After 3D printing, post-processing is crucial since it improves the produced object's appearance, robustness, and use. Upon exiting the printer, 3D printouts frequently have a rough surface quality, residual support structures, or material that has been thermally stressed. In addition to eliminating these flaws and enhancing appearance, post-processing methods like support removal, sanding, polishing, heat treatments, or painting significantly alter the printed part's physical characteristics to guarantee optimal functioning. Additionally, post-processing can help to combine 3D printed assemblies, guaranteeing a precise fit and clearance between parts, and, depending on the need, can improve the part's electrical conductivity or chemical resistance. Therefore, post-processing is an essential step in the 3D printing process since it helps customize the 3D printed object to its particular use case.
Post-processing is required after SLS 3D printing since the final product frequently has a rough surface texture and is covered in unfused powder. Excess powder is removed, the surface is smoothed, and treatments are used to strengthen the print and improve its characteristics, like color, glossy finish, and water and UV light resistance. Of course, more post-processing steps are needed to achieve higher performance requirements.
Why Post-Processing?
The process of post-processing in 3D printing has a big influence on how the printed object looks, works, and is made. Even though 3D printers can create parts from a variety of materials, the final product frequently needs to be improved to satisfy users. Raw 3D printed objects often need to have their mechanical characteristics improved, have visible layer lines, or have extra material called support structures. In post-processing, various methods including sanding, tumbling, painting, or applying solvents are used to assist remove these defects. Each of these techniques contributes to improving the object's appearance, refining the surface quality, or boosting durability—all of which are important in many industrial applications where accuracy and dependability are critical.
Furthermore, post-processing provides value to the part by improving its strength, flexibility, transparency, and heat resistance in addition to concentrating on surface enhancements. After printing, techniques like annealing can be applied to a part to improve its strength and decrease internal stresses; dying or painting can add color; and coatings can offer special qualities like electrical conductivity, water repellency, or UV resistance. Therefore, post-processing is a crucial stage that enables the customization and optimization of 3D printed items for certain use-cases and surroundings. It is impossible to overstate the significance of post-processing given the vast array of uses for 3D printing, ranging from prototype to production parts, in sectors as diverse as aerospace, automotive, architecture, and healthcare.
The Options for SLS Post-Processing?
The ultimate result of the printed components depends heavily on the Selective Laser Sintering (SLS) 3D printing post-process steps, which are mainly media blasting, powder recovery, and part extraction.
Part Extraction
As soon as printing is finished, part extraction begins. It entails carefully removing the things that were 3D printed from the powder bed. Using extraction equipment to carefully dig the objects without damaging them may be necessary at this stage, depending on the complexity of the printed parts' design and the amount of loose powder surrounding them. The technician uses compressed air and brushes to carefully brush away extra powder from the part's surfaces.
The build chamber, which encloses and holds the pieces during printing, is then thoroughly cleaned to remove any last bits of powder, guaranteeing that no two materials will come into contact with one another.
Recovery of Powder
A crucial step in the SLS process is powder recovery, which is sometimes referred to as powder recycling or reclamation. It entails gathering and recycling the powder that remains uncentered after partial extraction. The method separates the powder that has been utilized (but not sintered) from the particles that are too big or small to be reused using a screening device. In order to prepare for the next printing job, the recovered powder is often combined with new material in a precise ratio, as directed by the machine maker.
Reusing powder enhances material efficiency, however excessive usage of recycled powder might compromise future prints' surface quality and mechanical qualities, therefore close observation is needed. In addition, it guarantees waste reduction, enhancing the sustainability that additive manufacturing techniques already possess.
Media Blasting
The components may still have an uneven and powdery surface finish even after part extraction and powder recovery. Media blasting, sometimes referred to as bead blasting or abrasive blasting, is done to improve this. In order to smooth the object's surface and get rid of any leftover powder, pieces are put through a regulated stream of abrasive material at high pressure in this phase.
The chosen blasting medium is determined by the material of the 3D printed object and the desired polish. It is commonly composed of glass beads or sodium bicarbonate. Because blasting generates dust and requires protection gear for operators, safety measures must be followed.
