Several design considerations for AM

More commonly known as 3D printing, additive manufacturing (AM) offers advantages that can never be attained with traditional production lines: limitless design freedom, customisation, lightness, material efficiency, etc. To unlock its full potential, designers need to adopt a completely new approach and mindset. A key aspect is using the right methodology.

AM vs. traditional manufacturing processes

AM comprises much more than just design and methodology. It is a complete process in which every building block has an essential role to play. Before getting started with the part-printing process, it’s important to work with a design that appropriately considers the requirements, the production technology and the material.

One of the major trends over the last few years is the transition from the use of additive manufacturing in prototyping towards the production of 3D-printed parts for end-use parts. Whereas 3D-printed prototypes are often copy-prints of the design, end-use AM parts need to be redesigned or re-engineered in function of the technology to offer a competitive alternative.

Three facets of additive manufacturing 

AM is ideal to produce small and complex parts. However, as with any other design methodology, it is important to take various design considerations into account. Combining design with function, manufacturing and post-processing will help you to develop AM parts that meet every need.

Design for function

Due to its layering approach to manufacturing, AM makes it possible to create very complex parts in small series. Any complexity added within the same volume comes essentially for free. As a result, it’s only logical to add as much functionality to the part as possible. Abandon conventional design rules and create features that are impossible to manufacture using conventional techniques, such as complex internal cavities and undercuts. Integrate multiple parts into a single part to decrease assembly time and cost. Fasteners, welding and high tolerances are no longer needed.

Design for manufacturing

Designing in light of manufacturing rules that cover all AM technologies is tough, as there is a big difference between different AM processes and materials. However, there are general dos and don’ts to keep in mind during the design process.

Always try to :

  • minimise the amount of material and support structures used;
  • keep the size of the 3D printer in mind;
  • design small details according to printer specifications;
  • make it possible to remove excess powder or resin;
  • consider that the mechanical properties may be different in each direction due to the anisotropy of some processes.

Mind: more specific design rules depend heavily on the technology, material and printer. Our Sirris experts can help you with that. 

Design for post-processing

Although printing is nearly automatic, the process involves a lot of manual labour. This includes the removal of remaining powder and support structures and the post-machining of the part itself. The more manual labour required, the higher the final cost of the part will be. 

Reducing the need for post-machining is a key design goal.

Are the “required” tolerances really required? We often find tolerances in technical drawings because the designer is simply accustomed to including them. These tolerances might be impossible to achieve through 3D printing, and post-machining will be needed. That is why it is important to always ask yourself this question, to minimise a possible cost for post-machining.

Methodology in six steps

Most product designers aren’t yet familiar with AM. Because this manufacturing technology requires a specific approach, a more specific design methodology has been developed. The goal? To fully exploit the possibilities of additive technologies while also taking other manufacturing constraints into account.

Our general AM design methodology consists of six different phases and is based on the ‘global design process’. Would you like to know more on this methodology? We explain it to you in our e-book "Design for additive manufacturing: a feasible methodology".

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