Optimising material removal rate in free-form surface machining using fuzzy approaches

The conventional constant feedrate assignment in NC coding for the manufacturing of free-form surfaces cannot achieve an optimum material removal rate. It is because the actual cutting speed on the cutting edges of a bail-nosed cutter will change with the surface gradient. In addition, the machined surface quality depends upon a large group of machining parameters in a surface machining process, such as material hardness and the remained tool life. Using analytical equations to determine the material removal rate may not effectively enough to produce an optimum solution when the machining parameters are all considered. In this study, a fuzzy based material removal rate optimisation approach is proposed to estimate a correct feedrate for each cutting point on a free-form surface. A surface machining trial result demonstrated that the quality of the machined surface is improved when the fuzzy approach is applied, and the material removal rate is increased about 20 percent.