Hole quality and cutting time evaluation in the interpolated helical milling

The interpolated helical milling (IHM) is considered a very flexible strategy which allows milling, instead of drilling, holes with more generic tools. However, despite of its dissemination in industry, it is currently known that few research works have been carried out about the influence of cutting condition on the quality of holes and their cutting time. In this study, the production of holes was investigated using the IHM technique for rough and finish machining conditions, and the process performance was evaluated by the cutting time, and the holes surface roughness and roundness. Fifty four holes were milled in AISI 1045 steel bars with end mill cutters in a vertical machining centre; following Taguchi (L9) experiments where the cutting speed, circular feed per tooth and axial feed per tooth were analysed for rough operations, and for the finish operations, the radial depth of cut was also investigated. From the results, it can be concluded that high quality surface can be achieved at the rough phase. In this case, the combination of lower axial feed rates (ƒz) and higher cutting speed (Vc) should be selected to guarantee a higher hole quality, without compromising the productivity. [Received 13 April 2015; Revised 06 August 2015; Accepted 06 September 2015]