Speakers Detail Tooling, Micro-Porosity at 6th Annual AMC Technology Review.

The 6th annual "technology review," held in Charleston, South Carolina, on October 3-4, informed more than 60 attendees from the Defense Logistics Agency and the metalcasting industry of ways to reduce costs and lead-time in a short production run environment.

The technical program addressed research and development to improve processes, technology transfer to improve the industry through timely and efficient technology dissemination and developing supply chains to reap the benefits of metalcasting manufacturing. The event was grouped into three sessions devoted to rapid tooling, reject reduction and dimensional performance. Rapid tooling presentations included developing decision systems for short-run tooling and rapid evaluation of gating tooling strategy; reject-reduction presentations tackled aluminum casting reliability, machining and diecasting; and two papers on dimensional performance dealt with diecast dynamic tooling distortion and the production of accurate thin-wall steel castings.

The session on developing supply chains to meet DLA short production runs discussed how the development of cross-functional teams to procure castings at defense supply centers capitalized on diverse expertise to focus and resolve technical and business issues. This approach leaves a legacy that continues to evolve within individual centers and provides the seeds to spread throughout the entire DLA organization. The AFS Pattern and Foundry Tooling Div. has worked with Northwestern Univ. to develop a foundry tooling selection advisor for expendable mold casting processes. Proper foundry tooling selection is the critical step for time and cost-effective casting procurement.

Foundry-tooling technologies are in a rapid period of change. Since 1995, there are 20 new rapid tooling approaches identified, nine new reverse engineering technologies, and sand cores can be directly produced from CAD solid models. Selecting the most time and cost-efficient approach for creating the tooling required the production of a given quantity of castings for a specified casting geometry, casting process and available tooling builder. Foundry capability requires a systems approach to optimize all these factors. This program develops a broad understanding of the foundry tooling selection process for expendable mold casting. This enables the development of a foundry tooling selection advisor to integrate these many interactive factors yet ceasily assist the casting purchasing team to confidently identify alternatives to meet any procurement need. Efficient ways to maintain technical currency of the advisor to maintain the system in the rapidly evolving technology climate is essential to maintain a rob ust system.

The Univ. of Alabama at Birmingham discussed a project to quantify the effect of microporosity on tensile properties. This project also was designed to compare the capability of various traditional and nontraditional non-destructive evaluation (NDE) techniques to detect porosity and inclusions. In the project, 192 plate castings were produced for evaluation by ultrasonic and radiographic tests. Mechanical properties of selected test plates with various levels of porosity were measured to correlate with the magnitude and extent of different NDE indications.

The study found that porosity is the principal cause for immediately degrading the elongation and reduction in area, but had virtually no effect on static yield and ultimate tensile strengths. A computerized model for predicting and eliminating porosity was developed, and confirmation experiments were conducted on an aircraft flap control. No production castings were scrapped based on the numerical modeling recommendations.