Winners of the 2010 Powder Metallurgy Design Excellence Awards Competition, sponsored by the Metal Powder Industries Federation (MPIF), were announced at PowderMet2010, International Conference on Powder Metallurgy & Particulate Materials.
Receiving grand prizes and awards of distinction, the winning parts are outstanding examples of powder metallurgy’s (PM) precision, performance, complexity, economy, and innovative design advantages.
Grand Prize Awards
GKN Sinter Metals, Auburn Hills, Mich., USA, won the Grand Prize in the Automotive Transmission Category for a fully integrated planetary carrier and rocker-style one-way clutch assembly, an industry first.
Designed and made for Ford Motor Company and used in the Ford Super Duty truck five-speed automatic transmission, the application is a three-piece sinter-brazed planetary carrier. It consists of both PM copper-steel and sinter-hardened materials, assembled with a single-pressed cam plate, which is also sinter-hardened.
The application consists of four parts (cam plate, spider, clutch hub, and rocker plate) that are combined with 12 steel rocker struts and springs, a retainer plate, and snap ring to form the one-way clutch planetary carrier assembly. Providing a cost saving of more than 25%, the PM assembly replaced a two-piece riveted planetary carrier.
GKN achieved a density of 7.25 g/cm3 in the single-pressed complex sinter-hardened cam form without warm compaction and high-temperature sintering. Secondary operations are limited to machining the bearing journals, oil holes, and pinion holes.
Smith Metal Products, Lindstrom, Minn., USA, received the Grand Prize in the Hand Tools/Recreation Category for a 17-4 PH stainless steel hunting arrow tip, called a shuttle T-lock broadhead, made by metal injection moulding (MIM) for Trophy Taker, Inc., Plains, Mont.
Formed to a final density of 7.6 g/cm3, the unusual shape extends the design engineering advances of the MIM process. Other processes were considered but could not provide the necessary geometry for commercial production, and the prototypes cost many times more than MIM.
The broadhead has a yield strength of 137,000 psi and a tensile strength of 159,000 psi. The ferrule hardness is 36 HRC and the blade hardness is 38 HRC. Secondary operations are limited to final grinding of a razor sharp edge on the tip of the ferrule and the leading edge of the blade.
FloMet LLC, DeLand, Florida, USA, won the Grand Prize in the Aerospace/Military Category for a safe and arm rotor used in an explosive device for a Department of Defence application.
Produced by the MIM process, the 316L stainless steel part is formed to a density of 7.6 g/cm3. Its significant properties include an ultimate tensile strength of 75,000 psi, yield strength of 25,000 psi, 50 % elongation, 140 foot-pound impact strength and 67 HRB hardness. The complex shape features numerous outside radii and angular surfaces.
At least 12 functional features and surfaces are geometrically controlled by concentricity, profile, and true position tolerances. The part is assembled into a housing to provide the two-stage safety for the explosive device. It replaced a zinc die casting whose mechanical properties were ultimately not consistent enough to pass validation testing.
Industrial Motors/Controls & Hydraulics
Advanced Materials Technologies Pte Ltd, Singapore, won the Grand Prize in the Industrial Motors/Controls & Hydraulics Category for four complex 316L stainless steel MIM parts.
Consisting of a lock cover, lock barrel pin, lock barrel boss, and lock barrel square the parts are assembled into a locking device for heavy machinery operating in harsh environments.
Choosing the MIM process over casting provided superior surface finish that did not require polishing, enhanced corrosion resistance, as well as 30% cost savings.
The parts are formed to a density of 7.5 g/cm3 and feature a tensile strength of 75,000 psi, a yield strength of 25,000 psi, 50% elongation, and a 67 HRB hardness. They must undergo cyclical rotational testing of more than 300,000 cycles and a 48-hour salt-spray test.
Awards of Distinction
PMG Füssen GmbH, Füssen, Germany, won the Award of Distinction in the Automotive Engine Category for a complex PM steel crankshaft sprocket used in a V6 engine.
Made for iwis motorsysteme GmbH & Co. KG in Germany, the multi-level part has a density of 7.0 g/cm3, yield strength of 45,000 psi, and tensile strength of 54,000 psi. It features an inner ring diameter that is pressed and machined after sintering to achieve high-precision tolerances.
Even with secondary operations of sizing, machining, induction hardening, steam treating, and final grinding on the lower hub, PM still provided significant cost saving for the customer.
PMG Indiana Corporation, Columbus, Ind., USA, received the Award of Distinction in the Automotive Transmission Category for a one-way clutch outer race made for EXEDY Globalparts Corporation, Belleville, Mich.
Used in a torque-converter stator, the heavily loaded part transmits more than 202 foot-pounds of torque amounting to extremely high hertzian contact stresses on the cam surface and high tensile stresses in the hoop area.
