| COACHELLA, CA — Keeping military pilots out of harm's way is a mission of Armtec Defense Products Co. The firm's product line includes countermeasure devices like decoy flares that protect aircraft from heat-seeking missiles. The flares are encased in metal canisters, which are ejected from dispensers in planes or helicopters when pilots detect a missile attack. As they fall away from the plane the flares explode. Their infrared intensity simulates engine heat and draws missiles away from the aircraft.
The flares are made from a composition of magnesium and other chemicals that is mixed, extruded and pelletized. Armtec produces eight types of decoy flares for all branches of the U.S. military and for allied governments. To assure safe handling of the highly combustible pellets during manufacturing, Armtec uses special containers and lids that are fabricated by Formed Plastics Inc., Carle Place, NY, of Kydex GND, a conductive, fire-resistant grade of thermoplastic alloy sheet from Kleerdex Co.
Formed Plastics vacuum-forms several lids for Armtec: a mixing-vat-container lid that is 29 in. in diameter and 6 in. high; a blend-pot cover 18 in. in diameter and 24 in. high; a flare-composition-storage lid 25 in. in diameter and 2.75 in. high; and a slurry-pot cover 14 in. in diameter and 17 in. high.
Kydex GND sheet meets two important criteria: safety and formability. Safety is the overriding concern for Armtec. "The magnesium composition burns intensely and is extremely hazardous if mishandled," says Linda Swope, director of flare programs for Armtec, a subsidiary of Esterline Technologies Corp., Bellevue, WA. Static electricity can ignite the pellets, which are loaded into the flares by hand at Armtec's plant in East Camden, AR. It is thus critical to assure that no static electricity is generated during handling.
Surface resistivity of the Kydex GND sheet is 105 Ohms/square. It has outstanding deep-draw and forming characteristics, and importantly retains full conductive properties after fabrication. Kydex GND sheet is rigid (flexural modulus of 270,000 p.s.i.) and achieves uniform wall thickness and high detail during thermoforming. The product has a high level of chemical resistance and meets UL Standard 94 V-0 flame requirements. Kydex GND sheet is black and comes in a range of thicknesses and 10 textures.
Deep-Draw Forming Technique Assures Accurate Gauge
The Armtec lids are vacuum-formed in a "snap-back" technique, says Pat Long, president of Formed Plastics. The Kydex GND sheet is mounted on a clamping frame and transferred to a heating station where ceramic heaters warm the sheet evenly top and bottom. When the correct temperature is reached, the sheet is moved to a forming station. Here a pre-stretch box pushes against the bottom of the sheet. A vacuum is applied and the sheet is pulled into the box in a bubble-like shape. The depth of this pre-stretch bubble is controlled by an electric eye. When the bubble reaches the correct depth, the upper platen descends and the male mold drops into the bubble. A vacuum is drawn on the male mold and the sheet snaps back onto it. The lid is cooled with high-speed fans and removed.
The snap-back technique assures even distribution of material thickness, Long says. Each lid requires a different size sheet of Kydex GND: the mixing-vat-container lid blank is 36 by 36 in. and 0.312 in. thick; the blend-pot cover blank is 42 by 42 in. and 0.375 in. thick; the flare-composition-storage sheet is 34 by 34 in. and 0.250 in. thick; and the slurry-pot blank is 30 by 30 in. and 0.250 in. thick.
Lids are formed on a single-station model 84SP pressure-forming machine from Maac Machinery. The automatic unit has 48- by 96-in. platens and individually controlled ceramic heaters, Long says. The molds are machined from aluminum by Formed Plastics.
"The Kydex GND sheet met extremely high performance and fabrication requirements in this job," says Long. "The lids we formed with this material demonstrate the quality and value of this highly-engineered material."
For Armtec, the performance of the Kydex GND lids is critical to the safe production of a life-saving product. "Armtec's use of these antistat lids reflects our commitment to maintain the highest safety and quality standards possible for our people and our products," Swope says.
Armtec Defense Products Co.
85-901 Ave. 53
Coachella, CA 92236
USA
760-398-0143
www.armtecdefense.com
Formed Plastics Inc.
207 Stonehenge Lane
Carle Place, NY 11514
USA
516-334-2300
www.formedplastics.com
Maac Machinery
590 Tower Blvd
Carol Stream IL 60188
USA
630-665-1700
www.maacmachinery.com
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U.S. Air Force C-17 Transport plane releases decoy flares. Their high-intensity IR radiation draws heat-seeking missiles away from the aircraft. (Photo courtesy Defense Visual Information Center)
AH64-D helicopter releases decoy flares. Their high-intensity IR radiation draws heat-seeking missiles away from aircraft.
Blend-pot and slurry-pot covers are vacuum-formed of Kydex GND, a conductive, fire-resistant thermoplastic alloy sheet that prevents static-electricity buildup during handling of the highly combustible magnesium blend.
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