Stainless steel electrolytic polishing

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Hansheng's Stainless Steel Surface Treatment is an integrated offering that pairs high-precision CNC machining with multiple advanced surface finishing processes to produce aesthetically refined and functionally durable stainless steel components. The service covers the full workflow from precision machining (with micron-level tolerances) through surface preparation and finishing to deliver parts suited for medical, semiconductor, robotics, large industrial equipment and other demanding industries.

Core surface treatment processes

• Metal passivation (citric or nitric acid) to remove contaminants and form a protective chromium oxide layer while preserving dimensions.
• Electropolishing: electrochemical removal of microscopic material to smooth peaks/valleys, reduce bacterial/moisture adhesion, and produce bright, high-gloss surfaces with enhanced corrosion resistance.
• Stainless steel polishing & brushing: mechanical finishes including mirror polishing (No. 8 finish) and brushed satin (No. 4 finish) for decorative and practical surface textures.
• PVD coating (e.g., TiN, DLC): deposition of ultra-hard thin films to increase surface hardness, scratch resistance and provide long-lasting color for decorative or wear-critical parts.
• Sandblasting: abrasive media blasting to produce uniform matte/textured surfaces, reduce glare, and improve coating adhesion or serve as a functional pre-treatment.

Advanced machining & integration capabilities

• Ultra-Mirror Machining: near-optical surface quality directly from CNC with accuracy down to ±0.002mm, reducing need for manual buffing.
• Precision grinding: holding ±0.005mm tolerances for shafts, gears and substrates prior to finishing.
• Precision turning & milling: standard tolerances from ±0.005mm to ±0.01mm, with allowances for surface removal/addition during finishing.
• Complex geometries: 5-axis machining and Seibu WEDM (M50B) for intricate parts requiring minimal post-processing.
• Large-scale processing: Horizontal machining centers capable of handling parts up to 2100mm x 1060mm for large plates, frames and housings.
• In-house gear manufacturing and coating workflow: gear skiving and hobbing (Kashifuji, Ningjiang) combined with PVD for wear-resistant gears while preserving tooth-profile accuracy.

Quality assurance, design-for-finishing and testing

• Tolerance preservation strategy: engineers calculate and apply CNC offsets to compensate for coating thickness or material removal (for example leaving specific stock so final dimensions meet ±0.005mm requirements).
• Standards & testing: adherence to industry standards (examples cited include ASTM A967 for passivation and ASTM B912 for electropolishing practices) and provision of Salt Spray Test reports, surface roughness (Ra) measurements, and Certificate of Conformance on request.
• Design reviews (DFM): CAD review to prevent plating air pockets or acid traps and to optimize parts for finishing processes.

Industries supported

• Medical & Bio-Tech: electropolished surgical instruments, implants and sanitary components.
• Robotics & Automation: precision ground shafts and gears with wear-resistant PVD coatings.
• Large Industrial Equipment: large machined housings and frames with durable passivation or painting.
• Optical & Sensor: ultra-mirror machined components requiring minimal light scattering.

Technical features / specifications

• Typical machining accuracy: Ultra-Mirror Machining down to ±0.002mm.
• Precision grinding tolerances: ±0.005mm.
• Turning & milling tolerances: typically ±0.005mm to ±0.01mm (with engineered offsets for finishing).
• Maximum horizontal machining capacity: up to 2100mm x 1060mm workpieces.
• Key surface treatments available: metal passivation, electropolishing, mirror polishing (No. 8), brushing (No. 4), PVD coatings (TiN, DLC), sandblasting.
• Advanced equipment examples: Seibu Wire WEDM (M50B), Brother CNC lathes, Kashifuji gear skiving machines, Ningjiang hobbing machines, 5-axis machining centers, horizontal machining centers.
• Quality & test outputs: Salt Spray Test reports, Ra surface roughness measurements, Certificate of Conformance (available upon request).