Six ingredients for better additive manufacturing

AM processes give designers the flexibility to push the limits of engineering design beyond the constraints of traditional manufacturing methods. We’ve shortlisted some factors you should consider:

Part and design objectives: Part selection and design objectives are closely linked. Parts can be evaluated based on parameters including; size and weight, production volume and lead time, surface finish requirements, functionality and criticality and traditional cost of manufacturing. The best suited design objectives become evident during the selection exercise e.g. weight reduction, performance improvement, lead time reduction etc.

Availability of material: Designers need to be aware if the product material is available in powder or filament form for metal or plastic production. Most commonly used metals, such as stainless and maraging steel, aluminum, titanium, cobalt chrome and nickel-based alloys are easily available. For non-metals, ABS, PLA, nylon, polypropylene and polycarbonate are being offered by most machine and filament manufacturers. New materials are being progressively added.

Solving the right problem: The additive approach is increasingly being used in new product development (NPD) and in the re-design of existing parts for deriving greater value in terms of cost or performance. All parts need to perform safely and reliably in their operating environments, so it is important to have a thorough understanding of these and to look at the trade-offs between performance parameters.

Understanding process parameters: AM involves a layer by layer deposition of material to build a part. The quality of the finished component and its acceptance parameters like tensile strength, porosity, dimensional integrity, microstructure etc. are sensitive to the process parameters used on the machines. Engineers need to be cognisant of the limitations of the production environment and the direction of the build and the deviations (like warping) that are likely to occur. Ideally, the designer should also identify the critical load cases for the component so that the build can be planned to ensure highest structural integrity in the direction of critical loads.

Post processing, testing and qualification: In most cases, parts produced with AM would require post processing. These activities may involve support removal, cleaning, machining to desired tolerances and heat treatment. To avoid using the support structure when printing circular channels, the designer can modify the shape of circular holes to a tear-drop shape. 

Testing and qualification also require a designer’s attention. Organizations such as ASTM, ASME and SAE are working towards establishing design and testing standards for Additive approach. For qualification, most parts that have been re-designed using AM are being qualified using the same criteria that conventionally designed parts are required to meet. However, process standardization for each make and model of additive machines remains a challenge.

Hiring for Additive: The biggest challenge in re-thinking design for Additive Manufacturing is hiring. Designing for additive often requires breaking the mould of conventional design, bringing the functionality of the component into sharp focus and an ability to work in a rapidly evolving technical domain. This means that creative flare, innovative thinking and innate curiosity become some of the most essential traits required in a potential hire.

To conclude, designing for AM is a much sought-after skill set in engineers. The subject is already a part of curriculum in leading research universities across the globe. Partnerships in various forms can help advance the field further along its journey.

Atha Ur Rahman Khan is program manager entrepreneur for additive manufacturing and Dr Jan Radtke is vice president of New Business Accelerator at Cyient.