In additive manufacturing or three-dimensional (3D) printing, and particularly in the Laser Powder Bed Fusion (LPBF) processing of Ti–6Al–4V alloy, porosity defects are inevitable. It is believed that these defects have significant effects on the mechanical properties of the LPBF Ti–6Al–4V part.
Our most recent publication offers critical insights into the challenges and opportunities associated with LPBF-manufactured Ti–6Al–4V components, particularly regarding fatigue performance. The findings underscore the importance of precise parameter control in minimising defect formation, such as porosity and microcracks, which directly impact the mechanical reliability and longevity of printed parts. The findings of this study are particularly significant for the medical field, where Ti–6Al–4V is widely used to produce custom-made implants that are intended to remain functional within the patient for a life-time.
What is porosity in 3D printing and what causes this porosity?
Porosity in 3D printing refers to small voids or defects within a printed material that result from incomplete fusion or trapped gas during the printing process. In metal additive manufacturing, such as Laser Powder Bed Fusion (LPBF), porosity defects are a critical concern as they can compromise the mechanical properties and durability of the printed parts.
Lack-of-fusion porosity (LoFP) occurs when there is insufficient fusion between layers of the powdered material, leading to gaps or voids in the structure. Gas-entrapped pores (GeP), on the other hand, result from gas bubbles trapped during the melting and solidification process. Both produce defects that can affect the longevity of a 3D printed part.
What is the role of porosity defects in metal 3D printing?
While porosity has an indistinct impact on tensile strength and ductility under static loads, it significantly reduces fatigue performance in cyclic loading conditions, where repeated stress is applied. These defects act as weak points where cracks can begin, much like a small chip in glass that spreads under pressure, ultimately compromising the durability and reliability of components such as medical implants or aerospace parts. By identifying the causes of porosity and fine-tuning printing parameters, manufacturers can enhance the quality, consistency, and long-term performance of 3D-printed parts, ensuring they meet the rigorous demands of critical applications.
How Meticuly utilises advanced 3D printing technology to deliver highest quality 3D printed implants
Porosity plays a dual role in implant performance: while its open structure enhances osseointegration by fostering bone growth, excessive porosity defects can compromise the strength and longevity of implants, particularly in load-bearing applications like hip and knee replacements. Achieving the perfect balance is critical to ensuring both functionality and durability.
At Meticuly, we understand that balancing porosity and strength is crucial. Based on years of scientific research, we have optimised our 3D printing techniques to archive unmatched properties. For example, in our mandibular reconstruction plates, optimised printing parameters ensure superior strength, eliminating the risk of plate failure during mastication and daily activities. Similarly, our cranio-maxillofacial mesh implants for facial, orbital and cranial reconstruction, designed with ultra-thin profiles to minimise imaging artefacts, maintain robust mechanical properties while providing excellent biological response.
By fine-tuning every aspect of the 3D printing process, Meticuly delivers implants that meet the highest standards of performance, reliability, and patient outcomes.
References
Azeez, A., Chedtha Puncreobutr, Surasak Kuimalee, Thanawat Phetrattanarangsi, Thanachai Boonchuduang, Pariwat Taweekitikul, Chinnapat Panwisawas, Junji Shinjo, & Boonrat Lohwongwatana. (2024). Laser-inherent porosity defects in additively manufactured Ti-6Al-4V implant: Formation, distribution, and effect on fatigue performance. Journal of Materials Research and Technology. https://doi.org/10.1016/j.jmrt.2024.04.225
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