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About 3D printing

Benefits of SLS 3D printing

  1. Complex prints – a single complex part can be produced instead of several simpler parts that must be joined together.
  2. Direct production – Produced without the use of moulds or press tools. This reduces tooling and jig costs.
  3. High print accuracy – enables the production of fine structures, hidden details, thin walls and other complex shapes.
  4. Printing without support structures – their role is fulfilled by unburnt powder.
  5. Wider design options – Reduces the design constraints associated with traditional machining and casting production methods.
  6. Sustainability

Benefits of FFF 3D printing

  1. Lower weight – material is only where it is really needed.
  2. Piece production – significantly expands the possibilities of custom production.
  3. Flexibility – the necessary design change can be directly directed to production.
  4. Optimizing – FFF can be integrated into existing production processes. This leads to a reduction in the number of production steps and a reduction in costs.
  5. Cost – Relatively cheap printer operation and low cost of printing materials.
  6. Simple post-processing – Post-processing is uncomplicated, especially when using the right accessories.

About 3D printing - SLS and FFF

SLS (Selective Laser Sintering) is an advanced 3D printing technology that is used wherever the highest demands are placed on the strength and complexity of prints. That is, in industrial production and development. SLS printers feature a high-power laser that is capable of “sintering” small particles of polymer dust in the print chamber. This additive manufacturing technology is increasingly being used not only in industrial applications, as it makes it possible to produce very complex and functional components. The absence of support structures during printing, the role of which is played by “unbaked” dust, is also an undeniable advantage. Therefore, the SLS printer can also handle complex thin-walled prints containing internal elements. Elements produced by SLS technology achieve excellent mechanical properties, chemical resistance and strength at the same time as injection moulded parts.

Fused Filament Fabrication (FFF) technology, on the other hand, focuses on fusing a thermoplastic filament that is layered onto a printing substrate. FFF printers are known for their simplicity and wide availability of materials, making them ideal for a variety of professional applications. This technology enables rapid prototyping and production of functional parts with good accuracy and surface quality.

Both technologies, SLS and FFF, have their specific advantages and disadvantages. While SLS excels at producing complex and durable components without the need for supports, FFF offers flexibility in materials and ease of use. Depending on your needs, you can choose the right technology for your additive manufacturing projects.

SLS and FFF printing process

First, the printing powder and chamber in SLS printers are heated to a high temperature, but this does not yet reach the melting point of the material used. The printing mechanism then spreads the powder in a thin layer on the work plate by means of a recoater (a mechanical device that includes a roller that spreads the powder layer). Then comes the actual process of “sintering” the layer using a laser. The beam passes through a rather complex optical assembly and concentrates on the surface of the dust layer. As a result, it is “sintered”. Finally, the work plate moves downwards and the recoater applies another layer of dust. This process is repeated cyclically, with the previous layers melting as they sinter, resulting in a homogeneous print.

On the other hand, the printing process for FFF (Fused Filament Fabrication) printers starts with the filament being heated in an extruder where it is melted. The molten material is then extruded through a nozzle and applied to the print substrate layer by layer. This process continues until the model is complete. FFF technology is known for its simplicity and the wide range of materials available, making it ideal for rapid prototyping and the production of functional parts.

After the last layer of the SLS printer is completed, a cooling process follows, where the printer software does not allow the printout to be manipulated before the temperature drops to about 50 °C. For FFF printers, cooling is usually faster, but depends on the material used; some plastics may require additional cooling to minimize warping.

Overall, both SLS and FFF technologies offer unique advantages and are suitable for a variety of additive manufacturing applications. While SLS excels at producing complex and durable components without the need for supports, FFF provides flexibility in materials and ease of use.

Post-processing

After printing is complete, post-processing is an important step that varies depending on the 3D printing technology. With SLS (Selective Laser Sintering) printers, the excess, unbaked dust is first removed and can be reused for other print jobs. The print is then subjected to mechanical or chemical processing depending on the specific customer requirements. Common post-processing methods include smoothing, sandblasting, plating, dyeing or painting and gluing. The final appearance of the print can vary significantly and the final product may be indistinguishable from those produced by other technologies such as metalworking.

With FFF (Fused Filament Fabrication) printers, post-processing is also a key step. Once the printing is complete, the support structures, if any, must be removed and then surface finishing can follow. FFF prints can be further processed by various methods such as smoothing with chemicals or mechanical tools, dyeing or varnishing. These treatments make it possible to achieve the desired appearance and improve the physical properties of the final parts.

Both technologies offer different post-processing options that can significantly affect the quality and appearance of the final product. Depending on the specific needs of your project, you can choose the appropriate methods for editing your 3D prints to achieve optimal results.

Materials used

For SLS (Selective Laser Sintering) printing, polyamide-based thermoplastics, especially nylon (PA 12), are most commonly used. This material is very widespread in the industrial sector due to its excellent mechanical properties. It is lightweight, mechanically resistant and flexible at the same time. In addition, it is impact resistant and resistant to chemicals, heat, UV radiation and water. Where PA 12 is not sufficient, other polyamides (PA 11, PA 6, PA 2200) or PBT (polybutylene terephthalate) are used. In addition to rigid materials, soft materials in the form of elastomers such as TPE, TPU, PEBA or polystyrene (PS 2500) can also be used. A wide range of printing powders with various additives are also available today to improve the strength, stiffness, flexibility or chemical properties of prints. Most commonly, various additives in the form of glass or carbon fibre are added to PA11 material.

On the other hand, FFF (Fused Filament Fabrication) technology uses different types of filaments that are available in a wide range of materials. Standard thermoplastics include PLA, PET, ABS and ASA, which are popular for their easy printability and availability. For engineering applications, more advanced materials such as PA (polyamide), PC (polycarbonate), PEEK and ULTEM are used, which offer improved mechanical and thermal properties. FFF technology also enables the use of flexible thermoplastics such as TPU and TPE, which allow the printing of flexible components.

With a wide range of materials available for both SLS and FFF printers, you can choose the most suitable one for your specific application and achieve optimal results in production and prototyping.

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