Industry Insider Melissa Orme, PhD on 3D Printing in Aerospace and Defense

Women in 3D Printing’s mission is to increase the visibility of women in the Additive Manufacturing industry and encourage more women to use 3D Printing technologies. We have been doing so by highlighting female leaders and innovators on our platform since 2014. To provide even more insights on female experts in the Additive Manufacturing Industry, we are inviting women to contribute to this series by sharing their business and tech expertise through guest blog posts to be published as Industry Insiders series.

Melissa Orme, Ph.D. belongs to that small group of women who have worked ‘hands-on’ in the field of Additive Manufacturing since before the term “Additive Manufacturing” existed.  She earned her doctorate degree in Aerospace Engineering at USC. Her career has been divided between academia and small business.

On the academic front, she worked as a Professor at UCI for twelve years, where she rose to the rank of Full Professor. She was an early pioneer in the field of 3D printing of metallic parts resulting in 15 US patents and 3 pending. Her earliest of many Journal articles on Additive Manufacturing dates to 1993. Her cutting-edge research on net-form manufacturing of metallic components received international recognition and numerous awards, among which include the N.S.F. Young Investigator Award and the AAUW Judith Resnick Fellowship Award. During much of this time period, 3D printing machines for metallic materials were nonexistent or in a few cases, were in their research and development phase. It is fair to say that Melissa’s research program was ahead of its time. Her patented inventions relevant to 3D printing are concerned with novel AM methods with molten metal micro-droplets, novel methods of customizing the size distribution of metallic powders, and high-speed direct circuit board printing.

On the R&D front, she founded and managed as CEO a start-up, Rapid Analysis & Development Co., that developed her invention of direct digital solder pattern printing as an alternative to traditional electronics circuit printing. She currently serves as CTO of Morf3D, Inc. which focuses on Additive Manufacturing of metallic components primarily for the Aerospace and Defense Industry. In that capacity, she oversees the company’s AM development programs for small lot production, which includes new material parameter development, novel AM design implementation, component validation, and qualification.  Melissa continuously evaluates new Additive Manufacturing technologies for inclusion into Morf3D’s offerings. 

The ability to reduce the weight of a structural component while simultaneously increasing its functionality or complexity; or the ability to fabricate one part that serves the function of multiple parts, leading to reductions in design, manufacture, qualification, assembly, and part warehousing; are a few of the benefits associated with Additive Manufacturing causing the Aerospace and Defense Industry to employ the technology with growing frequency. The weight-based premium of propelling a structure through air or space necessitates the need to explore new design methodologies and manufacturing technologies that provide lighter components with added functionality.
Additionally, because many Aerospace and Defense platforms have operational lifetimes of several decades, Additive Manufacturing is key to battle component obsolesce and the logistical nightmare of warehousing thousands of spare parts. Additive Manufacturing enables parts to be ‘printed-on-demand’ from remote locations. Replacement parts can be made from digital files that have been archived, or for older parts, have been created by scanning the faulty part to be replaced.
Designing for Additive Manufacturing provides engineers the ability to design for function rather than manufacturability. Components no longer need to be formed by subtracting material from plates or bars. When designing for functionality, design engineers need to erase much of their past design experience if that was based on subtractive manufacturing and embrace the fact that new shapes and designs may be more functional than that to which they are accustomed.
Minimization of mass in a structural component can be achieved through the methodology of topology optimization, which places material only where it is required to support the component’s loading conditions, and removes it from all other locations; oftentimes resulting in a shape that mimics nature, leading to the often used term ‘bionic’ for topologically optimized parts. In the past, results of topology optimization exercises often led to elegant designs that were not possible to be manufactured with traditional (subtractive) methods. Hence, traditional manufacturing constraints limited the degree of optimization achieved. The advent of Additive Manufacturing, however, has removed many of the former constraints and has enabled the manufacture of highly complex optimized components. Additive Manufacturing is associated with its own set of design constraints, and hence there is not unlimited design freedom in Additive Manufacturing. Those constraints (e.g., support structures, powder removal) need to be understood and incorporated into the design for Additive Manufacturing exercise in order to achieve a highly optimized component that is able to be manufactured.

Figure SEQ Figure \* ARABIC 1: Google Lunar XPrize entry engine mount.
Schematic of baseline (unoptimized) leg and hub assembly to mount the engine (shown in green).

