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    PPB uses 3-D printers to create metal parts

    PPB uses 3-D printers to create metal parts

    Photo By Keith Hayes | Franklin Spain, engineering technician, looks on as Richard Pimentel, engineering...... read more read more



    Story by Keith Hayes 

    Marine Corps Logistics Base Barstow

    A pile of metal dust can now be formed in to a three dimensional solid object such as a vehicle part or specialized tool from a digital file at Production Plant Barstow, Marine Depot Maintenance Command aboard the Yermo Annex of Marine Corps Logistics Base Barstow, Calif.

    Three-dimensional printers create objects by depositing materials layer by layer in accordance to the object's 3D digital model. Printer processes vary, but the material is usually sprayed, squeezed or otherwise transferred from the printer onto a platform into almost any part or tool needed.

    The brand new Electro-Optical Systems M 400 3-D printer began operation May 29 in a specially constructed self-contained building at PPB.

    It is capable of using several different types of powdered steel, soft aluminum or titanium to construct metal parts and specialized tools.

    “The ‘M’ in the title stands for metal, as opposed to using polymer or plastic to make a part,” said Richard Pimentel, one of the engineering technician tasked with the setup and operation of the $2 million machine. “The 400 refers to the 400-millimeter cube (about 16 inches) per side size the machine is capable of producing.”

    He explained the printer takes a computer program of an object rendered into a three-dimensional pattern, loads it in to the machine, which then lays down a pattern of the metal dust, which is then micro-welded with 1 kilowatt lasers into solid metal. The part or tool is built using pass after pass, up to 1,600 hundred layers.

    “It’s a process called SLS, selective laser sintering,” Pimentel said. “It’s an additive process, rather than the more common subtractive method of taking a block of metal and shaving away material to shape it into an object.”

    The artisans at PPB who rebuild and refurbish military equipment quite often encounter parts which are no longer available and are too costly to recreate using the casting method, he said.

    “If we needed several hundred of a part or tool, then it would be worthwhile to go to a private manufacturer to have them casted,” Pimentel continued, “but with only one or two parts it would be very cost prohibitive. That’s where the value of the 3-D metal printer comes in.”

    The process can be fast, from as little as six hours to as long as 20 days to form with the EOS M 400 machine.

    “It depends on the complexity of the part,” Pimentel said. “This machine can construct ball and socket parts, or gears within gears that actually move and rotate inside other gears.”

    There are precautions that have to be taken using the machine, he said.
    “The powdered metal dust can flash burn if too much is released into the air and a spark is applied,” Pimentel said.

    The machine itself reduces the oxygen level in the build chamber to below that which is required to start a fire. If that safeguard weren’t there then the lasers could touch off a flash fire, he explained.

    “The waste that is created by the process can be dangerous, too,” Pimentel added. “It has to be specially packed with added chemicals to neutralize it then sealed up and let set for at least 24 hours before shipping it out for disposal. Also, when the operators are loading the powder into the hopper which feeds the machine they have to wear a breathing apparatus and protective coveralls to prevent inhalation of the powder or getting it on their skin because it is an irritant.”

    The building housing the printer is specially constructed to suppress any fires and dissipate static electricity to prevent sparks.

    The unused powder is not wasted. It is vacuumed up with a special device, run through a sieve to remove any impurities and then reused.
    “Ten kilograms (about 22 pounds) of powdered metal, aluminum or titanium, costs $7,000 a container,” Pimentel said. “Once you develop a 3-D program and load it into the machine, the computer analyzes how much powder will be used, so none is wasted.”

    “The printer is a real time and money saver when it comes to making special tools or parts that are simply not available anywhere,” Pimentel said.



    Date Taken: 06.14.2018
    Date Posted: 06.14.2018 18:31
    Story ID: 281004

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