Mechanism and Potentials for Reducing of Hole Straightness Deviation in Deep-Hole Drilling

Biermann, D.1, a; Kessler, N.1, b

1)
Institut für Spanende Fertigung, Universität Dortmund, Baroper Str. 301, 44227 Dortmund

a) biermann@isf.de; b) kessler@isf.de

Kurzfassung

Deep-hole drilling methods are used for producing bore holes with a high length-to-diameter ratio l/D usually greater than three. Furthermore these methods are characterized by a high quality of the bore hole and a high level of productivity. Nevertheless under certain conditions one of the quality characteristics, the hole straightness deviation, can lead to problems. In the worst cases this leads to additional costs through rejects. The mode of operation is an import aspect for the hole straightness deviation. Workpieces which cannot be rotated on the machine such as workpieces with eccentricly placed bore holes or workpieces of high weight have to be processed with a rotating tool. This article describes the mechanism of hole straightness deviation especially occurring in the mode of operation with a rotating tool with special focus on the influencing factors such as workpiece design and the process parameters cutting speed and feed rate. As another important aspect, the unsymmetrical thermo-mechanical load within the workpiece is investigated. Based on this, a new method for prevention of hole straightness deviation through the effect of thermally influence by a medium frequency-converter is proposed. This medium frequency-converter for inductive heating of electrically conductive materials is intended for influencing the hole straightness deviation, thereby increasing the quality of the bore holes and as a consequence reducing the number of rejected workpieces. In this context parameters with the highest influence such as duration of application and frequency of the converter and the distance from the inductor to the workpiece will be analyzed for later application to the real process.

Schlüsselwörter

Production Process, BTA Deep-Hole Drilling, Hole Straightness Deviation

Veröffentlichung

In: Proceedings of the 2nd Manufacturing Engineering Society International Conference, CISIF-MESIC 2007, 9.7.-11.7. 2007, Madrid, Spain, ISBN 978-84-611-8001-1, digital veröffentlicht