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MRAPs Present Challenges
February 1, 2010
5 Min Read
Defense spending is providing some life support for product development companies hard hit by weakness in automotive and other traditional manufacturing sectors.
Case in point: The Mine Resistant Ambush Protected Vehicle (MRAP) developed for use in Iraq and Afghanistan was a perfect fit in the toolbox of a prototyping/manufacturing company started in Michigan in the 1990s as an effort to diversify out of automotive.
More than $1 billion was set aside for development of the vehicles in 2007 after Defense Secretary Robert Gates said the acquisition of MRAPs were the highest priority of the U.S. Defense Dept. The Marine Corps ordered 2,300 of the vehicles and contracts were awarded to suppliers with different designs.
Competing designs were submitted by nine companies and the Marine Corps awarded contracts to several companies to expedite production and delivery. Designs were submitted by:
Armor Holdings (now part of BAE)
Force Protection Inc. (FPI)
General Dynamics Land Systems (GDLS)
General Purpose Vehicles (GPV)
Navistar International Military Group (IMG)
Protected Vehicles Inc. (PVI)
Textron Marine and Land Systems
OEMS such as Navistar quickly deployed an extended supply chain to design and produce the vehicles, which generally featured V-shaped bottoms to deflect the force of the blast from a roadside bomb.
A Michigan company, 3-Dimensional Services, was selected to develop 63 components in the door-assist module for the Navistar MRAP, working through Inteva Products, a subcontractor. Parts included the base plate, two latching components designed to be mounted to the body inside the door skin, hinges which are, similarly, covered by the door skin, side rods and slider blocks.
Production required several different types of process technologies. Forming was used to produce the angle supports for the slide system. Manual welding was required for the module's handles, levers and angle supports, while the main base plate and close out brackets were robotically welded.
Plastic injection molding, using DuPont Delrin polyacetal, as well as ExxonMobil Chemical's Santoprene thermoplastic elastomer (TPE) was used to make the wedges and handle covers. Laser cutting and CNC machining were primary operations used on nearly all of the module's metal parts.
"Our lasers - both 3- and 5-axis - can cut through thick armor plate or slice through thin sheet metal, all with amazingly tight tolerances," says Mike Brabandt, senior sales engineer for 3-Dimensional Services Group. The 3-axis laser-cutting systems offer speed, accuracy and flexibility, while the 5-axis systems are ideal for cutting complex contours and shapes.
Metals used for the module include A36 stainless, high-strength/low-alloy steel and, for the hinges, CNC 1045 steel. One of the challenges for the hull of the MRAP was availability of armor-plate steel. Only two mills in the U.S., Oregon Steel Mills Inc. and AreclorMittal Plate in Coatesville, PA, are qualified to produce armored steel for the Defense Department. Oregon Steel Mills is part of the Evraz Group, which has headquarters in Moscow. ArecelorMittal is based in Luxembourg City.
The prototype of the door module was completed in seven days, says Brabandt. There were four design iterations, completed in a month.
The final design of the MRAP door modules called for components to be zinc yellow chromate-plated for superior corrosion resistance, and for the module to be CARC (chemical agent-resistant coating) painted. CARC, which is typically used on today's U.S. military vehicles, is a polyurethane paint that provides superior durability, extends service life for military vehicles and equipment, provides surfaces with superior resistance to chemical warfare agent penetration and greatly simplifies decontamination.
3-Dimensional Services was founded in Rochester Hills, MI in 1991 by Douglas Peterson as a diversification away from the automotive industry. "We've been doing various defense development work, as well as projects in appliances, lawn equipment and elsewhere," says Brabandt. "We're also looking at a niche in the low-volume manufacturing area. Production houses have nibbled at some of that and prototyping has nibbled at the other part."
In the meantime, the company still has projects in automotive. 3-Dimensional Services established full-frame vehicle prototyping capabilities, typically those used in the production of full-size pickup trucks, vans and SUVs. The company also partnered with H&K Reflex, a German company, to produce automotive lenses.
So far results are mixed. Diversification into military products has been a plus. "We were able to stay strong a little longer because of our diversification," says Brabandt. The company's big toolbox fit just right for the MRAP requirements: fast turnaround coupled with low-volume production.
The company has a rapid prototyping department that includes selective laser sintering and stereolithography systems. Plastics molding capabilities include presses that run from 30 to 500 tons of clamping force. Stamping presses run from 20 to 7,000 tons. Software packages include CATIA, Delcam, Mastercam, Unigraphics, SolidWorks and Pro/ENGINEER.
3-Dimensional has worked on prototypes for alternate fuel vehicles and developed components for the Hertz NeverLost GPS system.
The MRAP, meanwhile, has gone out of production in favor of a more mobile version, called the M-ATV. It was announced last summer that only one version of the M-ATV will be built, and that contract was awarded to Oshkosh Corp. of Oshkosh, WI.
For more information:
Independent Suspensions for Combat Applications
MRAPs Present Challenges_A
MRAPs Present Challenges_B
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