A proprietary surface densification process forms the inner surface of the race to a minimum density of 7.7 g/cm3. The process provides improved durability over a fully dense hot-forged part.
ASCO Sintering Company, Commerce, Calif., won an Award of Distinction in the Hardware/Appliances Category for a high-strength sinter-hardened PM steel dead-locking lever made for a 40H series high-security mortise lock made by Stanley Security Solutions, Inc., Indianapolis, Ind.
Warm compacted and sintered to a density of 7.0 g/cm3, the part has a 145,000 psi ultimate tensile strength, a 9.5 foot-pound impact strength, a 40,000 psi fatigue strength, and a 30 HRC hardness. The part undergoes resin impregnation, deburring, zinc plating, and chromating.
By eliminating a milling operation, which uses cutting fluids that may contain harmful chemical agents that ultimately contribute to the “greenhouse effect,” PM not only provided a 40% cost savings but clearly demonstrated PM’s “sustainability” advantage.
Capstan Atlantic, Wrentham, Mass., won another Award of Distinction in this category for a high-density transfixed pinion gear and sector used in a high-volume printing application.
Formed to a density of 7.3 g/cm3, the parts have a 195,000 psi tensile strength, 185,000 yield strength, and a 75,000 psi fatigue limit. The pinion gear, which meets the AGMA Q9 precision level, is selectively roll-densified and crowned for bending-fatigue resistance and rolling-contact-fatigue resistance.
Both parts are hardened for wear resistance. Capstan’s proprietary high-strength PM process and gear-crowning design provided parts with twice the “in-service” life of those made via the previous manufacturing process and eliminated field failures due to tooth breakage experienced by those previous components.
Burgess-Norton Mfg. Co., Geneva, Ill., won the first Award of Distinction in the Hand Tools/Recreation Category for a final belt-drive sprocket which transmits torque from the transmission to the rear wheel on a motorcycle.
Replacing a sprocket made from hobbed cast iron, the high-volume PM steel part is produced on a 770-ton CNC hydraulic compacting press, which forms the outside-diameter flange on the top and a centre web on the bottom, a combination of features not possible with conventional compacting technology. It has a 50,000 psi minimum tensile strength, HRB 80 minimum apparent hardness with a steam-oxide surface treatment that has a 50 HRC hardness.
PM provided a cost savings of up to 30%, while improving reliability, quality, and wear and corrosion resistance over the wrought part. PM demonstrates its sustainability benefits by eliminating machining scrap and harmful coolants from the waste stream, while improving the end product’s fuel economy with a stronger, yet lighter, component.
Megamet Solid Metals, Inc., Earth City, Mo., won the other Award of Distinction in this category for an upswept grip safety used in the 1911-style 45-caliber pistol made by Colt’s Manufacturing Company, LLC., West Hartford, Conn.
The complex 17-4 PH stainless steel part is produced by the MIM process to a density of 7.6 g/cm3. The upswept design of the grip safety part, which was traditionally investment cast, would previously require extensive secondary machining.
Switching to the MIM process reduced customer lead times and provided exceptional cost savings, in addition to increasing production rates and producing a more uniform part. The upswept grip safety performs several functions: it blocks the trigger from firing, shields the hammer from impacting or injuring the shooter’s hand when the pistol cycles, and interacts with the shooter’s palm for comfort. Colt performed a 10,000-cycle test to qualify the part.
Industrial Motors/Controls & Hydraulics
Lovejoy Sintered Solutions LLC, Downers Grove, Ill., won two Awards of Distinction in the Industrial Motors/Controls & Hydraulics Category. The first award is for a rotating machine counterweight used in a refrigeration compressor for truck trailers.
Formed to a density range of 6.7 to 7.0 g/cm3, the PM steel counterweight has a tensile strength of 47,000 psi and 57–60 HRB hardness. It replaced a two-piece design that required machining the bolt and threaded holes in addition to separate tooling and presses for both parts.
The customer conducted fatigue and vibration testing and reports double the fatigue performance compared to the previous two-piece version. What’s more, assembly of those two pieces required the use of thread-locking fluid, which contains volatile organics; eliminating this fluid through the one-piece design is an obvious sustainability benefit of PM.
Lovejoy Sintered Solutions LLC, Downers Grove, Ill., and its customer Rosta AG in Switzerland received the final Award of Distinction in this category for a PM steel tensioner assembly used in a belt or chain-drive system.
Made to a density range of 6.2 to 6.9 g/cm3, the parts have an ultimate tensile strength of 43,000 psi, a yield strength of 39,000 psi, and a 70 HRB hardness. The application was originally an assembly of weldments of a steel tube and plate requiring sawing and stamping; PM eliminated the material loss associated with these operations.
Pressing the protractor into the arm eliminated the labour-intensive operation of roll printing an angle scale on the housing. In all, choosing the PM process provided a cost saving of 26% over the previously made version.
More information: www.mpif.org