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How Investment Casting Works

Investment Casting: the route, the tolerances it holds, materials and design tips, with an indicative cost. One of 56 processes in the free finder.

CastingFamily
+/-0.2mmTypical tol.
5Route steps
142Parts in finder

Investment casting builds a wax pattern, coats it in a ceramic shell, melts the wax out, then pours metal into the cavity. It gives near-net shape with fine detail.

At a glance

When to use it, and when not

Best for

Complex, detailed metal parts needing a good finish and tight tolerances, including superalloys and turbine hardware.

Watch for

Higher part cost and longer lead time than sand casting, and size is limited by the shell.

Step by step

The typical route

Raw material to finished part. Steps vary with material, volume and tolerance; this is the free route from the finder.

  1. Wax pattern

    Injection-mould wax copies and assemble a tree.
    Tooling Wax die   Tolerance -   Lead -

  2. Shell build

    Dip the tree in ceramic slurry and stucco, repeat, dry.
    Tooling -   Tolerance -   Lead -

  3. Dewax & pour

    Flash-fire out the wax, then pour metal into the hot shell.
    Tooling Furnace   Tolerance -   Lead -

  4. Knockout & cut

    Break the shell, cut parts off the tree, grind gates.
    Tooling -   Tolerance -   Lead -

  5. Finish & NDT

    Machine where needed, FPI/X-ray critical parts.
    Tooling CNC   Tolerance -   Lead -
Precision

Tolerances it can hold

TYPICAL TOLERANCE IT CAN HOLD
+/-0.2mm typicalcoarsefine+/-1mm+/-0.1mm+/-0.01mm+/-0.005mm
Where this process typically lands. Tighter is possible with extra operations like grinding, at higher cost.
Materials

Materials it suits

GradeWhy it suits this
Stainless 17-4PH / 316Strong, corrosion resistant
Carbon/alloy steelStrong, cheaper
Superalloy (Inconel)High-temp
Design

Design tips

A few general pointers for Investment Casting. The full, part-specific DFM list is in the dossier.

  • Isolated heavy sections. Core out or add feeders.
  • Tight tolerance left as-cast. Add a machining stock face.
Cost

What it costs

Near-net and great finish, so it saves machining on complex parts; the wax die is the cost to amortise.

PER-PART COST vs VOLUME
one-offat volumeVolume per order, low to highCost per part
Per-part cost drops as volume spreads tooling and setup over more parts. The exact figures for your part at your volume, in your currency, are in the dossier.
MODEL EST.
$460 to 785 per part at 1 off
A rough ballpark only. The dossier gives should-cost at your exact volume and currency, with the full breakdown.
GET THE FULL DOSSIER

Everything you need to quote and source it

The free route above is yours. To actually put a number on this process and buy it well:

  • Should-cost at your exact volume in 12 currencies, with the material, processing, tooling and overhead breakdown
  • Who to source from, typical MOQ and lead time, and the exact RFQ checklist to send
  • A quote checker that tells you if a supplier quote is fair, and the red flags to watch
  • The full DFM list and a ready-to-send RFQ draft
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Examples

Parts made by Investment Casting

142 parts in the finder use Investment Casting as their primary process. A sample, each with its own guide:

allis forcepsart castingartworkbone chiselbone curettebone platebone screwdrivercleatcufflinkdental bracketdental elevatordental scalerear speculument instrumentfigurinefirearm hammerfirearm searflute keygate valvegun receiverhinge casthinge ornatehip stemimplantimplant driverintricate metaliris scissorsjewelleryjewelrykerrison rongeurmanifoldmarine fittingmedalorthopedic broachorthopedic rasposteotomependantprostheticprosthetic jointpump rotorreamerrf componentsculptureskin hookstatuesurgical probesurgical retractortowel clamp
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FAQ

Frequently asked questions

How is a part made by Investment Casting?
Investment casting builds a wax pattern, coats it in a ceramic shell, melts the wax out, then pours metal into the cavity. It gives near-net shape with fine detail. The typical route is: Wax pattern; Shell build; Dewax & pour; Knockout & cut; Finish & NDT. Complex, detailed metal parts needing a good finish and tight tolerances, including superalloys and turbine hardware.
What does Investment Casting cost per part?
It depends on size, tolerance and volume. As a rough ballpark it starts around $460 to 785 per part at low volume and falls with quantity. The dossier gives should-cost at your exact volume and currency. Model estimates, not quotes.
What tolerance can Investment Casting hold?
Typically about +/-0.2 mm, tighter with extra finishing operations at higher cost.
What materials suit Investment Casting?
Common choices are Stainless 17-4PH / 316 (Strong, corrosion resistant); Carbon/alloy steel (Strong, cheaper); Superalloy (Inconel) (High-temp).
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