Improvement to High-Speed End Mill Boring Accuracy by a Simple Compensation Strategy (original) (raw)
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Influence of motion error of feed drive systems onto machined surface generated by ball end mill
Journal of Advanced Mechanical Design, Systems, and Manufacturing, 2014
Although glitches due to motion error of the feed drive systems are typically observed on the machined surface, the relationships between the motion error and glitches are not investigated up to now. The purpose of this study is to clarify the influence of motion error of feed drive systems onto machined surface generated by ball end-mill. In order to achieve the purpose, cutting tests and simulation of hemisphere shape are carried out. The cutting tests of hemisphere are carried out with two kinds of tool paths; uni-directional and bi-directional scanning paths. Parameters of the friction compensator of the NC controller are also changed to investigate the influence of motion characteristics of the machine. In addition, a simulation method for machined surface with the dynamic model of feed drive systems is newly developed. As the results of the cutting tests and simulations, it is confirmed that the proposed simulation method can accurately predict the influences of the motion errors and tool paths onto the machined surface generated by a ball end mill. It is also clarified that the both of motion path and motion errors influence the machined surface, because the innermost motion paths to the work piece are copied onto the finished surface. For example, even if a stepwise error exists on the motion trajectories, the error is not copied onto the finished surface when the surface is generated by bi-directional tool paths, although the error clearly copied on to the surface generated by uni-directional tool path.
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There is an ever-growing demand for high precision machining to obtain increased accuracy and surface finish, as they are key factors in product quality and performance. Machining operations, in general, are associated with errors of varying magnitude originating from different sources. As a result, the sizes of the machined features usually deviate from their desired, nominal values. Identification of error sources, techniques of measurements (on/off line), and efficient strategies for their compensation are the steps required to minimize, and, in some cases eliminate process errors. This paper focuses on modeling and compensation of geometric errors in machining operations specific to the line boring process. It is part of an undergoing research project focused on design and development of an agile precision line boring station for machining of long bores. After a brief overview of sources of geometric errors and their components, a methodology for their calculation is introduced. In this regard, error equations reflecting the effects of machine tool geometric errors at the tool tip are derived. It is shown that these equations can be further simplified without significantly affecting computational accuracy of the results. This makes the approach more attractive for real-time applications. A set of experimental data obtained from a prototype of the machine is used to study the effectiveness of the proposed approach and the results are reported. The paper concludes with discussions and presentation of different methods and available tools for real time compensation of these errors.
Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21
The purpose of this study is to clarify the influence of motion error of feed drive systems onto machined surface generated by ball end-mill. In order to achieve the purpose, cutting tests and simulation of hemisphere shape were carried out. As a result, it is clarified that the innermost motion paths to the work piece are copied onto the finished surface. For example, even if a stepwise error exists on the motion trajectories, the error is not copied onto the finished surface when the surface is generated by bi-directional tool paths.
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Deep hole drilling is a metal cutting method for producing primary cylindrical deep bores with a length-todiameter ratio larger than l/D = 10. Due to the increasing interest of different branches of the industry in inner contoured workpieces, the Institute of Machining Technology (ISF) and the BGTB GmbH developed a chamber boring system, which allows to contour boreholes in axial and radial directions. This paper presents the influence of different cutting speeds, feeds and workpiece materials on the contour accuracy and the mechanical tool loading.
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