Analysis of the Impact of Wiper Geometry Insert on Surface Roughness and Chips in Machining Materials Used in the Aviation Industry

Abstract

Nowadays, great emphasis is placed on increasing the effi ciency of machining processes. However, this cannot be done at the expense of quality worsening of the machined surface. In this paper the infl uence of Wiper geometry on Ra and Rz surface roughness parameters is described when fi nishing turning of materials used in the aviation industry: austenitic stainless steel XCrNiNb18-9, low alloy steel 14NiCr14 and aluminum alloy A356, as well as the chips generated in the cutting process in terms of shape were assessed. It was found that for the lowest tested feed rate during turning with a Wiper insert, the values of Ra and Rz parameters do not diff er signifi cantly from the roughness parameters obtained during machining with a conventional insert. The benefi cial eff ect of feed rate on surface roughness for the Wiper insert is clearly visible above f ≥ 0.12 mm/rev. The biggest diff erence in roughness parameters was recorded for the highest value of the applied feed f = 0.28 mm/rev. Using conventional insert, Ra and Rz values are almost three times bigger than for Wiper insert. The infl uence of the cutting speed on the Ra and Rz parameters depends on the type of material being processed. Increasing cutting speed from v c =120 m/min to v c = 200 m/min for stainless steel, Ra and Rz values decrease about 35%. Similar situation noticed for aluminum alloy, but increasing cutting speed decrease Ra and Rz values only about 18%. The situation is diff erent for low alloy steel. Increasing the cutting speed increases the Ra and Rz parameters by about 37%. Rz/Ra ratio shows that for feed rate f ≤ 0.12 mm/rev. cutting process is unstable, because the values are between 5.5-7.5, but should oscillate around 4. Increasing feed rate value to f = 0.2 mm/rev allows to stabilize the process and the ratio value is close to 4. Wiper insert create the same form chips as a conventional insert, using the same value of feed rate.