The Surface Analysis of Powder Metallurgy (P/M) Components Machined by Diamond-Like Carbon (DLC) Coating Cutting Tools

The surface analysis is one of the most important factors of the metal machining process due to the tolerance and geometry requirements. The characteristic of powder metallurgy (P/M) surface geometry is the main issue here, because the porous structure affects the surface quality. A discontinuous cutting path and some vibration occur when cutting tool passes from the edge of one pore to that of another. The amorphous material such as Diamond-like carbon (DLC) coating has been applied on the cutting inserts to improve the machinability. This paper will evaluate the surface finish of the P/M components by employing a DLC cutting insert. Due to the specific physical properties of DLC coating, it is important to understand the effects of DLC coated insert on the surface roughness at different cutting speeds and feedrates. This work investigates the factors of friction between the cutting tools, workpiece and observes how the coating material affects the finish surface. This paper will demonstrate the essential considerations of these cutting parameters. Single-point turning operations have been undertaken to show the relationship between the tool's wear and surface finish. The results include roughness average, surface profiles and 3-D topography. Experimental results will be mentioned and discussed toward the end of the paper.