Resource consumption reflects the material demand in the production process to a certain extent. Through the quantitative calculation of resource consumption, the resource demand in each process can be clarified, so as to reasonably optimize and control. According to the analysis, the resource consumption of Moldless sand casting process is related to many factors, and the resource consumption has the characteristics of diversity. Changing the mold forming method, the inherent properties of the mold and even the casting batch production conditions will lead to changes in sand consumption, metal consumption, power consumption and personnel arrangement in the casting process to varying degrees. According to the types and characteristics of resources consumed, the resource consumption composition of Moldless sand casting can be expressed by the following formula:
Where EM represents material resource consumption in sand casting; EN represents equipment energy consumption in sand casting; Et represents labor resource consumption in sand casting.
Material resource refers to the material input in the casting process for mold or casting forming. According to the property characteristics of materials, they can be divided into metal materials, modeling materials, auxiliary materials and energy materials. Taking the molten iron smelting of iron castings as an example, metal materials mainly include pig iron, scrap steel and reheated iron. If necessary, carburizing agent, ferrosilicon and ferromanganese shall be added to adjust their composition. The specific ingredients of medium frequency induction furnace production unit kg HT200 gray cast iron molten iron of a domestic sand casting enterprise should be noted that the proportion of various input raw materials is not always consistent, which depends on the actual production requirements. Molding materials usually refer to casting molding sand. Its consumption is mainly concentrated in the molding stage and is used for mold forming. Foundry will have different old sand recovery processes for different molding sand materials. Generally, the average recovery rate of molding sand is 80% – 98%. As the name suggests, auxiliary materials play an auxiliary role in the processing process and do not directly act on the mold or the casting itself. Such as inoculant, casting coating and cooling water. Energy materials, such as coke, natural gas and other energy materials, are used for melting molten iron, heating molds and drying core materials in the processing process. To sum up, the material resource consumption of Moldless sand casting can be expressed as the following formula:
Among them, EMA Δ 1，Emb Δ 2，Emc Δ 3 and EMD Δ 4 represents the consumption of metal materials, molding materials, auxiliary materials and energy materials respectively; a. B, C and D respectively represent the types of metal materials, molding materials, auxiliary materials and energy materials.
Energy resources refer to the energy consumption of equipment put into production, such as sand mixer, flow coater and other equipment involved in casting production activities. The consumption of labor resources is the amount of labor input in the casting production process. Because human factors are complex and difficult to calculate quantitatively, and the labor cost varies according to different regions and positions, the consumption of labor resources is quantified as the amount of labor input in each process, which can be expressed as the formula:
Where ETF represents the f-th casting process of the casting process; NF refers to the number of labor force in the f-th casting process; Count → indicates the counting process.
Schematic diagram of casting process corresponding to resource consumption of castings per production unit. Wherein, the dotted line indicates the flow direction of the casting process; PN and PN + 1 represent casting process nodes; Other symbols in the figure are the same as above. It can be seen from the figure that the consumption of labor resources and equipment energy consumption cover almost all casting processes, while metal materials and molding materials are concentrated in the early stage of casting process, which is the main part of material resource consumption.