Mechanical design, according to the requirements of use, conceive, analyze and calculate the working principle, structure, movement mode, force and energy transmission mode, material and shape of each part, lubrication method, etc. and translate it into specific descriptions. Working process as a basis for manufacturing.

Mechanical design is an important part of mechanical engineering, the first step in mechanical production, and the most important factor determining mechanical performance. The goal of the mechanical design is to design the best machinery under a variety of limited conditions (such as materials, processing capabilities, theoretical knowledge and calculation methods), that is, to make an optimal design. Optimal design requires comprehensive consideration of many requirements, generally including: best working performance, lowest manufacturing cost, smallest size and weight, most reliable in use, lowest consumption and least environmental pollution. These requirements are often contradictory, and the relative importance of them varies according to the type and use of the machine. The task of the designer is to weigh the weight according to the specific situation and make overall plans to ensure that the designed machine has the best comprehensive technical and economic effect. In the past, the optimization of design mainly relied on the designer's knowledge, experience and vision. With the development of new disciplines such as basic theories of mechanical engineering, value engineering, and system analysis, the accumulation of technical and economic data and materials for manufacturing and use, and the popularization and application of computers, optimization has gradually abandoned subjective judgments and relied on scientific computing.