• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.8 no.3
• /
• pp.83-91
• /
• 1999

In this paper, we suggest a virtual machining system that can simulate cutting forces of ball end milling at the stage of part design. Cutting forces, here, are estimated from the machanistic model that uses the concept of specific cutting farce coefficient. To this end, we need undeformed chip thickness which is used for calculating chip load. It is derived from the Z-map data of a CAD model. That is, chip load is the height difference between the cutting tool and the workpiece at an arbitrary position. The tool contact point is referred from the cutter location data. On the other hand, the workpiece height is acquired from the Z-map model of a CAD data. From the experimental verification, we can simulate machining process effectively to the slot and the side cutting of ball end mill.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.942-946
• /
• 1997

In this research,we suggest a virtual machining system that can simulate sutting forces at the stage of design. Cutting forces,here, are modeled form the machanistic model of the ball end milling. To this end, we need undeformed chip thickness which is used for calculating chip load. It is derived form the z-map data of a CAD model. That is, chip load is the height difference between the cutting tool contact point and the workpiece at arbitrary position. The tool contact point is referred from the cutter location. Form the experimental verification, we can simulate machining process effectively to the slot and the side cutting of ball end mill.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.3
• /
• pp.57-65
• /
• 1997

In this study, a cutting force in the Ball-end milling process is calculated using Z-map. Z-map can describe any type of cutting area resulting from the previous cutting geometry and cutting condition. Cutting edge of a ball-end mill is divided into infinitesimal cutting edge elements and the position of the ele- ment is projected to the cutter plane normal to the Z axis. Also the cutting area in the cutter plane is obtained by using the Z-map. Comparing this projected position with cutting area, it can be determined whether it engages in the cutting. The cutting force can be calculated by numerical integration of cutting force acting on the engaged cutting edge elements. A series of experiments such as contouring and upward/downward ramp cutting was performed to verify the calculated cutting force.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1148-1153
• /
• 2003

An adequate method for the prediction of machining errors is essential to improve productivity and product quality. But it is known that there is a remarkable difference between values calculated by conventional roughness model and measured values of actual machined surfaces under high efficient cutting condition. This paper introduces the theoretical analysis of characteristic lines of cut remainder to evaluate a geometrical surface roughness accurately. In this study, analytic equations of the characteristic lines are derived from the surface generation mechanism of ball end milling considering the actual trochoidal trajectories of cutting edges. The predicted results are compared with the results of conventional roughness model.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.04a
• /
• pp.125-129
• /
• 1996

In this study, a method is proposed for the cutting force prediction of Ball-end milling process using Z-map is proposed. Any types of cutting area generated from previous cutting process can be expressed in z-map data. Cutting edge of a ball-end mill is divided into a set of finite cutting edges and the position of this edge is projected to the cross-section plane normal to the Z-axis. Comparing this projected position with Z-map data of cutting area and determining whether it is in the cutting region, total cutting force can be calculated by means of numerical integration. A series of experiments such as side cutting and upward/downard cutting was performet to verify the simulated cutting force.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.721-724
• /
• 2000

This paper presents a prediction of tool deflection and resulting machining error fur sculptured surface productions in the ball-end milling process. Due to the different materials and the dimensions of the tool holder and cutter, a cantilever hem model with three uniform sections is proposed fur the tool deflection model. The ability of this model has been verified by a machining experiment. In this study, cutting force and machining error are investigated. This paper provides the prediction of machining error for sculptured surface to improve machining quality for industrial application.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.725-729
• /
• 2000

This paper presented a new model of NC verification in ball end milling. The model verifies the over cut the under cut and the surface roughness using NC file generated from CAM and cutting condition. The model uses Z-map model to verify workpiece. In this paper, the model used the velocities of x, y and z direction and obtained a center point of a ball end mill for modeling Z-map of workpiece. To investigate the performance of the model simulation study was carried out. As the results, the model gave geometry accuracy of workpiece, the surface roughness and the chip loads in finish cutting that can predict tool chipping.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.10a
• /
• pp.274-278
• /
• 2000

Ball end milling process is widely used in the die and mould manufacturing because of suitableness for the machining of free form surface. But, as ball end mill is long and thin, it is easily deflected by cutting force. In this study, Cutting force, tool deflection and surface precision was measured according to the change of depth and cutting location. Cutting force was acquired with tool dynamometer and a couple of eddy-current sensor measured tool deflection in x-y direction each. After machining, surface precision was measured with roundness tester and coordination measuring machine for sculptured surface angle change and cutting depth.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.1001-1004
• /
• 2000

As tools for machining precision components, end mills and ball end mills are widely used. For the end mills have longer cylindrical shape comparing diameter, liable to deflect and induce deterioration of surface roughness. Tool geometry parameters and cutting process have complex relations with each other. So, It is hard to determine hew to select optimal tool geometry. So, to improve the stiffness, relationship between cutting process and tool geometry must be studied. In this study, relations between grinding wheel geometry, setting condition and tool geometry are revealed. For the purpose of studying relations between each parameter, the equivalent diameter of tool has been calculated assuming tool as a simple beam. By the various cutting simulations and experiments, tool geometry and cutting process has been studied.

• Journal of Industrial Technology
• /
• v.21 no.A
• /
• pp.27-32
• /
• 2001

This paper deals with the study on the culling characteristics in ball-end milling process. First of all, the effects of the geometric cutting conditions such as the spindle speed, feedrates on the surface integrity and machining stability were evaluated by the analytical and the experimental approaches. A large amount of experimental sets are performed to evaluate the effects of chatter phenomenon on the machined surface. The optical microscope and the surface roughness measuring machine are used to measure the surface integrity and roughness of the machined surfaces.