despite the widespread use of drill bits, drilling is well known as one of the most complex machining methods. Because of this, people have been working on the improvement of the drill bit and the research of the drilling process. Based on the available English literature, this paper reviews the technical issues of the two-groove twist drill and the history, current status and development trends of the drilling research. 1. Main areas of research and technical issues In recent decades, research on drill bits and drilling has focused on the following five aspects besides the improvement of drill bit making materials: 1 Mathematical model of drill bit and geometric design research: including spiral groove, The establishment of the mathematical model of the flank, main and chisel edge, the optimization of the transverse section and the structural parameters of the drill tip, the calculation and control of the cutting angle (distribution), the static and dynamic analysis of the bit structure, the geometry of the drill tip and the cutting Research on the relationship between chip and chip performance. 2 Drill manufacturing method research: including the establishment and optimization of the relationship between the geometric parameters of the drill bit and the sharpening parameters of the flank, the evaluation of the manufacturing precision and the quality of the sharpening and the measurement and control of the manufacturing error, and the design of the cutting shape of the spiral groove processing tool Calculation, bit processing equipment, especially the development of CNC grinding machines and processing software. 3 Drilling process and drilling quality research: including various factors affecting the drilling process and analysis, modeling and monitoring of various physical phenomena (such as drilling force, cutting edge stress and temperature distribution measurement, modeling) And prediction); study of bit wear, damage mechanism and bit life; study of bit deformation, deflection, slippage during drilling and drilling tip; drilling process (eg vibration drilling, high speed drilling, deep hole) Drilling, stability of the drilling process, etc.) and drilling quality (pore position accuracy, straightness, surface roughness, cylindricity, diameter, orifice burrs, etc.). 4 drilling mechanism and various high performance drill bits (such as group drill, gun drill, dry cutting drill, micro hole, deep hole drill, long drill bit, indexable drill bit, synthetic material processing drill bit, woodworking drill bit, multi-spiral drill bit Etc.). 5 drilling process model verification and bit performance evaluation process automation, cutting conditions and bit shape selection database and knowledge base establishment. At present, the most dynamic research areas are mathematical models of drill bits, geometric design and manufacturing methods (equipment), drilling process modeling and drilling quality research. 2.1 Mathematical Model of the Drill The mathematical model of the drill bit is the basis for geometric design, manufacturing, cutting performance analysis and modeling of the drilling process. The first mathematical model of the drill bit was proposed by Galloway DF in 1957. He derived the parametric equation of the rake face of the straight edge drill bit, and gave the definition, calculation formula and measurement method of the front edge, the back angle and the bevel angle of the main edge, and proposed "the flank face of the drill bit as the bit in the sharpening process. A view of a part of a grinding cone formed after interaction with a grinding wheel. In the early 1970s, FujiiS et al. further studied the model proposed by Galloway DF, and proposed to use the cutting plane method to analyze the three-dimensional surface flank into a two-dimensional plane curve, and developed a computer-aided design of twist drill. program. In 1972, Armarego EJA and RotenberyA found that the flank face grinding method has four independent sharpening parameters, and generally only three geometric parameters of the drill tip are given, so the shape and edge of the flank face of the drill tip cannot be uniquely determined. Grinding parameters. To this end, they proposed using the flank clearance angle as a supplementary geometric parameter to obtain the only solution to the sharpening parameters. In 1979, TsaiWD and WuSM proved that the flank faces of tapered drills, Racon drills, auger drills and Bickford drill bits can be represented by quadrics, and a comprehensive mathematical model representing the geometry of the drill bit is proposed. Control the sharpening process. In 1983, Radhakrishnan L et al. proposed a mathematical model of the flank of a cross drill bit. They divided the flank into a first flank and a second flank: on the first flank, based on the Tsai model, an improved cone model was established; for the second flank, a second flank was established. A flat model. FugelsoMA proposed a mathematical model of the