Winning parts in the Metal Powder Industry Federation’s (MPIF) 2013 Powder Metallurgy Design Excellence Awards competition were announced at the PowderMet 2013 International Conference on Powder Metallurgy and Particulate Materials, Chicago, June 24-27.
It is clear from this year’s MPIF Awards that conventional press and sinter Powder Metallurgy (PM) technology is continuing to find new applications in many sectors, whilst also replacing traditional manufacturing processes thanks to the design, performance and economic advantages that Powder Metallurgy offers.
The continuing growth in the Metal Injection Moulding (MIM) industry is also evident, reflected in the large number of prizes presented to this sector in this year’s awards. MIM’s growing acceptance in the automotive industry as a trusted manufacturing route is clear, with both a Grand Prize and Award of Distinction being presented to MIM companies in this demanding sector. The MIM process was also the manufacturing method of prize winners in the hand tools/recreation, aerospace/military and medical/dental categories.
Grand Prize Awards
Indo-US MIM Tec Pvt. Ltd., Bangalore, India, received a grand prize in the automotive engine category for a sensing element, a threaded port, and a support ring made for Sensata Technologies Holland B.V., Almelo, the Netherlands.
Made via Metal Injection Moulding (MIM), these components are used in a sensor kit that measures the inlet pressure of the air fuel mixture in each cylinder of a passenger car engine. The length of the threaded port creates complexity, as do the thin walls and fragile features, and the stringent customer requirements on visual aspects add to the difficulty of manufacture.
Made of MIM-17-4 PH stainless steel, the parts have a heat treated yield strength of 160,000 psi, ultimate tensile strength of 178,000 psi, 7% elongation, 35–40 HRC hardness range, and 7.6 g/cm³ density. The parts are formed close to net shape, with only coining and passivation required on all three, plus CNC thread cutting on the port only.
This new application is estimated to save the customer 50% over the cost of manufacture using alternative technologies.
AMES S.A., Barcelona, Spain, was awarded a grand prize in the automotive chassis category for a compressor clutch that is part of an assembly in a braking system for heavy trucks and buses.
The system stops the compressor once the necessary air pressure is reached, which saves energy and helps reduce the vehicle’s fuel consumption by 7%. Made of a diffusion alloyed steel, the complex part is compacted on a CNC 400 mt press at a pressure of >87,000 psi to achieve a required density >7.0 g/cm³. Other properties include 66,000 psi yield strength, 103,000 psi ultimate tensile strength, 1% elongation, and 85 HRB hardness.
The PM design integrates into a single component what was originally designed as two separate toothed parts – the conical front, which connects to the crankshaft, and the opposite face, which connects to the compressor and a coupling. The full shape of the large (nearly 1 kg) part, other than the outer grooves, is reached directly from compacting. Secondary processing includes sizing, turning, drilling two blind holes, and several finishing steps.
PM was the only technology capable of producing this part at the customer’s cost target.
Lawn & garden/off highway
Capstan Tennessee Inc., Rockwood, Tennessee, USA, was given the grand prize in the lawn & garden/off highway category for a transmission rotor made for Caterpillar Inc., Peoria, Illinois. The rotor mates with a magnetic sensor that reads the rotating teeth to generate speed data used for controlling the shift point of transmissions powering large off highway construction vehicles.
Made of carbon steel, this single level part is pressed to a density of 6.85 g/cm³, sintered, and then re-pressed to 7.00 g/cm³. Other final properties include ultimate tensile strength of 30,000 psi, 20,000 psi min. yield strength (2% offset), and 75 HRF min. hardness. The 7.795 in. dia. is held within 0.006 in., while the angularity of the 40 teeth is maintained within ±1 degree. The 805 g part is pressed to net shape, with the drilling of the five true position holes being the only secondary operation.
In addition to the saving of 63% over the cost of machining, the critical thickness, flatness, and parallel tolerances maintained in its manufacture make the rotor a truly outstanding PM part.
Claw pole motor core stators made by Burgess-Norton Mfg. Co., Geneva, Illinois, won the grand prize in the hardware/appliances category. The parts are used to generate a magnetic flux that interacts with a rotor and permanent magnets to produce torque in a high efficiency brushless DC motor in an electric ceiling fan.
Both halves of the motor core are produced using one set of tools: heated fixed fill shelf die, core rod, single upper punch, and six thin walled lower fill punches. Formed from a high compressibility inorganically insulated iron powder, the parts are compacted with pressures exceeding 67 tsi to a density range of 7.4–7.5 g/cm³, typical ultimate tensile strength of 7,000 psi, and 19,000 psi transverse rupture strength. The parts are
compacted to net shape and require no secondary operations.