Media blasting can usually leave the pieces with a very smooth, uniform finish, making it difficult to detect that the product was constructed layer by layer. To protect the printed parts' finer details, it must be handled carefully.
Vibratory Tumbling
In the field of 3D printing, vibratory tumbling—a sophisticated post-processing technique—has been a game-changer for addressing the issues with surface roughness that are frequently encountered in the objects that are created. This method improves the surface polish of 3D printed products by eliminating layer lines using abrasive media and vibration in a closed system. Incorporating vibratory tumbling into the additive manufacturing process not only guarantees more polished and seamless final products, but it also presents a significant opportunity to enhance the parts' robustness, visual appeal, and overall functionality. Thus, the smooth incorporation of vibratory tumbling into 3D printing is poised to transform additive manufacturing's post-production procedure and broaden the uses and potential of this constantly developing technology.
Vapor Smoothing
One game-changing post-processing method used in the field of 3D printing is vapor smoothing, which allows produced items to have much better surface finishes. Using chemical vapors, this method dissolves the outermost layer of a 3D printed object, smoothing out the microscopic layer lines and producing a glossy, smooth surface. It enhances the part's technical qualities, such as strength and waterproofness, in addition to its visual appeal. Vapor smoothing's inherent automation, repeatability, and customization features have revolutionized 3D printing, accelerating the mass manufacturing of items produced with this technology and encouraging its wider use across a range of sectors.
Chemical Treatment
Various techniques, including immersion, spray coating, and vapor smoothing, can be used for chemical solution post-processing, in which the part is subjected to a particular chemical solution designed to react with the base material. By removing stair-stepping, filling micro-pores, and lowering roughness, this procedure can significantly improve surface quality, improving both the part's appearance and usefulness. Furthermore, chemical solution post-processing is an essential feature of SLS 3D printed production because chemically treated products can achieve improved dimensional precision, corrosion resistance, and a longer lifespan.
Spray Paint and Lacquer
Spray painting and lacquer post-processing are essential steps in the construction and finishing of many different items, greatly enhancing their durability and visual appeal. In order to apply coatings consistently over surfaces, spray painting uses an automated or manual technique that atomizes paint or other coating components into a fine mist stream. Contrarily, lacquer post-processing is applying a colored or clear wood finish that cures through a curing process or solvent evaporation to create a durable, protective surface. It significantly improves the painted surface's toughness, resilience to damage, and glossiness, making it an essential component of the product's appearance and lifespan.
Waterproof Coatings
In order to experiment with printing various materials and architectures, 3D printing is constantly evolving. The development of waterproof coatings is a new development in this field. This novel advancement tackles a major problem that 3D-printed items frequently encounter: water permeability, especially when producing parts for fluid-handling, hydraulic, or maritime applications. The use of watertightness coatings improves the products' longevity and functionality by rendering them impervious to liquids, including water. These advancements greatly broaden the possible uses of this technology, allowing it to bridge the gap between 3D printing and conventional production techniques in some situations and launching a new wave of water-resistant 3D printed goods.
Dyeing
One of the main benefits of post-production dyeing of 3D printed objects is the customization of aesthetics while preserving material and manufacturing efficiency. Fewer colors are frequently used in 3D printing because of limitations on the availability or cost of materials. By expanding the color spectrum, post-process dyeing allows designers to work with a wider range of hues without compromising the structural integrity of the 3D printed object. This feature greatly improves the product's aesthetic appeal, meeting specific design requirements and increasing the output's adaptability for a range of applications, from prototypes to finished components. Furthermore, dyeing can improve the overall finish and quality of the finished product by helping to cover up little flaws that are inevitable with 3D printing.
Metal plating
The primary goal of applying metal plating to 3D printed objects is to improve their functioning and visual appeal. Even though 3D printed parts are already rather robust, adding a metal coating increases their strength, resilience to wear, and durability, making them ideal for high-stress situations or hostile environments. Furthermore, the object's electrical conductivity can be improved by metal plating it after 3D printing, which makes it suitable for use in RF or electronic applications. Finally, a metal-plated finish adds to the visual appeal of 3D printed items, giving them a polished, high-end look that is reminiscent of conventionally manufactured goods.