cylindrical tip. In 1985, FuhKH et al. established a mathematical model of the flank face of a drill with a quadric surface to design it into an ellipsoid, a hyperboloid, a cone, a cylinder, or any combination thereof. For a long time, the main edge of the twist drill has been designed as a straight line. In 1990, FugelsoMA found that because the main edge of the tapered twist drill was required to be straight, the back angle of the main edge near the core was too small, if the drill was rotated 5° to 10° around its own axis before sharpening. This will solve the problem, but the main edge will become slightly curved. In the same year, WangY regarded the main edge as a curve, and used the polynomial interpolation method to establish the geometric model of the front rake face of the drill bit. In 1991, LinC and CaoZ proposed a comprehensive mathematical model of twist drills suitable for straight and curved edges, using tapered, cylindrical and planar flank faces. In 1999, RenKC and NiJ proposed to use the binomial formula to represent the main edge curve of arbitrary shape. The new rake face of the drill bit adopts a new mathematical model, and the vector analysis method is used to establish the sharpening parameters and geometric parameters of the flank face of the quadratic surface. Relationship between. 2.2 Structural optimization of the drill bit Due to the unsatisfactory cutting performance of the widely used tapered twist drill, people have been working on improving its structure (parameter) and sharpening method, and have proposed more than 200 different drill bit shapes. To improve its cutting performance. Among them, ShiHM et al. proposed a method of controlling the distribution of the rake angle of the main blade by changing the main blade direction, and in 1990 developed a curved edge twist drill that made the rake angle of each point on the main edge of the drill bit reach the maximum possible value. In 1987, LeeSJ proposed a method to optimize the design of the drill bit under the condition of considering the deviation of the drill bit to eliminate the swinging phenomenon of the drill tip during the drilling process. In 1995, when Selvamhe SV and SujathaC studied the deformation of the twist drill, the geometry of the drill bit was optimized by the finite element method, and the optimized structural parameter value (bit diameter 25 mm) obtained by minimizing the deformation of the drill bit was: helix angle 39.776 °, The transverse blade angle Ψ=54°～80°, the front angle is 120°. In 1997, ChenWC proposed a special truncated thick core twist drill with sufficient torsional stiffness and reasonable distribution of the main and chisel rake angles. In 2005, in order to ensure the optimization of the drillability of the drill bit, Paul A et al. proposed a new drill tip model based on the sharpening parameters, and used it to optimize the tapered drill tip, the Racon drill tip and the helicoid drill tip. Its cutting force is minimized. 2.3 Calculation of the spiral groove truncation and the cutting of the machining tool In 1975, DibnerLG proposed a method to simplify the calculation of the grinding of the spiral grooved grinding wheel, improve the precision of the groove machining and completely eliminate the influence of the diameter change of the grinding wheel. In 1990, EhmannKF proposed a method for cutting the helical groove machining tool based on differential geometry and kinematics. From 1998 to 2003, KangDC and Armarego EJA performed "positive problems" and "anti-problems" on spiral groove machining ("tool truncation by groove truncation" and "groove truncation by tool truncation") In this paper, a computer-aided geometric analysis method for the design and manufacture of spiral groove spiral groove drilling is proposed. 2.4 Research on Group Drills and Micro Drills In 1982, ShenJ et al. established the first mathematical model of group drills. Using this model, one can repeatedly grind a group of drills. In 1984, ChenL and WuSM studied nine typical group drills and improved the mathematical model of group drills, which provided the possibility of computer-aided design of group drills. In 1985, HsiaoC and WuSM proposed a specific method for assisting the optimization design of group drills by computer. In 1987, FuhKH proposed a method for designing and analyzing group drills using a comprehensive quadric surface model and a finite element method. LiangEJ proposed a group-drilling CAD/CAM integrated system based on knowledge base technology. In 1991, LiuTI designed and optimized a group drill for machining machine shaft oiling holes using a two-stage strategy. In 1994, HuangHT et al. derived the formulas for the working angle and the pre-angle of the working-edge cutting edge, and proposed an accurate geometric model of the group drilling considering the transition between the inner and the circular edges. In 2001, WangGC et al. applied a tilted solid block method to establish a new mathematical model of