They belong to a new generation of DC motors using soft magnetic composite PM materials to enable greater design freedom for designers of electric machines.
Indo-US MIM Tec Pvt. Ltd., Bangalore, India, received the grand prize in the hand tools/recreation category for a tool holder assembly made for Scintilla AG, Solothurn, Switzerland. The assembly that incorporates these two MIM parts, a tool holder and a grip spring tensioning part, goes into a woodworking tool for fine detail carving.
Part complexity made MIM the obvious choice as no other technology could produce the part as an integral unit and deliver it in the needed volumes at the target cost. Made of a low alloy steel, the parts are supplied in the heat treated condition. Properties include 7.5 g/cm³ minimum density, 225,000 psi ultimate tensile strength, and 200,000 psi yield strength. To overcome the possibility of distortion on the unsupported open end, the design provided supporting ribs. The grip support ring was produced per print with the help of one turning operation.
The MIM design contributes to a LEAN operation for the customer by substantially reducing lead time through the elimination of many processing steps.
Polymer Technologies Inc., Clifton, New Jersey, were presented with the grand prize in the aerospace/military category for two MIM parts, a U-bracket and stop used in a Feedbox Support Improvement Kit (FSIK) for an M249 squad automatic weapon (SAW) used by the US Military.
The device is designed to hold various size high volume magazine ammunition packs securely to the gun. It extends the service life of the weapon by enabling the soldier to repair it in the field, thus avoiding the cost of a new weapon.
Drop testing of the firearm with the device attached proved the integrity of the FSIK even while other components were damaged. The innovative I-beam and webbing design allowed the parts to meet the 32–38 HRC hardness range requirement and still maintain the total weight of the kit below 3.5 oz.
Moulded from MIM-17-4 PH stainless steel, the parts have >7.5 g/cm³ density, 130,000 psi ultimate tensile strength, 106,000 psi yield strength, and 6% elongation. The only secondary processing of these near net shaped parts are a coining operation to the bracket in order to achieve the tolerance required for the distance between the notch and the through hole, as well as tapping the hole to provide necessary threading. Both parts are black oxided to remove their reflective properties, a critical consideration for the safety of the soldier.
FloMet LLC/A QMT Company, Deland, Florida, was awarded the grand prize in the medical/dental category for a 17-4 PH stainless steel jaw made for US Endoscopy, Mentor, Ohio, and used in a Raptor™ grasping device.
Made via MIM, the jaws merge into one design that features both a rat tooth jaw and an alligator jaw, combining the functions of a grasper and a retrieval forceps that surgeons use to retrieve foreign objects in the body during minimally invasive procedures.
The component design is enormously complex due to its small size, thin wall requirements 0.25 mm (0.010 in.), and features required to achieve full functionality with the sharp talons and teeth at net shape. The parts have >7.5 g/cm³ density, 130,000 psi ultimate tensile strength, 106,000 psi yield strength, 6% elongation, and 27HRB hardness. Only minimal secondary processing (coining to help maintain the alignment of the jaws) was needed, as other geometries and tight tolerances were achieved in the as moulded condition.
Alternative processing methods could not have achieved the part’s intricate geometries at a reasonable cost. MIM is estimated to have saved more than 60% over die casting or machining the parts.
Awards of Distinction
Indo-US MIM Tec Pvt. Ltd., Bangalore, India, won the first award of distinction in the automotive engine category for a fuel control gear segment made for Bosch Limited, Bangalore, India. The part goes into a fuel control device that regulates the entry of fuel into the engine.
Converted from a machined part, the gear segment is fabricated via MIM from a low alloy steel at a saving of 80% over the previous method. Moulded to net shape and requiring no secondary operations, the part has a density of 7.5 g/cm³, 46,000 psi ultimate tensile strength, 19,000 psi yield strength, 25% elongation, and 100 HRB max. hardness. Nearly three million pieces are delivered annually to the customer.
GKN Sinter Metals LLC, Conover, North Carolina, won the other award of distinction in the automotive engine category for an aluminium rear cam cap. Used in a new automotive engine, the part serves a dual function of holding the camshaft in place as well as holding an auxiliary vacuum pump.
This is the first time an aluminium cam cap with the unique tombstone geometry has been manufactured via press and sinter PM. Until the present redesign, in which the part is compacted inverted, this feature could only be formed via die casting.
The part is formed to near net shape with only the cover seal area being CNC machined. Properties include 2.55 g/cm³ density, 22,000 psi ultimate tensile strength, 17,000 psi yield strength, and 60 HRE min. apparent hardness.
