Design for Additive Manufacturing

Learn about the design for Additive Manufacturing (AM) and its sections.
Submitted by Akash Periyasamy, on June 09, 2022

Additive manufacturing has the potential to be a revolutionary addition to your traditional manufacturing capabilities and can be implemented in two distinct ways: either very poorly, or very well. Designers and operators should consider a number of build-related factors when considering the setup of an AM machine, including the following sections.

Part Orientation

Orientation of the part within the machine can affect part accuracy. There may not be a proper orientation for many parts, since they have complex features along multiple axes. Additionally, maintaining the geometry of some features may be more important than others, so correct orientation may be a matter of judgment. Additionally, this judgment might also differ from other factors such as the time it takes to build a part (for example, taller builds tend to take longer than short ones, so taller parts may be better built lying down), whether a certain orientation generates more supports, or whether certain surfaces should be built face-up for a good surface finish when they are not in contact with support structures.

AM features that face upwards tends to be of the highest quality. As an example, upward-facing features are not in contact with the support required for many processes. For powder beds, the upward-facing features are smooth since they solidify against air, whereas downward-facing and sideways-facing features solidify against powder and thus have a powdery texture. The upside end of the extruded part is usually finished with high quality. Thus, it will reduce the need for further finishing in extruded components.

Removal of Supports

For those technologies that require support, it is a good idea to try and minimize the amount. Wherever the supports meet the part there will be small marks and reducing the number of supports would reduce the amount of part clean up and post-process finishing. However, as mentioned above, some surfaces may not be as important as others and so the positioning of the part must be weighed against the relative importance of an affected surface. In addition, the removal of too many supports may mean that the part becomes detached from the baseplate and will move around during subsequent layering. It will fail if distortion extends the part in the z-direction in such a way that it strikes the layering mechanism (such as a blade that spreads powder).

Hollowing Out Parts

If the hollow feature does not reduce the part's functionality, parts with thick walls may have hollow features. Using less material reduces the cost of the final component, reduces the build time, and reduces the final mass. The same can also be said for powder-based resin systems, as some liquid-based resin systems require draining holes to remove excess resin from within the part. There will be some additional time that will be reduced for hollowing the components. In order to do these, there is various software that is available on market for this purpose.

Inclusion of Undercuts and Other Manufacturing

Various stages of product development can be addressed by AM models. A part's aesthetics or ultimate functionalities may be the criteria used to evaluate an initial design. An earlier stage would give less priority to considering how manufacturing-related features can be integrated. Conventional manufacturing would require considerable planning to ensure that a part is fabricated correctly. The part itself can reduce further manufacturing process since the component can accommodate all inclusions and undercuts within it. These features will further reduce the cost and save a considerable amount of time.

Interlocking Features

The machine that is used to build components has a specified build volume which makes it difficult to build large components. A solution may be to break the design up into segments that can fit into the machine and manually assemble them tater. The regions where the breaks are made can be designed in such a way as to facilitate reassembly. Techniques can include the incorporation of interlocking features and maximizing surface area so that adhesives can be most effective. These zones should also be located in easily accessible yet difficult-to-observe locations.

Reduction of Part Count in an Assembly

The AM process occurs at the end of product development, so alternative manufacturing processes are not needed in the design process. As a consequence, if the assembly of the parts can be simplified through additive manufacturing, then it should be done. For example, an entire bolt and nut joint can be easily made into a single whole component that can be used in various other assemblies.

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