ASA AND SEVERAL COMPANIES ARE WORKING
together on an Aerospace Industry Technology Program (AITP) project to overcome key
technical barriers that limit casting applications in aerospace and other industries.
Volume 5, Number 1 January/February 1997
Technology Transfer
ASA AND SEVERAL COMPANIES ARE WORKING
together on an Aerospace Industry Technology Program (AITP) project to overcome key
technical barriers that limit casting applications in aerospace and other industries.
The U.S. foundry industry wants increased casting performance to meet consumer demands for lighter, stronger and less costly products. Foundries can enhance their competitiveness by meeting these demands with shorter, more flexible product cycles using computer modeling, process simulation and rapid prototyping.
Casting begins with the core-making process. Cores are produced by blowing or injecting a mixture of ceramic aggregate and free-flowing carrier into a die. Investment casting industry cores typically are composed of silica or alumina injected into a die with a wax carrier. Sandcasting industry cores typically are composed of silica coated with a resin binder and delivered to a die with air. Both core types must be strengthened after molding by appropriate chemical or thermal reactions prior to casting. Tool design, molding and curing process parameters are currently defined by trial-and-error techniques.
Sensors and control models will enable real-time,
intelligent process control.
The AITP project focuses on manufacturing and production processes by developing technologies for: predictive models to eliminate trial-and-error; real-time process monitoring and control to increase casting dimensional accuracy; and rapid prototyping to reduce prototype development time.
Project researchers are developing computational methods based on the physics of the processes that produce cores for investment and sand castings. They have developed extensive dimensional databases on cores to anchor the predictive models. Enhanced process design produces components more quickly, less expensively and at better quality because it eliminates trial-and-error and reduces variability.
Advanced sensor and controls have been installed on core machines so foundries can monitor and control the internal and external dimensions of their cores and castings in real time during the core-making process. By minimizing variability, better dimensional accuracy is obtained.
Production lead-time must be shortened. The project has developed technology that produces ÒwaxÓ patterns for investment castings, shortening casting development times to months and, ideally, weeks. Complex automotive sand castings and structural aerospace castings often have required three to four years to develop and certify. Rocket engine gas generator bodies that had been produced from several formed and welded components now can be investment cast as one piece.
The project team includes NASA executing agent, Lewis Research Center; project lead, Rockwell Aerospace/Rocketdyne Division, Canoga Park, California; Lockheed Martin Corporation, Denver, Colorado; Ford Casting Operations/Ford Motor Company, Dearborn, Michigan; General Electric CR&D, Schenectady, New York; PCC Airfoils, Inc., Beachwood, Ohio; Auburn University, Auburn, Alabama; Howmet Corporation, Whitehall, Michigan; University of Alabama at Tuscaloosa, Alabama; UES, Annapolis, Maryland; Aracor, Mountain View, California; Robinson, Inc., Beachwood, Ohio.
For more information, contact Carl Ray at NASA Headquarters.
Call 202/358-4652, E-mail: cray@hq.nasa.gov
or Neville Marzwell at Jet Propulsion Laboratory.
Call 818/354-6543, E-mail: Neville.I.Marzwell@jpl.nasa.gov
Please mention that you read about it in Innovation.
