Background of geometric structure feature Design of Sand casting

Taking the geometric structure characteristics of a plate casting as the research object, this paper carries out the application effect of the characteristic carbon benefit model of process design and its parameter optimization method in the traditional manufacturing industry. The basic shape of the casting is shown in figure 1. The material of the casting is gray cast iron HT250, the density is 0.72kg/cm3, the net weight of the casting is 186.138kg, the quality of the gating system is 17.127kg, and the total mass obtained by taking into account the machining allowance and draft angle of the casting surface is 203.7kg.

There are three holes with diameter of 45mm on the surface of the casting. The casting has strict requirements on the quality of the hole. The first process plan (FE1) will use the machining method to make the hole. According to the research range of the minimum casting hole of gray cast iron material, such as the hole of 30-50mm in Table 4-2, there are two hole making schemes, from which the process routes of the following process plan 1 (FE1) and process plan 2 (FE2) are obtained. The castings with the same quality requirements can be produced by the two processes through different processes.

The gating system design of the two process schemes is shown in figure 2. The internal dimensions of the upper and lower sandboxes are 840mm × 800mm × 245mm, and one product is made in each box. Self-hardening resin sand is used as moulding sand for castings and sand cores with a density of 1.48 g/cm3. If the recovery rate of used sand treated by sand treatment line of sand casting enterprises is 96%, the total mass of molded sand consumed by castings in the actual casting process is 4454.627 kg.

According to the classification of process planning features, the appropriate process parameters of process planning features and the process parameters of FE1 and FE2 are selected. In order to verify the feasibility of FE1 and FE2, ProCAST is used to simulate the pouring process of different process schemes, as shown in figure 3, the total shrinkage porosity and porosity of the two process schemes meet the quality requirements. There are no pores in the total shrinkage porosity diagram, indicating that there are no defects in the casting. The blue part of the voidage diagram shows the gap of the casting, and the gap in the gating system is due to the cooling shrinkage of gray cast iron and part of the gap on the surface of the casting. the gap on the surface of the casting can be machined in the later stage.