The international Metal Injection Molding (MIM) industry once again accounted for a significant proportion of the winning parts in the Metal Powder Industry Federation’s (MPIF) 2015 Powder Metallurgy Design Excellence Awards competition. The winnsers were announced at POWDERMET2015 San Diego, USA, May 17-20.
These award winning parts, stated the MPIF, forcefully illustrate the notion that PM finds creative solutions to fabricate parts that competing technologies would deem impossible. Whether conventional press-and-sinter or Metal Injection Moulding (MIM), PM answers the call of designers faced with difficult, even seemingly impossible, challenges.
Grand Prize Awards
Advanced Materials Technologies Pte Ltd, Singapore, earned the Grand Prize in the Automotive – Engine Category for a MIM bus nozzle used in a selective catalytic reduction (SCR) system of European commercial vehicles. The nozzle performs the SCR function using urea and compressed air to reduce the NOx produced during combustion to N2 and H2O.
Made of an austenitic stainless steel (AISI HK30), the part employs a patented technology that uses a removable polymeric insert to form the highly complex internal undercut channel, a feature the fabricator deems “impossible” to achieve using conventional machining.
All internal channels are achieved through MIM, while the threads on top are machined and Micro TIG welding is used to seal the small openings left by the polymeric insert; tip flatness is achieved through a grinding operation. It is estimated that fabricating the nozzle through the welding/brazing of multiple parts would have increased its cost by more than 200%.
Four MIM components made by Indo-US MIM Tec Pvt. Ltd, Bangalore, India, namely a catcher, tension bar, and new base cap and body, earned the Grand Prize in the Lawn & Garden/Off-Highway Category. The components, made for Danfoss, Denmark, are used in proportional valves found in hydraulic circuits of off-highway and farm equipment.
The two parts forming the new base are made of MIM 17-4 PH stainless steel, while the catcher and tension bar are formed of 4605 low-alloy steel. All dimensions of the two parts forming the new base are achieved in the as-MIM condition, including the internal thread in the body.
The catcher receives a grinding and burnishing to attain the OD tolerance and surface finish, while the tension bar needs only a turning operation to form an external thread without a parting line. The parts were formerly produced via machining, welding, conventional PM, and fastening.
By completely re-designing the parts to maximize the advantages MIM offers, the customer obtained savings estimated at 65%, with annual production of 350,000.
Advanced Forming Technology, An ARCMIM Company, Longmont, Colorado, USA, was awarded the Grand Prize in the Hand Tools/Recreation Category for a breech block made for Smith & Wesson. Fabricated via MIM from 4605 low-alloy steel, the block is inserted into the slide body of a .22 caliber pistol, creating the breech face and other critical functions.
The unique geometry of the part, composed of two large masses separated by a channel running axially down the length of the part, creating two distinct bodies connected by very small ribs, presented a significant challenge to keeping the part together during sintering and maintaining tight final tolerances.
The component was manufactured 100% to print with no secondary machining operations; it is heat treated to a hardness range of 37–45 HRC, receives a black oxide finish, and then undergoes a coining operation to qualify the width.
The fabricator believes this is the first breech block fabricated using MIM, an indication that it is possible to expand the application boundaries for MIM even in a mature arena such as firearms.
Awards of Distinction
Indo-US MIM Tec Pvt. Ltd, Bangalore, India, received the Award of Distinction in the Automotive – Chassis Category for a MIM 4605 low-alloy steel top plate made for Multimatic Inmet, Canada. The part goes into shock absorbers of Chevrolet Camaro automobiles. The complexity of the part, with its 18 holes and six thin ribs that connect to a ring around a central hole, presented a challenge to complete filling.
The gating and venting system played a key role in producing this part defect free. It is produced close to net shape, with surface grinding to achieve flatness and a facing operation to achieve height tolerance being the only secondary operations performed.
This application is a new design for MIM and delivers increased repeatability/accuracy of the shock absorber over the previous machined version, with estimated savings of 25%.
Indo-US MIM Tec Pvt. Ltd, Bangalore, India, also received the Award of Distinction in the Hardware/Appliances Category for two MIM 17-4 PH stainless steel parts, front and rear keepers that go into industrial electrical locks, made for Rutherford Controls Inc.
The parts’ complexity, with many cross holes and sharp knurl features, required the use of multiple slides, some moving at different angles.
The parts are made close to net shape requiring only a final coining to adjust a small distortion and a tapping operation on the front keeper. Annual quantities are 20,000 per part.
Indo-US MIM Tec Pvt. Ltd, Bangalore, India, received the second Award of Distinction in the Hand Tools/Recreation Category for a 4605 low-alloy steel bolt used in the Crickett 22LR rifle made by Keystone Sporting Arms, LLC. Made via MIM, the part replaced one produced by brazing together three machined parts, delivering an estimated 35% cost savings in the process.
The part’s design features many cross holes and undercuts, requiring complex side core matchings in the molding cavity. The fabricator delivers 60,000 pieces annually.
Indo-US MIM Tec Pvt. Ltd, Bangalore, India, received two Awards of Distinction in the Electronic/Electrical Category. The first award was given for a MIM 17-4 PH stainless steel shell made for Hirose Korea Co. Ltd.
The part goes into a charging assembly for mobile phones. The complex geometry of the part, with thin cross sections and internal undercuts, was achieved with a slide-in-slide mechanism moving on specially designed cam tracks. The MIM part replaced an earlier design that used sheet metal processing and welding, with an estimated 20% cost savings. Two million of the parts are delivered each month.
The second Award of Distinction in the Electronic/Electrical Category earned by Indo-US MIM Tec Pvt. Ltd, was for two parts, a male fool-proof device and a female polarizer, made for Amphenol Air LB France.
Made via MIM from 4340 low-alloy steel, the parts go into an electric connector assembly made for Airbus. Both parts are fabricated to net shape, with all dimensions achieved in the as-MIM condition; this includes the threads, which are formed through auto unwinding in the tooling. The fabricator delivers 320,000 pieces annually.