By changing the surface finish specification, the part's functionality can be altered and hopefully, improved. Bridging the gap between these two perspectives is the manufacturing engineer, who must determine how the machinist is to produce the surface finish specified by the design engineer. The methods one chooses to measure surface finish, therefore, depend upon perspective, and upon what one hopes to achieve. Turning, milling, grinding and all other machining processes impose characteristic irregularities on a part's surface. Additional factors such as cutting tool selection, machine tool condition, speeds, feeds, vibration and other environmental influences further influence these irregularities.
Texture consists of the peaks and valleys that make up a surface and their direction on the surface.
Roughness is essentially synonymous with tool marks. Every pass of a cutting tool leaves a groove of some width and depth. In the case of grinding, the individual abrasive granules on the wheel constitute millions of tiny cutting tools, each of which leaves a mark on the surface. Included in this article are several examples of how these gages are finding wide application on shop floors. Waviness is the result of small fluctuations in the distance between the cutting tool and the workpiece during machining.