micromilling

Micromilling is a subtractive manufacturing process that uses miniature cutting tools to remove material and create features at micro-scale dimensions. It is a subset of conventional milling focused on producing small, precise features such as micro-holes, slots, pockets, and sculpted surfaces. Features can range from tens of micrometers to a few millimeters in size, depending on tool geometry and machine capability.

Tools and equipment for micromilling are specialized for stiffness and accuracy. Micro end mills, often with diameters from about 0.1 to 1 mm and multiple flutes, are common. Tool materials include carbide and coated carbide, chosen for wear resistance. Machines used for micromilling require high rigidity, precise spindle control, and, in many cases, high spindle speeds to achieve sufficient material removal rates without excessive tool deflection. Through-spindle cooling and proper chip evacuation are important to maintain surface quality and tool life.

Process parameters in micromilling emphasize minimal depths of cut and careful feed per tooth to control surface finish and burr formation. Cutting speeds can be very high, and feed per tooth is typically small, on the order of a few micrometers to tens of micrometers per tooth. Tool wear and breakage are common challenges due to the small tool geometry and high cutting stresses, necessitating careful metrology and sometimes finishing passes.

Materials and applications span metals, polymers, and composite materials. Micromilling is used in microelectromechanical systems (MEMS), medical devices, electronics packaging, microfluidics, aerospace components, and prototyping. The approach enables complex 3D geometries with tight tolerances but requires precise equipment, careful process development, and robust quality control to manage defects such as burrs and surface imperfections.