That is not a criticism — it is simply how most engineers have been taught to design. But slicing a file to STL is not the same as designing for AM.
A CAD file sent straight to the printer will typically produce a part that does not perform as intended — and one where the real advantages of AM are left on the table. Think of material that did not need to be there, supports that could have been avoided, or functionality that could have been improved.
But DfAM goes further than that..
Orientation must be optimised with load paths in mind (think anisotropic behaviour) and surface quality (warping) — which also means accounting for overhangs beyond 45°. And then there are tolerances that need to factor in shrinkage and post-processing.
From a cost perspective, with higher-volume generic parts you also need to consider how many parts you can fit in a single build. With SLS you can nest (stack) parts and produce far more per build than with FDM or SLA — where nesting is not possible and support structures add to both material and post-processing costs.
A full DfAM review can reduce the cost of an AM part by 30 to 60% compared to printing a CNC design as-is. From a functional standpoint, you also need to look beyond pure manufacturability and consider:
- Applying hollow structures to reduce weight
- Adjusting topologies to suit the application
- Consolidating components into a single printed part
- Adding functionality (snap fits, hinges, gear features, etc.)
- Optimising cooling or airflow channels (grippers, moulds)
- Printing logos or serial numbers directly onto parts (mass customisation)
Taking the time to ask these questions — and having that conversation with your service provider, who is the specialist — is crucial. Not just for better decisions, but to build your own working knowledge of AM in the process.
