Variable Length Scale Surface Finish Assessment of Machined Grade 4 Titanium Alloy

Conventional surface roughness measurements provide surface topography information at one length scale only. Many applications, including osseointegration performance in the biomedical field, may requiresurface topography information at reduced length scales to improve performance. This paper presents an evaluation of surface roughness for length scales down to 5 microns for outside turned Grade 4 titanium alloy. The effect of cutting speed and feed rate are also evaluated. Surface roughness, skewness and kurtosis are evaluated at different length scales for different cutting parameters and compared to the theoretical expected behaviour. It was concluded that there exists a significant sub-micron surface roughness component that is not fully captured by the conventional roughness measurement techniques. It was also found that the variable length scale surface topography was affected by certain cutting parameters.