Brushing is one of the most popular surface finishes for stainless steel bathroom parts. It creates a uniform, fine continuous grain that delivers a sleek, premium metallic look while also hiding minor scratches from daily use. Compared to mirror polishing, brushing places different demands on automated process control precision.

1. Straight-line brushing: Parallel grain in a single direction, the most common finish for faucet handles and spouts, with clear, directional lines.
2. Snow / random brushing: Short, irregular, uniformly distributed grain with a finer feel, often used on large faucet body surfaces and requiring higher uniformity.
3. Satin brushing: Coarser short-grain matte finish, common for commercial-grade products with higher processing efficiency.

1. Abrasive Grit Selection
   • Coarse brush: 120# – 180#, prominent grain, robust texture
   • Standard fine brush: 240# – 320#, the most mainstream specification for bathroom products
   • Fine brush: 400# – 600#, extremely smooth touch, near semi-bright
   • Note: The base surface before brushing must be finished one grit grade finer than the brushing belt; otherwise, underlying coarse scratches will show through the grain.
2. Surface Speed Control

   Brushing typically uses lower surface speeds than polishing, with a recommended range of 2.5 – 15 m/s. Too high and the grain becomes faint and blurred; too low and grain becomes deep with uneven cutting.

   Straight-line brushing favors mid-to-high speeds; random brushing favors mid-to-low.

3. Contact Pressure & Contact Wheel

   Brushing requires steady, moderate pressure. Too much pressure causes deep grain and burning; too little causes faint, uneven grain. Soft contact wheels (Shore A 40–60) conform better to curved surfaces for consistent depth. Servo force control systems are standard for automated brushing, keeping pressure variation in a very tight range.

4. Feed Pattern & Overlap
   • Straight-line brushing: Feed along the grain direction with 30–50% overlap between passes to avoid step marks.
   • Curved surface brushing: Maintain consistent contact angle via multi-axis robot interpolation to prevent grain direction shifts or broken lines on radii.

1. Uneven grain depth / shading variation
   • Cause: Unstable pressure, poor contact wheel conformity, workpiece deformation changing contact area
   • Fix: Upgrade to servo force control, use contact wheels of appropriate hardness, add laser line scan to compensate for deformation
2. Splice marks / periodic cross-grain
   • Cause: Uneven belt thickness at the splice creates a repeating mark per revolution
   • Fix: Use lapless butt-spliced belts, optimize belt tensioning, increase feed speed slightly
3. Yellowing / burning on brushed surface
   • Cause: Excessive pressure, slow feed, belt clogging
   • Fix: Reduce pressure, increase feed rate, add belt cleaning mechanism, install mist cooling
4. Missed spots / chaotic grain on radii
   • Cause: Inaccurate path teaching, poor surface conformity on curves
   • Fix: Use offline programming to optimize curved paths, combine with force-control float to ensure consistent contact on fillets

For quality-focused bathroom brands, consistent brushing is a key part of product identity. Automated brushing with precise force and path control delivers batch consistency hard to achieve manually, making it a must for mid-to-high-end product upgrading.