Casting is an important teaching module of metalworking practice course. Its teaching content is composed of sand casting, lost foam casting and 3D precision casting. Due to the limited internship time, there is only one day for practical study of sand casting. The original practice content of sand casting includes three basic modeling methods: whole mold, sand excavation and parting mold; The whole mold modeling is first demonstrated and explained by the instructor, and the whole mold modeling practice operation is carried out on the basis of; The sand excavation modeling adopts the enlightening and guiding teaching. First, guide the difficulties faced in sand excavation modeling and analyze the relationship between the maximum cross section of the pattern and the parting surface, and consolidate the learning content through the problems existing in the practical operation and the demonstration and explanation of the instructor.
Parting molding mainly understands the structural characteristics of the pattern and the function of sand core and core head; Since the largest section of sand casting is in the middle, in order to facilitate mold lifting, the pattern should be made into separate patterns, so as to lead to separate pattern modeling; During the parting molding of two boxes, the parting surface and parting pattern coincide. Through the concept guidance and demonstration explanation of the instructor, a set of sand mold is finally made independently, and the pouring and sand falling cleaning are completed. However, due to the boring and single content of the original practical teaching, the slightly rigid teaching mode, the lack of space for active play, the students’ interest in learning is not high, and the overall understanding of sand casting has not been established, which can not achieve the expected teaching effect.
(b) Sand digging molding pattern and sand casting
(c) Parting molding pattern and sand casting
Figure a-c shows the pattern of practice and the corresponding cast sand castings.