Over the past decade, DEVCOM-AC and New Jersey Institute for Technology (NJIT) researchers have relied on a concept called volumetric energy density (VED)  to help set boundaries on which parameters to change to optimize the density of a new metal. The VED relies on the laser power (Watts), laser scan speed (mm/s), hatch distance (mm) and layer thickness (mm) to calculate how much energy is going into melting the metal alloy within the AM machine, shown below.

Within the VED construct, if a researcher is limited to having only 1 laser power setting it is still possible for them to vary the VED by changing the laser scan speed (v) or hatch distance (h).  This helps to increase or decrease energy within a certain volume using available equipment.

Once the variations in process parameters have been selected for the design of experiments (DOE), building parts can begin.  To save money on powder, it is recommended that a few small cubes (~15mm – 20mm) be built in various points on the build plate to show the dependency of location.

Once the cubes have been produced and removed from the build plate, obvious defects such as delamination should be noted. Typically, but not always, if the process parameters do not work well for small cubes they will not work well for larger parts.  However, for cubes that remain intact more investigation needs to be done to determine which process parameters produced cubes with the highest relative density.  Density can be measured using the Archimedes Principle or by visually inspecting polished metallurgical specimens and checking for porosity.

Running this DOE several times can confirm the consistency of the results.  Once a researcher is satisfied, the next step would be to produce larger specimens which are properly heat treated to commence other physical and mechanical testing. 

Interested in learning more about how to use Volumetric Energy Density for AM process optimization with NJII Defense?  Contact one of our experts today!

References

Jelis, E., Hespos, M.R., Feurer, M. et al. Development of Laser Powder Bed Fusion Processing Parameters for Aermet 100 Powder. J. of Materi Eng and Perform 32, 7195–7203 (2023). https://doi.org/10.1007/s11665-022-07638-y

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What is Thermal Distortion? 

Thermal distortion refers to the deformation of a material due to uneven heating and cooling during the additive manufacturing process. This phenomenon is especially common in metal 3D printing, where intense heat from lasers or electron beams is applied to build layers. As the material cools, it can contract non-uniformly, leading to warping or internal stresses. According to research from Penn State University, thermal distortion stems from localized heating and can result in significant dimensional inaccuracies in AM parts. This can impact the mechanical properties of the part, potentially causing defects or failures. 

How Does Thermal Distortion Create Problems for Advanced Manufacturing? 

Thermal distortion poses a significant challenge to the quality and reliability of parts produced via additive manufacturing. In defense applications, where precision and strength are paramount, even slight deviations can render a part unusable. According to the aforementioned study, thermal distortion can lead to cracks, residual stresses, and dimensional inaccuracies. These issues complicate post-processing steps and may result in costly material waste and production delays. Ultimately, this hampers the efficiency of AM in producing high-performance components required in defense applications. 

How Can We Mitigate Thermal Distortion and Produce Better Results? 

Mitigating thermal distortion requires an approach developed by NJIT and the DEVCOM – Armaments Center¹, to build small cubes first and ensure that voids and defects are minimized.  This helps to optimize process parameters while reducing the amount of powder that is wasted. With the increase in physical processing studies to build up the materials properties databases, it possible now to use computational tools. 

NJII is committed to leveraging data-driven methodologies and advanced simulation tools to mitigate thermal distortion in additive manufacturing. By integrating these approaches into our Defense Division’s AM processes, we aim to enhance part reliability, reduce material waste, and streamline production. As we continue to refine our techniques, we are confident that our AM capabilities will become even more efficient and robust, ensuring superior outcomes for our defense partners. You can learn more about NJII’s Defense Division by viewing our homepage. 

1. Jelis, E., Clemente, M., (Clark) Kerwien, S. et al. Metallurgical and Mechanical Evaluation of 4340 Steel Produced by Direct Metal Laser Sintering. JOM 67, 582–589 (2015). https://doi.org/10.1007/s11837-014-1273-8 

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Tensile testing allows engineers to assess how materials perform under stress by stretching them until they break. This process helps identify key characteristics such as tensile strength, yield strength, and ductility which are essential to develop engineering design ‘allowables’. In the Defense Division at New Jersey Innovation Institute (NJII), we emphasize using defined standards to ensure that additively manufactured metals can withstand extreme conditions, such as those encountered in military and aerospace environments. 