the group drill, which solved the problem of the uncertainty of the chisel edge geometry existing in the existing model and ensured the machinability of the designed group drill. Beginning in 1992, a research team consisting of LinC, KangSK, EhmannKF, and ChyanHC conducted a systematic study of micro drill bits. In 1992, they established a mathematical model of the planar micro-drill tip and proposed the corresponding sharpening method. In 1993, they proposed a mathematical model and a sharpening method for the micro-drilled tip of the spiral surface, and found that the micro-drilled tip of the spiral surface is superior to the commonly used planar micro-drill tip in terms of geometry and cutting performance. In 1997, they pointed out that the spiral micro-drill tip has two advantages compared to the planar micro-drill tip: 1 allows for a larger feed rate under the same working cutting angle distribution; 2 sharpening method It is simpler and less susceptible to sharpening errors. In 2002, they produced a series of drill tips for curved micro-holes with a curved blade. 2.4 Research on Group Drills and Micro Drills In 1982, ShenJ et al. established the first mathematical model of group drills. Using this model, one can repeatedly grind a group of drills. In 1984, ChenL and WuSM studied nine typical group drills and improved the mathematical model of group drills, which provided the possibility of computer-aided design of group drills. In 1985, HsiaoC and WuSM proposed a specific method for assisting the optimization design of group drills by computer. In 1987, FuhKH proposed a method for designing and analyzing group drills using a comprehensive quadric surface model and a finite element method. LiangEJ proposed a group-drilling CAD/CAM integrated system based on knowledge base technology. In 1991, LiuTI designed and optimized a group drill for machining machine shaft oiling holes using a two-stage strategy. In 1994, HuangHT et al. derived the formulas for the working angle and the pre-angle of the working-edge cutting edge, and proposed an accurate geometric model of the group drilling considering the transition between the inner and the circular edges. In 2001, WangGC et al. applied a tilted solid block method to establish a new mathematical model of the group drill, which solved the problem of the uncertainty of the chisel edge geometry existing in the existing model and ensured the machinability of the designed group drill. Beginning in 1992, a research team consisting of LinC, KangSK, EhmannKF, and ChyanHC conducted a systematic study of micro drill bits. In 1992, they established a mathematical model of the planar micro-drill tip and proposed the corresponding sharpening method. In 1993, they proposed a mathematical model and a sharpening method for the micro-drilled tip of the spiral surface, and found that the micro-drilled tip of the spiral surface is superior to the commonly used planar micro-drill tip in terms of geometry and cutting performance. In 1997, they pointed out that the spiral micro-drill tip has two advantages compared to the planar micro-drill tip: 1 allows for a larger feed rate under the same working cutting angle distribution; 2 sharpening method It is simpler and less susceptible to sharpening errors. In 2002, they produced a series of drill tips for curved micro-holes with a curved blade. 3. Research on Drilling Force Modeling 3.1 History of Drilling Force Modeling Over the past few decades, many methods for predicting drilling forces have been reported, most of which are used for standard twist drills. Due to the lack of advanced computer and measuring equipment, early research focused on the establishment of simple empirical torque and axial force models. The model parameters are the geometric parameters of the drill bit (such as drill diameter) and the amount of cutting. The modeling method is through a large number of The cutting experiment uses statistical methods to fit the empirical formula of the drilling force. The drilling force model established by the analytical method gradually emerges as people become more aware of the cutting process. In 1955, Oxford used a micrograph to record the chip deformation process of the main and chisel edges of the drill bit. It was found through experiments that there are three main cutting areas on the drill tip during the drilling process, namely the main cutting zone. The cutting edge of the cutting edge (the chisel edge) and the scribing area near the core. Later, ShawMC and Oxford CJJr demonstrated the importance of the chisel edge in drilling because it produced 50% to 60% of the axial force. In 1966, CookNH proposed a method for deriving the formula of drilling force using semi-analytical methods. ShawMC (1962, 1984) proposed a chip deformation model of the main edge of the drill bit based on an in-depth study of the chip deformation mechanism. Williams AR (1974) proposed a cutting force model for the main cutting edge of a bit based on