Hey casting folks, ever picked the wrong casting process? Today I'm breaking down the top 10 casting processes—every advantage, application scenario, and key parameter—explained thoroughly. Process logic and comparison tables are at the end. Whether you're making agricultural machinery or aerospace components, by the end you'll know exactly which process to choose.
1. The Jack-of-All-Trades of the Casting World
Sand Casting—sand as the mold, flexible and adaptable. The core logic of sand casting is using a collapsible sand material to build the mold. The sand mold collapses naturally as the casting solidifies, so you never have to worry about mold-release complexity. That means it can handle virtually every metal material and size imaginable—iron, steel, copper, aluminum alloys—from parts weighing a few grams to castings of several hundred tons.
Sand casting breaks down into manual sand molding and machine sand molding. Manual molding relies on human adjustment, making it ideal for low-volume production like art castings. Machine molding uses equipment for standardized operations, perfect for high-volume parts like automotive cylinder blocks and engine housings.
Sand casting's cost advantage is obvious: the sand is recyclable, and mold costs are low. But the downsides are just as clear. Because sand molds have limited strength, casting precision is generally only CT12 to CT10—a classic case of trading low cost for flexibility. It’s best suited for parts where precision isn't critical: construction machinery, farm equipment, automotive intake manifolds, engine housings, and other essential components.
Word of caution: Don't use sand casting for high-precision or high-gas-tightness parts. Sand molds are inherently permeable, so castings are prone to gas porosity.
2. The Speed King of Non-Ferrous Metals
Die Casting—high-pressure filling, rapid forming. The core of die casting is using high pressure to inject low-viscosity non-ferrous metal melt into a metal mold cavity. The metal solidifies inside the mold almost instantly, delivering parts in seconds. It’s a perfect match for high-volume, thin-walled components.
Common non-ferrous metals like aluminum, zinc, and magnesium alloys have low melting points and excellent fluidity. Under high pressure, they can rapidly fill complex, fine cavities: the micro-textures on phone mid-frames, laptop shells, and even Tesla vehicle body panels. Materials like cast steel, however, have high melting points and tend to solder/stick to the mold, making them unsuitable for die casting.
Choosing die casting means high upfront investment in exchange for low per-unit cost. Die-casting molds are typically made from H13 tool steel and can be reused for tens of thousands of cycles. The initial mold cost is high, but as production volume ramps up, the per-piece cost drops. Typically, after 10,000 pieces, the unit cost is about 30% lower than sand casting. It’s ideal for conventional parts in volumes above 10,000.
Critical note: Don't use die casting for thick-walled parts. When the metal solidifies rapidly, shrinkage porosity easily forms in thick sections. For example, on a 20 mm thick aluminum alloy part, die casting scrap rates can exceed 15%.
To be continued…