Powder metal's most innovative designs

Powder-metal parts for surgical instruments, pumps, power tools, and automobiles took top honors in the annual Metal Powder Industries Federation (MPIF) design competition. Winning parts were made with conventional P/M press and sinter processing, warm compaction, and metal injection molding (MIM). P/M ousted investment and die casting, forging, and machining as the process of choice for this year's winning parts. The winners demonstrate P/M net-shape capabilities, strength, economy, and reliability in demanding applications.

Parmatech Corp., Petaluma, Calif., and its customer SurgRx Inc., Palo Alto, Calif., won MIM grand prize honors for a high-compression jaw used in a device for laparoscopic vessel fusion. Top and bottom jaws, an anchor, and an I-beam are made of 17-4PH metal powders sintered to densities of over 7.6 gm/cm3. The parts sport thin walls and highly complex geometries that would be difficult to produce economically by other methods. The I-beam is the cutting mechanism. High compression is maintained as the blade advances from the proximal to distal end of the jaw. The system also incorporates smart electro-technology to rapidly fuse vessels without thermal effects.
The Ferrous grand prize went to ASCO Sintering Co., Commerce, Calif., for a four-part gear assembly. The armature, rotor blank, bearing, and pinion gear operate in a motor drive for automatic minivan sliding doors. The parts have a density of 7.0 gm/cm3, an ultimate tensile strength of 45 kpsi, and a yield strength of 32 kpsi. They are made from a P/M phosphorous iron alloy and they are net shape, except for the rotor that needs a turning operation on the hub.
Webster-Hoff Corp., Glendale Heights, Ill., took Stainless Steel grand-prize honors for a complex pump latch made for Phillips Plastics, New Richmond, Wis. The 316 stainless-steel latch attaches to a door handle on a medical infusion pump. It has a density of 6.7 gm/cm3, an 11.5% elongation, and ultimate tensile and yield strengths of 65 and 42 kpsi, respectively. Secondary operations are limited to deburring, tempering, glass-bead finishing, and tapping one hole. The P/M latch replaces a machined die-cast handle that attached to a stainless-steel latch with dowel pins and screws.
Gino Olivares S.R.L. from Italy took Overseas grand prize accolades for a transmission used in a portable hedge cutter. The six P/M parts (main gear with 51 teeth, two connecting rods, an inner part, spacer, and valve) range in density from 6.6 to 7.0 gm/cm3. Tensile strengths range from 74 to 87 kpsi.
Aplanetary gear set used in an automatic-latch system for rearhatchminivan doors captured the Innovative Functional Assembly grand prize. Capstan Atlantic, Wrentham, Mass., makes the assembly's seven parts — carrier plate, four planetary pinions, a ring gear, and a spur sun gear. The P/M parts are sinter-hardened to boost wear resistance and strength. A proprietary plating process helps them withstand a 200-hr salt-spray test. The planetary and ring gears are made to a density of 6.95 gm/cm 3 and have tensile and yield strengths of 100 and 90 kpsi, respectively. The spur sun gear has a tensile strength of 120 kpsi, yield strength of 105 kpsi, and fatigue limit of 35 kpsi.
AMIM award of distinction went to World Class Technologies Corp., McMinnville, Oreg., for a CarriÈre Distalizer. The complex part, designed by Class One Orthodontics, Lubbock, Tex., is made in two pieces. The first is a posterior pad with a socket. The other is an interior rod that has a ball on one end and a pad with a hook at the other. After sintering and polishing, the ball is pressed into the socket in the posterior pad to make the final assembly. The components are made from a nickel-free stainless steel and formed to a density of 7.6 gm/cm3. They have yield strengths of 80.1 kpsi, ultimate tensile strengths of 95.5 kpsi, and a 22% elongation.
Asecond MIM award of distinction went to Kinetics, Inc., Wilsonville, Oreg., for a lower jaw used in a medical suturing device. The jaw is made from 17-4 PH stainless steel. The jaw has a density of 7.7 gm/cm 3 and tensile and yield strengths 130 and 106 kpsi, respectively. Secondary operations include reaming three holes, coining, and sizing. The device from Opus Medical Inc., San Juan Capistrano, Calif., is used in torn rotator-cuff surgery.

Ferrous award of distinction honors went to an output shaft hub from Chicago Powdered Metal Products Co., Schiller Park, Ill., and a helical gear assembly from FMS Corp., Minneapolis.
The output shaft hub operates in a torque shift truck transmission. Ford Motor Co.'s Powertrain Operations, Livonia, Mich., originally designed the part as a forging but cut costs by 30% with P/M warm compaction. The part has a minimum density of 7.2 gm/cm3 and a minimum ultimate tensile strength of 155 kpsi. The external helical teeth and straight involute splines are net shape, and secondary operations are limited to deburring and minor machining.

The helical gear assembly from FSM drives a piston pump in a high-pressure industrial paint sprayer from Graco Inc., Minneapolis. The assembly consists of a 101-tooth helical-ring gear, hub, and counterweight. A proprietary heating process is used to assemble the helical-ring gear to the hub. The core holes in the flange and hub reduce material and help balance the component when assembled with a roller bearing. P/M replaces a machined zinc die casting and drops part cost by about 30%.
Abronze machining gib used as a leveling device in a vertical machining center won the award of distinction in the Nonferrous category. Made by Pacific Sintered Metals, Los Angeles, the P/M part costs 60% less than its machined predecessor. The gib has a density range from 6.8 to 7.2 gm/cm 3 and is oil impregnated and coined for better dimensional control.
Sinterstahl Polmetasa from Spain, won the award of distinction in the Overseas category for an external proportional valve in a new electronic automotive shock absorber. Made to a density of 6.7 gm/cm3, the complex copper-steel P/M part has an ultimate tensile strength of 49 kpsi, a yield strength of 45 kpsi, and a transverse rupture strength of 93 kpsi.