What Are Polishing Patterns?
Polishing patterns are distinctive surface textures achieved through various polishing techniques. These patterns range from stripes created by brushes or abrasives to more intricate designs. The appearance of the polished surface varies with the method used.
Glossy polishing employs buffing pads, resulting in finishes from coarse luster to mirror-like surfaces without visible polishing marks. Satin polishing, a type of vibration polishing, produces a surface with a random pattern of small arcs, often appearing as straight-line hairline patterns.
Scale polishing is characterized by a spun-polished pattern with a scaly appearance.
Uses of Polishing Patterns
For stainless steel, coarse-grain polished finishes are used in building materials and kitchen utensils, while finer, lustrous finishes find applications in vehicles, medical equipment, and food-related equipment. Mirror finishes with subtle striping are also popular for building materials and kitchen utensils. Hairline and vibratory grinding patterns are commonly used in building materials.
Buffing is utilized to minimize surface irregularities and remove dirt, enhancing appearance and aesthetics. It also helps prevent rust and dirt adhesion.
Polishing extends beyond metals to jewelry, marble, optical and electronic components, and even dental and biological substitutes.
Principle of Polishing Patterns
In precision machining, polishing with abrasive grains is prevalent. There are two main types: fixed abrasive, where grains are bonded into a wheel-like shape, and loose abrasive, involving discrete grains.
Fixed abrasive methods include honing and abrasive cloth processing while lapping and polishing are typical loose abrasive methods, each producing unique polished surfaces.
Two categories of abrasive grains are used: natural and artificial. For rough polishing, hard grains like alumina, silicon carbide, and diamond (Mohs hardness 9 or higher) are preferred. Softer, finer grains (Mohs hardness 7 or less) are chosen for fine polishing and finishing.
Lapping involves embedding hard abrasive grains into both the workpiece and the lapping tool, making each grain tip act as a microtool. Polishing is achieved by pouring fine abrasive grains onto a polisher plate and pressing the workpiece against it in relative motion.
Various abrasives, such as belt, film, and wheel types, are available in different coarseness levels. Precision grinding wheels for electronic components are used in lapping and edge grinding of semiconductor wafers and precision grinding of optical glass. Compounds, specifically designed for automotive repair, are also used as abrasives.