From Design to Perfection: Streamlining Additive Manufacturing through Advanced Post-Processing Techniques

Colin Spellacy, Head of Sales. Rösler UK / AM Solutions

Additive manufacturing (AM) has witnessed an exponential surge in recent years. The process’s ability to manufacture complex geometries, customised parts, and intricate designs is unparalleled. However, the often-overlooked linchpin that ensures AM parts reach their full potential is the post-processing phase. Among the various post-processing techniques, advanced mass finishing and shot blasting stand out as crucial elements in achieving efficiency and speeding up production. This article dives into the significant role they play and how carefully planned post-processing can be the difference-maker in AM. It also looks at real time examples of the successful use of these technologies in company settings

The need for post-processing in AM

To truly grasp the significance of post-processing within the realm of AM, you need to delve deep into the intrinsic characteristics of parts as they emerge fresh from the printer. The journey of an AM part doesn’t end as soon as it is printed; in fact, this is just the beginning. As they are produced, these parts, albeit technologically advanced and intricately designed, often bear the tell-tale signs of their fabrication process. They commonly exhibit rough and uneven surfaces, a direct result of the layer-by-layer construction method inherent to many AM technologies.

In addition to the surface roughness, these parts often come with support structures. These structures, while essential during the printing process to maintain the part’s shape and integrity, are extraneous once the part is complete and need to be removed. Beyond these, there may also be subtle imperfections, perhaps a tiny bulge, a minute cavity, or a slight misalignment, which, while not immediately detrimental, can affect the part’s performance or its visual appeal. Such nuances, if left unattended, can compromise the functionality of the part, or diminish its aesthetic value, especially if it’s intended for consumer-facing applications.

Mass finishing

Advanced mass finishing post-processing techniques are designed to improve the surface finish of AM parts. These methods, which include vibratory finishing and centrifugal disc finishing, use media and compounds in a contained environment to polish and smooth parts.

Advanced mass finishing plays a crucial role in the post-processing phase of AM, bringing several key benefits to the table. One of its primary advantages is the assurance of consistency and uniformity. Regardless of the diverse geometries of parts, mass finishing provides a consistent finish to each, ensuring that every piece meets the desired standard. Furthermore, this process significantly improves the surface quality of the parts. This enhancement is not just a cosmetic one; a better surface finish often translates to improved functional performance across various applications. Whether it’s reducing wear and tear in mechanical components or amplifying the aesthetic allure of consumer products, the benefits are tangible and manifold.

Additionally, scalability remains one of the standout attributes of advanced mass finishing. Especially pertinent for higher volume production, this technique is adept at managing multiple parts simultaneously. By doing so, it not only maintains the quality across the board but also guarantees a high throughput, making it an indispensable tool for industries aiming for both quality and quantity in their manufacturing endeavours.

Shot blasting

Shot blasting is another post-processing technique wherein tiny metallic or non-metallic shots are propelled at high velocity onto the AM part’s surface. This not only cleans the surface from contaminants but also prepares it for subsequent steps like painting or coating.

Shot blasting stands as a pivotal post-processing technique in AM, characterised by its speed and efficiency. The method can swiftly clean and prepare surfaces, positioning it as an ideal choice for expansive AM operations where time is of the essence. Beyond mere cleansing, shot blasting plays a pivotal role in surface profiling. The precision of the process ensures that the desired surface roughness is achieved, setting the stage for subsequent coatings. This meticulous preparation guarantees better adhesion of these coatings, which is integral for many applications.

Furthermore, the longevity imparted by shot blasting cannot be overlooked. The process meticulously removes both imperfections and contaminants from the parts. This thorough cleansing not only enhances the immediate appearance and functionality of the parts but also contributes to their long-term durability. As a result, shot blasted parts often boast a prolonged lifespan, offering users more value and reliability from each component, reaffirming the importance of this post-processing technique in the AM landscape.

Strategic integration in the AM process chain

The integration of advanced mass finishing and shot blasting into the AM process chain offers transformative advantages for businesses. One of the primary benefits is sequential optimisation. By adopting a meticulously planned sequence, parts transition fluidly from AM production to mass finishing and shot blasting. This streamlined process not only minimizes manual interventions but also ensures seamless transitions, making the entire production cycle more efficient and cohesive.

