Ultra-precision Machining Technology: A Comprehensive Analysis of Principles, Advantages and Application Fields

 

Ultra-precision machining is a key process for finishing and refining the surface of workpieces. It can reduce the surface roughness from Ra = 0.2 - 0.4μm to Ra = 0.006 - 0.05μm in a very short time, significantly eliminate grinding defects and improve the service life of workpieces. Its core advantage lies in improving the surface microstructure through micro-grinding, and it is widely used in fields such as precision machinery, automobile manufacturing, and electronic instruments.

 

I. Core Features of Ultra-precision Machining

1. Improved Surface Quality: By removing micro-burrs and the metamorphic layer, the surface roughness of the workpiece can be reduced to the sub-micron level, and the service life can be increased by more than 5 times.

2. Noise and Vibration Reduction: After assembly, the processed parts run more smoothly, with significantly reduced noise and vibration, especially suitable for high-precision transmission components.

3. High-precision Control: The removed allowance is less than 0.001mm, with low dimensional dispersion, and the processing stability is better than that of traditional grinding processes.

4. Optimized Lubrication Performance: A cross-hatch pattern structure is formed on the surface, which is conducive to the formation of an oil film and reduces friction and wear.

5. Efficiency and Economy: The processing time for a single part only takes a few seconds to more than a dozen seconds. The efficiency is dozens of times that of mirror grinding, and the equipment is simple and easy to automate.

 

II. Processing Methods and Process Parameters

1. Processing Forms: It covers geometric surfaces such as outer circles, bearing raceways, spherical surfaces, and planes. According to the workpiece positioning method, it can be divided into two types: non-centering and centering, and the feeding methods include axial, plunge, and circular feeding.

2. Oilstone Selection: Special oilstones with uniform grain size and good self-sharpening properties need to be selected. The abrasive (such as alumina and silicon carbide), grain size, hardness, and binder need to be customized according to the material characteristics.

3. Key Parameters:

   - Machining allowance: Usually controlled at the micron level and needs to be matched with the material hardness.

   - Oilstone pressure: It directly affects the cutting efficiency and surface quality and needs to be adjusted dynamically.

   - Vibration frequency and amplitude: High-frequency vibration (up to thousands of times per minute) combined with a small amplitude (0.1 - 3mm) achieves uniform cutting.

   - Workpiece rotation speed and feed rate: They need to be optimized in coordination to avoid over-cutting or insufficient processing.

 

III. Cutting Fluid and Supporting Technologies

The cutting fluid plays the roles of lubrication, cooling, and chip removal in ultra-precision machining. It is recommended to use a low-viscosity mixed fluid (such as 80% kerosene + 20% machine oil), which needs to be strictly filtered to remove impurities. In recent years, the introduction of green cutting fluid technology and intelligent filtration systems has further improved the environmental friendliness and stability of the process.

 

IV. Application Fields and Future Trends

1. Typical Scenarios:

   - Automotive industry: Surface strengthening of key components such as crankshafts and camshafts.

   - Precision bearings: High-precision finishing of raceways and rollers.

   - Electronic instruments: Ultra-smooth machining of optical components and micro-structural parts.

2. Technological Development: Combining with new technologies such as ultrasonic assistance and laser fine-tuning, ultra-precision machining is moving towards nanometer-level precision. At the same time, the application of intelligent equipment and real-time monitoring systems makes the processing process more controllable and efficient.

 

With its high efficiency and high precision, ultra-precision machining has become an indispensable part of modern precision manufacturing. With the progress of materials science and intelligent technology, this process will play a more crucial role in emerging fields such as semiconductors and medical devices.