How to Polish Tungsten Carbide Dies & Tooling？

Due to the surface hardness of tungsten carbide, which typically exceeds 90 HRA, polishing is quite challenging. Surface polishing can usually be completed using traditional polishing techniques, while advanced polishing equipment is required for polishing complex shapes or inner holes. Our company can achieve a surface finish of Ra0.005 after precision polishing of tungsten carbide.

I. Traditional Polishing Techniques

Traditional polishing is the most basic processing method, mainly including the following steps:

1. Grinding PretreatmentFirst, rough grinding and fine grinding processes are necessary. Rough grinding is used to correct surface irregularities, while fine grinding further eliminates deep grinding marks, preparing the surface for subsequent polishing.
2. Metallographic Sandpaper PolishingUse metallographic sandpaper of varying grits to progressively sand the surface, removing burrs and larger irregularities. Care should be taken to apply even pressure to avoid excessive local grinding.
3. Fine Polishing with Polishing PasteChoose professional polishing pastes such as W5-7, W8-10, or W20 and use them with degreased cotton or soft wooden sticks for detailed polishing. Rotational polishing on a lathe can be performed for regular circular inner holes.

Polishing paste of different mesh sizes

SPI levels corresponding to Ra values and polishing tools

II. Advanced Polishing Techniques

1. Ultrasonic PolishingThis method uses high-frequency vibrational energy to perform micro-cutting on the workpiece surface with polishing abrasives. It is especially suitable for polishing complex shapes and intricate inner holes. Diamond paste or resin grinding wheels can be used as polishing materials.
2. Abrasive Flow PolishingThis technique achieves a mirror finish in a short time through cyclic extrusion and grinding with fluid abrasives. It can significantly reduce demolding force and extend the service life of the workpiece.

III. Key Points in Process Control

1. Preparation
   • Clean and degrease the workpiece
   • Select suitable polishing tools and materials based on processing requirements
   • Confirm workpiece dimensions and roughness requirements
2. Process Control
   • Strictly control polishing speed and pressure
   • Monitor processing temperature to avoid overheating
   • Regularly check polishing results and adjust parameters promptly
3. Post-Processing
   • Thoroughly clean to remove residues
   • Perform drying treatment
   • Use a surface finish tester for quality verification

By selecting appropriate polishing methods and strictly controlling process parameters, the challenges of polishing tungsten carbide dies & tooling can be effectively overcome, achieving the desired surface finish. Our company’s polishing precision can reach Ra0.02 to Ra0.005. In practice, it is recommended to choose a suitable combination of polishing techniques based on the specific characteristics of the workpiece to ensure a balance of quality and efficiency.