• 제어로봇시스템학회:학술대회논문집
• /
• 1997.10a
• /
• pp.1407-1410
• /
• 1997

Advanced sensor design and filtering technology have been studied to obtain information for condition monitoring and diagnostics inmachining processes. To develope and economic monitoring system in end milling processes, indirect and reliable type of cutting force estimators were required. In this paper, an estimation method of cutting forces during end milling processes was studied through the measurement of current signals obtained from spindle and feeddrive motors. Cutting force and torque models were derived from the cutting geometry in down milling processes. Relationships between motor currents and cutting forces were also developed in the form of AC and DC components from the developed force models. The validity of the cutting force estimator was confirmed by the experiments under various cutting conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.10a
• /
• pp.31-35
• /
• 2001

Three dimensional dynamic cutting can be postulated as an equivalent orthogonal dynamic cutting through the plane containing both the cutting vector and the chip flow velocity vector in cutting process. An analytical expression of dynamic cutting force is obtained from the cutting parameters determined by the static three dimensional cutting experiments. Particular attention is paid to the energy supplied to the vibration of the tool behind the vertical vibration and the direction. The phase lag of the horizontal vibration of the tool behind the vertical vibration and the direction angel of the fluctuating cutting force must be regarded in point of stability limits. Chatter vibration can effectively be suppressed by enlarging the dynamic rigidity of the cutting system in the vertical cutting force direction. A good agreement is found between the stability limits predicted by theory and the critical width of cut determined by experiments.

• International Journal of Precision Engineering and Manufacturing
• /
• v.1 no.1
• /
• pp.15-21
• /
• 2000

This study presents a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool. The edge of a single point tool including a circular nose is modified to an equivalent straight edge, thereby reducing the 3-D cutting with a single point tool to the equivalent of oblique cutting. Then, by transforming the conventional coordinate systems and using the measurements of three cutting force components, the force components on the rake face and shear plane of the equivalent oblique cutting system can be obtained. As a result, the chip-tool friction and shear characteristics of 3-D cutting with a single point tool can be assessed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.1042-1047
• /
• 2001

A mechanistic model is developed to predict the thrust force and cutting torque of drilling process including wear. A mechanistic oblique cutting force model is used to develop the drilling force model. The cutting lips are divided into small elements and elemental forces are calculated by multiplying the specific cutting pressure with the elemental chip area. The specific cutting pressure is a function of chip thickness, cutting velocity, rake angle and wear. The total forces are then computed by summing the elemental forces. Measured cutting forces are in good agreement with the simulated cutting forces.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.04a
• /
• pp.454-459
• /
• 2003

The paper will present chip formation mechanism and surface integrity generation mechanism based on the systematical experimental tests. Some basic factors such as the end milling cutter tooth number, cutting forces, cutting temperature, cutting vibration, the chip status, the surface roughness, the hardness distribution and the metallographic texture of the machined surface layer are involved. the chip formation mechanism is typical thermal plastic shear localization at high cutting speed with less number og shear ribbons and bigger shear angle than at low speed, which means lack of chip deformation. The high cutting speed with much more cutting teeth will be beneficial to the reduction of cutting forces, enlarge machining stability region, depression of temperature increment, auti-fatigability as well as surface roughness. The burrs always exists both at low cutting speed and at high cutting speed. So the deburr process should be arranged for milling titanium alloy in any case.

• KSTLE International Journal
• /
• v.3 no.1
• /
• pp.17-22
• /
• 2002

Roughing of tool steel in its hardened state represents a real challenge in the die and meld industry and process improvement depends on research of tool material, coating technique, and lubrication. However, roughing of hardened steels generates extreme heat and without coolant flooding, tool material cannot withstand the high temperature without choosing the right tools with proper coating. This research conducted milling tests using coated ball end mills to study effects of cutting conditions and geometric parameters of ball end mills on the machinability of hardened tool steel. KP4 steel and STD 11 heat treated steels were used in the dry cutting as the workpiece and TiAIN coated ball end mills with side relief angle of 12$^{\circ}$ was utilized in the cutting tests. Cutting forces, tool wear, and surface roughness were measured in the cutting tests. Results from the experiments showed that 85 m/min of cutting speed and 0.32 mm/rev of feed rate were optimum conditions for better surface finish during rough cutting and 0.26mm/rev with the same cutting speed are optimum conditions in the finish cutting.

• Geomechanics and Engineering
• /
• v.20 no.5
• /
• pp.421-432
• /
• 2020

Cutting of rocks is very common encountered in tunneling and mining during underground excavations. A deep understanding of rock-tool interaction can promote industrial applications significantly. In this paper, a distinct element method based approach, PFC^3D, is adopted to simulate the rock cutting under different operation conditions (cutting velocity, depth of cut and rake angle) and with various tool geometries (tip angle, tip wear and tip shape). Simulation results showed that the cutting force and accumulated number of cracks increase with increasing cutting velocity, cut depth, tip angle and pick abrasion. The number of cracks and cutting force decrease with increasing negative rake angle and increase with increasing positive rake angle. The numerical approach can offer a better insight into the rock-tool interaction during the rock cutting process. The proposed numerical method can be used to assess the rock cuttability, to estimate the cutting performance, and to design the cutter head.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.2
• /
• pp.105-112
• /
• 2005

The guillotined cutting process for the pipe was studied in this paper. Until now guillotining mechanism can not be practically applied in the industries because of the deformation of sheared section around cutting area, the coarse sheared surface, and the burs. To find optimum shapes of blade, several types of blade were experimentally studied. The cutting force normal to the axial direction of the pipe was compared with the theoretical result based on the cutting energy. The experimental maximum cutting forces were very good agreement with the theoretical results. It also discussed that the design parameters of guillotining system such as the blade shape and the clearance between the blade and the die made effects to the deformation of the cutting cross section area. The results show that the guillotining method can be applicable to the pipe cutting system by optimizing the blade shape and the clearance between the blade and the die of the guillotined cutting system with respect to the sheared pipe material.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.6
• /
• pp.190-196
• /
• 1999

In this study, a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool has been established. The edge of a single point tool including circular nose is modified to the equivalent straight edge, then 3-D cutting with a single point tool is reduced to equivalent oblique cutting. Transforming the conventional coordinate systems and using the measured three component of cutting forces, force components on the rake face and the shear plane of the equivalent oblique cutting system can be obtained. And it can be possible to assess the chip-tool friction and shear characteristics in 3-D cutting with a single point tool.

• Journal of Surface Science and Engineering
• /
• v.34 no.4
• /
• pp.337-341
• /
• 2001

TiN coating of high speed end mill is recently generalized. The study of coating layer using ion plating is mainly about the coating method and the why of the longer life of coated tools. In CNC machning process, metal cutting isn't carry out until the tools including the end-mill and so on are fractured. Namely, it is difficult precision processing when the cutting force of the cutting tool is near the limit the fracture cutting force. So, the estimate of the life by wear and fracture is important. Therefore, this study is about the method to estimate the capacity of the coating layer in relation to the tendency of cutting force and the influence of the cutting capacity of coated end-mill by the condition N2, Ar, temperature. The cutting length is in inverse proportion to the cutting force ratio. So, the life of the TiN coated end mill can be predicated by the ratio of the increase of the cutting force.