• 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.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.212-219
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• 1998

During machining of dies and molds with sculptured surfaces. the cutter contact area changes continuously and results in cutting force variation. In order to implement cutting force prediction model into a CAM system, an effective and fast method is necessary. In this paper. a new method is proposed to predict mean cutting force. The cutter contact area in the spherical part of the cutter is obtained using Z-map, and expressed by the grids on the cutter plane orthogonal to the cutter axis. New empirical cutting parameters were defined to describe the cutting force in the spherical part of cutter. Before the mean cutting force calculation, the cutting force density in each grid is calculated and saved to force map on the cutter plane. The mean cutting force in an arbitrary cutter contact area can be easily calculated by summing up the cutting force density of the engaged grid of the force map. The proposed method was verifed through the slotting and slanted surface machining with various inclination angles. It was shown that the mean force can be calculated fast and effectively through the proposed method for any geometry including sculptured surfaces with cusp marks and holes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1003-1008
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• 1997

In this paper, the prediction of cutting force and tool deflection in the ball-end milling process are studied. Identifying various cutting region using Z-map, cutting force in the ball-end milling process can be predicted. Cutting force deflects the tool and the tool deflection changes the cutting force. Tool deflection is included in the cutting force prediction. Tool deflecition also causes machining error of the machined surface. A series of experiments were performed to verify the simulated cutting force and machining error.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.439-440
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.890-893
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• 2000

In this paper, the test of machinability according to the cutting positions when the ball end milling of hemispheric workpiece is carried out to find the optimum cutting position of free form surface die. Tool runout, cutting force. and chip form are measured. The results show that the optimum cutting condition to get the constant feed per tooth is the inclined angle of 40 degree of workpiece.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.23-24
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• 2010

• 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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• 1995.10a
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• pp.179-184
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• 1995

A new cutting parameter is defined in the spherical part of ball end-mill cutter. A series of slot cutting experiments were carried out to obtain the cutting parameter. The cutter contact area is expressed as the grid posiotion in the cutting plane using Z map. The cutting forces in each grid are calculated and saved as force map, prior to the average cutting forces calculation. The cutting force, in the arbitrary cutting area, can be easily calculated by summing up the cutting forces of the engaged grid in the force map. This model was verified in the inclined surface cutting by cutting test of a cylindrical part.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.197-200
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• 1997

In the metal cutting, machining accuracies had affected by tool deflection that had been generated by acting cutting force on the cutting edges. Generally, the CAD/CAM and a solid modeler had used for the simulation of cutting process only. Some NC codes for metal cutting have been generated by these simulation results. But, machining errors that had generated by the tool deflection has not solved using these system. In this study, determination algorithm for integration zone has been studied using the commercial solid modeler. The tool deflection error has calculated by the integration zone between the small chip and the cutting edges.

• 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.