2002 AFS Casting Contest: industry's top components recognized.

Earning top industry recognition, these award-winning components depict how cast designs are answering the call for increased performance and cost-reductions.

Sixteen component designs, including a "Casting of the Year," earned top industry recognition for 2002 at the American Foundry Society's (AFS) 106th annual Casting Congress & CastExpo in Kansas City, Missouri, on May 7.

This second-annual AFS Casting Contest (sponsored by the MS Marketing Services Div. and Engineered Casting Solutions magazine) attracted 53 components from every metal type and casting process, and were entered by both casting producers and OEM manufacturers alike. Six independent judges evaluated each casting on its own merit, with particular emphasis on criterion that centered on benefits delivered to the customer, illustrative of the unique capabilities of the casting process, and overall contribution to growth and expansion of the casting market.

Key among the benefits OEMs found through these designs were gains in: speed-to-market, part consolidations and inventory reductions, reductions and/or elimination of machining, welding and assembly, design flexibility, weight reduction and dimensional tolerance improvements. These award-winning components and the other contest entries are arming AFS' efforts in showcasing the possibilities metalcasting can offer to design engineers and purchasing agents--the very people who will create the demand for cast products into tomorrow.

This article was adapted from one that appeared in the Summer 2002 issue (12th annual Casting Source Directory & Reference Edition) of Engineered Casting Solutions. For a free publication detailing each of these award-winning components, circle 341 on the Reader Action Card on the last page.

Casting Supplier: Madison-Kipp Corp., Madison, Wisconsin 

Component: Fuel rail housing for four-cylinder, 2.0 and 2.2-L passenger car models.

Application: High-volume passenger cars.

Casting Process: Semi-solid casting.

Metal: 357 Aluminum, T-5, Heat-Treat.

Dimensions: 12 x 2.25 in.

Weight: 1.07 lb.

Converted from: Traditionally designed as fabricated steel tube and plastic.

* An engine configuration required a fuel rail housing capable of withstanding high levels of impact without failure. The customer decided that traditional fabricated brazed steel tube and plastic designs would not meet the stringent impact requirements and opted for a cast component.

* The customer, first-tier supplier, and casting and machining component supplier worked together to develop a casting that met the 7000-lb crash test load and elongation requirements while keeping overall mass and costs to a minimum.

* Increased dimensional accuracy of critical features (especially injector positioning) produced close tolerance machining for special features and resulted in leak-free performance without impregnation (this was aided by semi-solid casting's inherent low porosity characteristic).

Casting Supplier: Citation--Texas Foundries, Lufkin, Texas

Component: Lower control arm for DaimlerChrysler's 2500/3500 Dodge Ram.

Application: Vehicle suspension.

Casting Process: Horizontally-parted green sand molding.

Metal: Austempered ductile iron.

Dimensions: 23 x 16 x 6 in.

Weight: 34 lb (assembled).

Converted from: Stamped steel weldment,

* This one-piece casting was converted from a four-piece fabrication that consisted of three stamped steel parts and one casting welded together.

* Using finite element analysis, Citation Corp. optimized the design, which was verified by bench testing.

* The redesign to a casting reduced the component weight by 5 lb per control arm (two control arms/vehicle) and eliminated the bushings used in the previous design. In addition, DaimlerChrysler has projected a $1.5-million savings in tooling cost over the life of the program due to the conversion to casting.

* The cast ADI control arm achieved equivalent fatigue life and other performance objectives as the stamped steel weldment. In addition, the design eliminated stress problems traditionally encountered at all welded areas.

* The component is machined and assembled by the foundry before shipment to the customer.

Casting Supplier: Intermet Corp. Hannibal Plant, Hannibal, Missouri 

Component: Instrument panel frame for General Motors' luxury car platform.

Application: Provides structural support for vehicle instrument panel and controls motors and other electric components.

Casting Process: Cold-chamber diecasting.

Metal: AM-50 magnesium.

Dimensions: 56 x 21 x 14 in.

Weight: 15 lb.

Converted from: Stamped steel assembly.

* Intermet provided onsite design-for-manufacturability support to GM on this 15-lb, two-piece casting design.

* The new design provided the platform (100,000 assemblies shipped in 2001) with a 75% weight savings over the previous stamped steel assembly as well as a cost savings due to the elimination of complex assembly operations previously required.

