Why Shrink Allowance Matters in 3D Printed Casting Patterns

A casting pattern is not the same size as the finished part. Metal shrinks as it cools, and that shrinkage must be accounted for before the mold is made. This is called shrink allowance, and it is one of the most important details in foundry patternmaking.

At Jaeger Technology Group LLC, we design and produce 3D printed casting patterns with shrink allowance built into the CAD model.

What Is Shrink Allowance?

Shrink allowance is the intentional increase in pattern size to compensate for metal contraction during solidification and cooling. Different metals shrink by different amounts, so the pattern must be scaled based on the casting material and foundry requirements.

Common considerations include:

• Metal type
• Casting geometry
• Wall thickness
• Foundry process
• Machining allowance
• Dimensional tolerance
• Directional shrinkage concerns

Why 3D Printing Helps

With 3D printed patterns, shrink allowance can be applied digitally and consistently. The CAD model can be scaled intentionally, reviewed before printing, and revised if needed.

This is especially useful for:

• Prototype castings
• Sand casting patterns
• Match plates
• Loose patterns
• Core boxes
• Industrial replacement parts
• Production support tooling

Digital control reduces guesswork and makes it easier to reproduce the same tooling later.

Work With Jaeger Technology Group LLC

If your foundry needs 3D printed casting patterns, shrink allowance support, match plates, loose patterns, or foundry tooling, Jaeger Technology Group LLC can help create practical, foundry-ready patterns for your casting workflow.