MPIF award winning Metal Injection Molded (MIM) parts 2010
October 20, 2010
Winners of the 2010 PM Design Excellence Awards Competition, sponsored by the Metal Powder Industries Federation, were announced at PowderMet2010. As in previous years, the Metal Injection Moulding sector scooped some of the key awards.
Grand Prize Winners
Stainless steel hunting arrow tip: Smith Metal Products, Lindstrom, MN, USA, received the Grand Prize in the Hand Tools/Recreation Category for a 17-4 PH stainless steel hunting arrow tip (Fig. 1), called a shuttle T-lock broadhead, made by MIM for Trophy Taker, Inc., Plains, MT, USA.
Formed to a final density of 7.6g cm3, the unusual shape extends the design engineering advances of the MIM process. Other processes were considered but could not provide the necessary geometry for commercial production, and the prototypes cost many times more than MIM.
The broadhead has a yield strength of 137,000 psi and a tensile strength of 159,000 psi. The ferrule hardness is 36 HRC and the blade hardness is 38 HRC. Secondary operations are limited to final grinding of a razor sharp edge on the tip of the ferrule and the leading edge of the blade.
Military “safe and arm” rotor: FloMet LLC, DeLand, FL, USA, won the Grand Prize in the Aerospace/Military Category for a safe and arm rotor (Fig. 2) used in an explosive device for a US Department of Defense application.
Produced by MIM, the 316L stainless steel part is formed to a density of 7.6g/cm3. Its significant properties include an ultimate tensile strength of 75,000 psi, yield strength of 25,000 psi, 50% elongation, 140 foot-pound impact strength and 67 HRB hardness.
The complex shape features numerous outside radii and angular surfaces. At least 12 functional features and surfaces are geometrically controlled by concentricity, profile, and true position tolerances. The part is assembled into a housing to provide the two-stage safety for the explosive device. It replaced a zinc die casting whose mechanical properties were ultimately not consistent enough to pass validation testing.
Industrial lock parts: Advanced Materials Technologies Pte Ltd, Singapore, won the Grand Prize in the Industrial Motors/Controls & Hydraulics Category for four complex 316L stainless steel MIM parts: lock cover, lock barrel pin, lock barrel boss and lock barrel square (Fig. 3).
These are assembled into a locking device for heavy machinery operating in harsh environments. Choosing the MIM process over casting provided superior surface finish that did not require polishing, enhanced corrosion resistance, as well as a 30% cost saving.
The parts are formed to a density of 7.5g/cm3 and feature a tensile strength of 75,000 psi, a yield strength of 25,000 psi, 50% elongation, and a 67 HRB hardness. They must undergo cyclical rotational testing of more than 300,000 cycles and a 48-hour salt-spray test.
Award of Distinction
Pistol upswept grip safety part: Megamet Solid Metals, Inc., Earth City, Mo., won an Award of Distinction for an upswept grip safety part (Fig. 4) used in the 1911-style 45-caliber pistol made by Colt’s Manufacturing Company, LLC., West Hartford, Conn.
The complex MIM 17-4 PH stainless steel part is produced to a density of 7.6g cm3. The upswept design of the grip safety part, which was traditionally investment cast, would previously require extensive secondary machining.
Switching to the MIM process reduced customer lead times and provided exceptional cost savings, in addition to increasing production rates and producing a more uniform part. The upswept grip safety performs several functions: it blocks the trigger from firing, shields the hammer from impacting or injuring the shooter’s hand when the pistol cycles, and interacts with the shooter’s palm for comfort. Colt performed a 10,000-cycle test to qualify the part.