detailed process planning is required for every part, subassembly and the final assembly.The information is usually displayed on process sheets, one for each part of subassembly. The process sheet contains a sequential list of operations which must be performed to produce the part. It specifies the raw material, clarifies special instructions, and indicates the tools and machines required. This step is particularly important, because design features that lead to difficulties in production are revealed. Such difficulties should have been minimized earlier by timely consultations between product designers and tool designers. Similarly,questions about materials should have been resolved by consultation with metallurgists