Why Tensile Testing Matters in Additive Manufacturing 

Additive manufacturing offers the unique advantage of creating complex geometries that traditional manufacturing methods cannot achieve. But with these new possibilities come new challenges. Metals produced through AM processes, such as laser powder bed fusion or directed energy deposition, often exhibit different mechanical properties compared to conventionally produced metals – even when accounting for similar alloy compositions. Factors such as build orientation, number of parts on a build plate, surface roughness, residual stresses and how the parts are removed from the build plate can affect the final product’s strength and performance.  

Tensile testing provides vital information but performing it in a standardized way, using ASTM E8/E8M, for example, is critical so that the information can reproduced.  Therefore – even before tensile testing starts – it is essential that the metal AM parts be heat treated properly according to their alloy composition and then machined to removed surface defects. For defense applications, performing all steps in the process ensures that components such as missile parts, aircraft frames, or armor materials perform as expected, reducing the risk of failure during critical missions. 

Advancing Defense Capabilities Through Material Science 

At NJII, our focus is on pushing the boundaries of material science for defense. Through rigorous tensile testing, we can verify that additively manufactured metals meet the stringent requirements of defense applications. Whether it’s ensuring that a part can withstand the stresses of high-speed flight or endure harsh environmental conditions, our material engineers work diligently to test and validate these materials. 

By following strict testing protocols, and carefully documenting any deviations, we provide the defense industry with confidence in the integrity and durability of the components we develop. This not only enhances the safety of military personnel, but also strengthens the technological capabilities of our nation’s defense systems. 

NJII’s Defense Division is committed to the development of advanced manufacturing and 3D Printing technologies and techniques. Our flagship COMET Program combines public and private resources to advance workforce development within additive manufacturing and defense technologies. You can read about COMET here. 

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Upon the completion of the Prusa assemblies, we were split into four teams for a weeklong design sprint, where we were challenged to leverage the capabilities of the new Prusa printers to design engaging and print friendly tchotchkes representing the COMET Project. Each team included engineers and designers with diverse experiences and knowledge, who quickly had to collaborate to achieve a final design. Designs from the four teams included a drone kit card that displayed last year’s final project, a gear driven rocket launcher, a clicker coin, and a modular fidget tank (all four designs can be seen below). We all learned new skills from this one-week design sprint, gaining insights into how to properly brainstorm, collaborate, rapidly prototype, and present our design process in a professional setting. In the two weeks following the handout project, we were placed into new teams and tasked with designing remote-controlled vehicles that could traverse an obstacle course designed to simulate a jungle environment, which served as a locomotion study for the final project.

We were given an Arduino-mega starter kit and small DC motors to complete the project. Teams were quickly faced with challenges of electronics issues, scope creep, and time constraints. While the vehicles may not have perfectly traversed the course, it made for an effective learning exercise to better design solutions with given constraints. In the remaining time of the internship, all nineteen interns started working on the final project. The prompt, provided by engineers at DEVCOM AC, Picatinny Arsenal, asked us to design a design a mesh network of an unmanned ground vehicle and aerial drone to conduct reconnaissance in dense jungle terrain, where the aerial drone serves as a range extender for the ground vehicle when communication is not possible through the foliage. Taking maximum advantage of our new collaboration skills, we went through a weeklong research and brainstorm phase to better define the prompt, gather insight into the terrain and climate the network would operate in, and agree on a design. Moving forward, we created internal deadlines and a Gannt chart before splitting into sub teams based on areas of expertise: software, ground vehicle, drone, and electronics. We have been meeting often making sure we are staying on time, ordering the proper parts, avoiding scope creep, and staying on the same page as we work toward the final design. We look forward to using COMET’s advanced manufacturing capabilities to help create our final product and we’re very excited to present our final design to stakeholders at the end of the summer. If you’d like to learn more about COMET and the work we did this summer, you can view the COMET overview page on NJII’s website.

