How to Finish 3D Printed Parts- A Study Guide

Your 3D prints may come out rough, with visible layer lines and imperfections. Without proper post-processing, your parts look unfinished and unprofessional, leading to reduced functionality and aesthetic appeal. Let’s explore the solutions.

Finishing 3D printed parts is essential for improving the appearance, strength, and functionality of prints. Methods like sanding, priming, and painting are common ways to smooth out rough surfaces and enhance the final product. Post-machining varies depending on the material, such as ABS, VeroBlack, or PLA. Each material has its unique properties and requires specific techniques to achieve the desired finish. For example, ABS may require a more aggressive sanding approach due to its hardness, while PLA might benefit from a gentler touch to avoid damaging the delicate structure.

Now that you know why post-processing is essential, let’s dive into how to properly finish 3D printed parts based on their material.

Three Materials for 3D Printing

There are a variety of materials used in 3D printing, each with unique properties that require different finishing techniques. Here, we’ll focus on three common materials: ABS, VeroBlack, and PLA.

ABS

ABS (Acrylonitrile Butadiene Styrene) is a strong, durable plastic commonly used for 3D printing parts that require impact resistance. ABS can be challenging to post-process because it tends to warp, but with the right techniques, you can achieve a smooth finish.

VeroBlack

VeroBlack is a photopolymer resin often used in high-detail 3D printing for prototypes and functional parts. It offers a smooth finish straight off the printer, but further post-processing can enhance its appearance and strength.

PLA

PLA (Polylactic Acid) is a biodegradable plastic used in a wide range of 3D printing applications. It’s one of the easiest materials to post-process due to its lower melting point and ease of sanding.

Overview of Post-machining

Post-machining involves several steps to improve the surface finish, remove imperfections, and make parts more functional or aesthetically pleasing. The most common techniques include sanding, priming, painting, and specialized treatments such as vapor smoothing or chemical polishing.

Why Do 3D Printed Parts Need Post-Machining?

3D printed parts often have visible layer lines, rough textures, and pockmarks. Without post-processing, these imperfections can affect the part’s performance, especially for moving parts or components requiring a smooth surface. Post-machining enhances both the appearance and mechanical properties of the final product.

ABS (Printed on a Dimension Elite)

When ABS is printed on a high-end 3D printer such as the Dimension Elite, it can demonstrate its unique advantages and characteristics.

ABS 3D Printed Part Finishing Process: Materials Needed

To finish ABS prints, you’ll need the following materials:

Sandpaper (100-400 grit): Used to remove imperfections and smooth the surface.

Primer: Provides a base layer for paint and fills in small imperfections.

Spray paint or lacquer: Adds color and protection to the finished part.

Acetone for vapor smoothing (optional): Creates a glossy, injection-molded finish.

ABS 3D Printed Part Sanding

Begin by sanding the part with 100-grit sandpaper to remove large imperfections and visible layer lines. Gradually move up to finer grits (200, 300, 400) to smooth the surface. Pay extra attention to curved areas to avoid flat spots. Use a sanding block or sponge to ensure even pressure and a smooth finish.

ABS 3D Printed Part Priming and Painting

Once the part is smooth, apply a coat of primer. This will fill in any remaining imperfections and provide a good surface for paint adhesion. Allow the primer to dry completely before applying additional coats or moving to the painting step. After priming, you can paint the part in your desired color using spray paint or lacquer. Apply several thin coats for best results, allowing each coat to dry completely before adding the next.

ABS 3D Printed Part: The Final Result

After finishing, ABS parts will have a smooth, polished surface that’s resistant to wear. The acetone vapor smoothing method can further enhance the finish, giving the part a glossy, injection-molded look. Be cautious when using acetone vapor smoothing, as it can also soften the ABS material and cause warping if not done correctly. Always follow safety guidelines and wear appropriate protective gear when using acetone.

VeroBlack (Printed on an Objet30)

VeroBlack 3D Printed Part Materials Needed

For finishing VeroBlack, you’ll need a range of materials to ensure a high-quality, professional-grade finish. Here’s what you’ll need:

Fine grit sandpaper (200-600): Used to smooth out imperfections and achieve a fine finish.

Primer: Provides a base layer for paint and ensures a uniform surface.

