The specific content of mechanical parts as a discipline includes: connection of parts. Such as screw connection, wedge connection, pin connection, key connection, spline connection, interference fit connection, elastic ring connection, riveting, welding and bonding. The size and quality of machined parts are related to the variety of materials and the method of blank preparation. When casting materials are used to make blanks, they are generally not limited by size and mass; When forging materials are used to produce blanks, attention should be paid to the production capacity of forging machinery and equipment.

1. First consider the use requirements:

The vibration, impact, high temperature, low temperature, high speed and high load of parts should be treated with caution);

Limitations on the size and quality of parts; The importance of the part. (Relative importance for the reliability of the whole machine)

2. Process requirements:

Blank manufacturing (casting, forging, plate cutting, bar cutting); machining; Heat treatment; Surface treatment.

3. Economic requirements:

Material price (comparison of blank cost and processing cost of Xitong round steel and cold-drawn profile, precision casting and precision forging);

Processing batch and processing cost; Utilization rate of materials; (For example, the specifications of plates, bars and profiles should be reasonably used);

Substitution (try to replace relatively expensive rare materials with cheap materials, such as spheroidal graphite in some wear-resistant parts)

4. Heat treatment conditions: select different materials with and without heat treatment conditions;

5. For the weight requirement, the parts that are often carried in hand are required to be light, and the materials with small specific gravity can be selected under the condition of meeting the mechanical strength.