Winning parts in the Metal Powder Industry Federation’s (MPIF) 2012 Powder Metallurgy Design Excellence Awards competition were announced at the PowderMet 2012 International Conference on Powder Metallurgy and Particulate Materials, Nashville, June 10-13.
The parts exemplify PM’s special engineering benefits, namely net shape, precision, innovative fabrication methods, production efficiency, energy and materials savings, and manufacturing cost reduction.
These advantages, state the MPIF, continue to stir designers to choose PM for critical applications in auto engines and transmissions, electronics, medical devices, agricultural equipment, consumer products, military, and emergency applications. In an increasing number of design decisions, PM jumps to the front of the line ahead of traditional forging, die casting, stamping, investment casting, and machining processes.
Grand Prize Awards
GKN Sinter Metals, Auburn Hills, Michigan, USA, won the grand prize in the automotive engine category for a VVT rotor adapter assembly consisting of a PM steel rotor and adapter. The parts are joined by an adhesive, which joins them during machining cross holes and other features on the inside diameter, and seals the joint between them.
The assembly, used in a Chrysler V-6 engine, is mounted to the engine camshaft. Formed to a density of 6.8 g/cm3, the rotor has an ultimate tensile strength of 60,000 psi, yield strength of 55,000 psi, and a 23,000 psi fatigue limit. The adapter is formed to a density of 6.9 g/cm3, and has a minimum ultimate tensile strength of 58,000 psi, and yield strength of 53,000 psi.
After sizing and grinding, there is no other machining performed on the rotor. The adapter is not machined prior to assembly and is made to net shape with vertical slots for oil feeding. However, the customer machines the cross holes for the oil feed.
GKN Sinter Metals also won the grand prize in the automotive transmission category for a unitized one-way clutch (OWC) module made for the Chrysler Group LLC, Auburn Hills, Michigan.
The module has four PM steel parts (powder-forged race and cam, and two pressed-and-sintered retainer plates) as well as 22 additional parts (clips, springs and roller elements). This product is the first self-contained loose-roller OWC module for torque converter stator applications using all PM and powder-forged main components.
The retainer plate has net-shape features that cannot be formed by other manufacturing processes without major secondary operations. Selecting the PM process reduced production costs by 20% and increased the volume rate by 50%. PM’s reliability is supported by more than 10 million OWC assemblies in the field with zero warranty claims.
The grand prize in the automotive chassis category was awarded to Capstan Atlantic, Wrentham, Mass., for a complex PM steel two-stage helical gear and spur pinion used in a power liftgate actuator.
Made to a nominal density of 6.85 g/cm3, the combined helical gear–and-pinion design features precision journals for precise orientation in the actuator assembly. The part has a tensile strength of 65,000 psi and a yield strength of 55,000 psi.
The precise elemental gear data tolerances enable quiet gear performance, decreasing noise, vibration, and harshness.
Lawn & Garden/Off-Highway
FMS Corporation, Minneapolis, Minnesota, USA, won the grand prize in the lawn & garden/off-highway category for a PM steel gear race used in the OnTrac2 GPS-assisted steering system made for Novariant Corporation, Fremont, California, USA.
The system positions agricultural planting and harvesting equipment to more accurately perform tillage, spraying, and spreading as well as reducing skips and overlaps, thus reducing fuel consumption. Molded to a density of 6.7 g/cm3, the part has an ultimate tensile strength of 60,000 psi, minimum yield strength of 50,000 psi, 125,000 psi transverse rupture strength, and 23,000 psi fatigue limit.
The complex net-shape design features 112 gear teeth and 16 assembly holes. In addition to a 60% cost savings over the previous machining method of making the part, the PM design reduced the assembly part count from 24 to six parts. Selecting PM also cut lead times and allowed for easier assembly and disassembly in the field.
A copper-infiltrated PM steel inside deadbolt chassis made by ASCO Sintering Co., Commerce, California, USA, for a new commercial electronic lock system won a grand prize in the hardware/appliances category.
