• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.03a
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• pp.25-29
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• 1998

One of the crucial problems that must be solved in a computerised unmanned machining environments requires the development of algorithm in order to predict the reliable cutting conditions on surface roughness. This paper is to develop the mathematical models for choosing the suitable cutting conditions and assist a comprehensive understanding of its machinability properties for cutting process by Ball End Mill. The mathematical equations developed to predict the surface results. It has been found that theoretical results obtained from the empirical equations agree with the experimental results of surface roughness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.329-330
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• 2007

• Journal of the Korean Society for Precision Engineering
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• v.16 no.2 s.95
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• pp.123-129
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• 1999

Ball-end milling process is widely used in the die and mold manufacturing because of suitable one for the machining of free-form surface. During the process, the pencil cutting operation can be adopted before finish cut to eliminate overload in uncut area caused by large diameter of ball-end mill. The ball-end mill cutter for the pencil cutting is easily deflected by cutting force due to the long and thin shape, and the tool deflection in pencil cutting is one of the main reason of the machining errors in a free-form surface. The purpose of this study is to find the characteristics of deflected cutter trajectory by constructing measurement system with eddy-current sensor. It was found that the severe reduction of corner radius produced the overcut during the plane cutting. Up cutting method induced the overcut both plane and slope cutting, but down cutting one induced the undercut. From the experiments, down cutting with upward cutting path can generate the small undercut surface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.765-768
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• 2005

Ball end milling is widely used in machining free surfaces. It is important to predict machining forces in this machining. In this study, cutting forces are predicted for different machining conditions in ball end mill contouring machining. These cutting forces influence tool deflection. In this study tool deflection is calculated for various cutting conditions. The model developed in this study can be used to predict machining accuracy in contouring machining.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.125-128
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• 1997

They use a Ball End-mill in order to manufacturing sculptured surface when making metal mold, mold, cars and aircraft. In the work of a Ball End-mill case, customers do not often satisfied with manufacturing precision. Eventually, they have to re-work for the purpose of meeting manufacturing precision. There are resulted in lots of loss, whereby, in terms of both time and costs. The reasons of tolerance reducing manufacturing precision are thermal strain, the surface is damaged because of increasing cutting force and tool wear, tool deflection etc.. We focus on, however, manufacturing precision caused due to deflection of tool.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.347-350
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• 2003

Many researches on the prediction of cutting forces of ball-end mil is have been achieved since before several decades ago. These kinds of researches have been concentrated on the study on how to make the prediction equations for the cutting forces based on 2-D cutting experimentation. The results of them were really good and impressive. But it's not proper to practical uses for industrial fields, because if sculptured surface were to be machined, then it would be very difficult to understand the complicated kinematical interaction between the sculptured surface and the flutes of a ball-end mill. So, we propose the method for solving these kind of problems using existed commercial CAD/CAM software; Unigraphics. Furthermore, the modification of tool path which is done off line is offered to increase the precision of cutting.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.119-126
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• 2007

Generally, the machinability of materials that have a good mechanical properties is poor. The material having a high strength, high toughness in high temperature and wear resistance, it is difficult to remove a chip from workpiece. STD11 and NAK80 are kinds of these materials and these materials can be used in many industrial fields. But it is limited in use because of high cost and poor machinability. In this experimental study, the cutting of STD11 and NAK80 were used to decide the machinability and the tool shape of CBN ball end mill. From the results, the CBN ball end mill is verified that the estimated cutting edge shape of rake angle 30 degree has consistent effect on the tool wear and cutting force.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.52-57
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• 2000

STD11 is one of difficult-to-cut materials and its cutting characteristic data is not built enough. A bad cutting condition of it leads to low productivity of die and mould, so it is necessary to evaluate the machining characteristics of STD11. In this paper, the relations of the geometry of ball-end mill and mechanics of machining with it are studied. The helix angle of ball-end mill varies according to a location of elemental cutting edge in the cutting process are difficult to calculate accurately. To calculate instantaneous cutting forces, it is supposed that the tangential, radial and axial cutting force coefficients are functions of elemental cutting edge location. Elemental cutting forces in the x,y and z direction are calculated by coordinate transformation. The total cutting forces are calculated by integrating the elemental cutting forces of engaged cutting edge elements. This model is verified by slot and side cutting experiments of STD11 workpiece which was heat-treated to HRC45.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.3
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• pp.433-442
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• 1989

Owing to the development of CNC machine tools and automatic programing software, the milling process with ball-end mill has become the most widely used process where three-dimensional precision machining is important. In this study, the ball-end milling process has been analyzed and a cutting force model has been developed to predict the cutting force acting on the ball-end mill on given machining conditions. The development of the model is based on the analysis of geometry of a ball-end mill an the oblique cutting process. The cutting edges of ball-end mills are considered as a series of infinitesimal elements and the geometry of the cutting edge element each cutting edge element is straight. The oblique cutting process in the small cutting edge element has been analyzed as orthogonal cutting process in the plane containing the cutting velocity vector and chip-flow vector. Hence, with the orthogonal cutting data obtained from orthogonal turning test, the cutting forces can be predicted through the model. The predicted cutting forces has shown a fairly good agreement with the test results in various plane cutting conditions.

• Journal of Computational Design and Engineering
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• v.2 no.4
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• pp.233-247
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• 2015

In this paper, the cutting force calculation of ball-end mill processing was modeled mathematically. All derivations of cutting forces were directly based on the tangential, radial, and axial cutting force components. In the developed mathematical model of cutting forces, the relationship of average cutting force and the feed per flute was characterized as a linear function. The cutting force coefficient model was formulated by a function of average cutting force and other parameters such as cutter geometry, cutting conditions, and so on. An experimental method was proposed based on the stable milling condition to estimate the cutting force coefficients for ball-end mill. This method could be applied for each pair of tool and workpiece. The developed cutting force model has been successfully verified experimentally with very promising results.