ANIL KUMAR is Senior Engineer - ACE at ANSYS
What has been hailed as the transformer, in terms of industrial production, is now all set to take a further leap with simulation. Although it is common to use terms like rapid prototyping and 3D printing to refer to additive manufacturing (AM), they are in reality its sub-divisions. AM is a process that creates a physical object from a digital design. When conventional engineering techniques are adept in manufacturing and designing, AM is what takes production to the next level.
WHY ADDITIVE MANUFACTURING?
Additive manufacturing facilitates the creation of lighter and stronger parts and systems. This technological advancement is the result of the transition from analogue to digital. With the evolution in imaging, communication and engineering, AM is now bringing increased flexibility and efficacy to the manufacturing sector.
AM creates an object by adding material. With earlier methods, materials are removed through milling, crushing, machining, shaping, etc., while with AM, it can be done in precise geometric shapes by depositing material layer-by-layer using 3D object scanners. In short, it improves performance, simplifies fabrication and complex geometrics to deliver a near perfect outcome.
One can produce better shapes and designs through AM. There is also no need to weld or attach individual components together as even hollow centres and difficult shapes can be produced as a single piece. This also means that there will be no weak spots, and it is therefore stronger.
One other major advantage of AM is speed. Alteration of designs no longer needs countless meetings between engineers. The CAD software enables making changes simple and at your fingertips. The complete model can actually be produced overnight with rapid prototyping. One can imagine the reduction of cost in such a scenario and the impact that has on production and there is so much flexibility for engineers. AM has also helped design drive production. Earlier, design was always influenced by the limitations of production and many concepts have had to be shelved because of impracticalities.
AM helps produce three-dimensional parts layer-by-layer from a variety of materials. Here, a digital data file is transmitted to a production machine and that ultimately translates an engineering design into a 3D-printed part. Originally, AM was applied as a rapid prototyping method — a fast-track technique to create parts before manufacturing by recognised methodologies like injection moulding, casting, forming, joining, etc. It was also used for mostly plastic parts. Metal-based AM processes that were developed in the 1990s were truly transformative. The need of the hour was to 3D print metal parts directly and with the launch of laser sintering systems it became possible. It also provided an alternative to the manufacturing processes that are direct and multi-stage.
Engineers undertake a lot of time and effort to design a product, and are also required to reach a specific tolerance. However, metal AM can cause thermal stresses that can eventually distort the parts. Even a slight distortion can affect the overall assembling of the end product and can significantly affect the performance as well.
SIMULATION TO THE RESCUE
Simulation offers you a tool to predict and compensate for these part deformations. A complete simulation workflow for AM lets you perfectly evolve your R&D efforts for metal AM into a fruitful manufacturing operation. Additive print is one such tool that uses these estimates to ensure that the print develops into the part the engineer originally intended. It is an easy-to-use, powerful standalone solution that is essential for AM operators and designers that helps in building parts.
Simulation can enable prediction of the final shape of the printed part and its prediction of distortion offers engineers an insight into how parts will distort during a build. It provides visualisation that allows users to evaluate how their assumptions of distortion and residual stress affect as-built parts, to enable successful selection of part orientations and support strategies. It enables the visualisation of differences between the original, non-deformed geometry and the final deformed geometry, before and after removal from supports.
With the graphical visualisation of the layer-by-layer distortion and stress, optimal support structures, distortion-compensated STL files and the potential blade crash, the possibilities are myriad. Thus, it reduces physical trial-and-error experiments, mitigates uncertainty, designs geometries for more accurate printing, accelerates production, helps one gain confidence, in terms of cost and reduces build failures for laser powder bed fusion. Apart from this it can also predict potential blade crash locations via colour maps.
Traditional trial-and-error methods that were used to perfect products are now outdated as there are many factors that can affect your print. Additive print simulations show how different scan vectors affect the thermal/ physical properties of the part. It also shows the ineffective heat transfer that causes porous regions and bad microstructure within the part. Another important thing is the stress and strains from the cooling metal that affect the effectiveness of supports. It can also predict and correct blade crashes. Simulation is therefore an effective way of optimising the printing of parts.
Simulation is transforming all industries. The auto industry has been one of the first to adapt thanks to the new metal AM solutions that has helped trim manufacturing time to a large extent. With technology and simulation users can actually print complex metal parts that are lightweight successfully, in the first try itself and also analyse the behaviour and microstructure properties. Apart from the success ratio, these solutions have a positive impact on reducing the cost of AM as it limits design constraints, reduces waste and even shrinks the overall time required to print. This in itself is a giant leap in manufacturing. Thanks to simulation, metal AM has the potential to change the entire manufacturing landscape.
Meeting the growing market demands that arise due to increasing product complexities are tough, when one only uses the traditional manufacturing methods, as there is bound to be a lot of delay in bringing out the final version of the product. It is pertinent to seek alternative methods to build these epoch-making products for the next generation. In case of a new launch, time is crucial, as companies seek ways to bring out products in a timely and cost-effective manner.
The current AM process is not only time-consuming, but also expensive. What becomes a limiting factor is the high price of metal powders and 3D printing materials. This ominously restricts the opportunities for trial-and-error throughout the whole printing process.
Another massive concern about AM, when it comes to metal, is the discrepancy of the composition and performance that is often the result. The metal powders that are ostensibly alike, in terms of grain size and chemical analysis can result in parts with different properties using seemingly parallel AM processes. What this can do is cause an error in the outcome and also makes it necessary for additional manufacturing steps. This inconsistency in the composition and structure can not only impact the final product performance, but also its quality and safety.
With simulation, the complete additive simulation workflow shrinks all those limitations and also streamlines the entire process. This empowers users to virtually test their product designs well before printing the same. This is a quick process and by integrating simulation prior to the printing process, there is a massive reduction in the cost of physical trial and error. Designers can now design, test and validate the performance of a part at the design stage even before turning on the printer.
With simulation, one can get results that demonstrate to engineers exactly what will occur during the printing process. Before the actual printing, these designers are informed of all the scenarios that can be the outcome. To put it simply, it tells you whether your part will be a success or failure and also the exact point where the error will take place and how and why. Therefore, simulation prior to printing is something that radically brings down trial and error and the overall cost of the otherwise expensive printing process.
Simulation can help iterate designs 10 times faster and with 100 times fewer parts. It is a total re-imagination of the future and transforms how products are made. It empowers designers to enhance weight reduction and lattice density and also create, repair and clean up CAD geometry. One can simulate the additive process and conduct structural and thermal analysis for data validation. Simulation is the answer to AM’s requirement of predictive tools.
Simulation has stepped in when engineers had all but given up on the deformities that kept happening in print even after adding supports and changing the framework. Simulating the additive process, running the automatic compensation algorithm and printing according to specifics are just what is helping AM take that much-needed leap into the future.