SLS FAQ

Process

• What is SLS 3D printing?+

  SLS 3D printing, or Selective Laser Sintering, is an additive manufacturing process that uses a high-powered laser to sinter small particles of polymer powder into a solid structure. The process involves spreading a thin layer of powder over a build platform, then using a laser to fuse the material layer by layer, based on a 3D model. It’s known for its ability to create complex geometries and is commonly used for prototyping and low-production runs of functional polymer components.

• How does SLS 3D printing work?+

  SLS 3D Basic Printing Process:

  1. Preparing the Powder Bed: A thin layer of powder material is spread over the build platform.

  2. Scanning with a Laser: A laser selectively sinters the powder, fusing particles based on a 3D model.

  3. Lowering the Build Platform: After each layer is sintered, the platform lowers, and a new powder layer is applied.

  4. Repeating the Process: The steps are repeated layer by layer until the object is complete.

  5. Cooling and Post-Processing: The printed object cools down, excess powder is removed, and any finishing touches are applied.

• How to smooth SLS prints?+

  To smooth SLS prints, you can use several post-processing techniques, such as:

  ● Sandblasting: This involves shooting a stream of abrasive material at the print to smooth the surface.

  ● Vibratory Tumbling: Parts are placed in a vibrating bowl with ceramic materials to smooth the finish gently.

  ● Vapor Smoothing: Applying a solvent vapor to the print to create a glossy finish.

Materials

• What types of materials are used in SLS 3D printing?+

  SLS 3D printing uses a wide range of materials, including nylon, TPU, aluminide, polycarbonate, polypropylene, and specialized ceramics and composites.

  
  

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• What is the most common polymer for SLS 3D printing?+

  Nylon, the most common polymer in SLS 3D printing, is valued for its high tensile strength, abrasion and impact resistance, low friction coefficient, and chemical resistance.

  
  

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Capabilities

• Why does SLS make strong parts?+

  SLS 3D printing produces strong parts with strong layer adhesion, durable polymer powders, support-free structures, and high precision, making their strength comparable to traditionally manufactured items.

  
  

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• What are the advantages of SLS 3D printing?+

  The benefits of SLS 3D printing include mature technology, the ability to print without support structures, design freedom, strong mechanical properties, material efficiency through recycling, and a wide range of surface finishes and color options.

  
  

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• Why are SLS 3D printers so expensive?+

  SLS 3D printers are expensive because of the complex technology, high-quality components, skilled operation requirements, and large R&D investment.

  
  

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• Are SLS printed parts waterproof?+

  SLS prints are water-resistant but not inherently waterproof. The parts can withstand exposure to water but may not be suitable for prolonged immersion unless they are post-processed with a waterproof coating or sealant. For applications requiring waterproof parts, additional finishing steps are recommended to ensure full water resistance.

• Why do SLS printed parts shrink?+

  SLS printed parts may shrink due to the following reasons:

  
  

  ● High Temperatures: During printing, parts are exposed to high temperatures, causing some shrinkage as they cool.

   

  ● Material Contraction: The sintering process involves heating and cooling, which can lead to material contraction or shrinking.

   

  ● Internal Stresses: As layers are added and cooled, internal stresses can develop, leading to shrinkage.

• How accurate is SLS 3D printing?+

  SLS 3D printing is accurate and precise, making it ideal for manufacturing small, intricate parts. It has a dimensional tolerance of ±0.15% and a lower limit of ±0.2 mm, ensuring parts are produced with close adherence to the original design specifications.

• What are the applications of SLS printing?+

  SLS 3D printing is utilized across various industries for its ability to create durable and complex parts, such as:

  
  

  ● Aerospace: Manufacturing lightweight components for spacecraft and satellites.

  ● Automotive: Producing intricate parts for vehicles.

  ● Healthcare: Creating custom medical devices and prosthetics.

  ● Consumer Goods: Fabricating products with complex geometries.

• What is the price range of SLS 3D printers?+

  ● Entry-level SLS 3D Printer: $10,000 to $20,000.

  
  

  ● Mid-range SLS 3D Printer: $50,000 to $100,000.

  
  

  ● High-end Industrial SLS 3D Printer: Over $250,000.

  
  

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• Is it possible to buy a cheap SLS printer?+

  Yes, it is possible to purchase a relatively inexpensive SLS printer. Entry-level models such as the Sinterit Lisa are available at a lower cost, making them accessible for design studios, schools, and hobbyists interested in making SLS prints.

• How fast is SLS 3D printing?+

  SLS 3D printing speed varies, but it’s generally known for its high productivity. The laser’s fast scanning speed and the ability to nest multiple parts in a single build increase throughput, making SLS one of the most efficient plastic additive manufacturing techniques.

• Can SLS print large parts?+

  SLS 3D printing can produce large parts, but it’s more optimized for smaller parts due to the ability to stack them efficiently in the build chamber. For large parts, it’s important to consider the printer’s build volume and the potential need for assembling multiple sections post-printing.

Comparison

• Is SLS better than MJF?+

  SLS is a mature powder bed fusion technology with a wide material range and color tinting, ideal for visual prototypes and medium-sized parts, while MJF offers better resolution, isotropy and recyclability for smaller functional parts; the choice depends on project requirements.

  
  

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• What is the main difference between SLS and FDM?+

  The main difference between SLS and FDM 3D printing lies in their processes and part quality: SLS uses a laser to sinter powder for highly detailed, complex parts without support structures, while FDM extrudes thermoplastic filaments layer by layer for more cost-effective, larger, lower-resolution parts.

  
  

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• What is the main difference between SLS and SLM?+

  The main difference between SLS and SLM is that SLS uses a laser to sinter polymer powders to create plastic parts, while SLM completely melts metal powders to create fully dense metal parts.

  
  

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