Made to a density of 7.4 g/cm3, the part has an ultimate tensile strength of 110,000 psi, 75,000 psi yield strength, and 100 ft/lbf unnoticed Charpy impact strength. Maintaining the density between the hub and flange is especially critical. The part has two PM posts manufactured and installed while maintaining true position and squareness.
Secondary operations include adding the tapped posts, two slots on the shelf flange, two counterbores, and a countersink. PM was selected over castings and stampings, which could not meet strength or Builders Hardware Manufacturers Association requirements for integrity during high-temperature tests.
FloMet LLC, Deland, Florida, USA, won the grand prize in the aerospace/military category for a very complex 17-4 PH stainless steel rotor made by metal injection molding (MIM) and used in a hand-emplaced munition device.
The intricate design is demonstrated by its four holes on two perpendicular planes, two angled slots with square corners, and numerous internal and external radii, flats, slots, and cutouts. All of these features require very tight tolerances: 0.0025 inches to 0.005 inches. Moreover, the square bottom-hole could only be formed by MIM because prior attempts with other fabrication processes, including machining, proved unsuccessful.
It is estimated that the machined version of the part could cost as much as five times that of the MIM design. The rotor is made to a density of 7.5 g/cm3 and has an ultimate tensile strength of 75,000 psi, yield strength of 25,000 psi, a six percent elongation, and 27 HRB hardness.
Parmatech Corporation, Petaluma, California, USA, won the grand prize in the medical/dental category for a mechanical introducer device used in minimally invasive OB/GYN surgery.
Made for STD Med, Stoughton, Massachusetts, USA, the device contains five 17-4 PH stainless steel MIM parts: right and left cover, curved needle, curved needle linkage, and center linkage. The covers have a complex three dimensional geometry incorporating assembly pins and slots for moving the internal parts that require smooth action for suturing.
Formed to a net shape requiring no machining, the parts are assembled by the customer who performs laser welding on the cover seam/joint. The parts are made to a density of 7.65 g/cm3. Choosing the MIM process provided a 70% cost savings over equivalent machined parts.
Electrical /Electronic Components
The grand prize in the electrical /electronic components category was won by Capstan California Inc., Carson, California, and its customer Reliable Security Group Inc., Signal Hill, California, USA, for a soft magnetic PM alloy coil housing used in a magnetic door closer for emergency/fire protection applications.
Formed as a single shape to a density of 6.8 to 6.9 g/cm3, the new PM design replaced a three-piece assembly. Critical design features include the locations of drafts, radii, and chamfers, as well as redefining tolerances for a near-net shape part.
Secondary operations include resin impregnation and zinc plating. The one-piece design provided a 21.5% cost savings over the previous assembly.
Industrial Motors/Controls & Hydraulics
Capstan Atlantic, Wrentham, Massachusetts, USA, won the grand prize in the industrial motors/controls & hydraulics category for a PM steel alloy power take-off clutch hub.
Formed to a density of 7.05 g/cm3, the complex multi-level part replaced a machined design.
Typical properties include an ultimate tensile strength of 80,000 psi, yield strength 90,000 psi and a 92 HRB apparent hardness.
The part is designed to withstand very high torque levels in service and the flange is strong enough to resist repetitive bending fatigue.
The grand prize in the consumer market segment category was won by Smith Metal Products, Lindstrom, Minnesota, USA, for a 17-4 PH stainless steel MIM top and bottom of an eyeglass-frame bridge made for Superfocus LLC, Van Nuys, California.
Featuring very thin walls, the parts form the bridge section over the nose, which also houses an actuator for changing the magnification level of the glasses. The as-sintered density is 7.6 g/cm3.
Awards of Distinction
SolidMicron Technologies Pte Ltd., Singapore, won the first award of distinction in the automotive—engine category for a 440C stainless steel MIM sealing seat used in a direct fuel injector assembly.
Made for Magneti Marelli S.p.A. Powertrain, Bologna, Italy, the complex part has a multiple angled slot and top holes requiring precise tool design and fabrication.
The near-net-shape part has a density range of 7.54 to 7.65 g/cm3, a tensile strength of 232,000 psi, and yield strength 203,000 psi.
