Products and their components are designed to perform certain specific functions. Every product has some design specifications which ensure its functionality aspects. The task of manufacturing is to produce components such that they meet design specifications. Process planning acts as a bridge between design and manufacturing by translating design specifications into manufacturing process details. It refers to a set of instructions that are used to make a component or a part so that the design specifications are met, therefore it is major determinant of manufacturing cost and profitability of products. Process planning answers the questions regarding required information and activities involved in transforming raw materials into a finished product. The process starts with the selection of raw material and ends with the completion of part. The development of process plans involves mainly a set of following activities; •Analysis of part requirements
•Selection of raw workpiece
•Selection of manufacturing operations and their sequences •Selection of machine tools
•Selection of tools, tool holding devices, work holding devices and inspection equipments •Selection of manufacturing conditions i.e. cutting speed, feed and depth of cut. •Determination of manufacturing times
(2) The manual experience-based planning method
The manual experience-based process planning is most widely used. It is mainly based on a manufacturing engineer's experience and knowledge of production facilities, equipment, their capabilities, processes, and tooling. The major problem with this approach is that it is time consuming and developed plans may not be consistent and optimum. The feasibility of developed process plan is dependant on many factors such as availability of machine tools, scheduling and machine allocation etc. Computer aided process planning is developed to overcome this problems to some extent.