* The two-piece magnesium casting design improves the component's dimensional capability, strength, stiffness and modularity when compared to stamped steel or hybrid (steel/magnesium) assemblies or one-piece magnesium instrument panel beams. It also offered benefits in noise/vibration/hardness and dynamic side impact. In addition, the two-piece casting reduced time-to-market and total system and program-life cost.

* In terms of product design, the 2-piece casting offered: additional design complexity; access to more sides; maximum component consolidation; reduced machining, standardization of sections across design platforms; and RH/LH drive flexibility.

* The two castings are assembled with a heat-cured adhesive, an arrangement that permits flexibility in future vehicle changes and updates.

* The simplified casting design provides several tooling advantages, including reducing time and cost for changing during production as each section can be changed independently, reducing the cost of design changes.

Casting Supplier: Grede Foundries, Inc., Miiwaukee Steel Div., Miiwaukee, Wisconsin

Component: Articulating hinge.

Application: Main structural hinge for Timbco Hydraulics' 20-ton rough-terrain log forwarder.

Casting Process: Green sand molding.

Metal: 1040 steel.

Dimensions: Hinge: 35 x 24 x 18 in.;

Bearing plate: 32 x 30 x 15.5 in.

Weight: Hinge: 564 lb; Bearing plate: 450 lb.

Converted from: Fabrication.

* The two-piece hinge and bearing component originally was a welded assembly consisting of 25 pieces for the hinge plate and 40 pieces for the bearing plate.

* The fabrication had multiple segments, extensive welding lines and sharp corners, each of which acted as stress concentrators that reduced performance and durability. The component was not optimized for weight savings and required full face machining on plate faces. It also suffered from significant variation in tolerances and alignment due to fixturing/welding variability.

* The hinge plate and bearing plate castings reduced the total assembly weight by 15% by decreasing the mass in unstressed sections of the component.

* More robust cross-sections in stressed areas and generous radii on the contours reduced stress concentrations and improved the component's strength.

* Final assembly time was reduced through the elimination of variability in tolerances and alignment that occurred during fixturing/assembly/welding of the previous fabrication.

* Castings provide 47' of articulating range in both directions, proven through solid modeling.

* The use of "feed pads" reduced the feeding requirements.

* Providing raised pads to define only the machined areas on the casting resulted in a 70% machining reduction for the casting when compared to the fabrication.

Casting Supplier: Wescast Industries, Inc., Brantford, Ontario, Canada

Cast Component: 2.3L, 14 valve exhaust manifold for Mazda.

Application: Automotive exhaust manifold.

Casting Process: Green sand molding.

Metal: Silicon-molybdenum ductile 4 iron.

Dimensions: 17 x 13 x 5.5 in.

Weight: 14.5 lb.

Converted from: Stainless steel welded fabrication.

* This single casting component features 4-mm thick walls. It is delivered fully machined to the automaker.

* By redesigning to a casting, the foundry eliminated all welds (12-15 welds were required on previous tubular designs) and provided a 50% cost savings.

* Wescast generated several cast designs for the component to optimize the air flow characteristics. A combination of analytical (computational fluid dynamics) and experimental (rapid prototypes and flow bench) tools was used to optimize manifold runner balancing, sensor positioning and catalytic converter flow uniformity. The final design optimization removed 4.3 lb and lowered the unit price by $1.55 from the foundry's initial casting design.

* Testing for torque/power, thermal behavior, volumetric efficiency and sensor response was performed by the OEM customer and the casting design had the same or better performance than the previous fabricated tubular design.

Casting Supplier: Aarrowcast, Inc., Shawano, Wisconsin / Caterpillar Agricultural Products, Dekaib, Illinois

Component: Track roller frame for a belted agricultural tractor undercarriage.

Application: Supports tractor track assembly

Process: Green sand molding.

Metal: Ductile iron (IE112).

Dimensions: 10 x 2 x 1 ft.

Weight: 530 lb.

Converted from: Steel fabrication.

* This two-piece casting design was converted from a 38-piece steel fabrication design.

* The design, foundry, pattern and machining engineers worked on Concurrent Product and Process Design issues to maximize the benefits obtained from the castings.

* Casting allowed material to be added only to the areas that exhibited high stress and by eliminating possible distortion due to weld stress.

* The new design resulted in overall cost savings, higher strength and an improved part appearance.

