1. Use requirements (first consideration)
1) Working conditions of parts (vibration, impact, high temperature, low temperature, high speed and high load should be treated with caution);
2) Limits on part size and quality;
3) Importance of the part. (Relative importance to overall reliability)
2. Process requirements
1) Blank manufacturing (casting, forging, plate cutting, rod cutting);
2) Machining;
3) Heat treatment;
4) Surface treatment.
3. Economic requirements
1) Material price (comparison between blank cost and processing cost of ordinary round steel and cold drawn profile, precision casting and precision forging);
2) Processing batch and processing cost;
3) Utilization rate of materials; (For example, the specifications of plates, bars and profiles should be used reasonably)
4) Substitution (try to use cheap materials to replace relatively expensive rare materials, such as replacing copper sleeves with nodular graphite in some wear-resistant parts, replacing some sleeves machined by turning with oil bearing, and replacing steel gears or copper worm gears with nylon under low speed load).
In addition, consider the supply of local materials
1. Basic requirements for mechanical design
a) Pay attention to the coordination and balance of the requirements for the machine functions! Prevent the occurrence of cask effect
b) Requirements for machine economy
The design economy can be put into production and launched in a short period of time to recover the consumption during the development period, or even design and manufacture at the same time
The use of economy should have the best performance price ratio (the products start to earn money in small batches, and then they can be improved better)
2. Basic requirements for the design of mechanical parts
a) It can work normally and reliably within the scheduled working period to ensure various functions of the machine
b) To minimize the production and manufacturing costs of parts
c) Use common standard parts in the market as much as possible
d) For products that may be serialized, the commonality of parts shall be considered at the beginning of design as much as possible, and those that cannot be used shall be similar in structure as much as possible, so as to reduce the workload of process planning and fixture design in the manufacturing process.
