Manufacturers requiring same-day black finishing of small lots of aluminum parts can safely blacken parts in-house and achieve a durable and attractive satin black finish using the new mini BK-LC line, according to the manufacturer Birchwood Casey.
The Lumiclad process uses a dip-tank procedure to form a durable black oxide coating on aluminum. In contrast to the conventional black anodizing, the Lumiclad process uses only one heated tank in the process line and does not require electrolytic current. The process works well on all cast and wrought aluminum alloys and forms a smooth, black finish that is tightly adherent to the aluminum substrate, with no rub-off.
Since the Lumiclad finish is only 1.5 microns thick, it will not shrink hole diameters or add measurable thickness. Part dimensions are easily maintained, without requiring critical surfaces to be undersized to allow for excessively thick coatings, as is often the case with anodizing. Designed primarily for indoor applications, the finish enhances the overall appearance and appeal of the part, with an inherent lubricity that aids in assembly and break-in of mating surfaces. This combination of properties makes it especially useful for pistons, valves, machine components, tooling, fixturing or other precision machined components.
The process is fast—30 minutes for most alloys—and meshes well with workflow patterns, thereby eliminating the lengthy turnaround times and high costs of outside finishing. In-process inventory levels can be lowered because parts can be blackened on a just-in-time basis.
Occupying only about 20 square feet, the mini BK-LC line fits well almost anywhere in the plant, such as in the tool room, prototype or maintenance area or in a manufacturing cell. It is especially useful in job shops where short run blackening is often needed quickly.