In recent years, with the vigorous development of manufacturing industry and the acceleration of the diversification of product market demand, the traditional sand casting for the trial production of new products can not meet the needs of enterprises and markets. With the rapid development of 3D printing technology and rapid casting technology, the low-cost and short cycle production and trial production of new products has become an important means for enterprises to quickly enter and occupy the consumer market. At present, the Institute of process materials of the first tractor Co., Ltd. of China YTO Group Co., Ltd. has three digital Moldless casting precision molding machines and laser sintering molding machines for rapid casting production of casting sand cores and sand molds. One of them is a three-axis digital die-free precision forming machine; One is the latest five axis digital Moldless precision molding machine put into use in 2014, which can process sand molds with large size (2000 mm, 1500 mm, 400 mm) from multiple angles; One is a laser sintering molding machine for 3D printing and molding sand core. The equipment can use 3D printing technology to accurately and quickly print the products required by customers. These advanced equipment provide a strong hardware equipment guarantee for the trial production of new products by various professional factories under China YTO Group.
On the premise of perfect hardware facilities, the trial production of new products also needs a series of design, such as parting process design, gating system design, smelting process design, etc., in order to produce qualified castings. The casting process scheme will be studied according to the specific situation of cr2002.37.101 gearbox housing casting (as shown in the figure), so as to ensure the production of qualified gearbox housing castings with the best process and the shortest production cycle.
The improved process is used for rapid casting production, the casting defects such as porosity are completely eliminated, and the surface quality is good. Using the improved “integral core” process scheme, the cumulative error during mold assembly is greatly reduced, and the dimensional accuracy of sand core is improved from 1.5 ~ 2 mm to 0.1 mm. After casting, the dimension in the length direction is measured to be 494.1 mm, which is consistent with the expected results. In the process of rapid casting production of gearbox shell for tractor, five axis digital modelless precision forming machine, three axis digital modelless precision forming machine and laser sintering forming machine operate at the same time, the production efficiency is the highest, and the processing time of the whole set of sand mold and core is shortened by 23 H.