Figures 1 and 2 illustrate an example of topology optimization and Additive Manufacturing for a space craft component that is scheduled for flight in the 2017 calendar year.  Figure 1 is the baseline rendering of an unoptimized engine mount assembly to be part of SpaceIL’s entry in the Google Lunar Prize competition.  Figure 2 is a photograph of its optimized and manufactured counterpart that was designed, printed, tested, and qualified through a partnership with RUAG Space and Morf3D.  The silver heat shield and the engine are not part of the topology optimization or additive manufacturing exercise.  The assembly manufactured includes four legs and one central hub that were Additively Manufactured from aluminum alloy on an EOS M290 (i.e., with the process of powder bed fusion).

Additively Manufactured, topologically optimized leg and hub assembly to mount the engine (replica shown in black) Note: the silver heat shield and engine are not a part of the Additive Manufactured assembly.

The entire design (including topology optimization), manufacturing, mechanical and material testing and qualification took a total of 8 weeks, demonstrating that Additive Manufacturing is an enabling technology for faster access to space, which is a motivating factor of the competition. In addition to the accelerated design and manufacturing, the optimized component resulted in significant weight reductions (2.95 kg as compared to its original 4.0 kg).

 

Despite the many benefits of Additive Manufacturing in the Aerospace and Defense industry, there are relatively few metallic structural components in service today. This is in part because it is a new technology, without the benefit of heritage database from which to draw design allowables, and frankly, the stakes are high. Vehicles and platforms on which these parts are placed are expensive, they carry valuable payload, and their function may be of critical importance to national security. These missions, whether they be government or commercial, cannot afford to insert what some may consider ‘experimental’ or ‘untested’ components. Hence, the Additive Manufacturing industry must not only convince the Aerospace and Defense industry that these parts are of sound quality, they must also produce a manufacturing flow and database that ensures that these parts are indeed sound.

The largest hurdle in Additive Manufacturing of flight hardware is overcoming the notion that their material and mechanical properties are not repeatable and reliable. In defense of the Additive Manufacturing industry, often times the manufacture of these components are subcontracted to service bureaus that are not provided with adequate information for repeatability in printing across locations and vendors. One service bureau may print the part on its x axis, and the other on its y axis, resulting in different microstructures and in turn to different mechanical properties due to the fact that different scan patterns were employed to achieve the final identical shapes. Thus, five different service bureaus may provide five identical shapes that possess five unique data sets with respect to material and mechanical properties, leading the potential user industry to claim that the process is unreliable.
If the service bureau has employed a quality process and manufacturing flow; if their raw material is of certified quality; if they have locked down their successful build parameters (i.e., part orientation, part nesting, layer thickness, plate temperature), process parameters (i.e., laser power, scan speed, hatch distance), and support structure details; then the parts they manufacture will be made with a high degree of repeatability. However, comparing the mechanical properties of these parts to those manufactured by another vendor that has employed different build parameters, process parameters, and support structure designs will likely lead to the conclusion that the process is not repeatable across different vendors.
Hence, it is not sufficient to design a component for AM and assume that it will be built with mechanical repeatability across vendors unless details of the build, laser, and support parameters are also provided.

Even if build and processing parameters are specified, one may still not assume that every part printed will have an identical microstructure, and hence, mechanical properties. This is because other factors such as, but not limited to: powder quality, fluctuations in laser power, platform temperature, and inert gas flow are not usually accounted for. Nondestructively testing every component is costly and not sustainable, as it negates the advantage of rapid turn-around-time between concept and qualification. Hence, other methods that guarantee the quality of production components are required. One such method is in-process monitoring during the manufacturing process. In-process monitoring is best employed for production parts, in which the details of the build, layer by layer, are compared to the layer-wise build details of a nominal part. Components that deviate from the nominal build characteristics can be flagged for detailed inspection such as CT scanning.

Hence, by locking all build and processing parameters, and by employing in-process monitoring, Additive Manufacturing provides the ability to produce quality components in a reliable and repeatable fashion at single and across multiple service providers, enabling the Aerospace and Defense industry to reap the many benefits of Additive Manufacturing.


More information about Morf3D is available here. 

This is a guest post in our series Industry Insiders. if you’d like to participate in this series then contact us for more information.

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