High-quality paint or lacquer: Adds color and a protective layer to the finished part.

Wet sanding supplies (optional): Water, a sponge, and a bowl for wet sanding to achieve an even smoother finish.

VeroBlack 3D Printed Part Sanding

VeroBlack parts generally come out smoother than ABS due to the material’s resin-based composition. Start sanding with 200-grit sandpaper to remove any imperfections. Gradually move up to 600 grit for a finer finish. Wet sanding can be used to achieve an even smoother surface by adding water to the sanding process, which helps to reduce friction and heat, resulting in a finer finish.

VeroBlack 3D Printed Part Priming and Painting

After sanding, apply a primer to ensure a uniform surface. This will provide a good base for the paint and help to fill in any remaining imperfections. Once primed, paint the part with high-quality spray paint or lacquer. Since VeroBlack has a smoother and less absorbent surface than ABS, it may require fewer coats of paint to achieve a uniform finish.

VeroBlack 3D Printed Part Final Results

When finished, VeroBlack parts have a professional-grade surface with high levels of detail and a smooth finish. This material holds up well to painting and other finishing processes, making it ideal for prototypes, presentation models, and other applications where a high-quality finish is required. Additionally, VeroBlack’s resin-based composition allows for intricate details and smooth transitions, making it a versatile material for a wide range of applications.

PLA (Printed on a 5th Gen Replicator)

PLA 3D Printed Part Sanding

PLA is easier to sand compared to ABS. Start with 200-grit sandpaper and move up to 400 or 600 for smoother finishes. PLA is softer, so be cautious not to over-sand, which could distort details.

Finishing PLA 3D Printed Parts

To finish PLA, you can use simple sanding methods and apply a primer for paint. Wet sanding is particularly effective for PLA to avoid the material overheating during sanding.

PLA 3D Printed Part Priming and Painting

Priming PLA helps to smooth out the surface and prepare it for painting. After priming, use spray paint for a polished finish. Since PLA is softer, ensure that the paint layers are thin and even to avoid cracking.

PLA 3D Printed Part Final Results

Finished PLA parts have a smooth surface and can be painted to achieve various aesthetics. The lower melting point of PLA makes it less durable than ABS but easier to finish.

Differences in Process

Post-machining techniques differ for each material. ABS benefits from acetone vapor smoothing, while VeroBlack requires less sanding but benefits from finer grit. PLA’s softness makes it the easiest to sand but more susceptible to warping during the finishing process.

Differences in Time

ABS: Typically requires more time for finishing due to its need for multiple sanding steps and vapor smoothing.

VeroBlack: Requires less time for sanding due to its smoother starting surface.

PLA: Quick to sand but requires careful handling to avoid overheating.

Differences in Cost and Materials

ABS: Requires additional materials like acetone for smoothing, making it more expensive.

VeroBlack: Higher-quality paints and lacquers can increase costs, but fewer finishing materials are needed.

PLA: The lowest-cost option, but may require more primer for smooth results.

Special Post-Machining Technology

ABS steam smoothing, UV curing of resin printing, and metal electroplating are the three major post-processing technologies for optimizing 3D printed parts. ABS steam smoothing softens the plastic through steam penetration, eliminates printing marks, gives the parts a smooth appearance like injection molded parts, and may enhance their mechanical properties.

Resin printing uses UV curing technology to ensure that photosensitive resins are quickly cured and formed, and the hardness and wear resistance of the parts are significantly improved, and the texture is more delicate after post-processing. Metal electroplating adds a metallic luster to 3D printed parts, which is not only beautiful, but also gives them conductive, anti-corrosive and other properties, broadening the scope of application. These technologies work together to not only improve the appearance of 3D printed parts, but also enhance their practicality and market competitiveness, meeting diverse needs.

In conclusion

Post-machining is essential to achieving high-quality, fully functional and aesthetically pleasing 3D printed parts. Choosing the right finishing technique is critical for different materials, as each material has its own unique properties and requirements.

VMT provides one-stop services from 3D printing to post-processing, including customized post-processing solutions such as grinding and painting, to ensure that the parts meet high quality standards and meet customer needs. Choose VMT to save time and worry and create professional-grade 3D printed parts.