Winners of the Metal Powder Industries Federation's (MPIF) 2009 PM Design Excellence Awards Competition were announced at the PowderMet2009 Conference in Las Vegas earlier this year. MIM once again featured prominently and the winning parts reviewed below highlight the diversity and capabilities of the process. Review first published in PIM International Vol. 3 No.3 September 2009.

Grand Prize Winners

Stainless steel compressed air nozzle

FloMet LLC, Deland, Florida, USA, won the hand tools/recreation category Grand Prize for a 316L stainless steel compressed air nozzle (Fig. 1) made for Silvent AB, Borås, Sweden.

The hollow nozzle consists of top and bottom halves that are moulded separately and then joined together into one piece during debinding and sintering.

The nozzle’s air flow capacity is tightly controlled to ensure optimum use of compressed air as well as to comply with US and EU machine device noise regulations.

It can withstand high ambient temperatures and corrosive environments, and meets hygienic requirements of the food processing industry.

The part was produced on an all electric Milacron 55 ton injection moulding machine (Roboshot SiB 55) using a two cavity mould, using feedstock produced in-house by FloMet. After sintering, the seams where the two sections join together are laser welded for a leak-free seal.

A unique process was also developed for the processing of the threads used to mount the part, ensuring that the part conformed to stringent specifications. The part has a density of more than 7.6g/cm³, an ultimate tensile strength of 75,000psi (517MPa), yield strength of 25,000psi (172MPa) and a 50% elongation.

FloMet operates out of a purpose built 40,000ft² facility which houses 19 moulding machines, nine debinding ovens and 10 sintering furnaces. Current employment is 120 people, producing nearly $20 million in sales.

Flagstaff nose / EMI nose shield

Advanced Materials Technologies Pte Ltd., Singapore, won the Grand Prize in the electrical/electronic components category for a 17-4 PH stainless steel MIM flagstaff nose or EMI nose shield (Fig. 2), which serves as an external connector for a high-performance fibre optic module.

The part has a density of 7.5g/cm³, tensile strength of 130,000psi (896MPa), yield strength of 106,000psi (730MPa), an eight percent elongation, and a 27 HRC as-sintered hardness.

Secondary operations are limited to coining on the two latches and the application of a 0.5 micron gold coating for appearance and corrosion resistance.

Manufactured from feedstock produced in house, this part is moulded on an Arburg injection machine using a two cavity tool. Following solvent and thermal debinding parts are sintered in a batch furnace.

The original design of this part was produced by zinc die casting, however this process produced parts that proved to be too brittle and deformed when exposed to heat.
During the initial design stage for MIM, the most challenging problem was the forming of the thin wall structure, which is as thin as 0.03mm in some areas.

Specifying MIM gave the customer an estimated 40% cost savings and during peak production, annual volume is in the region of 500,000 parts.

AMT can process up to 500 tons of powder annually. The company has more than 100 employees and forecasts that sales for 2010 will be in the region of US$15 million.

Awards of Distinction

Handgun housing block

Parmatech Corporation, Petaluma, California, USA, won the Award of Distinction in the hand tools/recreation category for a 420 MIM stainless steel housing block (Fig. 3) used in a 45-caliber handgun. This contains the firearm’s spring mechanism and provides sliding action with other mechanical parts.

This complex MIM part features wings, undercuts, through-holes and blind holes, as well as thin and thick cross sections. Formed to a final density of 7.7g/cm³, the part has a tensile strength of 261,000psi (1800MPa), yield strength of 218,000psi (1500MPa), and a 48–52 HRC hardness range.

This part is manufactured from feedstock produced in-house using a two cavity mould. Debinding and sintering are done via a batch process.

Parmatech state that MIM was, from an early stage, the selected process technology due to material strength requirements and cost of component fabrication. Design challenges included the use of coring to reduce part weight without affecting performance, the use of second operation machining technology on certain dimensions, and size control as various parts interact in the assembly with this component.

From part/tool release to first batch for production delivery took approximately 12 weeks and in excess of 100,000 units are produced annually.

Incorporated in 1973, Parmatech’s MIM plant today covers approximately 32,000ft² and employs around 80 people. The company states that it has shipped over 7.2 million parts over the last year and forecasts 15% overall growth in 2009. Major markets served include the medical, defence and general industrial sectors.

Rifle handle body and yoke

Megamet Solid Metals Inc., Earth City, Missouri, USA, received the Award of Distinction in the aerospace/military category for a MIM handle body and yoke (Fig. 4) for its customer, Colt Canada Corporation, Kitchener, Ontario, Canada.

Made from 4140 low-alloy steel to a density of 7.4g/cm³, the parts are core components in a folding-front-grip assembly that attaches to the Picatinny Rail system used on modern military rifles. Challenges presented by the geometric complexity of the parts are efficiently and cost-effectively solved by the MIM process. The parts are sintered in a nitrogen atmosphere followed by post-sintering operations that include coining, reaming, and tapping. The components are quenched and tempered to a 45-50 Rockwell C hardness range. Parts are supplied to the customer with a manganese phosphate finish.

Megamet produced this part using BASF’s Catamold feedstock system. The two parts are moulded in one tool using a 110 ton Toyo injection moulding machine with a 1+1 cavity family tool. A CM furnace is used for debinding, with sintering taking place separately in a pusher furnace. The body and yoke parts were both designed specifically for the MIM process, however the yoke’s shape presented challenges to all stages of the process.

“Moulding requires an elaborate three slide tool and in order to support the complex shape during both debinding and sintering a custom multi-level ceramic support system was developed. The challenge presented by the body piece is driven by intersecting internal geometry. The roundness and concentricity requirements of intersecting holes require constant vigilance and control in all stages of the MIM process”, stated Megamet.

Megamet Solid Metals currently operates a 17,000ft² facility that houses engineering, manufacturing and administrative functions. Thanks to strong growth over a number of years, it is reported that Megamet will be moving into a fully renovated 28,000ft² facility during fourth quarter of 2009.

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