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MRO providers are discovering ways to innovate their procedures while remaining viable and profitable through the current downturn in government spending.

With such challenges as base closings, shrinking defense budgets, and sequestration, the worldwide maintenance, repair, and overhaul (MRO) sector is projected to experience a significant decline over the next few years.

This landing gear knuckle illustrates how electron beam melting (EBM) technology can be used to produce one-of-a-kind parts rapidly without any tooling. Since the part is built layer-by-layer, the microstructure is completely uniform regardless of whether a thick section or thin section is examined. This homogeneous microstructure translates into uniform, consistent mechanical behavior. The material possesses complete isotropy. Thermal shunts fabricated as the part is being built (visible on the part) are used to keep the temperature isothermal and are easily broken off after the part has been built. (All images: CalRAM)

According to Hal Chrisman, leading analyst and Vice President at aviation consultancy ICF SH&E, “it appears that defense operations and maintenance spending will drop nearly 8%.” He added “forecasting, which is especially critical in the aftermarket world, is very tricky this year.”

Underscoring this problem, international aerospace and defense consultants IHS stated in their report, Overcoming MRO Supply Chain Dys function, “Look closely at the product lifecycle within the typical MRO organization and you’ll notice that 50% of open work orders are waiting for parts; 30% of in-house stock will never be used; 8% of SKUs are duplications; and, on average, employees spend 25% of the workday looking for parts."

Parts management becomes even more critical as the military fleet ages and consumes all available replacement parts. MRO operators must face difficult financial choices in controlling these costs: either replicate components such as those made from titanium from scratch through a lengthy and costly remanufacturing effort, or delay those expenses by cannibalizing other aircraft for “used” replacement parts, thereby decreasing the reliability of repaired aircraft while rendering some aircraft unflyable.

Tool-less Additive Manufacturing

This warm air mixer is a component designed by Northrop Grumman for the U.S. Navy’s unmanned combat aerial surveillance system. CalRAM fabricated this complex component in one piece from Ti-6Al-4V using its EBM technology. If traditional manufacturing processes were used, this component would have been made in several pieces that would have had to be joined. The demonstration of part count reduction without the need for tooling illustrates how additive manufacturing can be used to reduce cost and shorten delivery schedule.

To address such issues, a cost-effective manufacturing technology is being applied to titanium parts manufacturing for the MRO, aviation, and defense industries. CalRAM fabricates 3-D, near-net-shape components by melting titanium (and other metal) powders one-layer at a time using an electron beam. Employing electron beam melting (EBM) machines built by Arcam, CalRAM’s tool-less additive manufacturing technology is said to "rapidly create solid titanium objects faster and with less cost than traditional methods."

Located in Simi Valley, just north of Los Angeles, CalRAM says it is the only independent AS9100C certified, EBM-based manufacturer in the U.S. Offering this technology to MROs and other suppliers in the aviation and aerospace industries, the company has been producing titanium components for airframe primes and gas turbine engine aircraft manufacturers for almost a decade.

During CalRAM’s manufacturing process, electron beam paths are defined by proprietary software that “slices” existing 3-D design models into a series of separate layers, much like the views in a modern CAT scan. Powder is spread on the “start plate” by a traversing rake in the build chamber and then sintered to the plate using heat from the electron beam.

A pump-fed, liquid rocket engine uses Shrouded impellers in the turbo pumps for high-efficiency pumping, and they are generally made from high-value materials, like titanium alloys, because of their high specific strength. As such, they are extremely expensive to produce and may take several months or longer to be made. Using EBM technology, they are producible in days and have been shown to meet or exceed burst speeds.

After the layer is sintered to ensure a conductive path for the electrons, the beam passes over the surface a second time at higher energy to melt and consolidate material that will form the finished part. This process is repeated, layer-by-layer, until the entire part is complete. Since parts are formed directly in the powder bed, EBM is fast with maximum build times less than 60 hours. And because EBM requires absolutely no custom tooling, the company’s layer-built components can save 85 to 90% of the MRO operator’s cost for replacing titanium products.

The process is said to also save designers up to 90% of their development time by substantially compressing the “design-test-redesign” process as well. After receiving the customer’s CAD file, CalRAM can deliver a titanium component in about two weeks, making development hardware available for installation and testing in days instead of months. Further iterations, if required, follow the same path, significantly reducing a client’s time to market.

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