May 20, 2026

Recently, our factory completed a batch of precision SS316 pump piston components for a coffee equipment application. The customer required an extremely fine surface finish on the outer diameter to ensure stable sealing performance and smooth movement during operation.

To achieve the required surface roughness specification, we combined precision CNC turning with external cylindrical grinding (OD grinding). This process helped maintain dimensional accuracy while significantly improving the surface quality of the stainless steel parts.

According to the drawing requirements, the target surface finish was Ra 0.2–0.4 μm, Rz 1.0–3.0 μm, and Rmax 6.3 μm. After machining, the parts were inspected using a surface roughness tester, and both Ra and Rz values met the customer’s requirements.

The material used was food-grade Stainless Steel 316, suitable for high-end coffee machine and fluid control applications.