What is the difference between investment casting and sand casting?

Investment casting uses a one-piece ceramic shell made around a wax pattern, giving finer detail, smoother surfaces and closer tolerances. Sand casting is cheaper for large, simple parts.

Is investment casting expensive?

The wax die is an upfront cost, but each part often needs little machining, so for complex parts in medium quantities it is frequently the cheapest route.

What sizes can be investment cast?

From a few grams up to tens of kilograms in most foundries; very large parts are usually sand cast.

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Investment casting

Also called: lost wax casting, precision casting, investment casting job work, investment castings

Investment casting (lost wax casting) makes metal parts by coating wax patterns in ceramic, melting the wax out and pouring metal into the shell. It gives fine detail, smooth surfaces and close tolerances, often with little machining, in steel, stainless steel and other alloys.

Quick facts

Typical part weight: From a few grams to tens of kilograms
Surface finish: About Ra 3.2–6.3 µm as cast
Tolerance: Closer than sand casting; roughly ±0.1–0.3 mm on small dimensions
Materials: Stainless and carbon steels, alloy steels, nickel alloys, brass and bronze
Tooling: A wax die (mould for the wax patterns)
Best quantities: Hundreds to tens of thousands

How it works

Wax is injected into a metal die to make a wax copy of the part
Wax patterns are fixed onto a wax tree
The tree is dipped in ceramic slurry and sand, layer by layer, to build a shell
The wax is melted out (lost wax), leaving a hollow ceramic mould
Molten metal is poured into the hot shell
The shell is broken away, parts are cut from the tree and finished

When to choose it

Complex shapes that would need a lot of machining
Fine detail, thin walls, letters and logos
Stainless steel and alloys that are expensive to machine
Medium to large quantities that pay for the wax die

What to send

3D model and drawing, marking machined faces
Material grade and any test certificates needed
Quantity per year
Critical dimensions and tolerances
Heat treatment and finish required

Need investment casting done?

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Related job work

Machines

VMC (vertical machining centre)

Materials

Questions

What is the difference between investment casting and sand casting?: Investment casting uses a one-piece ceramic shell made around a wax pattern, giving finer detail, smoother surfaces and closer tolerances. Sand casting is cheaper for large, simple parts.
Is investment casting expensive?: The wax die is an upfront cost, but each part often needs little machining, so for complex parts in medium quantities it is frequently the cheapest route.
What sizes can be investment cast?: From a few grams up to tens of kilograms in most foundries; very large parts are usually sand cast.

The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 8 October 2026.