Objective: Determine die tooling dimensions for the investment casting process to
produce casting parts at nominal dimensions within tight tolerances.

Background: Die tooling dimensions are determined by adjusting blue-part
dimensions based on proprietary and plant experience.
To date, there are no industry-wide guidelines to tooling engineers for die dimensioning.

Approach: Develop plant procedures and computational models to determine
dimensions for wax patterns, shell molds, casting parts, and die tooling.

Accomplishments:

Wax: Pioneered the measurement of viscoelastic properties of waxes. Determined
wax pattern dimensions using computer models.
Distortion of wax patterns can be qualitatively predicted using viscoelastic models.

Shell: Obtained constitutive equations for thermal radiation effects within the shell mold.
Casting temperature can be predicted with confidence using new thermal radiation models.

Benefits: Reduce scrap by improving dimensioning practices, reduce the downtime
due to mold rework, allow the use of thinner walls, increase productivity of the design
process. Projected benefits: Scrap deduction from 4% to 3%. Increase in yield from 55 to 65%.

Industrial support
AFS consortium of twelve investment casting companies

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Acknowledgements Industrial Materials for the Future (IMF), Industrial Technologies
Program, Energy Efficiency and Renewable Energy, U.S. Department of Energy.