Casting Supplier: Pacific Cast Technologies, Inc., Albany, Oregon 

Component: Thrust Beam (8/vehicle) for Boeing Delta IV Satellite Launch Vehicle.

Application: Provides attachment points for booster fuel tanks to the main fuel tanks.

Casting Process: Investment casting.

Metal: Titanium (Ti6-4).

Dimensions: OAL 91.6 in.; OAW 36.8 in.; OAH 18 in. with 0.25-5.0 in. cross sections.

Weight: 330 lb.

Converted from: Aluminum forging.

* Pacific Cast Technologies and Boeing teamed in a concurrent engineering forum to design the casting parameters without additional safety factors, providing excellent ultimate tensile properties.

* First parts were produced via rapid prototyping, allowing for the successful completion of test pieces in advance of production hardware.

* State-of-the-art welding techniques were concurrently developed to allow the castings to be produced in halves and then metal-welded together, producing more efficient manufacturing and cost control, Specialized local heat treat procedures were also developed for the weld joint.

* At 91.6 in., this component is the longest titanium casting to date on an aircraft or launch vehicle.

* Fracture toughness is 30% greater than previous forging.

* The 1000-lb/vehicle weights savings allowed by the conversion permits much larger payloads (12.2 tons), resulting in $95 million in savings over the life of the program.

Casting Supplier: Consolidated Casting Corp., Hutchins, Texas 

Component: Tab ring liner for a natural gas-powered combustor assembly for Honeywell Power Systems.

Application: Component aligns combustion chamber, controls air flow.

Process: Investment casting.

Metal: AMS 5390 Ni alloy.

Dimensions: 5.5-in, diameter by 0.75 in.

Weight: 0.62 lb.

Converted from: Machined/welded fabrication.

* The combustor assembly is a critical part of the microturbine power generator for the Parallon 75.

* The original component consisted of 16 individual machined tabs that were electron beam-welded in 64 places onto a fabricated tube. With direct responsibility and considerable input into the design of the new combustor assembly, Consolidated Casting Corp. redesigned the tabs as a single ring casting in which two rings are cast at once.

* Each finished ring component is buttwelded into a 0.080-in, wall sheet metal tube, as opposed to the individually welded tabs of the original design.

* The foundry also assembles the complete combustor assembly, which includes five investment castings, sheet metal tubes, a machined pin, stampings, tubes and fittings.

* The change in design reduced the subassembly time by 26 mm and achieved a greater than 50% per-part cost reduction.

Casting Supplier: General Motors Powertrain

Casting Process: Lost foam casting.

Cast Components: Inline 5 cylinder block for GMs new Vortec 3500 (3.5L) light truck engine (Defiance, Ohio); Inline 6 cylinder head for GM's new Vortec 4200 (4.2L) truck engine (Saginaw, Michigan).

Metal: A356 Aluminum, T-6 Heat Treat.

Dimensions/Weight Block--24 x 16.9 x 12 in., 86 lb; Head--29.9 x 15.7 x 5.9 in., 49.7 lb. The block features dual balance shifts, while the head is a double overhead cam design with variable exhaust cam phasing. Both components were designed for lost foam (6-layer and 5-layer foam patterns for the block and head, respectively) to incorporate features that normally exist as separate components or require extensive machining.

Block:

* This all-new aluminum block is 20 lb lighter than the comparable iron design and improves fuel economy, emissions, horsepower and noise/vibration characteristics.

* A 610-mm long and 12-mm diameter cast-in main oil passage feeds high-pressure oil to the balance shaft and crankshaft-bearing surfaces and the cylinder head, eliminating three long drilling operations.

* Six 75-mm long, 7-mm diameter oil feed holes are cast in from the main oil passage to each crankshaft bearing surface, eliminating drilling.

* Four 75-200 mm long, 7-mm diameter oil feed holes are cast from the main oil passage to both balance shaft bearing surfaces, eliminating drilling and four sealing plugs.

* Cast-in-place balance shaft covers eliminate separate covers and eight mounting bolts as well as eliminates machining for the cover mounting face and bolt/dowel holes.

* Four oil holes of varying size are cast-in for the oil filter, eliminating two drilling operations.

* At full production, this block saves GM $1.5 million per year, while avoiding a $14.1 million investment in capital equipment that would have been required for machining features ultimately produced as-cast.

Head:

* The aluminum design saved 13 lb per head.

