Polishing and Custom Mechanical Finishing for Aluminum Extrusion Products
Polishing and custom mechanical finishing add durability and style to aluminum extrusion products, using chemical or mechanical processes.
Mechanical finishing can produce a variety of cosmetic finishes and textures, whether it is a rough surface, a patterned matte look, or a classic mirror-shine finish. Mechanical finishes are achieved using various methods like buffing, brushing, bead blasting, grinding, or tumbling.
If the final aluminum extrusion product needs to be anodized, the mechanical finishing must be completed first. This allows the surface texture created by the mechanical finishing to show through the transparent, uncoloured anodized layer, and enhances the appearance of the product. Polishing and custom mechanical finishing also serve the purpose of removing any irregularities, imperfections or defects on the surface of the extruded aluminum.
Grinding is the most common method of mechanical polishing to abrade hard materials and tighten the tolerance of the product’s surface. A rotary grinder is used in this process, where an abrasive material is placed on the wheel or belt that is attached to it. The rough surface rubs against the metal surface, removing any excess material or irregularities from it. Since this process generates significant heat, the grinding is performed at low speed and a lubricating fluid is used to cool the grinder and the extruded aluminum.
Brushing is another technique used to produce a desired texture on aluminum extrusion products. It is not actually performed with a brush, but with sandpaper, or even Scotch-brite™, usually in the form of a large belt sander, which is also known as a timesaver. The finish produced by brushing may consist of tiny parallel lines that are etched on the surface of the product in the same direction, or as tiny grooves to create a feathery texture and reduce the reflective qualities of the aluminum. Another popular effect is a crosshatched pattern of lines. This finish is commonly used in shower and tub enclosures, picture frames and other aluminum extrusion products.
Another mechanical finishing process is bead blasting, which creates a granular finish that helps to hide excesses of imperfections on a surface. Tumbling is a multi-purpose mechanical finishing method, which facilitates deburring, washing, and polishing.
Polishing and custom mechanical finishing greatly enhance the value and appeal of aluminum extrusion products with minimal additional expense.