This is normally expressed in micrometers (Microns) or microinches. Variables affecting the resultant finish are grit size, tool load, condition of the tool, feed rate, traverse rate condition of metal to be polished and lubricant used, if any.įor precise and consistent results, the surface finish should be specified in a range or maximum level of roughness average (Ra). The specification of grit reference cannot be equated to a consistent surface finish. Increasingly stringent specifications are now being demanded for the surface finish on all items of process equipment in the pharmaceutical and biotechnology industries and many suppliers of valves and pipe work are now quantifying the surface roughness of their product. The number of different surface finish standards being used by different equipment manufacturers has created a great deal of confusion and misunderstanding throughout the industry. Measuring and specifying surface finish has, until recently, been left to a varying amount of speculation. Due to the rounded profile, electropolished surfaces are far easier to clean than surfaces mechanically polished alone. This action produces a smoothing and rounding of the surface profile. Peaks are dissolved more quickly than valleys as a result of the greater concentration of current over the protuberances.
This electrolytic process, the opposite of the plating process, is designed to remove metal without smearing or folding. The most effective method of eliminating burrs, folds, inclusions and other abnormalities is through Electropolishing. Local corrosive cells cannot be set up, because the local galvanic differences caused by polishing stresses in the stainless surface have been eliminated. An electropolished surface is essentially balanced. Mechanical polishing or machining leaves numerous surface scratches which cause areas of differing electrical potential due to surface stresses. Mechanical Polishing and ElectroPolishing Machining and mechanical polishing
Star offers sight glasses, sanitary fittings, and visual flow indicators in a wide range of surface finishes.