* A cast-in 10-mm diameter U-shaped main oil passage (1473 mm in length) eliminated drilled passages and four of the six sealing plugs.

* 14 cast-in feed holes (6 mm in diameter and 40 mm long) from the main oil passages to each camshaft bearing surface eliminated drilling. 12 cast-in-place lash adjuster oil drain notches eliminated special drilling operations.

* 3 A.I.R. passages (including those to the exhaust port) are cast-in (350, 250 and 35 mm long with 12 and 8 mm diameters), eliminating drilling.

* "L"-shaped PCV passage is cast in, eliminating two drilling operations.

* Nine cast-in oil drainback holes (68 mm deep, 10 mm in diameter) from the valve train to the deck face replaced drilling operations.

* At full production, this cylinder head design saves GM $1.6 million annually. Also, a $10.2 million machining equipment investment was avoided.

* The Vortec 4200 16 engine was recognized at one of 2002's "10 Best Engines" by Ward's. The engine is featured in the GMC 2002 Envoy (recognized by Motor Trends as the 2002 Sports/Utility Vehicle of the Year) and the Chevy Trailblazer (named the 2002 Truck of the Year by the North American International Auto Show).

Honorable Mentions

Casting Supplier: Wellsville Foundry, Inc., Wellsville, Ohio 

Component: Heat exchanger.

Application: Generates steam.

Process: Nobake sand molding.

Metal: Glass 35 gray iron.

Dimensions: 23 in. x 10-in. diameter.

Weight: 115 lb.

Converted from: Several fabrications and assemblies.

* The component requires seven rings of 31 fins each. Originally, seven fabrications were welded together to form a continuous ring tube welded to an end cap and flange.

* The new one-piece casting design (with 217 0.25-in.-wide fins) is of uniform wall thickness and is non-leaking because it has no weld joints.

* The casting offers a significant lead-time reduction over the previous fabrication/assembly, lasts longer and improves the efficiency of the final product while providing a significant cost savings to the customer.

Casting Supplier: Irish Foundry & Manufacturing, Inc., Seattle, Washington 

Component: Water softener.

Application: Food service industry.

Metal: Aluminum 356-T6, Heat-Treat.

Casting Process: Lost foam casting.

Dimensions: 13 x 4 x 3.5 in. and 17.5 x 13 x 3.5 in.

Weight: 6.5 and 22 lb, respectively.

Converted from: Fabrication.

* Converted from a three-piece fabrication, this two-piece cast component resulted in a 60% cost reduction for the customer.

* Lost foam casting allowed designers to eliminate internal draft and incorporate intricate as-cast internal passageways for the water to pass through in operation.

* The as-cast features provided by lost foam casting reduced machining costs on the component by 50%.

Casting Supplier: Columbiana Foundry Co., Columbiana, Ohio

Component: Axle housing for Goodman Equipment Corp.

Application: Housing for a tunnel locomotive.

Process: Chemically bonded sand.

Metal: Steel.

Dimensions: 36 x 11 x 24 in.

Weight: 380 lb.

Converted from: Machined weldment.

* This 36 x 11 x 24-in, casting was originally designed as a machined weldment.

* By converting the component to casting, a 33% cost savings was realized by the customer due to the elimination of the assembly time for the component.

Casting Supplier: Piad Precision Casting Corp., Greensburg, Pennsylvania

Component Rack block and gear.

Application: Hydraulic-activated pumps for fire trucks.

Process: Permanent mold casting.

Metal: A021 Aluminum bronze.

Dimensions: 2.75 x 2.75 x 2 in., 5 x 2.5 x 2 in.

Weight: 3 lb., 2.74 lb.

* After a stainless steel version was thought to be cost prohibitive, these parts were considered for production from machined aluminum-bronze bar stock. By instead creating a new casting design to utilize the chill mold process, key requirements of high-strength, corrosion resistance, minimal finishing and precision were met at a reduced total product cost.

Converted from: Machined bar stock.

* The casting design allowed the foundry to cast the teeth to size with less than a 0.015 backlash. Gear diameters and tooth profiles are cast within [+ or -]0.005-in. tolerance range. Lifecycle testing has shown no measurable wear on either component.

* The foundry supplies machine-finished components to the customer. This design allowed the customer to maintain its market share by attaining a 20% cost savings over an initial stainless steel design.

Casting Supplier: John Deere Foundry Waterloo, Waterloo, Iowa

Component: Suspension lower control arm for the new John Deere 8020 series large-row crop tractor.

