How to Polish 3D Printed Stainless Steel

3D printed stainless steel parts are popular for their incredible durability and strength. However, post-processing, especially the polishing process, often determines the appearance and functionality of the final product. Polishing not only enhances the beauty of the part, but also improves its smoothness and durability. This guide will explore how to polish 3D printed stainless steel parts and ensure that they achieve professional-level appearance and performance.

JLC3DP customers share metal prints on reddit, comparing polished and unpolished

Source:https://www.reddit.com/r/3Dprinting/comments/1en3pr0/ever_wondered_what_polished_3d_printed_metal/

Why polish 3D printed stainless steel?

Polishing 3D printed stainless steel parts has multiple benefits:

Improve appearance: Achieve a smooth, shiny and professional finish.

Reduce surface roughness: Reduce imperfections left by the printing process and make the surface smoother.

Enhance functionality: Reduce friction and prevent dirt accumulation, thereby improving the performance of the part.

Improve corrosion resistance: Polished surfaces can better resist corrosion by eliminating micro-crevices, extending the life of the part.

Polishing methods for 3D printed stainless steel

Preparation before polishing

Evaluate the surface: Inspect the printed part for large imperfections, such as bumps or misalignments. Use cutting tools or files to remove these impurities to ensure an even polishing effect.

Clean the parts: Use compressed air or an ultrasonic cleaner to remove any loose powder, dust or debris. This will ensure a smoother polishing process and avoid unnecessary scratches or scratches.

Manual Polishing

Manual polishing is suitable for small parts or areas that require fine polishing. First, use coarse sandpaper (200-400 grit) to remove obvious surface roughness or imperfections. Then, gradually switch to finer sandpaper (600 grit and above) for further polishing to achieve a smoother surface. When polishing, it is recommended to use circular motions to apply force evenly and avoid leaving deep scratches on the surface. This method is more time-consuming, but it can provide high fineness and control, and is suitable for parts that require higher precision.

Wet polishing: This refers to polishing with water or other liquids on sandpaper, which can prevent overheating and reduce dust. It is more common in fine-grained sandpaper (such as 600 grit and 1200 grit).

Tumble Polishing

Tumble polishing is suitable for polishing multiple parts at the same time, especially for large-scale production. Place the part and abrasive media (such as ceramic, steel or plastic beads) in a vibrating tumbler and adjust the run time to the desired polishing effect. Tumble polishing can evenly polish multiple parts and is suitable for batch processing, but it needs to be checked regularly to avoid over-polishing. This method is not suitable for very complex or delicate parts because it has a low processing accuracy.

Electropolishing

Electropolishing is a polishing method that uses an electrochemical reaction. First, the part is immersed in a special electropolishing solution and the appropriate current is applied according to the material requirements. Through the action of the current, the tiny surface irregularities are chemically removed, leaving a smooth surface. After polishing, rinse the part with distilled water and dry it thoroughly. Electropolishing provides a uniform and efficient surface treatment, especially for parts with complex geometries.

Mechanical Polishing

Mechanical polishing is suitable for parts that require a mirror effect and can quickly achieve a high-gloss surface. It is also the most commonly used polishing method. Use a polishing wheel and polishing pad with a coarse polishing compound for initial smoothing, and then switch to a fine polishing compound and soft wheel for a final high-gloss polish. When polishing, make sure to apply even pressure and check regularly to avoid uneven gloss or scratches on the surface. After polishing, clean the part to remove any residual polish. Mechanical polishing requires fine control to avoid over-polishing or surface damage.

Mechanical Polishing Operation Steps： https://x.com/JLC3DP/status/1740677507626733884/video/1

Best Tips for Polishing

Prevent overheating

During polishing, overheating can cause part deformation or performance changes. Maintain appropriate speed and pressure, such as keeping the polisher at about 900 rpm and using fast-cutting paste to reduce friction heat. At the same time, periodic pauses to let the part cool are also effective protective measures.

Choose the right tools and methods

Choose the right tools and techniques based on the complexity and size of the part. Abrasive discs with polyester film are suitable for rough machining and can produce a consistent roughness on the surface. For complex geometries, electrolytic polishing may be a better choice. In addition, it is recommended to check the abrasive of the polisher to ensure that the hardness is appropriate. Too hard or too soft will affect the effect.

Polishing tips

Changing the polishing direction can help to even out the process, especially for parts with uneven shapes and sizes. If possible, polish in the direction of the scratch or mark to make it easier to remove the flaw. When applying the polish, apply small amounts and multiple times to avoid residual oil on the surface and keep the surface clean.

Maintenance and Use of Tools and Materials

Ensure that polishing wheels and polishing compounds are used separately to avoid mixing different polishing compounds. When changing polishing compounds, clean the polishing wheel residue with a wire brush. For small parts, the drill bit can be fixed in a vise to improve polishing efficiency, and use a high-quality wax polish to protect the prepared surface.

Safety and Prevention

Before polishing, remove all paint layers from the metal surface to ensure smooth operation. Always wear appropriate safety equipment, such as goggles and gloves, to prevent injuries caused by tool splashes or high temperatures. In addition, it is recommended to test on scrap parts before polishing to familiarize yourself with the process and avoid damaging important parts.

Polishing 3D printed stainless steel parts can significantly improve their appearance and performance, allowing your printed works to reach professional-grade standards, with smooth surfaces and high durability, perfect for a variety of application needs. If you need high-quality 3D printing and post-processing services, welcome to explore JLC3DP. We provide you with cutting-edge 3D printing solutions to meet all your needs.