2006 Casting Competition: representing industries as diverse as automotive, aerospace, military, marine, art and agriculture, this year's casting competition winners demonstrate the breadth of casting capabilities.
More than 30 components were submitted for this year's competition, representing every type of metal and casting process. Whether they were able to cut down on machining time, reduces weight, save money or improve functionality, each component demonstrated the metalcasting industry's ingenuity, creativity and capability.
Following is a profile of each of the award-winning components--two Castings of the Year, three Best-in-Class and two Honorable Mention winners--including detailed information on the castings and the benefits they provided.
Castings of the Year
Fansteel/Wellman Dynamics, Creston, Iowa
Metal: ZE41 Magnesium.
Process: Nobake casting.
Weight: 97 lbs. (44 kg).
Dimensions: 30 x 11 in. (76.2 x 28 cm).
Application: Air inlet frame and gearbox for accessory drives.
Converted from: Two separate components.
* The casting redesign eliminated more than six hours of assembly and processing time and reduced the part weight by 11 lbs. The casting also saved the customer more than five hours of machining and assembly time.
* Small diameter sand cores were used to cast-in features that replaced external hoses for lubrication, distribution.
* The casting redesign combined two parts--an air inlet frame and a gearbox--and features pipes and external hoses cast-in.
Vehicle Hull Section
Denison Industries, Denison, Texas
Process: Nobake casting.
Weight: 665 lbs. (301.6 kg).
Dimensions: 48 in. dia. (122 cm); 72 in. long (183 cm).
Application: Integrated structural housing for a large unmanned underwater military vehicle.
Converted from: Machined, welded fabrication.
* By converting this previously machined and welded design into a casting, lead time and labor were drastically reduced.
* This 48 x 72-in. casting, which features 0.1875-in. (4.76-mm) wall thickness, was successfully cast on its first pour.
* Overall, the casting conversion resulted in a 50% reduction in lead time and a 15-20% reduction in cost.
Vehicle Hull Section
It took some convincing, but after Lockheed Martin finally decided to try its vehicle hull section for an underwater unmanned military vehicle as a casting, Denison Industries Inc., Denison, Texas, was up to the task. Previously produced as a welded fabrication, the large vehicle hull section was a monster to machine and assemble into its concentric form. Casting the hull section would reduce the lead time by half and eliminate most of the machining, but the question remained as to whether the section would find success as a converted cast component.
"The difficulty is that when something has never been done like this before, getting people to buy into the new idea is hard," said John Brandes, manager of special programs at Lockheed Martin.
But the potential cost and time savings associated with casting a component was attractive enough to help persuade Lockheed to pursue the idea if it could find a metalcasting facility with the ability to do it. "Denison Industries strives in markets that demand highly engineered, core intensive castings with complex geometry. This casting is a prime example of our capabilities," said Shawn Ingram, sales and service manager at Denison Industries. And, with added expertise and insight from consulting metallurgist Leo Powers and pattern shop Tri-City Pattern, Fruitport, Mich., Denison Industries went to work.
"We just looked at it as a bit of a challenge," said Jim Ball, engineering manager at Denison Industries. "We thought we could apply what we've learned from other jobs, so we felt the casting was possible."
Lockheed Martin had several requirements for the vehicle hull section. The casting could not deviate from the original overall weight, the structural properties had to meet strict government guidelines, and the lead time had to be reduced.
"The most attractive aspects of the casting conversion were schedule and cost reduction," Brandes said. "The consistency and conformity achieved through casting was attractive as well. But we were most concerned with cutting down the length of time it takes to get the component."
In order to make the casting work, Denison and Tri-City Pattern had to work together to design a pattern that would center the casting to allow it to achieve the proper wall thickness throughout the 48 x 72-in. (122 x 183-cm) hull section.
"We took some extra pains in the construction of the pattern to make sure we kept everything square and perpendicular rather than just building a quick prototype," said Rod Van Velzen, Tri-City Patterns.
Because of the hull section's size, dealing with the mold was a major challenge as well. More than 45,000 lbs. (20,412 kg) of sand is used per casting, and the molds measure 6.5 x 8 ft. (2 x 2.4 m) tall.
"Due to the size and geometry of the sand cores and mold, we performed the core make, core assembly, pour off and sand removal all in the same spot," said John Manning, coreroom manager
The pattern was designed to produce a mold in which the outside sections would align with the inside sections to achieve consistent wall thickness in the cylindrical casting as forces of the mold worked against the casting walls. Steel inserts were used in some places to keep the sand from crushing the mold.
Denison also devised a custom locator for the mold to keep it in place during moves. Additionally, a cast iron base was made for the mold to ensure the mold was completely flat and level.
Throughout the casting design process, Denison relied on casting process modeling to study the fill scenarios for every design iteration. Denison also met weekly with Lockheed engineers Ken Kurtz and Melody Langeneckert to discuss the casting and go over ways to reach the best, most successful design. Through communication, shared knowledge and plenty of foresight from the technicians at Denison, the first pour of the vehicle hull section resulted in a successful casting.
"We were really quite excited. There was a lot of concern overall, and to see it pour as well as it did at the first shot was great," said Kurtz. "There was a lot of risk, and after that first pour, we were just ecstatic by what was accomplished."
"Between the consortium of Leo Powers, Jim Ball, John Manning and Rod Van Velzen, they did their homework," Denison Industries President Chris Norch said. "They took an aggressive approach to this project, looked at all the areas that could cause a problem, and made sure to find a solution."
Overall, the casting conversion resulted in a 50% reduction in lead time in a 15-20% reduction in cost while meeting the structural requirements.