The MIM process provided a 30%–40% cost savings over alternative manufacturing processes.
Burgess Norton Mfg. Co., Geneva, Illinois, USA, won the other award of distinction in the automotive—engine category for a soft magnetic solenoid core for its customer Cummins Inc.
Used in a high-pressure diesel-engine fuel injector, the core has a difficult-to-form deep pocket with high wall aspect ratios.
The part is pressed to a net-shape 7.5 g/cm3 density. Proprietary compacting and thermal processing produce a high-strength core with superior magnetic properties.
The part is made from a high-purity iron powder with an inorganic coating electrically insulating the particles.
The award of distinction in the automotive—transmission category was won by the Asturias/Spain plant of the PMG Group, for a PM steel synchronizer hub made for Aichi Machine Industry Co., Ltd., Japan.
The complex five-level part is used in the first and reverse gears in a double-clutch transmission. Powder Metallurgy provided a 25% cost saving over a broached steel part.
ACL Bearing Company, Tasmania, Australia, won the award of distinction in the automotive—chassis category for a PM sinter-brazed spacer tube made for Futuris Automotive Interiors (Australia) Pty Ltd, Edinburgh, South Australia, and used in a steering-column tilt/reach assembly.
Formed to a density of 6.8 g/cm3, the complex part has a tensile strength of 65,000 psi, 50,000 psi yield strength, 7% elongation, and 60 HRB hardness.
PM provided a 40% cost savings over fabricating the part by broaching.
Lawn & Garden/Off-Highway
Porite Taiwan Co., Ltd., Taiwan, ROC, won the award of distinction in the lawn & garden/off-highway category for a PM steel gear used in an output box in a tiller transmission.
Made for Pubert SAS, Chantonay, France, the complex part is made to a density of 6.8 g/cm3.
It has an ultimate tensile strength of 104,000 psi, 131,000 psi compressive yield strength, and a minimum 28 HRC hardness.
Capstan Atlantic, Wrentham, Massachusetts, USA, won the appliance category award of distinction for a seven-level rack used in an industrial washing machine.
Made to a density of 6.8 g/cm3, the part has sectional density that is kept equal within 0.08 g/cm3. The part has a minimum yield strength of 43,000 psi and typical 55,000 psi tensile strength.
PM replaced a die-cast part that needed extensive machining.
Megamet Solid Metals, Inc., Earth City, Missouri, USA, won the award of distinction in the recreation category for a cable-tie hand tool assembly of six 17-4 PH stainless steel MIM parts (pinion, nosepiece, pawl gripper, insertable rack, cutoff cam, and short link) made for HellermannTyton, Milwaukee, Wisconsin, USA.
Made to a density of 7.6 g/cm3, the parts are produced to net shape with only four requiring minor secondary operations such as reaming and coining.
Industrial Motors/Controls & Hydraulics
Capstan California and its customer Sperry Product Innovation Inc., Woburn, Massachusetts, USA, won the award of distinction in the industrial motors/controls & hydraulics category for a porous bronze filter used in a solvent pumping purification system.
The filter is gravity sintered to a density of 5.1 to 5.2 g/cm3. The special mold design eliminates most secondary operations on the part, except for deburring the edge. It also allows step grooves to be molded into the part.
Industrial Motors/Controls & Hydraulics
Advanced Materials Technologies Pte. Ltd., Singapore, won the other award of distinction in the industrial motors/controls & hydraulics category for 316L and 440C stainless steel parts (catch X-Z datum, catch bias Z datum, front and rear support tabs) used in an industrial printer module.
Achieving a yield strength rate of 234,000 psi, the 440C tabs support and align the print head module and are subjected to impact force during printing.
The 316L catches guide and feed paper to the printing module. Choosing the MIM process over casting and machining yielded a 40% cost savings.
Smith Metal Products, Lindstrom, Minnesota, USA, won the award of distinction in the electrical/electronic components category for a 17-4 PH stainless steel lever made for Methode Electronics, Harwood Heights, Ill.
The intricate MIM part is used in a latch ejector mechanism for pluggable gigabit Ethernet connections.
More information: www.mpif.org