Metal 3D printer manufacturer Nikon SLM Solutions has developed new material parameters for NASA‘s GRCop-42 copper alloy.
These parameters aim to meet the increasing demand for GRCop-42 in the space industry. The objective of this “ready-made solution” is to overcome powder supply issues and enable service providers to efficiently 3D print space components using Nikon SLM 3D printers.
The material parameters are designed keeping scalability in mind and are specifically optimized for large-format 3D printers such as the NXG XII 600. According to reports, the new parameters enable a density of 99.97% and stable properties in both single- and multi-laser overlap zones of the printer’s build area.
Nikon SLM Solutions, in its recent case study, expressed its commitment to provide solutions to GRCop-42, eyeing wider adoption across the space industry.
Nikon SLM Solutions allows for reduced supply chain schedules and improved the prospects for future space projects. These results combined with SLM’s open architecture allows scaling the parameter set up to larger platforms such as the NXG XII 600 and NXG XII 600E with a 1.5-meter build height.
NASA’s GRCop-42 material
GRCop-42 was developed back in 2019 by a team from the NASA Marshall Space Flight Center (MSFC) in Alabama and the NASA Glenn Research Center (GRC) in Ohio.
Part of NASA’s broader GRCop alloy group, this copper-chromium-niobium material showcases high thermal conductivity and strength. It’s developed to rapidly dissipate heat, with an optimization for the production of liquid rocket engines that need thermal stability and creep resistance.
Rocket engine producer PANGEA Aerospace and additive manufacturing engineering organization AENIUM have previously collaborated to build and industrialize 3D printed propulsion systems with GRCop-42 utilization. Together they strived to leverage the material properties of the copper alloy to construct a functional, economically feasible, and time-efficient PANGEA Aerospike engine.
Nikon SLM is not the pioneer in developing an exclusive 3D printing process for GRCop-42. In 2021, aerospace additive manufacturing service provider Sintavia developed its own 3D printing guidelines and heat treatment post-processing procedures for the NASA-developed copper alloy.
Sintavia’s GRCop-42 3D printing parameters were developed on an M400-4 3D printer from Munich-based 3D printer manufacturer EOS. These parameters are timely and reportedly deliver components with densities of a minimum of 99.94%. Furthermore, they can provide least tensile strengths of 28.3 ksi, minimum ultimate yield strengths of 52.7 ksi, and minimum elongations of 32.4%.
Optimizing GRCop-42 to meet growing demand
During the material parameter development process, GRCop-42 powder supply was ensured by Nikon SLM Solutions’ global production partners. The quality was specified, and the quality of each batch was internally screened.
The company employed two SLM 280 2.0 700W 3D printers during the initial development process. These new parameters are said to offer comparable or superior results to other laser powder bed fusion (L-PBF) 3D printers on the market.
Scalability from small parts to larger components often presents challenges in the development of 3D printing parameters. Nikon SLM looked into parameters such as laser hatch, border contours, and up- and downskin to optimize surface roughness.
The most effective parameters were chosen and examined using high-exposure area builds to determine robustness over the whole build platform. The team at Nikon SLM followed this with a parameter release candidate that was trialed using various approaches, and a sequence of qualification jobs. These 3D printing jobs were performed to compile statistical mechanical property data for the entire 3D printing platform, and across multiple builds.
The parameter release candidate offered a realistic view of the mechanical attributes expected from high-exposure 3D prints. These attributes encompass a 290 MPa yield strength, 535 MPa ultimate tensile strength, and 22% elongation after break for vertically machined components. Horizontally machined components provided a 340 MPa yield strength, 545 MPa ultimate tensile strength, and 21% elongation after break. According to the company, large components with both thin and thick walls that have undergone hot isostatic pressing (HIP) treatment can considerably surpass these values.
The adjustment of scaling factors and beam compensation values are said to have been a key part of the parameter development process. According to Nikon SLM Solutions, these parameters are key to 3D printing parts with high accuracy.
The company argues that its way of developing parameters included necessary modifications for scaling and beam compensation. These reportedly were validated and standardized on parts, including test artifacts of differing sizes and shapes.
In the future plans, Nikon SLM Solutions will venture to evaluate the effects of HIP post-processing on mechanical properties, the scalability of post-processing parameters to the NXG XII 600, and parameter optimization for larger parts.
3D printing space-ready components
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