Application: Links the steering knuckle and chassis on the independent front suspension.

Process: Sand casting.

Metal: Austempered ductile iron.

Dimensions: 25.6 x 30.3 x 9.4 in.

Weight: 145 lb.

* While steel forging was originally considered for this component, it became apparent that the part could be produced more economically and in less development time as a casting. A cast design in austempered ductile iron would provide a weight advantage but still maintain the mechanical properties to withstand the high loads endured as the lower mounting part for the suspension cylinder.

* Finite element analysis predicted that the component would meet aggressive load goals, which was confirmed by lab- and field-testing.

* The casting design allowed: three bores to be cored out; machining time and weight to be reduced; and greater overall design flexibility such as draft and material flow considerations. A large core was used in the largest cross-sectional areas of the component to enhance the austempering process and reduce part weight.

* The casting process allowed relatively quick and inexpensive geometry changes to be made during prototyping stages.

RELATED ARTICLE: 'Casting of the Year' Award Goes to Prototype Casting Inc.

AZ91D Magnesium Castings for the InFocus Projector Cast Conversion from Plastic Injection Molding

With the production of a set of AZ91D magnesium castings produced via the rubber/plaster mold process, Prototype Casting, Inc., Denver, Colorado, is the 2002 recipient of the APS "Casting of the Year." While electronic enclosure parts are typically produced from plastic injection molding, InFocus (Wilsonville, Oregon) targeted cast magnesium to meet numerous design challenges on its new notebook-sized data/video projector.

Weight was of no small consequence in this application. After all, the unique selling proposition of InFocus' LP 130 is that at only 3 lb, it's a "no-compromise" portable projector offering 1000 lumens of brightness.

Two of these industry-leading cast components are housings for the projector while the third casting interfaces the lamp module and other critical components within the projector. The projector housings, which measure 8.5 x 6.25-in., weigh just 0.22 lb (100 g), while the 4.5 x 3-in. interface casting weighs only 0.05 lb (23 g). The typical wall section on these parts is 1.2 mm (0.05 in.).

* Previously produced via plastic injection molding, the cast design offered improved durability and rigidity, high heat tolerance and EM shielding benefits. EMI plating requirements were also eliminated.

* The casting design offers thermal and dimensional stability, and the metal's inherent thermal conductivity helps passively conduct heat from critical components.

* By converting to casting from plastics, a dimensional improvement was achieved, as critical areas are post-machined to tighter ([+ or -]0.002 in.) tolerances.

* Compared to plastics, the cast design provided a significant weight reduction and stiffness improvement. The equivalent plastic design would have required 2-mm (0.08-in.) wall sections.

The award-winning components clearly illustrate the flexibility and versatility of cast metals and how the process can benefit virtually any industry, says Prototype Casting Sales Manager Brett Peak. "While state-of-the-art compact electronic devices are not typically considered as casting candidates, new advances in casting technology and rapid prototyping offer engineers significant design freedom and time-to-market advantages."

He added that the two firms' close relationship allowed design modifications that reduced potential difficulties--a key concern on such thin-wall, highly angled magnesium components--well before manufacturing commenced. "InFocus's casting knowledge and the involvement of Tooling Engineer Greg Sample Sr. during the design phase are excellent examples of the firm's dedication to casting and the understanding of the importance cast components play within their products."

InFocus Principal Product Design Engineer Brian Heintz commended Prototype Casting on its in-depth knowledge of the project and ability to produce highly challenging components in the narrowest of time frames. "Prototype Casting worked to understand the intended purpose of the parts before starting its process. I can't imagine the mess we would have been in had we bypassed this phase of the program."

Heintz said the up-front dialogue on tradeoffs enabled optimal molding and post-finishing success in the shortest possible time. "From the moment CAD files were transferred, the total process--all the way through post-machining--took only 20 days." He also recognized the foundry's diligence in stretching the capability of the plaster cast process by minimizing the discrete components of the molds. "This allowed for a more stable, fully filled casting that could be machined to tolerances as tight as [+ or -]0.002 in."

Judges' Comments: "An excellent example of near-net-shape, thin-wall casting possibilities"..."Very impressive, spectacular component cast cost-effectively in a conventional process"..."Extremely thin, difficult and rangy part"..."Clearly a better product when compared to an injection molded part."