Benefits of Investment Cast vs. Sand Cast

Blowhole defect in a cast iron part.
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Technical Process

For sand casting, molten alloy is poured into a sand mold at room temperature. Any moisture in the mold produces gases/vapors resulting in casting defects that can undermine the life of the component. Numerous types of defects can occur during sand casting including mold erosion, metal penetration, sand fusing to the casting, drops, run outs, scabs, swells, and burn-ons.

The investment casting process pours molten alloy into a hot, dry ceramic shell, hence no gases are created. Hot-shell pouring ensures greater fluidity of the molten alloy. Investment castings cool more uniformly through the cross section. As a result, there is less residual stress and fewer cracks are created as the molten alloy cools.

General Benefits of Investment Cast Work Trays

  1. Longer service life
    For example, investment cast HU furnace trays typically last longer than equivalent sand cast trays.

  2. Less porosity
    Investment cast trays are less porous than sand cast trays. In addition to longer life, the smooth finish drags out less oil with every quenched load.

  3. Dimensional precision
    Investment casting provides a greater level of dimensional precision. It is possible to make thinner, structurally sound components, with investment casting.

  4. Lighter designs
    Investment cast trays may be manufactured to tighter tolerances than sand cast trays. It is therefore possible to design lighter-weight components. Not only does less weight reduce acquisition costs, it may also increase the furnace’s production rate.

  5. Environmental impact
    Sand casting results in serious environmental pollution in the form of sand waste. Investment casting uses wax patterns which can be mostly reclaimed and reused.