Gains mark 1992 ICI gathering.

The 40th Investment Casting Institute (ICI) technical conference was one of the busiest in the last several years, according to Henry Bidwell, executive director of ICI.

It was attended by more than 600 foundrymen from 17 countries and was the first ICI conference to feature exhibits by casting equipment manufacturers and materials suppliers.

More than 70 companies displayed a wide range of products and services, many of them new and all essential to the investment casting industry. Prominent among them was equipment for rapid prototyping of casting designs, including a demonstration of the direct shell production casting (DSPC) apparatus.

A new dual-track induction melting furnace, an automated cluster assembly machine, the newest PC-based robot and an automatic wax injection machine were also among the latest equipment technology on display. Wax, binders, refractory and metal suppliers also participated.

The major focus of the conference, which was held October 9-13 in Chicago, Illinois, were the 34 technical presentations that drew heavy attendance. They ranged from solidification modeling to abrasive flow machining.

Modeling

The ability to predict casting properties and structures is an important manufacturing and economic requirement for investment casters.

The importance of these requirements was evident in several presentations on computerized part analysis as a means of reducing lead times and costs.

Seven papers were presented on the current technology and availability of 3-D fluid-flow and solidification computer models and the unique approaches required for a simulation of investment cast components. A paper presented by UES Processing Inc., Dayton, Ohio, stressed the capabilities of micromodeling to predict dendrite growth patterns and size in a pseudobinary, two-phase (Al-Cu) alloy.

The Magma Foundry Technologies, Inc., Arlington Heights, Illinois, presentation covered the specialized requirements that account for different heat transport mechanisms from the metal to the ceramic mold; radiation losses from mold surfaces to the air and adjacent surfaces; and the "heat sink" areas developed in a ceramic shell.

The University of Alabama revealed preliminary results of a three-year, AFS-sponsored study on the utility of criteria functions to predict porosity formation. The work identified different methodologies to calculate criteria functions and evaluated the predictive accuracy of each. A critical step in this investigation was the casting verification of the functions within foundries.

Sandia National Laboratories, Albuquerque, New Mexico, presented four papers on the results of its modeling work on flow and solidification. Sponsored by the U.S. Dept. of Energy, the "FASTCAST" project seeks to integrate diverse technologies in feature-based solid modeling, finite element analysis, rules for casting, gate/runner geometry and mold analysis.

The results of a study for thin-walled 17-4PH alloys showed the effective "radius of influence" and terminal fill volume times for various gate designs, paralleling an AFS project to develop a modulus-based gating design program. Results of this program and a comprehensive manual will be available this year.

Rapid Prototyping

Rapid prototyping technology is the newest tool available to investment casters. This equipment produces prototype designs without tooling. Sandia National Labs made a presentation on its experiences with rapid prototyping using stereolithography and selective laser sintering.

Used with DSPC, this new technique produces a shell directly from a CAD file. An entire multiple-part cluster can be created that may obsolete traditional investment casting processes.

Shell Production/Control

The ability to develop new casting designs and applications was addressed in presentations on recent advancements in shell system materials and controls that dramatically reduce the time from first dip to metal pouring.

Remet Corp., Chadwicks, New York, introduced an alternative binder system to ethyl silicate binders that allows drying rates comparable to ethyl silicate while using any standard refractory.

If circumstances cannot accommodate an alternative shell system to ethyl silicate, a new volatile organic compound (VOC) treatment process called biofiltration, introduced by RMT Inc., Madison, Wisconsin, offers an alternative system now being foundry-tested.

Additional papers by DuPont Co., Wilmington, Delaware; Ransom & Randolph Co., Maumee, Ohio; and Minco, Inc., Midway, Tennessee; dealt with the problems of how to stabilize colloidal slurries and extend their useful lives.

Other papers presented information on wax injection and reclamation; new shell room equipment and post casting operations; cleaner metal melting technologies; and metal matrix composites for investment casting applications.

Thirty-three of the 34 presentations are available in proceedings published by ICI.

The 1993 technical conference will be held October 9-13 at the Drake Hotel, Chicago.