I. Characteristics and Advantages of Diamond Micropowder

1. High HardnessDiamond is the hardest substance in nature, with a Mohs hardness of 10. This allows diamond micropowder to effectively cut the surface of optical glass, even high-hardness optical glass can be precisely ground.

2. Uniform Particle SizeThe particle size of diamond micropowder can be precisely controlled within a very small range, for example, from submicron to tens of microns. This uniform particle size distribution ensures that the optical glass surface can be uniformly removed during grinding and polishing, resulting in high flatness.

3. Good Abrasion ResistanceDiamond micropowder has excellent abrasion resistance and maintains its cutting ability during long-term grinding and polishing, reducing the decrease in processing precision caused by abrasive wear, thus ensuring the stability and consistency of the processing process.

II. Role in Optical Glass Grinding

1. Coarse Grinding StageIn the initial stage of optical glass processing, diamond micropowder with a relatively large particle size, usually around tens of microns, is used. These larger diamond micropowder particles can quickly remove most of the excess material from the surface of the optical glass, preliminarily processing the shape of the glass blank into a profile close to the final product, laying the foundation for subsequent fine processing. For example, for an optical glass lens blank with an initial thickness of 10 mm, coarse grinding can quickly reduce its thickness to close to the final design thickness, such as about 1.5 mm, while preliminarily forming the curved surface shape of the lens.

2. Fine Grinding StageAs the grinding process progresses, diamond micropowder with a smaller particle size, generally between a few microns and a dozen microns, is gradually replaced. In the fine grinding stage, diamond micropowder is mainly used to further improve the flatness and smoothness of the glass surface and reduce the surface roughness. Through fine grinding, the surface roughness of the glass can be reduced from a few microns after coarse grinding to the submicron level, preparing for the subsequent polishing process. For example, after fine grinding, the microscopic undulation of the optical glass surface can be controlled within 0.1 microns, greatly improving the optical uniformity of the glass.

III. Role in Optical Glass Polishing

1. Ultra-fine GrindingIn the polishing stage, diamond micropowder with extremely fine particle size, usually in the submicron range or even finer, is used. These ultra-fine diamond micropowders can perform ultra-fine grinding on the surface of the optical glass, filling and repairing small scratches and defects left during fine grinding, making the glass surface reach extremely high flatness and smoothness. For example, after polishing, the roughness of the optical glass surface can be reduced to the nanometer level, almost reaching atomic-level smoothness.

2. Improve Light Transmittance and Imaging QualityThrough the fine polishing of diamond micropowder, the microscopic defects on the surface of the optical glass are greatly reduced, and the propagation of light in the glass is smoother, thereby improving the light transmittance of the optical glass. For some high-precision optical imaging systems, such as telescopes and microscopes, this high-transmittance and low-scattering optical glass can significantly improve the clarity and resolution of the image, making the observed image clearer, more delicate, and with higher color reproduction.

IV. Processing Technology Control

1. Selection and Preparation of Grinding FluidDiamond micropowder is usually used in combination with grinding fluid. The function of the grinding fluid is to suspend the diamond micropowder, allowing it to be evenly distributed between the grinding tool and the surface of the optical glass, while also playing a cooling and lubricating role, reducing heat and friction during the grinding process. The composition and viscosity of the grinding fluid need to be precisely adjusted according to the material of the optical glass, the particle size of the diamond micropowder, and the requirements of the processing technology. For example, for optical glass with higher hardness, it may be necessary to use grinding fluid with higher viscosity to better suspend the diamond micropowder and provide stronger cooling and lubrication effects.

2. Control of Grinding Pressure and SpeedWhen using diamond micropowder for grinding and polishing, it is necessary to precisely control the grinding pressure and speed. Excessive grinding pressure may cause cracks or excessive wear on the surface of the optical glass, while insufficient pressure will affect processing efficiency. The grinding speed also needs to be adjusted according to the material of the glass, the characteristics of the diamond micropowder, and the processing stage. In the coarse grinding stage, a higher grinding speed and greater pressure can be used to quickly remove material, but in the fine grinding and polishing stages, the speed and pressure need to be reduced to achieve high-precision surface processing. For example, during coarse grinding, the grinding speed may be set to several hundred revolutions per minute, and the pressure is several kilonewtons; while during polishing, the grinding speed may be reduced to tens of revolutions per minute, and the pressure is also reduced to several hundred newtons.

3. Cleanliness of the Processing EnvironmentBecause the particle size of diamond micropowder is very small, dust and impurities in the processing environment are easily mixed into the grinding fluid, affecting the processing quality. Therefore, optical glass processing usually needs to be carried out in a clean environment, such as in a dust-free workshop, using an air filtration system and regular cleaning to maintain the cleanliness of the environment, ensuring that the diamond micropowder can perform its best in a clean environment and avoiding scratches or defects on the surface of the optical glass due to impurity particles.