Metal Molding Designs Reduce Components

Newcost-cutting designs are fueling continued growth for metal injection molded (MIM)parts, albeit at a slower rates than previous years, and two examples are grandprize winners in the 2011 Design Excellence Awards sponsored by the MetalPowder Industries Federation (MPIF).

Parmatech Corp.earned the grand prize in the hand tools/recreation category for a large-game420 stainless steel hunting arrowhead. Made for Optek Precision Tooling Ltd.,the part features a critical straightness necessary for accuracy. Showing theversatility of the molding process, the external thread for attachment to thearrow shaft is molded in the design.

The part is formed to a final density of 7.7 g/cm³ and has a48-52 HRC (Rockwell scale) hardness range.

Optek saved 50 percent of the cost of machining the broadhead fromstainless steel bar through use of metal injection molding. The customersharpens the arrow head edge, the only secondary operation performed.

FloMet LLC earned a grand prize fora housing cup and lid used in an audio device with magnetic shieldingcapabilities. The MPIF judges described it as the first application is of itskind in the high-power audio device sector.

The anti-magnetic MIM material with high-nickel content provides electromagneticinterference.

The lid must fit securely into the cup opening to prevent moisture and particulatesfrom entering the housing, as well as maintaining the EMI shielding capability.

Manufactured to 8.30 g/cm³ density, the parts have anultimate tensile strength of 84,000 psi, yield strength of 32,000 psi and a 40percent elongation.

Combining these multiple components through the MIM process providedsignificant cost savings, in addition to eliminating up to 40 percent scraploss.

The North American powder metallurgy industry, which includes MIM, wasup 35 percent in 2010 compared to 2009, according to the MPIF.

"We are back on the growth track, regaining momentum in nearly everyquarter," says Michael E. Lutheran, president of the MPIF.

The most important MIM markets are medical, firearms, electronics,dental, automotive, and telecommunications. It's estimated that about 40companies in the United States make MIM parts with an estimated $200 million inannual sales. Captive production at large firearms and medical parts producersaccount for about 30 percent of total production of MIM parts in the UnitedStates.