How precise are tolerances for medical die cast parts?

How Precise Are Tolerances for Medical Die Cast Parts?

General Tolerance Capabilities in Medical Die Casting

Medical die cast parts must meet stringent dimensional tolerances to ensure proper assembly, device functionality, and regulatory compliance. According to ISO 8062-3 and NADCA (North American Die Casting Association) standards, typical as-cast dimensional tolerances for precision components are:

• Linear tolerances: ±0.05 mm for features under 25 mm

• Flatness/straightness: ≤0.13 mm per 25 mm span

• Hole position tolerance: ±0.10 mm for holes under 10 mm in diameter

These tolerances can vary based on geometry, material, and mold design. Medical components—such as instrument housings, control enclosures, and mechanical supports—commonly require dimensional repeatability across high volumes.

Factors That Influence Tolerance Achievement

Material Selection

Alloy properties directly affect dimensional control during cooling and ejection. For example:

• A360: Excellent castability and minimal shrinkage, resulting in high dimensional accuracy.

• Zamak 3: Offers outstanding repeatability, ideal for thin-walled precision parts used in diagnostic instruments.

Mold Design and Tooling

Tool and die making plays a critical role in achieving high-precision outcomes. Key tooling strategies include:

• Uniform thermal control across the mold

• Draft angles optimized to prevent drag marks

• Insert design for critical dimensional features

Post-Machining for Tight Tolerances

For features requiring tighter tolerances than achievable in the casting process alone—such as press-fit diameters or threaded holes—post machining is employed. CNC operations can reduce tolerances down to ±0.01 mm, supporting highly precise components like pump housings or alignment brackets.

Supporting Services for High-Precision Medical Casting

To meet precision and compliance needs in medical applications, we offer:

• Material and Prototype Validation

  • Rapid Prototyping: Validate form, fit, and function early using actual casting materials.

  • Casting Material Selection: Helps determine alloys with superior dimensional control and corrosion resistance.

• High-Tolerance Production and Finishing

  • Post Process for Die Castings: Includes deburring, sandblasting, and machining to meet ISO 13485 and ISO 2768-mH tolerance classes.

• Integrated Quality Control

  • Die Casting Inspection: Coordinate measurement machines (CMM) and digital inspection ensure dimensional traceability and PPAP documentation.

Our one-stop manufacturing solution ensures you receive precise, validated parts tailored for regulatory compliance and device integration.