Surface texture in CNC machining refers to the microscopic irregularities on the surface of a part, which significantly impact its functionality, aesthetics, and performance. Various manufacturing methods are employed to create specific surface textures, tailored to the application’s requirements, such as friction reduction, improved adhesion, or enhanced visual appeal.

　　One common method is abrasive machining, which uses grinding wheels, sandpaper, or abrasive belts to create controlled surface textures. Grinding, a precision abrasive process, can produce fine surface finishes with Ra values (arithmetic mean deviation) as low as 0.025 μm, suitable for components like bearing races where smoothness is critical. For rougher textures, sandblasting is used, where high-velocity abrasive particles (such as aluminum oxide or silica) are directed at the surface, creating a uniform matte finish with Ra values ranging from 1 to 10 μm. Sandblasting is often used to prepare surfaces for coating or painting, improving adhesion by increasing surface roughness.

　　Milling and turning with specialized tools are also employed to create structured surface textures. By programming the CNC machine to vary the feed rate, spindle speed, or tool path, specific patterns such as grooves, dimples, or threads can be machined into the surface. For example, ball-end mills can create sinusoidal or grid patterns with precise depths and spacing, which are used in applications like heat exchangers to enhance heat transfer by increasing surface area. Threaded textures, produced using thread mills or taps, are essential for components requiring mechanical fastening, ensuring secure connections.

　　Laser texturing is an advanced method that uses a laser beam to ablate material from the surface, creating highly precise and complex textures. This non-contact process allows for the creation of microstructures with features as small as a few micrometers, such as microchannels, pits, or pillars. Laser texturing is widely used in automotive components to reduce friction (e.g., piston rings with micro-dimples that trap lubricant) and in mold making to replicate intricate textures on plastic parts, such as leather grain or brushed metal finishes. The flexibility of laser texturing enables customization of surface patterns to meet specific functional or aesthetic needs.

　　Electrochemical machining (ECM) and electrical discharge machining (EDM) are also used for surface texturing. ECM uses electrolysis to dissolve material, creating smooth or patterned surfaces without mechanical stress. It is suitable for complex shapes and hard materials, producing textures with high precision. EDM, on the other hand, uses electrical discharges to erode material, allowing for the creation of rough or patterned surfaces on conductive materials. EDM texturing is often used in die and mold making to create textures that improve the release of molded parts or enhance their appearance.

　　The choice of surface texture manufacturing method depends on factors such as the material, required texture parameters (roughness, pattern, depth), precision requirements, and production volume. Each method offers unique capabilities, enabling CNC machinists to produce parts with optimized surface properties for diverse applications.