Which post-processing methods are available for 3D printing?

There are several post-processing methods that can be used to improve the surface finish, accuracy, and overall quality of 3D-printed parts. Below we have listed some common methods.

The specific techniques used will depend on the type of 3D printing technology, the materials used, and the desired properties of the finished object. Certain post-processing methods can be combined to get the benefits of multiple techniques.

Vibratory tumbling

The printed part is placed in a vibratory tumbler with abrasive media (such as ceramic or plastic beads) to smooth out the surface and remove any support material. Vibratory tumbling can produce matte or semi-gloss finishes, depending on the media used as well as the amount of time spent tumbling.

Heat treatment

Heat is applied to the printed part to improve its strength and reduce porosity. This is almost always done for metal 3D prints, as it reduces the internal stresses created during printing and ensures a strong, durable result.

Sanding

Abrasive materials (such as sandpaper) are used to smooth out rough or uneven surfaces on the printed part. A common method is sandblasting, which is a very effective way of both depowdering freshly printed SLS parts and getting a nicer finish. A variety of surface textures are achievable through different sanding methods.

SLS 3D printed part treated with sandblasting to achieve a smoother surface.

Chemical treatment

Chemicals are used to improve the surface finish of the printed part, or to remove support material. The finish depends on the properties of both the chemicals and the material of the print, and how these interact with each other. Often, a glossy or semi-glossy finish can be achieved.

Painting

A coat of paint is applied to the printed part to improve its appearance or to protect it from the elements. A variety of finishes can be achieved. Spray painting offers the most even result and a variety of both colors and finishes. It’s also appropriate for a broad range of sizes. Most paints and 3D-pieces will require a primer.

SLS 3D printed parts spray painted to look like gold medals.

Coating

3D-printed objects can be coated with a variety of materials, including plastics, metals, and ceramics, to enhance their surface properties and appearance. Coating methods include spraying, dipping, and roller coating.

Machining

Traditional machining techniques (such as milling or turning) are used to remove excess material or to achieve a high level of accuracy.

Dipping

The printed part is dipped in a liquid bath to smooth out the surface or apply a coating. Most surface textures can be achieved, depending on the substance used.

Vapor smoothing

The printed part is exposed to a vapor (such as acetone) to smooth out the surface and improve the part’s overall appearance. A benefit of vapor smoothing is that it reaches all surfaces of the part, not just those visible, which is particularly useful for more complex parts.

SLS 3D printed part treated with vapor smoothing (right).

Polishing

Abrasive materials and techniques (such as buffing or abrasive blasting) are applied to improve the surface finish of the printed part. A variety of surface finishes are available through polishing methods, though the most common result is a matte or velvety finish.

SLS 3D printed part treated with mechanical polishing to achieve a smoother surface.

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