Comparison of chip surface temperature between up and down milling orientations in high speed rough milling of hardened steel

High speed milling (HSM) as a manufacturing process has been in intense use in recent years. Recently, a relatively new technique of rough milling using diameter cutters equal to or less than 10 mm has emerged such that rough milling employing high axial depths (Ad) of cut (10 mm ≤ Ad ≤ 20 mm) and low pick feed without compromising cutting speed and feed rate is used. The current study investigates the feasibility of employing high depths of cut (10-20 mm axial depth of cut) by using an infrared red technique to measure the chip surface temperature. This is in order to assess its machinability characteristics on HSM difficult-to-machine material such as hardened steel AISI H13, with a view to improve the metal removal rate, by employing a cutter path strategy known as raster, a combination movement comprising consecutive up and down milling. This paper specifically presents an investigation into the comparison of the effects of chip surface temperature generated primarily between up and down milling orientations, and the secondary effects of cutter conditions and axial depths of cut. The experimental results show that the chip surface temperature generated when up milling were in general lower as compared to down milling at all cutter conditions and axial depths of cut employed.