Introduction to Commonly Used Casting Processes
2019-08-28
Water Glass Sand Mold Casting
Sand-mold cast wear-resistant parts for crushers are still very common locally, such as jaw plates, high-chromium hammer heads, crushing walls, and gyratory crusher walls. In crusher equipment, these components—being relatively large and less precise in terms of dimensional accuracy—are particularly well-suited for sand-mold casting. For instance, with jaw plates, the finished products typically require minimal lathe finishing. Similarly, only specific areas of crushing walls, gyratory crusher walls, and roll skins need lathe work, making sand-mold casting an ideal choice. As a result, wear-resistant parts like jaw plates, high-chromium hammer heads, crushing walls, gyratory crusher walls, and roll skins produced via sand-mold casting tend to outlast those made using other processes—such as lost-foam casting—by more than 20%.
Lost-foam casting
"Lost-foam casting," also known as "evaporative-pattern molding," "styrofoam mold casting," "full-mold casting," or "cavityless casting," among other terms, is a casting method that essentially uses expanded polystyrene foam plastic instead of traditional patterns. After the pattern is created, molten metal is poured directly into it without removing the pattern. Under the intense heat of the scorching liquid metal, the foam pattern vaporizes and burns away completely, leaving behind the exact shape of the desired casting. Once the metal cools and solidifies, the final product—precisely the intended casting—is ready.
V-Process Casting
V-process casting and lost-foam casting are also known as vacuum casting, named after the initial letter "V" derived from the English word "Vacuum." Unlike traditional sand casting, this method eliminates the use of binders. In V-process casting, a plastic film seals the sand box, and a vacuum system extracts air from within the mold, creating a pressure differential between the inside and outside of the mold. This forces the dry sand to compact tightly, forming the desired cavity. After core placement, mold assembly, and pouring, the vacuum is maintained during solidification. Once casting is complete, the negative pressure is released, causing the compacted sand to collapse and revealing the finished part.
Resin Sand Casting
Resin sand castings are a general term for molds and cores made from molding sand coated with a solid resin film on the surface of the sand grains before shaping or core-making—this type of sand is called coated sand, also known as shell (core) sand. Resin sand casting involves mixing raw sand with resin to form resin sand, which is then poured into the mold cavity. The resin sand is subsequently heated or activated with a catalyst to solidify into its final shape. Once the core is formed, it’s placed into the casting mold for the actual pouring process. Resin sand castings are characterized by their fine surface finish, high dimensional accuracy, and superior quality.
Duma Machinery's main products include: mantle and concave liners, crushing walls, and distribution plates for cone crushers; jaw plates, side guards, and pressure bars for jaw crushers; lining plates for ball mills, autogenous mills, and other equipment; impact crusher hammers and impact plates; as well as hammer heads, screen bars, liner blocks, and other wear-resistant alloy steel components for metal shredders.