MOST SURFACES have regular and irregular spacings that tend to form a pattern or texture on the surface. This surface texture is generated by a combination of various factors that are due either to the manufacturing process or the material being finished. Of the factors due to the material, the most fundamental is the microstructure of the material. For example, cast aluminum surfaces generally produce a granular surface when machined, while wrought aluminum alloys can be machined to produce a highly reflective, flat, and smooth topography. Internal stress in the material, released after machining, can also contribute to surface deformation.

The machining or finishing process itself has the greatest impact on the geometry of the surface. A major factor is the action of the cutting tool on the material. Elements such as tool shape, speed, feed, and cutting fluid can be varied to affect the surface topography. Other factors affecting the surface are the instability of the cutting tool due to chatter or imbalance in the grinding wheel, and errors in the machine tool guideway.

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