a two-point cutting model of a single point tool and determined the diameter of the bit marking zone. Armarego EJA (1972) applied the bevel cutting theory and proposed a prediction model for the cutting force of the plane drill tip. Wiriyacosols (1979) et al. based on the thin shear zone (shear plane) theory of chip deformation, the main and chisel edges of the drill are considered as a series of unit bevel or right angle cutting tools associated with cutting conditions, by accumulating The cutting force of these unit tools is used to predict the drilling force, ie the unit tool linear synthesis method. Based on the theory of shear planes, Oxley CJJr (1959, 1962), Armarego EJA (1972, 1979) and WastonAR (1985) respectively established different drilling force models; Stepenson DA (1988, 1989) proposed calculations. Mathematical method of drilling force. 3.2 Development of drilling force modeling The research on drilling force modeling is deepening with the development of various new drill bits and drilling processes. WuSM et al. have done a lot of work in establishing a group drilling force model. Among them, LeeSW (1986) and FuhKH (1987) based on the working cutting angle, using the bevel cutting model for the main cutting edge, and using the right-angle cutting model for the second cutting edge, the cutting force model of the group drill is established; HuangHT (1992) et al. proposed a method for predicting the axial force and torque of a group drill using a mechanical model of a conventional twist drill. Armarego EJA and ZhaoH (1996) established a thin core core standard twist drill, thin core multi-groove drill and arc center edge twist drill cutting force prediction model. Bhatnagar N (2004) and others studied the unintended damage of the workpiece when drilling anisotropic fiber-reinforced composites with four different drill tips, and established a model for drilling axial force and torque. SahuSK (2004) et al. proposed a cutting force prediction model with a chip breaker cone taper drill, which is calibrated with drill bits with four different chip breakers and is suitable for drill bits with any chip breaker shape. ElhachimiM (1999) developed a cutting force model for high-speed cutting bits using a right-angle and bevel cutting model. The test was performed at a speed of 4000 r/min to 18000 r/min and a feed rate of 0.12 mm/r to 0.36 mm/r. The results are consistent with the model prediction values. Wang LP (1998) and others proposed to obtain the dynamic mechanical properties of the entire drill bit by vibration analysis of the unit cutters that make up the main and chisel edges, and based on this, established a prediction model of dynamic axial force and torque during the vibration drilling process. As the research progressed, the researchers found that the mechanical models that were established in the past could not be applied to the new drill type due to structural differences. To this end, Stepenson DA (1992) used a unit tool bevel cutting force model calibrated with a large number of turning experiments to establish the main blade torque and shaft for drilling gray cast iron with any bladed carbide or inlaid carbide drill. Force and radial force prediction models. LinGC (1982) and Watson AR (1985) pointed out that the underestimation of drilling torque and axial force is due to chip evacuation. This discovery eventually led to the generation of unit tool nonlinear synthesis method, and also used analytical methods to build complex The cutting force model of the blade bit is made possible. WangJL (1994) studied the chip evacuation during the cutting process, and applied the unit tool nonlinear synthesis method to establish the cutting force model of any blade bit based on the empirical unit tool bevel cutting force model. In addition to the basic geometry of the drill bit, many factors in the drilling process can affect the drilling force. In 1996, ChandrasekharanV et al. considered the manufacture of the drill bit and the sharpening error such as the contour of the two main edges, the radius error, the axial deflection, etc., and established a complete three-dimensional cutting force model of the tapered bit, and then It expands to predict the cutting force of any shape drill bit (eg group drill). SriramR established a model for predicting the radial force of drilling while considering the influence of drill sharpening and installation error on the drilling force. In 2001, GongYP and EhmannK established a micro-hole drill axial force, torque and radial that take into account the geometry of the drill bit, sharpening and mounting errors, and the influence of bit deflection on the dynamic cutting thickness and cutting area of ​​the main and chisel edges. Force model. 