Deep hole drilling processes for high-alloyed materials are characterised by worn guide pads and chatter vibrations. In order to increase feed rates, process stability and bore quality in STS deep hole drilling, various investigations were carried out with adjustments to the tool. First, a new process chain for the production of tribologically optimised guide pads and their effects on the guide pad shape is described in detail. The results of these studies show that the shape change in the area of the axial run-in chamfer through a micro finishing process leads to a better bore hole quality. Furthermore, the influence of guide pad coating and cooling lubricant on the deep hole drilling process was investigated. In addition, the machining of the austenitic steel AISI 304 is analysed by using a conventional steel boring bar and an innovative carbon fibre reinforced plastic (CFRP)-boring bar. While the conventional drill tube oscillates with different eigenfrequencies, the CFRP-boring bar damps chatter vibrations of the drill head and stabilises the process. Even at higher feed rates up to f = 0.3 mm, it is possible to machine austenitic, difficult-to-cut-materials with significantly reduced vibrations.

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Deep hole drilling is a process for the production of cylindrical bore holes with a large length to diameter ratio. The variation of parameters is limited to those ones of the conventional drilling process such as rotation and feed motion. A special deep hole drilling process, named “chamber-boring”, was developed for the production of contoured bore holes in axial direction [1]. For specific applications not only a contouring in axial direction is required but also a radial contouring is necessary. In the course of a ZIM – project (Central Innovation Programme for SMEs), supported by the Federal Ministry for Economic Affairs and Energy (BMWi) and in close collaboration with the BGTB GmbH and the Institute of Machining Technology (ISF), a new “chamber boring system” which allows contouring of boreholes in axial and radial directions was developed. Based on this machining system, the manufacturing of pipes with a wavelike cross section in radial direction is possible.

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