www.engineeringnews.co.nz 15 The barrel and receiver were made a direct metal laser sintering (DMLS) process, which heats up the particles of powder below their melting point. Both of the parts took about 70 hours to print and then another five hours of post-process machining. conventional grenade launchers to within 5%. Furthermore, the weapon showed no signs of degradation after firing. RAMBO and its 3D printed ammo are currently undergoing additional testing to evaluate their reliability, survivability and failure rates. Additive manufacturing is now to 3D what black is to the fashion industry: a fundamental. RAMBO consists of 50 components with just the springs and fasteners not printed. A majority of the modified M203 grenade launcher was developed using additive manufacturing process, which is a type of 3D printing that layers materials as it prints to create a 3D object. However, the trigger and firing pin were printed in 4340 alloy steel and the barrel and receiver from aluminium. A M781 40 training round was chosen as the design for the 3D printed grenades. Because the traditional training rounds are made using zinc case, which cannot be printed, the team had to find another method. After a few trial and errors, researcher decided to use a wax printer to make the mould for the grenade bodies (pictured), which they could pour molten zinc into a plaster mould. Here, wax moulds are ready for placement in plaster moulds, one of four methods used to print the M781 ammunition. Zinc, used in the projectile body of the round, cannot be 3D-printed, but since AM affords quick changes and eliminates the need for retooling, alternative approaches could easily be explored to identify a new component that could be used. A majority of RAMBO was created using the additive manufacturing process, which is a type of 3D printing that layers materials as it prints to create a 3D object. In fact, more than 90% of the components in the prototype grenade launcher were printed with AM, in just 35 hours and on a single build plate. ARDEC researchers developed the AM effort to identify faster, less costly methods for producing the fielded grenade launcher The making of RAMBO
EN-Apr17-eMag
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