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Contested Logistics refers to the strategic and operational hurdles faced when external actors attempt to disrupt and degrade the supply chains and logistical support systems that are crucial for sustaining military operations. This includes attacks on supply lines, cyber interference, and the physical targeting of logistical hubs. This concept is helping to shape military strategy by emphasizing the need for flexibility, technological innovation, and advanced planning. The ability to maintain a continuous flow of supplies and reinforcements under adverse conditions can determine the success or failure of military operations. 

Contested Logistics in the Future of Combat 

The U.S. Department of Defense (DoD) utilize contested logistics through three avenues: Point of need, repair depots, and engineering support/R&D. Each of these avenues contain the necessary elements to carry out logistical functions in real-time, such as battlefield damage and repair, maintenance and sustainment, and engineering changes. The DoD also identifies four cross-cutting functions that impact each avenue: Policy, data and cyber, education and training, and safety. 

As military strategies evolve, Contested Logistics will play a pivotal role in shaping new doctrines. The focus will shift towards decentralized and flexible supply chains that can quickly adapt to changing battlefield conditions. This may involve the use of advanced technologies such as autonomous vehicles, drones, and artificial intelligence to predict, identify, and mitigate logistical threats. Additionally, the integration of real-time data analytics will enable military planners to make informed decisions, optimizing supply routes and minimizing vulnerabilities. 

How NJII’s Defense Division Plays a Role 

NJII’s Defense Division is at the forefront of addressing the challenges posed by Contested Logistics. The Collaborative Operationalized Manufacturing Engineering and Training (COMET) Program supports the DoD by providing workforce development and training for specialized equipment and specific circumstances. For example, COMET supported the DoD’s first-of-its-kind Point of Need Manufacturing Challenge in 2023, which consisted of various advanced manufacturing training tasks in a simulated extreme cold weather environment.  

NJII’s relationships with private and public military organizations make us a key contributor to autonomous supply systems, communication and security networks, and technological operations for the U.S. Army. By staying at the cutting edge of technological advancements, NJII is poised to play a vital role in ensuring the effectiveness and sustainability of military operations in increasingly complex and contested environments. 

To learn more about how NJII’s Defense Division is pioneering innovative solutions to meet the challenges of Contested Logistics and enhance military readiness, visit our Defense Division homepage.

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Polymers

Landing 360 uses 2 different polymer processes – material extrusion and vat photopolymerization. Material extrusion is also called fused filament fabrication (FFF) and is the most well-known of the AM techniques as it’s used by many hobbyists and schools. In this method, a polymer filament is driven into a hot nozzle where it melts and is extruded out onto a build plate. Using a software program, the nozzle rasters across the build plate, depositing extruded material layer by layer until complete. Material extrusion equipment ranges from simple machines that produce toys and parts with visible extrusion lines (ie. low resolution) to complex production-quality machines that make parts to tighter tolerances and higher strengths. Landing 360 has Prusa Mk4, Stratasys F370, F450, and F900, as well as the Ultimaker 5s.

The second polymer process utilized by Landing 360 is vat polymerization, also called stereolithography (SLA). This process builds parts within a vat of resin, which is subject to a laser or ultra-violet (UV) source that causes it to harden. Following a software program, the laser rasters across the build area hardening the resin, layer by layer, until complete. Vat polymerization equipment builds parts that are good for toys, models and various prototypes. These parts can be clear or translucent but are not necessarily noted for having high strength. Landing 360 currently possesses the Form 3 and Stratasys Neo.

Metals

Landing 360 has 3 different metal processes – powder bed fusion, directed energy deposition (DED) with the metal wire process, and cold spray. Each process has its strengths with respect to the alloys used, the speed of production, part resolution and the amount of post-processing necessary to achieve the proper part geometry and strength.

