1. Product design principle reasonable design should ensure the necessary functions of the product and minimize the manufacturing cost, which is the subject to be explored in this paper.

(1) It must meet the requirements of customers for product functions and services. Construction machinery provides customers with not only product functions, but also after-sales services to support these functions. Therefore, the design process should not only aim at the different functional characteristics of the product, but also make the product have good maintenance convenience.

(2) Comply with the national industrial development policies and relevant laws and regulations.

(3) Adhere to the "three modernizations" principle of standardization, generalization and serialization.

(4) Meet the social requirements for environmental protection.

(5) Comply with the law of technological innovation and pay attention to the protection of intellectual property rights.

(6) Starting from the actual process level and production capacity of the enterprise, it emphasizes the combination of design, process and production. Product design is not only drawing design, but also process design and production design. The production design shall be mainly studied from the following aspects:

① Simplify the function or shape of parts;

② Maximize the standardization, generalization and serialization of products;

③ Try to make the material brand, variety and specification specified in the design drawings consistent with the use of existing materials;

④ More effective combination of blank process and machining process;
⑤ Judge the rationality of process design according to the processing technology, operation rules and relevant information adopted by the current normal production of the enterprise;
⑥ Select the dimensional tolerance and surface roughness that can be guaranteed by mature processing technology;
⑦ Comprehensively analyze the information related to the production process.