The cylinder block, cylinder head and chassis box of tractor are complex castings, which have the characteristics of large mold (core) size, complex structure and thin wall. In the process of new product development, there are often some problems such as high development cost, long cycle and high scrap rate. For example, the cylinder block of the engine is a key casting with the heaviest weight, the highest complexity and the greatest production difficulty in the diesel engine. The core making and molding process of traditional mold casting needs to make multiple sets of complex metal molds, and the casting quality is difficult to control. Dozens of new casting products need to be developed every year. The traditional mold casting method is used for the trial production of complex castings such as engine cylinder block and cylinder head. There are the problems of “high investment, high energy consumption, high pollution, low quality, low benefit and low output”. There is an urgent need for new fast, efficient and low-cost casting methods.
In view of the above problems, the research on rapid casting method of tractor complex castings mainly involves the following aspects.
(1) Study on rapid. According to the material, performance and structural characteristics of tractor complex castings, the rapid casting process is studied and the required equipment, software and tooling are determined.
(2) Research on casting process and parting design. According to the structural characteristics and process flow of complex castings, the pouring system design, core material selection and cold iron placement method of castings, as well as the parting design and assembly method of sand core in sand mold are studied.
(3) Research on dieless forming. According to the parting design scheme and forming equipment, the forming methods of reduced material manufacturing and increased material manufacturing of complex castings are determined.
The new product development of tractor complex castings by Moldlesshas the following advantages.
(1) It has the characteristics of digitization, precision, flexibility and green. It is an accurate forming manufacturing method based on resource saving and environment-friendly.
(2) The comprehensive use of additive manufacturing and additive manufacturing can give play to their respective advantages: the additive manufacturing method of Baozhu coated sand core with high strength and good surface quality is manufactured by selective laser sintering forming machine and SLS method, which has slow speed and high cost, but the strength of the formed sand core is high, which can be used for the dieless forming of thin-walled sand core in complex castings; The material reduction manufacturing method of making sodium silicate and resin sand core by mold cutting forming machine has high forming efficiency and good sand mold strength after forming. It can be used for dieless forming of sand core with simple shape.
(3) This method can reduce the cycle and cost of new tractor product development and promote the technical level of tractor parts casting.