The magnesium intermediate case produced by Fansteel/Wellman Dynamics is a demonstration of how metalcasters can work with their customers to provide viable and useful solutions to common problems. By combining two parts and casting-in several pipes and external hoses, Fansteel/Wellman Dynamics was able to reduce assembly and machining time for its customer while also lowering overall part weight.
Pratt & Whitney Canada, Longueuil, Quebec, Canada, manufactures engines for the aviation industry, as well as for some industrial applications. Used on the Cessna Citation Bravo, Excel and Ultra Encore business class private jets, the company's popular 500 series engines spent a lot of time in assembly and machining during manufacture.
Before the intermediate case was designed, the engine's air inlet frame, which provides structural support, and the gearbox (for accessory drives) were produced as two separate components. Once the components were produced and in the hands of Pratt & Whitney, there was a long, time-consuming process of machining and assembling the two castings.
Pratt & Whitney wanted to redesign the 500 series engines to improve the efficiency of the manufacturing process on their end. The solution was to redesign the main structural component by consolidating many costly and labor intensive parts into one solid unit with cast-in features.
Fansteel/Wellman Dynamics Engineering Manager Pat Pattabiraman worked with the chief engineer from Pratt & Whitney Canada to create a design that would be both efficient and cost-effective to produce. Pratt & Whitney's desire to combine the air inlet frame and gearbox was actually only a portion of what the company wanted to achieve. The firm also wanted to cast-in most of the external oil lines using small diameter pipe cores that are long and serpentine in shape. This reduced the amount of time, labor and inventory they had to endure with the old design and improved the mechanical properties of the system.
The intermediate case was the solution to Pratt & Whitney's problem. By combining more than 30 individually purchased parts, the design efforts of Fansteel/Wellman saved the firm more than five hours of machining and assembly time per part and provided for an appreciable cost savings. However, solving Pratt & Whitney's manufacturability problems presented a whole new set of challenges for Fansteel/Wellman.
The company's greatest challenge was to continuously link the 137 separate cores to provide adequate ventilation during the pouring process. After several trial and error runs, the engineering team at Fansteel/Wellman was able to create enough passages for the gas to escape without rupturing the cores or the walls of the mold. "The dedicated team's efforts allowed us to significantly reduce the amount of rework and scrap on these castings," said Jeremy Gerritsen, engineering continuous improvement team leader for the intermediate case project.
In the end, Fansteel/Wellman produced a casting that saved its customer time and money while also meeting their strict requirements for quality. To ensure these requirements are met, every intermediate case must go through thorough x-ray examination as well as pass ASTM Grade B specifications. Jim Smith, Fansteel/Wellman's ASNT level 3, worked with Pratt & Whiteny Canada's NDT professionals to better define the radiographic acceptance criteria imposed by the drawing and specification requirements.
Pratt & Whitney was able to adopt the conversion principles from this project to the other two engine models in the 500 series family.
Break-Away Hinge The Dotson Company Inc., Makato, Minnesota
Metal: Ductile iron 65-45-12.
Process: Green sand casting.
Weight: 5.5 lbs. (2.5 kg).
Application: Sprayer units.
* The design of the mated castings, measuring 9 x 3 x 3 in. (23 x 7.62 x 7.62 cm), allows the sprayer boom to "break-away" when it hits an object. The sinusoidal curves in each casting allow the parts to rotate up to 90[degrees] and then naturally lock back into place.
* The alternative of using solid machined steel was 5 times more costly than ductile iron castings.
Shift Tower Assembly Lunt Manufacturing Co. Inc., Schaumburg, Illinois
Metal: Magnesium alloy AM60B.
Process: High pressure die casting.
Weight: 2.3 lbs. (1.04 kg)
Application: Bracket assembly used to support shifting mechanisms.
Converted From: Multiple steel fabrication.
* The one-piece magnesium design, measuring 8.7 x 8.9 x 13 in. (22.1 x 22.6 x 33 cm), offered the lowest weight and unit price of any alternatives, including aluminum, steel, plastic and reinforced nylon.
* The design uses variable wall thickness (2-10 mm) and incorporates weight-saving holes. The magnesium casting weighs 75% less than the previous steel design.
Deep Sea Diving Helmet Aristo-Cast, Almont, Michigan
Metal: 316 stainless steel.
Process: Investment casting.
Weight: 13 lbs. (5.9 kg)
Application: Deep sea diving helmet.
Converted from: Carbon fiber
* Previously designed as a carbon fiber piece, the alternative 316 stainless steel provided significant cost savings in labor costs by removing the need to core.
* Stainless steel provided the high tensile, high yield and high strength material that the end customer needed for its application.
Hog Bank Boose Aluminum Foundry Co. Inc. Reamstown, Pennsylvania
Metal: 319 aluminum.
Process: No bake.
Weight: 166 lbs. (75.3 kg).
Application: Commercial art piece.
* Primarily designed for fund raising events, the hog opens new markets in commercial art for the metalcasting facility.
* The 60 x 28-in. (152 x 71 cm) aluminum piece features a twist-out tail casting.
* Six other hogs will be cast, painted and sold as commercial, high-end artistic pieces.
Radial Heatsink Armstrong Mold Corp. East Syracuse, New York
Metal: A356-T6 aluminum.
Process: Plaster mold.
Weight: 1.2 lbs. (0.54 kg).
Application: Avionics heat dissipation.
Converted from: Hogout pin stacked assembly.
* The casting conversion provided 75% time savings and over 85% cost savings in labor.
* This 9 x 9 x 1.1-in. (23 x 23 x 2.8-cm) component uses 1,750 cast-in pins. The first samples were available in four weeks.
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|Article Type:||Cover story|
|Date:||Jun 1, 2006|
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