The award of distinction in the automotive transmission category was won by Burgess-Norton Mfg. Co., Geneva, Illinois, for a ramp plate used in an electronically activated locking differential in European light commercial vehicles. These differentials significantly improve on demand vehicle traction in adverse conditions by directing 100% of the drive torque simultaneously to both wheels.
Made using FL-4400 prealloyed steel, the parts are pressed, sintered, soft turned, heat treated (Q&T) and then hard turned to generate concave back face features. Unique processing and part density enable the production of a component that exhibits the strength and wear properties of FL-4405-125HT on the ramp face and soft magnetic properties on the back face.
The use of PM provided cost savings estimated at 20-40% over machining a component with similar functional performance.
ASCO Sintering Co., Commerce, California, won an award of distinction in the hardware/appliances category for an inside hub adaptor, made for Ingersoll Rand Security Technologies (Schlage), Carmel, Indiana. The copper infiltrated PM steel part is used in modern, high end electronic commercial and residential door lock systems including the latest touch screen devices.
The part has seven functional levels that are pressed using three upper punches, two separate shelf levels, and two lower punches, with a proprietary triple upper actuating mechanism used to achieve extensive powder transfers and fill compensation. The adaptor is pressed to net shape with plating as the only secondary operation performed. Properties include 7.7 g/cm³ density, 95,000 psi ultimate tensile strength, 8% elongation, 100 ft.∙lb. unnotched Charpy impact energy, and 90 HRB hardness. Aggressive PM part design yielded 40% savings over alternative methods.
FMS Corporation, Minneapolis, Minnesota, also won an award of distinction in the hardware/appliances category for an assembly consisting of a rack, pinion, and bushing used in a patented pergola louver system that allows the pergola to convert to a water tight shelter.
The sinter hardened steel rack and five level pinion and the copper steel bushing are pressed to net shape with one cross drilled hole being the only secondary operation performed. The assembly was designed to be sinter bonded for strength.
The parts have a typical density of 6.7 g/cm³, 75,000 psi ultimate tensile strength, 135,000 psi transverse rupture strength, and 20 HRC min. apparent hardness and 52 HRC min. particle hardness. Because of the large number of assemblies required in each louver system, the PM process gave the customer the only cost effective option, delivering an estimated 75% savings over the machined alternative.
An award of distinction in the hand tools/recreation category was earned by Parmatech Corporation, Petaluma, California, for an actuator used in a tool less locking system that enables quick changing of a shotgun stock.
Made via MIM of a low alloy steel, the complex design part required the use of stepped ejector pins on the sloped surface to allow for smooth ejection with no part damage. It has a 0.05 mm (0.002 in.) straightness requirement of the longer than 25.4 mm (1 in.) shaft and a tight profile requirement of the curved and sloped cosmetic surface. The part is moulded and sintered close to net shape to 7.48 g/cm³ density, and is coined in order to achieve repeatability.
Choosing MIM over casting and machining the part provided a cost savings of 25–35%.
A star shifter made by FMS Corporation, Minneapolis, Minnesota, for Polaris Industies, Wyoming, Minnesota, and used in its Victory motorcycle transmission, won another award of distinction in the hand tools/recreation category.
The first PM component in this six speed transmission, it functions as the cam interface in a mechanism that enables the engagement and shifting among all the gear combinations. This six level part is made of sinter hardened steel, moulded in a CNC servo controlled, multi action hydraulic press to a typical density of 6.65 g/cm³. Other properties include 75,000 psi ultimate tensile strength, 135,000 psi transverse rupture strength, and 20 HRC min. apparent hardness and 52 HRC min. particle hardness.
The customer estimates a 45% cost savings over the previously forged part.
Polymer Technology Inc., Clifton, New Jersey, received the award of distinction in the medical/dental category for a stainless steel shuttle used in a smart stapling device for both open and minimally invasive arthroscopic surgery.
It is part of a device that interacts with a disposable staple cartridge in a computer controlled device that provides a high level of precision, consistency, accuracy, agility and compressive force for the surgeon using it.
Manufactured via MIM, the shuttle incorporates two separate components that previously were combined via laser welding. Making this intricate, small, and lightweight 0.175 oz. component presents many challenges, including the extremely thin walls, tight radii, and true position geometries, especially the two leg tips, which need to maintain their required strength and piercing sharpness. Part properties include 7.75 g/cm³ density, 200,000 psi ultimate tensile strength, 160,000 psi yield strength, 11%-30% elongation, and 82 HRB hardness.
The shuttle is formed to nearly net shape, requiring only minimal secondary operations of reaming and then tapping the small hole, as well as providing proprietary sintering fixtures to maintain the straightness callout for the parallel walls.