In casting production, the selection of raw materials is crucial. It not only affects the quality of castings, but also directly affects material consumption and production costs. Therefore, when selecting raw materials, we need to consider multiple factors comprehensively.
First, raw sand is an indispensable raw material in the casting process. There are many types of raw sand, including ordinary sand, washed sand and scrubbed sand. Among them, scrubbed sand is the first choice because it has a low mud content and can effectively reduce the waste of resin. Of course, when selecting raw sand, we should also follow the principle of proximity to reduce transportation costs. At the same time, raw sand with a low angular coefficient is also one of the preferred options.
Secondly, the selection of resin is equally important. The quality of resin directly affects the quality of casting. Inferior resin not only increases the amount of addition, but also affects the quality of the molding sand, resulting in an increase in casting waste. Therefore, when selecting resin, we not only need to understand the production equipment, process and quality control methods of the manufacturer, but also need to strictly inspect the various indicators of the resin. Of course, it is also a good choice to learn from the experience of similar manufacturers and choose products from well-known large companies with good reputation.
In addition, the selection of other raw materials such as curing agents and coatings should not be ignored. Although these raw materials do not have a major impact on the quality of castings, their impact on casting costs cannot be ignored. Therefore, when selecting these raw materials, we also need to consider their quality and compatibility with the main materials.
In terms of particle size selection, for medium and large parts, we recommend the use of 40/70 mesh raw sand, and for general parts, 50/100 mesh. At the same time, it is necessary to ensure that the chemical composition of the raw sand meets the requirements, such as the SiO2 content must exceed 90%, the mud content must be controlled below 2%3%, and the water content must be within 12%. In addition, the micro powder content (below 140 mesh sieve) should not exceed 5~0%, the acid consumption value must be less than 5ml, and the loss on ignition must be controlled within 5. In terms of particle shape, we hope to get round or polygonal raw sand.