3.2 Development of drilling force modeling The research on drilling force modeling is deepening with the development of various new drill bits and drilling processes. WuSM et al. have done a lot of work in establishing a group drilling force model. Among them, LeeSW (1986) and FuhKH (1987) based on the working cutting angle, using the bevel cutting model for the main cutting edge, and using the right-angle cutting model for the second cutting edge, the cutting force model of the group drill is established; HuangHT (1992) et al. proposed a method for predicting the axial force and torque of a group drill using a mechanical model of a conventional twist drill. Armarego EJA and ZhaoH (1996) established a thin core core standard twist drill, thin core multi-groove drill and arc center edge twist drill cutting force prediction model. Bhatnagar N (2004) and others studied the unintended damage of the workpiece when drilling anisotropic fiber-reinforced composites with four different drill tips, and established a model for drilling axial force and torque. SahuSK (2004) et al. proposed a cutting force prediction model with a chip breaker cone taper drill, which is calibrated with drill bits with four different chip breakers and is suitable for drill bits with any chip breaker shape. ElhachimiM (1999) developed a cutting force model for high-speed cutting bits using a right-angle and bevel cutting model. The test was performed at a speed of 4000 r/min to 18000 r/min and a feed rate of 0.12 mm/r to 0.36 mm/r. The results are consistent with the model prediction values. Wang LP (1998) and others proposed to obtain the dynamic mechanical properties of the entire drill bit by vibration analysis of the unit cutters that make up the main and chisel edges, and based on this, established a prediction model of dynamic axial force and torque during the vibration drilling process. As the research progressed, the researchers found that the mechanical models that were established in the past could not be applied to the new drill type due to structural differences. To this end, Stepenson DA (1992) used a unit tool bevel cutting force model calibrated with a large number of turning experiments to establish the main blade torque and shaft for drilling gray cast iron with any bladed carbide or inlaid carbide drill. Force and radial force prediction models. LinGC (1982) and Watson AR (1985) pointed out that the underestimation of drilling torque and axial force is due to chip evacuation. This discovery eventually led to the generation of unit tool nonlinear synthesis method, and also used analytical methods to build complex The cutting force model of the blade bit is made possible. WangJL (1994) studied the chip evacuation during the cutting process, and applied the unit tool nonlinear synthesis method to establish the cutting force model of any blade bit based on the empirical unit tool bevel cutting force model. In addition to the basic geometry of the drill bit, many factors in the drilling process can affect the drilling force. In 1996, ChandrasekharanV et al. considered the manufacture of the drill bit and the sharpening error such as the contour of the two main edges, the radius error, the axial deflection, etc., and established a complete three-dimensional cutting force model of the tapered bit, and then It expands to predict the cutting force of any shape drill bit (eg group drill). SriramR established a model for predicting the radial force of drilling while considering the influence of drill sharpening and installation error on the drilling force. In 2001, GongYP and EhmannK established a micro-hole drill axial force, torque and radial that take into account the geometry of the drill bit, sharpening and mounting errors, and the influence of bit deflection on the dynamic cutting thickness and cutting area of ​​the main and chisel edges. Force model. 3.2 Development of drilling force modeling The research on drilling force modeling is deepening with the development of various new drill bits and drilling processes. WuSM et al. have done a lot of work in establishing a group drilling force model. Among them, LeeSW (1986) and FuhKH (1987) based on the working cutting angle, using the bevel cutting model for the main cutting edge, and using the right-angle cutting model for the second cutting edge, the cutting force model of the group drill is established; HuangHT (1992) et al. proposed a method for predicting the axial force and torque of a group drill using a mechanical model of a conventional twist drill. Armarego EJA and ZhaoH (1996) established a thin core core standard twist drill, thin core multi-groove drill and arc center edge twist drill cutting force prediction model. Bhatnagar N (2004) and others studied the unintended damage of the workpiece when drilling anisotropic fiber-reinforced composites with four different drill tips, and established a model for drilling axial force and torque. SahuSK (2004) et al. proposed a cutting force prediction model with a chip breaker cone taper drill, which is calibrated with drill bits with four different chip breakers and is suitable for drill bits with any chip breaker shape. ElhachimiM (1999) developed a cutting force