How to Smooth 3D Prints and Get High-Quality Results

3D printing allows for the creation of complex parts, but depending on the technology used, printed objects may have visible layer lines or a rough surface. Many applications require additional finishing to achieve a smooth and refined look.

Knowing how to smooth 3D prints is very important for improving both aesthetics and functionality.

There are several methods for smoothing 3D prints, each suited to different materials and printing processes. This guide will explain the best techniques for polishing 3D prints for FDM, SLA, and SLS technologies.

Why Smoothing 3D Prints is Important

Many 3D-printed parts require post-processing to achieve a more refined finish. Rough surfaces can impact functionality, especially when parts need to fit together precisely. For consumer-facing products or prototypes, smoothing helps produce a professional appearance.

The method used for polishing 3D prints depends on the material and printing technology. FDM prints typically have noticeable layer lines, SLA prints may require additional sanding for clarity, and SLS prints have a powdery texture that gets better with specialized post-processing.

Methods for Smoothing 3D Prints

Each 3D printing technology requires a different approach to surface finishing. The techniques discussed in this article cover some ways we found effective to achieve a better final result.

How to Smooth 3D Prints Made with FDM Technology

FDM printing builds objects layer by layer, which results in visible ridges that may require additional work to improve the surface quality.

• Vapor Smoothing for ABS – ABS plastic can be smoothed using acetone vapor. This process slightly melts the outer layer, giving the part a polished appearance. However, acetone smoothing does not work for PLA or PETG, so alternative methods must be used.

  
  

• Filler Priming and Painting – Applying a filler primer before sanding helps to fill small gaps and surface deficiencies, making it easier to achieve a better finish. This technique is useful when a high-quality surface is required.

  
  

How to Smooth 3D Prints Made with SLA Technology

SLA printing produces highly detailed parts, but some finishing may still be necessary to remove support marks.

• Wet Sanding for Clarity – When working with clear resins, wet sanding is often required to remove fine scratches and improve transparency. Starting with a lower grit and gradually increasing to ultra-fine grits results in a polished look.

  
  

• UV Curing and Polishing – SLA parts must be fully cured before post-processing. Polishing compounds or coatings can further improve the appearance, especially for optical or decorative applications.

  
  

For SLA prints that require maximum clarity, additional steps such as applying a clear coat can enhance the final finish.

Struggling with support removal? Read our expert tips on how to remove supports from 3D prints to get professional-quality finishes.

How to Smooth 3D Prints Made with SLS Technology

SLS printing produces durable parts with a slightly rough, powdery surface. While this texture is acceptable for many functional applications, additional finishing improves the appearance and feel of the final product.

• Manual Sanding, Filler Priming, and Painting – While manual sanding is a practical method to smooth SLS-printed parts by progressively using finer sandpaper, achieving a high-quality finish is best accomplished with filler priming and painting. These additional steps help to refine the surface further, eliminate imperfections, and enhance the overall appearance and durability of parts.

  
  

• Media Tumbling for Bulk Finishing – When dealing with multiple parts, tumbling provides a consistent polish by using abrasive media to wear down the roughness. This process is useful when high efficiency is needed.

  
  

• Dyeing and Sealing – SLS parts can be dyed to create a uniform color, and applying a sealant helps improve surface smoothness while adding protection.

  
  

For those looking to achieve high-quality surface finishing for SLS parts, professional services offer tailored solutions. A trusted SLS printing service can ensure the right post-processing techniques are applied based on the project’s specific needs.

Best Practices for Polishing 3D Prints

Selecting the best smoothing method depends on the material, intended use, and desired appearance of the part. The following best practices help ensure successful post-processing:

• Use the Right Tools – Fine-grit sandpaper, polishing compounds, and chemical treatments should be chosen based on the material.

  
  

• Work Gradually – Sanding or polishing should be done in stages, moving from coarse to fine methods for the best results.

  
  

• Consider Protective Coatings – Some prints benefit from a final protective layer to enhance durability and appearance.

  
  

Choosing the Right Method for Your Application

When deciding on the best method for polishing 3D prints, consider the final application of the part.

• Prototypes and Display Models – SLA prints offer excellent detail, but additional polishing may be needed for visual clarity.

  
  

• Functional Parts and Enclosures – SLS prints provide high strength and durability, but surface smoothing may improve appearance and usability.

  
  

• Consumer Products and Painted Surfaces – FDM prints can be refined with primer, sanding, and painting for a professional look.

  
  

Understanding how to smooth 3D prints is essential for achieving professional results. Each technology requires a different approach, whether through sanding, vapor smoothing, or chemical treatments. For businesses seeking high-quality finishing, working with a 3D printing service Boston ensures that parts are processed with expert-level precision. If you need assistance with smoothing 3D prints, polishing techniques, or selecting the best finishing method, we will be glad to help optimize your parts for the best possible results.