Metal finishing constitutes the concluding phase in the manufacturing process, serving dual purposes of enhancing aesthetics and providing environmental protection. It extends to refining surface roughness beyond machining capabilities, crucial for components requiring precise mating or sealing. Additionally, metal finishing encompasses techniques such as cleaning, descaling, and deburring. In essence, a diverse array of metal finishing processes is employed for multifaceted objectives. This concise guide explores key finishing methods, delving into applications and considerations essential for selecting an appropriate metal finishing process.
Metal plating involves the use of chemical baths to deposit thin layers of metals, such as zinc, nickel, cadmium, or chromium, onto substrates. Electroplating utilizes an electric current to coat the substrate, while electroless plating employs an autocatalytic process catalyzed by the substrate itself. Typically, this chemically intricate process is outsourced to specialized plating service providers due to its scale and complexity.
Metal plating contributes to enhanced product durability, corrosion resistance, surface friction, and overall appearance. For instance, in galvanized metal, zinc plating acts as a sacrificial anode, corroding to protect the underlying substrate. It’s important to note, however, that plating is not ideal for smoothing out surface defects.
Surface finishing machines, utilizing abrasive belts or wire brushes, create a uniform grain texture, smoothing product exteriors and generating slightly rounded edges. This method is commonly applied to enhance aluminum panels for metal photo prints and signage. Additionally, wire brushing serves to eliminate slag from welding and remove scale and grit from metal surfaces prepping them for cleaning. Chemical and acid baths are then employed to thoroughly clean oil residues before plating or coating processes.
Grinding machines employ abrasive wheels to refine surfaces, offering various types designed for distinct levels of surface smoothness. Grinding serves to diminish surface roughness resulting from machining and is often the final step in the machining process to achieve specific tolerances. The most prevalent type is the surface grinder, complemented by specialty grinders like centerless and blanchard grinders, the latter being particularly valuable for precision in oversized parts.
A crucial stage in numerous metal manufacturing processes is heat treatment, employed to imbue desired characteristics in the material once its final shape is achieved. For instance, gears undergo heat treatment post-cutting, typically through inductive or flame heating methods. This process enhances wear resistance at the tooth surfaces while reinforcing the strength of the underlying teeth. Hardening involves a quenching operation, a pivotal step in altering the metal’s grain structure.