10 Most Commonly Used FDM 3D Printed Parts Post-Processing Processes. Which One Should I Choose?

Fused Deposition Modeling (FDM) is one of the most popular 3D printing processes for creating prototypes, functional parts, and low-volume production runs. While FDM 3D printing offers impressive design flexibility, post-processing is often needed to improve the quality, aesthetics, and functionality of the printed part. In this article, we’ll explore the 10 most commonly used FDM 3D printed parts post-processing techniques and help you decide which one is best for your project.

1. Support Removal

Support structures are often required during the FDM process to support overhangs and complex geometries. After printing, these supports need to be removed. This process can involve mechanical removal, manual scraping, or dissolving the supports using a solvent, such as water-soluble PVA support material.

2. Sanding

Sanding is one of the most common post-processing techniques for improving the surface finish of FDM 3D printed parts. It removes layer lines and imperfections, leaving a smoother and more polished appearance. Sanding is often done using different grits of sandpaper, starting with coarse and moving to finer grits.

3. Vapor Smoothing

For parts printed with ABS or similar materials, vapor smoothing is an effective technique. The part is exposed to a vapor of a solvent (usually acetone) that melts the outer surface, smoothing out the layer lines and improving the part's overall finish. This method enhances both the look and strength of the part.

4. Painting and Coating

After sanding, painting or coating a 3D printed part can significantly improve its appearance and protect it from environmental factors. Spray paints, primers, and epoxy coatings are commonly used to give parts a glossy or matte finish. This post-processing method is particularly useful for creating aesthetically pleasing prototypes.

5. Heat Treatment

Heat treatment can be used to enhance the strength and durability of parts printed with certain materials like ABS, nylon, or polycarbonate. By heating the part to a specific temperature and allowing it to cool slowly, the molecular structure is altered, improving mechanical properties like impact resistance and tensile strength.

6. Chemical Smoothing

Chemical smoothing uses specific solvents to dissolve the outermost layer of the print, creating a smooth and glossy finish without the need for sanding. Materials like PLA can be smoothed using chemicals like chloroform or acetone, offering an efficient way to improve surface quality.

7. Tumbling and Polishing

Tumbling involves placing multiple 3D printed parts into a drum with abrasive media. The drum rotates, causing the parts to collide with the media, effectively smoothing rough surfaces. Polishing further enhances the surface finish, particularly for metal 3D printed parts.

8. Assembly

For larger or more complex parts, assembly is often necessary. 3D printed components can be assembled with other printed parts or external hardware like screws and nuts. This process is essential when creating multi-part prototypes or functional assemblies that require multiple pieces to work together.

9. Surface Texturing

Surface texturing techniques such as bead blasting or engraving can be used to add functional textures or aesthetic designs to 3D printed parts. This is particularly beneficial for creating custom finishes or improving grip on parts like handles or control knobs.

10. Infiltration

Infiltration involves applying a material to the 3D print to increase its density and strength. For example, a common process is to soak the print in a liquid resin or wax that fills the voids between the printed layers, improving both the strength and the surface finish of the part.

Which One Should I Choose?

The post-processing method you choose will depend on the specific requirements of your project, such as the desired aesthetic finish, strength, and functionality of the part. If you need a smooth, polished finish for a prototype, sanding, vapor smoothing, or chemical smoothing may be the best choice. For parts that require enhanced strength or durability, heat treatment or infiltration can provide the necessary improvements.

Ultimately, the selection of post-processing techniques for your FDM 3D printed parts should align with the goals of your project. Whether you are creating a functional prototype, a custom part for manufacturing, or an aesthetically refined model, FDM post-processing processes offer a variety of options to achieve the perfect result.