What Makes SLS 3D Printing Better than Others?

 Selective Laser Sintering, or SLS, remains one of the most popular 3D printing techniques in use today. It melts the raw material and arranges it layer by layer to make the shape entered described in the CAD file. Mostly, grains of the thermoplastic polymer is used as the raw material in SLS 3D printing.

Today, selective laser sintering has become increasingly popular for producing prototypes and functional parts of machinery in small batches. The reasons behind the popularity of SLS printing are its extensive freedom in designing, higher accuracy in production, and consistent quality with functional physical properties.

SLS 3D Printing becomes the optimal solution for prototypes and spares part manufacturing when the designer is aware of the capabilities and limitations posed by the technology.

What important characteristics of SLS 3D Printing should a Designer know?

If the designer is aware of the extent of freedom and limitations of the 3D printing technique, then they can successfully design and manufacture stunning, precise, and durable components.

Designers need to be aware of four characteristics of SLS 3d printing to make extremely accurate and advantageous models:

1 — Parameters of printer
Almost all manufacturing parameters are set by the machine manufacturer for SLS 3D printing. By default, the layer height is set between 100 to 120 microns. SLS does not require a support structure which is one of its unique characteristics. This allows designers to use SLS 3D printing to create free-form geometric shapes would otherwise be impossible to manufacture using conventional manufacturing methods.

2 — Layer Adhesion
SLS printing ensures that the bond strength between two consecutive layers is maximum. This provides SLS-manufactured parts with nearly isotropic properties. SLS parts have optimal modulus and tensile strength apart from being at least 30% porous. The porosity is what provides SLS parts with the peculiar, grainy finish on the surface. The SLS parts can also absorb water and thus are easy to dye in a large range of colors too.

3 — Warping and Shrinkage
SLS 3D printed parts are likely to warp & shrink. This is because as the sintered layers begin to cool down, their size decreases and causes internal stresses, thus pulling the underlying layer upwards. Typically, you can expect around 3 to 3.5% shrinkage and expert designers take this into consideration to ensure accuracy in the finished product.

Flat, large surfaces are prone to warping. This can be remedied by orienting vertically in the build-platform. However, you can also choose to reduce its volume by lessening the thickness of the flat areas and adding cutouts to the original design.
4 — Removing powder
Escape holes are essential for 3D models to remove the un-sintered powder from within. Experts recommend adding at least two 5mm-wide holes for this. Alternatively, designers can print 3D models using SLS 3D printing with a hollow design, thus not needing the escape holes.
Conclusion
The extensive liberty in designing, the precision and accuracy of rendering, and the durable quality of raw materials used in SLS 3D printing make it a better choice than others.