Surface finish is the tactile and visual signature of CNC aluminum parts. Achieving the desired finish is a meticulous process, and coolant plays a significant role.
Due to its unique properties, aluminum presents several difficulties during milling processes. Its tendency to adhere to cutting tools, a phenomenon known as built-up edge, can lead to poor surface finish and premature tool wear. Moreover, aluminum's high thermal conductivity results in elevated temperatures at the tool-chip interface, exacerbating tool wear and reducing surface finish quality.
Coolant effectively counteracts these challenges through its threefold action: lubrication, cooling, and chip evacuation.
By forming a thin, protective layer between the cutting tool and the workpiece, coolant reduces friction and minimizes the likelihood of built-up edge formation. This lubricating film facilitates smoother tool movement and diminishes the chances of aluminum adhering to the tool.
Chip evacuation is an equally important function of coolant. Face milling aluminum often results in the formation of long, stringy chips that can hinder the machining process, leading to poor surface finish and increased tool wear.
Coolant aids in breaking down these chips into smaller, more manageable fragments, allowing for smoother chip evacuation. This reduces the likelihood of chip jamming and prevents chips from scratching the machined surface, further enhancing the final finish quality.