The world of 3D printing is rapidly evolving, offering endless possibilities in the creation of complex, intricate parts. Yet, one key issue that continues to challenge this advanced technology is the longevity and performance of 3D printed materials designed for extreme conditions, where deterioration over long periods of time has proven to be the downfall for many of these specialised components.
In response to such limitations, Light Coatings – based at Sci-Tech Daresbury in the Liverpool City Region – has developed groundbreaking PVD (physical vapor deposition) coating processes designed specifically for 3D printed polymers. These high-performance surface coatings are already revolutionising how industries – from aerospace to electronics – employ 3D-printed parts, as companies can prototype and produce parts with enhanced properties, boasting new levels of strength, conductivity, and durability.
Application of PVD coatings to 3D-printed parts
Applying PVD coatings to 3D-printed components was once thought impossible due to the challenges of high-energy UV, plasma environments, and the vacuum process. Using our extensive expertise in advanced surface coating technologies, our team has successfully adapted these techniques to meet the unique demands of 3D-printed polymers, unlocking new possibilities for high-performance applications.
We begin the process by vaporising the coating material, such as metal, ceramic or alloy. This vaporised material then condenses onto the surface of the part, creating a very thin, dense, uniform coating.
While coating geometry poses challenges due to the line-of-sight requirement, specialised tooling and optimised processes reduce these limitations. Successful coatings have been achieved in features as small as 2mm in diameter and 5mm in depth, though internal cavities continue to be a hurdle.
How different industries use PVD coatings
An array of industries have benefited from using PVD Coated 3D parts for their complex components.
While defence, automotive and aerospace find great value in the process’ potential for reduced friction and enhanced durability of moving components, components in aggressive environments, and hard, decorative components, the Electronics sector benefits from enhanced conductivity and protection in semiconductors and circuit boards.
When crafting cutting tools, PVD coating is key in machining, extending tool life by improving wear resistance and cutting characteristics. And in optical applications, the process improves the clarity and functionality of surface properties without the use of hazardous chemicals, primers, or chemical discharge. This technology which is used extensively with metals is now being applied to 3D printed polymers.
Testing results
Test materials include engineering polymers such as Ultem 9085, 1010, Antero 800NA, PEEK and Onyx along with more common materials such as Nylon, PLA, PETG, and PC. Among the materials tested, only the printed onyx samples presented persistent processing challenges, ultimately proving unsuitable for processing.
This material demonstrated substantial and continuous outgassing, creating significant obstacles in process control and extending processing time. Further analyses indicated the presence of air pockets, likely surrounding embedded fibres, which continued to release gases despite prolonged vacuum treatment. With further work on the printing process with the supplier it is likely possible to reduce this issue.
The materials were coated with a range of metals and oxides and tested for wear rate removal over fixed durations with some materials providing an 8x reduction in wear. In addition coating performance including adhesion, abrasion and optical transmission was characterised with significant improvements identified in many applications in a similar way that such coatings improve the performance of metals, ceramics and machined/moulded polymers.
PVD coatings are redefining 3D printing
We have recently made significant progress in applying thick copper and aluminium coatings to 3D-printed polymers, achieving layers over 3µm thick on low temperature materials such as PLA. We’re also developing methods for rapid, low-temperature metal deposition on polymers, which could make durable coatings more cost-effective, and in turn, accessible.
Additionally, work is currently underway in DLC (diamond-like carbon) processes, alongside multilayer and hybrid coatings, for a variety of new applications. This includes using vacuum deposited buffer layers, as well as combinations of metals, nitrides, and carbides to create hard, durable, and in some cases, decorative coatings.
Ultimately, expanding the use of 3D-printed components and coatings enables them to meet higher performance standards while remaining accessible for new applications across multiple industries. This further expands the suitability of 3D printed polymer components for end applications rather than prototyping only.
Conclusion
PVD coatings are redefining 3D printing and have become essential in enhancing moulded and machined polymers for a range of applications, from optics to conductive and wear-resistant components. However, the rise of 3D-printed polymers introduces new challenges for PVD, including compatibility with vacuum and plasma processes, complex geometries, coating uniformity, and temperature constraints.
Through recent advancements, Light Coatings has made significant strides in adapting PVD techniques to improve the surface properties of 3D-printed polymers, opening doors to new applications. Building on these advancements, Light Coatings has identified 3D printing technologies and materials that can actively enhance PVD processes. And several of these innovations have already been integrated into their manufacturing practices, with plans to make these advancements broadly accessible in the future.
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