Post-processing in SLS 3D printing technology

Post-processing in SLS 3D printing technology using powdered polymers (PA12 or TPU) is a key stage that transforms raw prints into high-quality finished products. The process involves several steps, including depowdering, sanding, dyeing, and gluing smaller parts into large objects that could not be printed in one piece. The company that specializes in 3D SLS printing and advanced post-processing of parts printed from polyamides is Technology Applied – the largest Polish company providing 3D printing services.

Depowdering, i.e. removing not sintered powder, is the first, basic activity that should be performed after completing the 3D printing process. This is usually done manually using brushes, compressed air or specialized cleaning equipment. Careful removal of excess powder is important to maintain detail and print quality – especially for thin walls less than 0.8 mm thick.

In the case of some elements, cleaning them from powder is the end of the work and the detail can be sent to the customer or used in the application. However, if the part is to obtain a smoother surface, it is necessary to polish it. Various types of sandpaper are used for this purpose, from coarse-grained to very fine-grained, depending on the degree of smoothing required. Grinding machines are also often used for a faster and more uniform finish.

By default, 3D prints made of polyamide 12 using SLS technology are white. If coloring is necessary, it can be done using the pressure-immersion method or traditional varnishing. The pressure-immersion method involves immersing the 3D printed part in the dye under pressure, which allows the color to penetrate deeply into the material. Under the influence of pressure, the parts slightly expand and the dye permanently penetrates their structure. Traditional varnishing, on the other hand, involves applying paint with a brush or spray, which gives greater control over the color and finish. Technology Applied offers both dyeing methods – pressure dyeing applies to a palette of several selected colors, while spray painting can be used to tint a part in virtually any color from the RAL palette.

In the case of large 3D prints that do not fit into the working chamber of the 3D printer, it is necessary to glue them from several pieces. Specialized adhesives such as epoxy or cyanoacrylate are used to connect parts with PA12. These adhesives provide a strong and durable connection while maintaining the mechanical properties of polyamide. Technology Applied has industrial 3D printers from EOS, where the longest part can be just over 60 cm. However, thanks to the gluing provided by the company, you can produce parts with dimensions exceeding 1 meter in the selected XYZ axis.

The post-processing process in SLS 3D printing with PA12 is a multi-stage process that requires precision and skill. From depowdering to gluing, each step is crucial to the quality of the final product, affecting its appearance, durability and functionality.

Photos: www.ta.parts