Final parts built on SLM 280 Twin Laser
Software developer, solidThinking has delivered the latest editions of its complementary design software products solidThinking Evolve and solidThinking Inspire 2017, crammed with new user-requested features for motion analysis, topography optimisation, symmetry and depth of field.
Built with a focus on improving usability for designers and engineers, key updates to Inspire 2017 include a new Motion tool that allows users to easily mechanise their models and predict loads for moving parts, a Topography Optimisation tool to change shapes of shell structures using stamped bead patterns to improve structural performance, Bolt Pretension tool for more accurate results when bolts are under pretension, and updated Partition Tools that allow users to divide a part into design and non-design regions by selecting a hole, pocket or face to offset.
Over in Evolve 2017, the biggest improvements come in the form of Planar Symmetry and Radial Symmetry tools to replace Mirror and Polar Copy tools, improved import and export for certain file formats, a new length parameter for the Line tool and Rounded Polyline tools and improved Curve Offset tool for working directly on surface edges. In addition to these new features, all images rendered in Evolve will now include a Depth Channel (tiff), which can be used in post-processing tools including Adobe Photoshop to simulate natural blurring of foreground and background elements when viewed through a camera lens.
Bracket set up with loads and design space in Inspire.
Each of these enhancements have been implemented to streamline the overall design process by putting generative design and optimisation features into the hands of engineers and industrial users. One such user is Sintavia, a global leader in independent metal additive manufacturing (AM) for critical industries such as aerospace, oil and gas, automotive and powder generation, who recently used the new solidThinking Design Suite to optimise a traditional aerospace part.
With six printers from four of the world’s largest additive machine manufacturers, hot isotonic press, vacuum heat treatment, wire EDM, CT scanning, mechanical testing and materials lab, Sintavia is unrivalled when it comes to in-house capabilities that serve some of the world’s most demanding industries.
In a recent project, Doug Hedges, President of Sintavia set out to prove the ability to additively manufacture aerospace replacement parts. The goal was to produce an optimised design for an aerospace bracket, an aftermarket aviation part for a low-pressure turbine used 12 times per engine that would reduce weight whilst exceeding existing mechanical properties.
Doug explained: “My goal is to streamline maintenance, repair and overhaul organisations using generative design and additive manufacturing. If these organisations adopt these technologies, they can see many benefits including streamlined (internal) fabrication, easier make vs. buy decisions, virtual inventory, replacement of obsolete or discontinued parts, and improved performance characteristics of the parts can be achieved including decreased weight, increased strength, and increased fatigue characteristics."
Optimised bracket.
To begin, the original part was scanned with a blue light scanner to produce a high-fidelity CAD model. The team then determined all of the loading conditions that the part would experience during use and applied them to the design in solidThinking Inspire. After separating all design and non-design spaces, multiple optimisation iterations were ran including modified design spaces, compression testing and factory of safety. Finally finite element analysis (FEA) was run on the results to compare and determine the best optimisation result before taking the design into solidThinking Evolve and using the PolyNURBS tools to refine its final geometry.
Final design in hand, Sintavia went ahead and produced the part on its SLM Solutions 280 twin laser machine in Inconel 718 powder. The part then underwent in-house vacuum treatment and removal from the build plate using EDM before additional post processes including support removal, sand blasting, polishing, and hot isotonic pressing to avoid any cracking.
The part has undergone several tests including fatigue, metallurgy and load testing with 5000Ibs. The results were positive and the optimised part managed to outperform the original in every test boasting a 15% weight reduction, three times increase in fatigue life and reduced porosity. Now Sintavia plans to further optimise the part and a range of others for AM.
Doug added: “With the engine turbine part, I want to continue to work to further reduce the mass. We also plan to strengthen the collar, and may even work on a design with integrated bearings.”
