The Investment Casting Institute (ICI) concluded its 52nd Technical Conference and Expo program at the Northern Kentucky Convention Center in late September.
The non-profit organization sponsors a Casting Contest at its annual meetings. The winners in four categories ( automotive, industrial, aerospace and space technology) were announced during the conference.
Investment casting became popular about 50 years ago because of the flexibility in designing patterns, the kinds of materials that can be used, and the surface quality that it provides.
Each of the 2004 winners demonstrates the benefits of using investment casting by reducing costs, eliminating assembly, improving performance, simplifying manufacturing and reducing lead time.
Aristo Cast Inc. fuel pump remover for Ford Focus
Aristo Cast Inc. from Almont, MI was the winner in the automotive category. Aristo Cast designed a fuel-pump remover for Ford Motor Co., in response to a recall of the Ford Focus.
Ford faced an emergency recall of its new breed of automobiles. The recall of the Focus required a tool that would cut through the four supports on the bottom of the tank and in a gas fume environment. A tool made of a non-sparking material and that yielded high strength was necessary.
Aristo Cast filled in the rest of the puzzle, selecting aluminum bronze to manufacture the tool and tapping into its previous experience with rapid prototyping technology and casting expertise. The company is able to create parts directly from math data.
Aristo Cast provided prototypes within two days and was able to provide 17,100 aluminum bronze castings in just seven weeks from the final design to arrival at auto dealerships around the world.
The finished product saved Ford the cost of replacing the fuel pumps. The quick design and execution earnd Aristo Cast the 2004 automotive award, one of three awards recently won by the company.
ICI recognized Aristo Cast in 2003 with it's Best in Class award. The company earned the award for its telescopic trailer tow mirror mount for pickup trucks. The mirror mount was fabricated with magnesium, a media that very few investmentcasting firms use.
Signicast Corp.'s winning design in the Industrial category.
In the industrial category, Signicast Corp., Hartford, WI, won for its improvement to a sayflink (part of a safety harness device). Signicast evolved the sayflink from a three-piece assembly requiring machining, stamping, forming, and welding to a two-piece investment casting piece.
The sayflink is a moveable device that is attached to a horizontal safety wire, as part of a safety harness. It can stop the fall of a worker in the case of an accident.
Cast in 17-4 PH stainless steel, the improved sayflink consists of two lightly machined investment castings, one containing the tang feature. The original assembly was of two heavily machined pieces, stamped and formed, and a welded tang, sliding over the intermediate bracket of the harness.
The revision is 20% lighter than the original, making the sayflink easier to handle in a dangerous situation. By casting the item, Signicast was able to add large radii and smooth edges where the safety wire slides through.
The strength of the sayflink was increased because of the manufacturing. The ability to sculpt the exact dimensions and shape the product minimized high stress levels in the piece. Removing the machining, stamping, forming, and welding in production also resulted in a drop in cost.
Signicast has revolutionized investment casting by a process called Continuous Flow Manufacturing. It is the uninterrupted processing of products from one work cell to the next, varying the required work pace to achieve the minimal level of backlog, in order to keep the work flowing smoothly to the customer on time.
Miller Casting's exhaust housing won in the aerospace category
Miller Casting Inc. won the ICI aerospace award for its improvements on exhaust housing, using investment casting. The piece illustrates the use of investment casting with small core passages and varied wall thickness.
Designed for an aircraft engine, the Whittier, CA group chose investment casting in part because of the many transitions (from thin wall thickness to thick wall to thin) and the small core passages that accompany the piece.
After several iterations using a rapid prototyping process, the design was decided upon and the tool was cast in Inconel alloy 718, measuring 15 inches in diameter and 5.5 inches high.
MTU, a German aerospace manufacturer, is using the piece now in an experimental developmental engine. Additional testing is underway and production will begin in the near future.
Space technology category
Applied Materials Science Inc. won for space technology improvements
The fourth winner, in the space technology category, is Applied Materials Science Inc of Nashua, NH. Its sun sensor bracket was the first piece investment casting manufactured of beryllium-aluminum metal matrix (MMC) to be employed by NASA.
The bracket (2.75 in. high, 2 in. wide, 1.5 in. deep) holds the sensor to the back of a satellite acquiring solar power. The bracket provides the opportunity for other cast components to displace fully machined components or the assembly of machined parts, another cost-saving option.
The bracket's manufacturing is lighter. Reportedly, using beryllium-aluminum metal matrix (Be-Al) will save NASA anywhere from $7,500-$9,400 per satellite because the piece is 22% of the weight of the original piece (3/8 of a pound.)
Be-Al is also three times stiffer than the aluminum alloy that it replaces. The alignment is improved because of the increased stability of the material. The lead time is reduced on future shipments because the manufacturing (hard tooling, decreased machining and the elimination of the T651 heat treatment).
The casting passed all screening tests from NASA engineering, withstanding static loading tests and random vibration tests. The casting x-ray requirement imposed was a grade C by NASA, but the part exceeded all requirements, earning a grade B.
Secondary operations of the bracket included alodine coating (for flight hardware), machining, and black anodizing.
The contest was developed to recognize investment casting facilities that manufacture components which best illustrate investment casting and demonstrate problem-solving techniques for the customers.
The 2004 winners all were able to reduce cost and improve performance, whether through the actual manufacturing of the tool or through the application of the tool. This contest draws attention to the benefits and the advances in investment casting in today's market.
Other applications in high melting alloys
Precisions Metalsmiths Inc., announced the award of a new patent for the investment casting of high melting alloys. The new investment, developed by Robert A. Horton and Claude H. Watts and assigned to PMI, was recently issued a US Patent (6,746,528), one of 200 US or foreign patents earned by PMI for its work in casting methods, materials and processing equipment.
Specifically developed for the investment casting of platinum jewelry, the new solid mold can be used for other high melting alloys and new investment material offers significant advantages over existing platinum investments.
The new investment produces superior finishes because it was specifically developed for jewelry. Instead of requiring acid or another type of liquid, the new investment uses water, decreasing the potential for accidents, saving time and cutting back on costs. The lone hazardous substance (as in all platinum investments) is silica.
The new process is flexible. Molds can be invested and cast the same day, or invested, fired overnight, and cast the following day, leaving room for scheduling adjustments. There is no loss in quality and in many cases the results were actually improved.