model for high-speed cutting bits using a right-angle and bevel cutting model. The test was performed at a speed of 4000 r/min to 18000 r/min and a feed rate of 0.12 mm/r to 0.36 mm/r. The results are consistent with the model prediction values. Wang LP (1998) and others proposed to obtain the dynamic mechanical properties of the entire drill bit by vibration analysis of the unit cutters that make up the main and chisel edges, and based on this, established a prediction model of dynamic axial force and torque during the vibration drilling process. As the research progressed, the researchers found that the mechanical models that were established in the past could not be applied to the new drill type due to structural differences. To this end, Stepenson DA (1992) used a unit tool bevel cutting force model calibrated with a large number of turning experiments to establish the main blade torque and shaft for drilling gray cast iron with any bladed carbide or inlaid carbide drill. Force and radial force prediction models. LinGC (1982) and Watson AR (1985) pointed out that the underestimation of drilling torque and axial force is due to chip evacuation. This discovery eventually led to the generation of unit tool nonlinear synthesis method, and also used analytical methods to build complex The cutting force model of the blade bit is made possible. WangJL (1994) studied the chip evacuation during the cutting process, and applied the unit tool nonlinear synthesis method to establish the cutting force model of any blade bit based on the empirical unit tool bevel cutting force model. In addition to the basic geometry of the drill bit, many factors in the drilling process can affect the drilling force. In 1996, ChandrasekharanV et al. considered the manufacture of the drill bit and the sharpening error such as the contour of the two main edges, the radius error, the axial deflection, etc., and established a complete three-dimensional cutting force model of the tapered bit, and then It expands to predict the cutting force of any shape drill bit (eg group drill). SriramR established a model for predicting the radial force of drilling while considering the influence of drill sharpening and installation error on the drilling force. In 2001, GongYP and EhmannK established a micro-hole drill axial force, torque and radial that take into account the geometry of the drill bit, sharpening and mounting errors, and the influence of bit deflection on the dynamic cutting thickness and cutting area of ​​the main and chisel edges. Force model. 3.2 Development of drilling force modeling The research on drilling force modeling is deepening with the development of various new drill bits and drilling processes. WuSM et al. have done a lot of work in establishing a group drilling force model. Among them, LeeSW (1986) and FuhKH (1987) based on the working cutting angle, using the bevel cutting model for the main cutting edge, and using the right-angle cutting model for the second cutting edge, the cutting force model of the group drill is established; HuangHT (1992) et al. proposed a method for predicting the axial force and torque of a group drill using a mechanical model of a conventional twist drill. Armarego EJA and ZhaoH (1996) established a thin core core standard twist drill, thin core multi-groove drill and arc center edge twist drill cutting force prediction model. Bhatnagar N (2004) and others studied the unintended damage of the workpiece when drilling anisotropic fiber-reinforced composites with four different drill tips, and established a model for drilling axial force and torque. SahuSK (2004) et al. proposed a cutting force prediction model with a chip breaker cone taper drill, which is calibrated with drill bits with four different chip breakers and is suitable for drill bits with any chip breaker shape. ElhachimiM (1999) developed a cutting force model for high-speed cutting bits using a right-angle and bevel cutting model. The test was performed at a speed of 4000 r/min to 18000 r/min and a feed rate of 0.12 mm/r to 0.36 mm/r. The results are consistent with the model prediction values. Wang LP (1998) and others proposed to obtain the dynamic mechanical properties of the entire drill bit by vibration analysis of the unit cutters that make up the main and chisel edges, and based on this, established a prediction model of dynamic axial force and torque during the vibration drilling process. As the research progressed, the researchers found that the mechanical models that were established in the past could not be applied to the new drill type due to structural differences. To this end, Stepenson DA (1992) used a unit tool bevel cutting force model calibrated with a large number of turning experiments to establish the main blade torque and shaft for drilling gray cast iron with any bladed carbide or inlaid carbide drill. Force and radial force prediction models. LinGC (1982) and Watson AR (1985) pointed out that the underestimation