Furthermore, this integration lends itself to a high degree of customisation. Recognizing that every part might have unique requirements based on its end-use, businesses can adapt and modify the post-processing steps to achieve specific, desired outcomes. This flexibility ensures that each component is optimally treated for its intended purpose. Additionally, the enhanced quality control provided by these post-processing methods significantly diminishes the necessity for reworks. As a result, businesses can enjoy considerable time and resource savings, further emphasizing the value of incorporating advanced mass finishing and shot blasting in the AM process chain.

Case Studies

AM Solutions has supplied numerous companies across the world with AM post-processing technologies, and here we look at two real time examples of the benefits of using shot blasting and mass finishing.

Weerg – Shot Blasting: Weerg Srl (the largest global user of the HP’s MJF AM process) uses shot blasting technologies from AM Solutions to post-process AM parts, specifically the S1 and S2 machines.

After a preliminary de-powdering operation on the S1 (a compact plug-and-play system), the shot blasting machine is then used by Weerg for the automatic cleaning and surface finishing of AM components. The efficient 2-in-1 concept helps not only to keep the investment costs and space requirements low, but also reduces energy consumption and substantially decreases processing times. While previous to the use of the S1 shot blasting technology 60 minutes were required for cleaning and surface finishing of a printing job, using the S1 it only takes 20 minutes.

In addition to the significant time savings, the S1 also permits a higher throughput of components. Previous to the use of shot blasting, often because of their size and fragility, many components had to be manually post-processed. The percentage of components that can now be cleaned and finished mechanically has increased for Weerg from 60 to 90%. An additional benefit is that considerably less personnel are required for post processing. Instead of two people only one person is needed to do the same job.

Weerg also uses AM Solutions’ S2 continuous flow shot blast system. The S2, the first of its kind in the world, is used for the automatic cleaning and surface finishing of plastic components printed with powder-bed based printing technologies. This highly productive machine requires very little operator time and offers, therefore, tremendous potential for cost savings.

Designed for 24/7 operation, the S2 handles the output of several printers. The special troughed belt made from polyurethane ensures gentle handling of the work pieces and, because of this, prevents any nicking of delicate components. This eliminates the need for costly reprints. The built-in blast media recycling and cleaning system and the automatic monitoring of the shot blast process guarantee high-quality consistent results in short cycle times, even for delicate, complex components.

Weerg is utilizing the S1 and S2 machines with identical processes and blast media for a wide variety of components. This guarantees a high degree of flexibility for the post processing operation.

Mass Finishing – Heliguy: Commercial drone innovator heliguyTM uses mass finishing to optimise parts for various of its product range. heliguyTM has a suite of AM equipment in-house in its production facilities, and uses AM Solutions’ M1 Basic post processing machine to enhance the surface of AM parts, which in turn improves component performance and aesthetic quality.

The M1 Basic is used for the surface smoothing and polishing of single parts and small batches, and is able to handle both plastic and metal AM parts. Multiple parts can be simultaneously treated in separate processing chambers through the installation of divider plates.

Mass finishing via the M1 Basic machine not only enhances the surface of heliguy’s 3D printed parts — which both improves performance and look and feel — but it has helped in the development of innovative drone solutions by driving the company’s in-house design and development capabilities to manufacture its own parts. Mass finishing using the M1 Basic is refining parts made using the AM process, providing better-looking and better quality commercial-grade end-use products. In smoothing and polishing parts, it also enables heliguyTM to create a perfect surface for painting or dye, which is another important element of improving the aesthetics.

Crucially, the M1 Basic is a very versatile mass finishing machine, allowing the company to work with a greater ecosystem of materials to expand its product offerings and to truly keep its manufacturing in-house.

Conclusion

The growth and adoption of AM in industries worldwide have spotlighted the importance of a robust and efficient process chain. As AM continues to redefine manufacturing paradigms, businesses must recognize the pivotal role of advanced mass finishing and shot blasting in optimizing efficiency and accelerating production.

As the saying goes, “A chain is only as strong as its weakest link.” In the world of AM, a well-thought-out post-processing strategy could very well be the strongest link in the chain.