Design and Grinding of Multi-Flute Drills
| Autor: | Jung-Fa Hsieh, 謝榮發 |
|---|---|
| Rok vydání: | 2003 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 91 Multi-flute drilling is an efficient means of making high accuracy holes without reaming. Because of the current lack of a comprehensive mathematical model for this kind drilling, this paper presents a complete and simple method for designing multi-flute drills. There are three special features of the proposed model. The first is that rotational axial-type cutting tools and disk-type abrasive wheels are modeled by revolution geometry, so that the normal and tangent vectors of flute and flank surfaces can be obtained explicitly. Consequently, rake and clearance angles of cutting and chisel edges can be investigated according recommended ISO standards. The second feature is that we integrate the mathematical models of flute and flank surfaces, so that cutting and chisel edges and their various characteristic angles can be obtained by numerical calculation. A simple way to determine the rake angles and wedge angles and clearance angles is presented by using the unit normal of the ISO-recommended reference planes. This model is comprehensive, simple, easy to use, and is capable of describing a wide range of drill design features. This paper analyzes three types of drill geometries for conical, hyperboloidal and ellipsoidal drills. Presents a model to determine and express drill geometries and characteristics (semi-point angle, tool cutting edge inclination, chisel angle, normal rake angle and normal clearance angle) according to all current international standards. Finally, This paper presents a kinematic model to produce multi-flute drills on a 6-axis CNC tool-grinding machine. The ability matrix of a 6-axis CNC tool-grinding machine is established by Denavit-Hartenberg notation. Moreover, due to manufacturing difficulty reasons, most grinding wheel are solid without any inner concave surface to cast drill flanks into convex surfaces to provide clearance angles in drill. Therefore, a concept of virtual hollow grinding wheel and virtual solid dresser is invented to overcome that difficulty. Eventually, we generate the desired configuration matrices to express the positions and orientations of the grinding wheel during the machining of the flutes and flanks. NC data equations are obtained by equating the corresponding elements of the ability matrix and the configuration matrices of grinding wheel. To verify the validity of the proposed methodology, a designed three-flute drill was machined on an Ewag 6-axis CNC tool-grinding machine. This paper combines the activities of drill design and manufacturing, thus making the production process more flexible, automatic, cost efficient and controllable. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|