Selective Laser Sintering (SLS) Finishes Guide

Several post-processing options are available after printing a part via Selective Laser Sintering (SLS). Some of these options are standard and applied to every part. Others are optional but can significantly impact the look, feel, and functionality.

So, which post-processing option is suitable for your SLS components? This guide explains the different options and when to consider each one.

Understanding SLS Finishes

SLS finishes refer to the various surface treatments and post-processing techniques applied to SLS 3D-printed parts to enhance their appearance, functionality, and durability.

These finishes are crucial because they can significantly impact the final product’s quality, making it more suitable for its intended application. By understanding the different types of SLS finishes, you can select the most appropriate option for your specific needs, ensuring that your parts look good and perform well.

Media Blasting

This standard process is included in any order from the MakerVerse platform. Parts printed via SLS typically contain loose powder and a grainy finish, but media blasting remedies this. An abrasive media (such as sand or glass beads) is applied to the part under high pressure.

Media blasting’s benefits are functional (gaining a specific surface roughness) and optical (a clean, polished surface). Once media blasting has finished, the component might be produced completely, or the additional post-processing options detailed below might take place.

When to use this: Always. Media blasting is a standard process that improves surface quality and removes excess powder.

Media Tumbling 

Media tumbling is a smoothing process beyond what’s possible with media blasting. During the tumbling process, the parts are added to a tumbler and then deburred, finely ground, and polished by the movements of the container. The result is a satin-like finish that is unattainable through media blasting.

However, media tumbling is not recommended for parts with fine details and intricate features, as the process can alter dimensions and round edges and potentially damage smaller components. The part loses some material during this process. This could impact the look and mechanical properties of the part. For example, if the part has sharp edges or fragile features, media tumbling can adversely affect the final result.

When to use this: If a satin-like finish is needed and the part is not fragile.

Vapor Smoothing

This is another smoothing option. However, this one is performed chemically rather than mechanically. During vapor smoothing, the top layer of the part is dissolved in a vapor chamber.

Maintaining dimensional accuracy during vapor smoothing is crucial, as the process can significantly impact the precision and performance of the final part. The result is a smooth and even surface that retains the part’s mechanical properties.

When to use this: When the surface needs to be smoothed and evened but is too fragile for media tumbling.

Color Dyeing

Parts printed through SLS are typically white, so adding additional colors is popular in post-processing. In the dyeing process, the SLS component is immersed in a water bath with a colored dye of choice. The resulting chemical reaction causes the dye to penetrate the component, adding a homogenous color gradient to the part.

When to use this: When only a single color is needed or if the part has a complex geometry

Painting

In painting, a professional spray painting system adds additional colors to the printed part. The part is cleaned, and a clearcoat is applied to protect the paint. Painting offers a nearly infinite range of colors but can be challenging if the part’s complex geometry.

When to use this: When multiple colors or a range of colors are needed. Ideal for evaluating a printed prototype.

Quality Measurements

Quality measurements don’t change a part’s properties, but they can be invaluable in ensuring that the part is printed exactly as expected. Several quality measurements are available on the MakerVerse platform.

Optical 3D Scan: High-quality stereo cameras compare the original design geometry with the finished part. The scan provides a false-color image that allows users to spot geometric deviations from the original design. This option is ideal for a quick evaluation of dimensional stability.

Surface Roughness: A sensitive stylus measures the roughness of a part’s surface. It is best performed when the statistical deviations of a surface from the ideal form are required.

When to use this: Whenever in-depth quality control is needed. It can be helpful before sourcing a larger batch of parts.

Next Steps

SLS 3D printed parts offer a range of benefits, including high accuracy, complex geometries, and fast production times.

However, the surface finish of SLS parts can be rough and may require post-processing to achieve the desired finish. Understanding the different types of SLS finishes and design considerations allows you to select the most suitable post-processing technique for your specific application.
Whether you require a standard or an advanced finish, MakerVerse offers a range of options to enhance your parts’ functionality and aesthetic appeal.