Front Face Flow Drilling of Lightweight Cast Materials

Biermann, D.1, a; Walther, F.2, b; Hannich, S.1, c; Wittke, P.2, d

1)
Institut für Spanende Fertigung, Technische Universität Dortmund, Baroper Str. 303, 44227 Dortmund
2)
Fachgebiet Werkstoffprüftechnik (WPT), TU Dortmund

a) biermann@isf.de; b) frank.walther@tu-dortmund.de; c) hannich@isf.de; d) philipp.wittke@tu-dortmund.de

Kurzfassung

Front face flow drilling, which has been investigated at the Institute of Machining Technology (ISF), TU Dortmund University, represents a new application of the conventional flow drilling process. With this new technique it is possible to form closed holes with diameters, which can exceed the local wall thickness of the profile. By using a subsequent threading operation, it is possible to generate solid joints. In this article investigations regarding the machining of the aluminium cast alloy AlSi10Mg are presented. The feasibility of the front face flow drilling application was analysed for the machining of thin profiles with a wall thickness of tW = 6 mm. Flow drilling tools with a diameter of dFD = 5.4 mm have been used. Feed forces as well as torques were measured during the flow drilling process. In order to generate solid threads, a high quality of the formed holes has to be ensured. To quantify the quality, measurements of the circularity as well as the diameters were carried out. Both aspects can have an influencing effect on the threading operation. Due to the low formability of the used alloys, adjustments of the flow drilling process had to be realised. Besides the variation of process parameters such as peripheral speed and feed velocity, a pre-heating of the tool was conducted to raise the formability of the workpiece material and to increase the process stability. The pre-heating of the tool was accomplished by using a portable induction system with an integrated temperature control. As a result of the investigations, suitable process strategies will be recommended regarding a stable front face flow drilling operation of the lightweight cast alloy AlSi10Mg. Further research regarding front face flow drilling is planned towards an adaptation to magnesium cast alloys.

Veröffentlichung

Procedia Engineering, 207 (2017), S. 956-961, doi: https://doi.org/10.1016/j.proeng.2017.10.858