Roughing
Roughing called in machining processes , the metal-cutting pre-machining of workpieces with large chip volume . Roughing processes are used particularly in turning and milling and serve to bring the workpiece as close as possible to the final contour. This is achieved through coarse-toothed tools, large cutting depths, large feeds and low cutting speeds, so that chips with a relatively large volume are produced. The roughing process usually leaves rough surfaces with poor dimensional accuracy .
The difference between the pre-machined part (rough machining) and the finished part is called the allowance. The exact finished contour of the dimensionally accurate workpiece is produced in further passes with finer tools ( finishing ), whereby finer chips are removed and a higher surface quality is achieved.