It’s a common misconception in metal additive manufacturing that post-processing is a cure-all. While finishing operations like CNC machining, polishing, and heat treatment play a critical role in achieving dimensional accuracy and surface quality, they can’t reverse foundational issues baked into the part during the print itself. Many defects, such as lack of fusion, porosity, and internal cracking; are created during the build and can remain hidden beneath even the most polished surface.
The problem lies in the nature of laser powder bed fusion (LPBF), where each layer introduces opportunities for imperfections. If process parameters like laser power, scan speed, or layer thickness are off, these defects can form and propagate unnoticed. Even minor inconsistencies in powder quality, environmental conditions, or recoating behavior can introduce buried flaws that later compromise performance.
Post-processing can smooth out rough surfaces and improve fatigue resistance to a degree, but it has limits. It cannot mend internal porosity, repair a delaminated layer interface, or eliminate voids from incomplete fusion. Once these issues are present inside the part, they weaken structural integrity and may only reveal themselves through unexpected failure in the field or during destructive testing.
The solution? Prevention through smarter printing. This includes rigorous simulation during design, tight process control, and in-situ monitoring strategies like melt pool sensing or optical tomography. These tools help catch defects as they form, before they become embedded liabilities. Finishing is important, but prevention is smarter engineering.