Metal Molding Designs Reduce Components

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

Parmatech Corp. earned the grand prize in the hand tools/recreation category for a large-game 420 stainless steel hunting arrowhead. Made for Optek Precision Tooling Ltd., the part features a critical straightness necessary for accuracy. Showing the versatility of the molding process, the external thread for attachment to the arrow shaft is molded in the design.

The part is formed to a final density of 7.7 g/cm³ and has a 48-52 HRC (Rockwell scale) hardness range.

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

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

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

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

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

Combining these multiple components through the MIM process provided significant cost savings, in addition to eliminating up to 40 percent scrap loss.

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

"We are back on the growth track, regaining momentum in nearly every quarter," 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 40 companies in the United States make MIM parts with an estimated $200 million in annual sales. Captive production at large firearms and medical parts producers account for about 30 percent of total production of MIM parts in the United States.