The machining accuracy core of ultra precision lathes is achieved through "hardware accuracy foundation+environmental control noise reduction+process and detection closed-loop", ultimately achieving nanometer level (usually ≤ 100nm) dimensional accuracy and submicron level positional accuracy.
1. Core hardware: Basic guarantee of accuracy
High rigidity machine tool structure: Natural granite, artificial granite, or aerospace grade alloy materials are used, which have good thermal stability, high damping, and can reduce vibration and thermal deformation.
Ultra precision spindle system: equipped with air static pressure, liquid static pressure or magnetic levitation spindle, the spindle rotation error is controlled at the nanometer level to avoid machining deviation caused by spindle eccentricity.
High precision feed system: using ball screws (pre tightened to eliminate gaps) or linear motors, combined with grating ruler closed-loop feedback (resolution up to nanometer level), to ensure the positioning accuracy and smoothness of the feed motion.
High quality cutting tools and clamping: using superhard cutting tools such as diamond (PCD/PCBN), with cutting edge sharpness reaching nanometer level; Clamping tools such as vacuum suction cups and precision chucks have high coaxiality and low deformation characteristics to avoid workpiece clamping offset.
2. Environmental control: eliminate external interference factors
Constant temperature control: The processing environment temperature is stable at 20 ± 0.1~0.5 ℃ to avoid dimensional deviation caused by thermal expansion and contraction of machine tools, workpieces, and cutting tools due to temperature changes.
Vibration isolation design: The machine tool is installed on a vibration isolation foundation or air spring to isolate the impact of ground vibrations (such as factory equipment operation and personnel movement) on the cutting process.
Clean environment: located in a clean workshop (usually Class 100~1000), reducing dust and impurities from adhering to the surface of workpieces or cutting tools, avoiding scratches or machining errors.
3. Process and Testing: Dynamic Optimization and Precision Closed Loop
Precision cutting parameter optimization: using small cutting parameters (low cutting speed, small feed rate, shallow cutting depth), reducing cutting force and cutting heat, and lowering workpiece deformation and tool wear.
Real time monitoring and compensation: By using equipment such as laser interferometers and ball bar instruments, the geometric errors (such as straightness and perpendicularity) and motion errors of the machine tool are detected in real time, and dynamic compensation is carried out through a numerical control system.
Online/offline detection verification: During the processing, contact probes (such as Renishaw probes) are used to measure the dimensions of the workpiece online, or precision instruments such as atomic force microscopes and laser interferometers are used for offline detection after processing to ensure that the accuracy meets the standard.