Blade stopper takes powder-metal prize

U.S.-based powder-metal companies garnered many top honors at the recent international P/M design competition.

The Metal Powder Industries Federation (MPIF), Princeton, N.J., gave Burgess-Norton Mfg. Co., Geneva, Ill., high marks in its annual Powder Metallurgy (P/M) Design Awards competition for a drum and pulley system used in a blade override system for a power lawn mower. The organization's annual contest highlights engineering benefits designers can glean when converting from castings, stampings, and machined assemblies. Winners come from conventional pressand-sinter, warm compaction, and metal-injection molding. The P/M parts are used in applications including hand tools, lawn & garden, and appliances.

Burgess-Norton's Lawn & Garden/Off-Highway Grand Prize-winning steel parts are formed to a density of 6.9 gm/cm3 with an ultimate tensile strength of 40 kpsi (280 MPa) and 50 to 80 HRB hardness. P/M let the company form a molded key on the pulleys and hexagonal pockets on the drum that receives bolts for the mower's blade. The pulleys are sinter-bonded into a single component. This helps drop assembly costs 20% compared to previous assemblies made from machined, cast, and stamped parts. Annual production exceeds 300,000 parts.

Hawk Precision Component, Sinterloy Facility, Spring Grove, Ill., took the Hardware/Appliance Grand Prize for its copper-steel latch-bolt actuator. It is formed to a density of 7.3 gm/cm3 and features nine geometrically complex levels. It actuates three latches as a security feature in a swinging patio door. It connects to and is controlled by the door handle. The zinc-plated part features yield and ultimate tensile strengths of 60 kpsi (410 MPa) and 87 kpsi (600 MPa), respectively. It has an elongation of 3% and an 89 HRB hardness. P/M provided an estimated cost savings of 35%.

Pacific Sintered Metals, Los Angeles, took the top prize in the Hand Tools/Recreation category. The high-speed tool goes into a hand-operated device from Cooper Tool, Springfield, Ohio. It installs tubes in heat exchangers by expanding and locking them in place. The steel parts are compacted and liquidphase sintered to a full 8.1 gm/cm3 density, heat treated to a hardness of 61 to 63 HRC, and triple tempered for toughness. The part's thin sections and multiple steps are molded to a near-net shape and then ground to a sharp edge. The PM M2 steel outperformed machined wrought bar stock and cut costs by a staggering 90%. Advanced Materials Technologies Pte Ltd., in Singapore captured the Electronic/Electrical Grand Prize for an intricate flip slider and hinge barrel. The metal injection-molded parts make up a dual-hinge opening mechanism for a mobile phone from Motorola Inc. The mechanism lets the phone's clamshell cover slide down and flip open in a single movement. The parts are 17-4 PH stainless steel and sport a 7.6-gm/cm3 density, 172-kpsi (1,185-MPa) ultimate tensile strength, 6% elongation, and a 30 HRC hardness. MIM let designers build thin, complex walls with overhanging features. Both parts are coined, machined, polished, and plated. Fully machined parts reportedly would cost five times that of the MIM design.

MPIF AWARDS OF DISTINCTION
Another lawnmower part took the award of distinction in the Lawn & Garden/Off-Highway category. The mowerblade brake-clutch input hub from Fansteel America Sintered Technologies, Emporium, Pa., for Warner Electric Inc., South Beloit, Ill., halved part costs over the previous design. The hub has a 60 HRB hardness and a density of 6.7 gm/cm3. It also features ultimate tensile, fatigue, and yield strengths of 60 kpsi (410 MPa), 50 kpsi (340 MPa), and 55 kpsi (380 MPa), respectively.

A P/M sintered-hardened steel crankshaft gear made by Capstan Atlantic, Wrentham, Mass., took the Hardware/Appliance award of distinction. The highprecision 18-tooth, 27° helical gear serves in a residential standby generator. It is first formed with a 0.9842-in. (25-mm) face (AGMA Class 7 gear), but subsequent boring, facing, and broaching give it an AGMA Class 10 accuracy rating. The gear has a density of 7 gm/cm3, a yield strength greater than 65 kpsi (450 MPa), and an apparent hardness range of 52 to 60 HRA. The final award went to Precision Powdered Metal Parts Inc., Pomona, Calif., in the Hardware/Appliance category. The door latch retractor was made for Kaba Ilco Corp., Winston-Salem, N.C., and is used in an airport-door combination lock. The four-part assembly (outside sleeve, cam, inside sleeve, and retractor) is made from copper-infiltrated steel. The parts have an 80-kpsi (550-MPa) tensile strength, 70-kpsi (480-MPa) yield strength, and a 23-kpsi (160-MPa) fatigue limit. P/M replaced imported investment castings that couldn't meet tolerance and surface-finish specs.

MAKE CONTACT
Advanced Materials Technologies Pte Ltd, +65 6863 6551, amt-mat.com
Burgess-Norton Mfg. Co., (630) 232-4100, burgessnorton.com
Capstan Atlantic, (508) 384-3100, capstanatlantic.com
Fansteel-American Sintered Technologies Inc., (814) 486-0400, www.fansteel-ast.com
Hawk Precision Components, Sinterloy Facility, (815) 675-2373, hawkcorp.com/powder.html
Kaba Ilco Corp., (800) 849-8324, kaba-ilco.com
Metal Powder Industries Federation, (609) 452-7700, mpif.org
Pacific Sintered Metals, (310) 715-9800, pacificsintered.com
Precision Powdered Metal Parts Inc., (888) 228-5761, www.precisionpm.com
Warner Electric Inc., (800) 825-6544, warnerelectric.com