Rule Based Process Planning System for Hole Feature Machining

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CHAPTER 5 SELECTION OF CUT DATA AND TOOLS 5.1 Feed Rate and Cutter Speed One of the problems in machining parts is knowing how fast the cutter (or part) should be turning and at what rate the cutter should be fed through the material. Proper feed rate and cutter speed (or spindle speed) should be selected in order to achieve optimum production at minimum cost. The information is known as machinability data and is available in a number of handbooks. Cutter speed and feed rate are required for every machine operation with the exception of tapping, which requires only cutter speed because threads guide tap. In this research, the feed rate and the cutter speed are computed from database drawn from the Metcut Machining Data Handbook [9]. This database consists of tables for specific operations and workpiece materials. According to operation, tool material, and hardness of the tool material, recom­mended feed per minute (fpm) can be drawn from the database, and recommended inch per revolution ( ipr) can be drawn with additional parameter of hole diameter. Thus, in deriving feed rate and cutter speed, required input parameters are type of machining operation, cutting tool material, workpiece material (type and specific grade), hardness of the workpiece material (hardness number and hardness measur­ing method used), and hole diameter. The hardness of workpiece material may be omitted, and then default table is used for feed rate and cutter speed computation. The type, the specific grade, the hardness number, and the hardness measuring