Powder bed fusion uses particles of metal that are pushed onto a build plate which are then fused into place with a fine energy beam (laser or electron) that rasters across the build plate following a software design program. Once a layer is complete, the build plate shifts down, more powder is spread across the build plate, and the energy beam rasters again. The process continues until the part is complete. Powder bed fusion creates near net shaped parts which require higher strengths than polymers. These parts need post-processing in the form of heat

treatment and final machining. Landing 360 is currently working with the EOS M290 and Xact Metal XM 200G.

Directed energy deposition (DED) with the metal wire process is similar to the material extrusion process. DED feeds metal wire into a laser, melting the wire; the molten metal is then deposited layer by layer until complete. This process does not produce near net shaped parts as fine as powder bed fusion and requires post-processing heat treatment and final machining. Landing 360 has the Meltio Engine, integrated into a 5-axis CNC Haas milling machine.

Landing 360 also has a cold spray AM unit the SPEE3D Warp Speed. Cold spray is unique compared to other AM techniques which use energy sources to fix particles or set resin in a specific pattern. Instead, during the cold spray process, metallic powders are accelerated in a high-velocity gas stream. When these powders impact the build plate, they deform and bond together, building up a mass of material. Unlike conventional AM methods, the cold spray nozzle does not raster over the build plate in a precise fashion and, as a result, produces a part that is a near net shape which requires post-processing and final machining. However, an advantage of cold spray is that it can be used to repair parts by restoring material that has been worn away through use.

Whether you’re developing parts to be used as prototypes to check form and fit, performing manufacturing R&D, producing metal replacement parts or even repairing parts, Landing 360 has access to a wide range of equipment to help customers determine their best path forward. Learn more about the COMET program and about our Advanced Manufacturing Facility.

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NJII approaches operationalization in the following broad areas:

1. Harden and ruggedize technology for use in harsh conditions.
2. Increase Technology Readiness Levels (TRL) and Manufacturing Readiness Levels (MRL) of advanced manufacturing processes.
3. Reduce risk to defense program offices by ensuring new technologies can function within current and legacy systems.
4. Support workforce development efforts among the DoD and defense industry partners.

Hardening, or ruggedizing technology, is often the critical first step to operationalize technology.  This is demonstrated using DoD performance specifications and environmental testing.  How technology will be deployed will determine the type of testing it will be subjected to – temperature extremes, shock & vibration, submersion, etc. 

The technologies studied at the COMET center include additive manufacturing (AM), printed electronics, additively manufactured electronics (AME) and robotic systems used for manufacturing and inspections.  Some of these technologies are more mature than others, meaning they have a higher Technology Readiness Level (TRL) Technology Readiness Level (TRL) – AcqNotes.  Along the same lines, sometimes a technology is mature, but the manufacturing methods used to make it are not repeatable. This would be described as having a low Manufacturing Readiness Level (MRL) Manufacturing Readiness Level (MRL) – AcqNotes. At the COMET center, NJII works to be a trusted agent in working to define whether technology, and the manufacturing needed to produce it, is ready for operation.

Working with defense program offices to reduce risk is another way that NJII works to operationalize technology. Working to enhance the safety of manufacturing operations or improve the accuracy of new inspection systems can ensure that work stoppages are avoided or that only qualified products make it out to the field.

Finally, one of the most important ways that NJII-COMET operationalizes technology is through our workforce development programs. Advanced Manufacturing and a high MRL can only truly be operationalized with a skilled workforce. NJII teams up with customers at the DoD and partners in industry to identify the specific skills needed to get this technology into the field. By learning to operate the specific manufacturing equipment being evaluated by the DoD, on projects of real-world importance, COMET trainees are able to immediately make an impact when they transition to their next role in the Defense Industrial Base (DIB), Organic Industrial Base (OIB), or as a civilian DoD researcher.

Through this systematic approach NJII works towards operationalizing lifesaving technology, getting it into the hands of warfighters where it makes an impact. Visit the NJII Defense Division Home Page and the COMET Center webpage to learn how NJII is driving innovation for the Department of Defense. 

Looking to get involved? Contact us today!

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