of drilling torque and axial force is due to chip evacuation. This discovery eventually led to the generation of unit tool nonlinear synthesis method, and also used analytical methods to build complex The cutting force model of the blade bit is made possible. WangJL (1994) studied the chip evacuation during the cutting process, and applied the unit tool nonlinear synthesis method to establish the cutting force model of any blade bit based on the empirical unit tool bevel cutting force model. In addition to the basic geometry of the drill bit, many factors in the drilling process can affect the drilling force. In 1996, ChandrasekharanV et al. considered the manufacture of the drill bit and the sharpening error such as the contour of the two main edges, the radius error, the axial deflection, etc., and established a complete three-dimensional cutting force model of the tapered bit, and then It expands to predict the cutting force of any shape drill bit (eg group drill). SriramR established a model for predicting the radial force of drilling while considering the influence of drill sharpening and installation error on the drilling force. In 2001, GongYP and EhmannK established a micro-hole drill axial force, torque and radial that take into account the geometry of the drill bit, sharpening and mounting errors, and the influence of bit deflection on the dynamic cutting thickness and cutting area of ​​the main and chisel edges. Force model. 3.3 Drilling force modeling method With the advancement of technology, the method of establishing a predictive drilling force model is also developing. In 1997, IslamAU and LiuMC proposed a method for predicting the axial force and torque of group drills using artificial neural networks. The training data was extracted directly from the literature. In 2001, KawajiS et al. also proposed a method for estimating and controlling the axial force of drilling using a neural network model: 1 constructing an axial force neural network model offline; 2 based on the model, training through online least squares method, Establish a simulated neural controller; 3 Apply the trained neural controller to the drilling system to obtain axial force. In 1999, ChenY applied the finite element method to analyze the bevel cutting process of a tool with a cutting edge radius, and established a drilling force model of any blade bit calibrated with a finite number of arbitrary edge drills. In 2004, Strenkowski JS et al. used an Euler finite element model to simulate the cutting force of a unit tool that forms a cutting edge, and proposed a method for predicting the axial force and torque of a twist drill using finite element techniques. In 2002, YangJA et al. proposed a drilling process simulation model implemented with the I-DEASCAE software system to predict dynamic drilling forces. 4. Research trends (1) Drilling process modeling has become a research hotspot affecting various factors of the drilling process, including bit geometry, manufacturing and installation errors, physical properties (static and dynamic characteristics), cutting conditions, ambient temperature, workpiece size And materials, etc. will gradually be included in the scope of modeling research, drilling types, cutting conditions and drilling process related drilling power, drilling temperature, bit wear and life, chip deformation and discharge, drilling quality, drilling Efficiency and drilling costs will be the object of modeling the drilling process, the modeling method will be more diversified, the accuracy of the model prediction will be further improved, the drilling model will not only be used for simulation and forecasting, but also more Used to guide the optimization and monitoring of bit design, manufacturing and drilling processes. (2) The geometric design and manufacturing method of the drill bit will remain the focus of research. New drill types suitable for processing various materials and processing conditions will continue to emerge. Research on micro-drills for micro-machine manufacturing and printed circuit board manufacturing will move toward In-depth. The research on the manufacturing method of the drill bit will be developed in the direction of the integrated manufacturing system. The automatic sharpening problem of the drill bit, especially the group drill, will be solved, and the integration, automation and intelligence of design and manufacture will be paid special attention. (3) The research on drilling mechanism will be gradually paid more attention to the research on the drilling mechanism and the drilling mechanism research. The research on drilling mechanism is the bottleneck restricting the research of drill bit and drilling technology; drilling is the most complicated One of the cutting processes, and basic research on the cutting principle will inevitably shift from relatively simple turning machining research to more complex drilling machining research.
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