What post-processing treatments can enhance the mirror finish achieved by EDM?

Post-Processing Treatments to Enhance EDM Mirror Finish

1. Electropolishing

Electropolishing is a non-mechanical, electrochemical process that selectively removes surface material to further reduce roughness and enhance surface clarity. After EDM processing, applying electropolishing to components made from materials like SUS316L or Ti-6Al-4V Grade 5 can lower Ra values below 0.1 µm. It also improves corrosion resistance and removes micro-burrs, making it suitable for medical implants and pharmaceutical tooling.

2. PVD Coating

Physical Vapor Deposition (PVD) enhances the durability, hardness, and aesthetics of mirror-finished components. Following EDM, applying PVD coatings like TiN, CrN, or DLC to parts such as Tool Steel H13 or Inconel 718 improves wear resistance and maintains the polished surface under operational loads, especially in aerospace and industrial molds.

3. Heat Treatment

Post-EDM heat treatment stabilizes the microstructure and eliminates residual stresses induced during sparking. For hardened materials like Tool Steel D2 or Ti-6Al-4V ELI, it ensures dimensional stability and surface integrity. This is critical in applications where thermal fatigue or dimensional precision is essential.

4. Passivation

Passivation is especially useful for stainless steels such as SUS630/17-4 PH. After EDM, passivation removes free iron and enhances corrosion resistance without altering the surface smoothness, making it ideal for medical and food-grade components.

5. Polishing (Mechanical or Vibro-Finishing)

For aesthetic parts, light mechanical polishing or tumbling may be applied after EDM. These techniques can help improve visual gloss or refine small remaining imperfections, particularly for consumer-facing or decorative components.

Recommended Service Combinations from Neway 3DP

To maximize the finish quality of your EDM-processed parts, we recommend:

• EDM Machining Achieve sub-micron surface precision on internal and external features.

• Electropolishing Improve cleanliness, bio-compatibility, and surface uniformity.

• PVD Coating Protect mirror-finished parts with decorative or functional coatings.

These integrated post-processing workflows ensure high-performance parts for aerospace, medical, and high-end industrial use cases.