What Is Micro Milling?

Micro-cutting is a fast and low-cost way to machine small parts. With the diversified development of micro-electro-mechanical systems and micro-mechanics, the demand for micro-components with different mechanical properties and electronic characteristics has become increasingly urgent. MEMS technology has become one of the fastest-growing industries in the world, and industries that require the manufacture of extremely small, high-precision parts, such as biological, medical equipment, optics, and microelectronics (including mobile communications and computer components) have a large demand . However, not every micro-element used in MEMS or micro-mechanics can be produced using integrated circuit technology, so new materials and new micro-manufacturing technologies and micro-cutting technologies have been researched and developed.

For the division of scales, researchers from different research institutions and different research fields have different opinions.

During micro-cutting, due to the small size of the workpiece, large cutting depths and feeds are not allowed in terms of strength and rigidity. At the same time, in order to ensure the dimensional accuracy of the workpiece, the thickness of the final cut surface must be less than its accuracy. Value, so the cutting volume must be small. For example, the cutting depth is sometimes smaller than the grain diameter of the material, so that cutting can only be performed in the grain. At this time, cutting is equivalent to cutting one discontinuity. The physical essence of cutting is to cut the bond between material molecules and atoms. To achieve the removal of atoms or molecules, the traditional cutting theory based on continuum mechanics is no longer suitable for micro-cutting. Therefore, the study of the micro-cutting mechanism needs to be studied by a method different from the traditional plasticity theory.

Using the strain gradient theory, scale effects and dislocation effects can be predicted, and the results are consistent with the experiments. Microindentations, crack tip fields, interface cracks, filament torsion, and thinness have been successfully analyzed in the field of micromechanics and micro-components. Beam bending and other problems have begun to be applied in the research of microforming. Using strain gradient plasticity theory to study microcutting deformation will be the direction of microcutting mechanism research.

Strain gradient plasticity theory is a generalization and improvement of traditional plasticity theory, and it is a necessary bridge between classical plasticity mechanics theory and atomic simulation. In recent years, various strain gradient plasticity theories have been developed. The typical ones are CS (couple stress) strain gradient plasticity theory, SG (stretch and rotation gradients) strain gradient plasticity theory, and MSG (mechanism-based strain gradient) strain gradient plasticity theory. .

In order to improve machining efficiency, the spindle speed of micro-cutting machine tools is very fast. To meet torque requirements, electric spindles and hybrid angular contact bearings are commonly used. The working table of micro-cutting precision machine tools is generally composed of

Micro-cutting

(1) Basic research on the application of micro-cutting: including the research on key technologies of cutting and processing equipment for micro parts, mainly researching high-speed spindle systems, positioning, motion and control technology of precision worktables, composite micro-cutting processing equipment and technology; micro-cutting tool materials and Research on tool making technology; rapid clamping and testing of micro-cutting tools and workpieces and monitoring technology of micro-cutting process.

(2) Research on micro-cutting mechanism: mainly study the non-uniform deformation field of micro-cutting under the effect of thermal-mechanical coupling stress, study the constitutive equation of workpiece material at the micro-scale, analyze the size effect, non-uniform strain, The effects of dislocations on shear deformation stress and energy; study the effects of minimum cutting thickness on chip morphology, formed surface formation, cutting force, cutting temperature, etc., and the microstructure of the workpiece material on surface roughness and subsurface Influence of damage, establish the theory and technical system of micro-cutting; study the simulation technology of multi-scale micro-cutting, and lay the foundation for the application of micro-cutting technology.

(3) Research on micro-cutting technology: including micro-cutting processing technology for various new materials such as steel, titanium alloy, stainless steel, aluminum alloy, ceramics and other non-metal materials and various composite materials, and micro-cutting CAD CAM technology.

(4) Research on the economy and reliability of micro-cutting technology. ^[1]