On-Line Dressing Technology Of Arcshaped Metal Bonded Grinding Wheel For Grinding Large Aperture SiC Mirror

Nowadays,with the rapid development of space technology, there is a demand for large aperture and high precision space mirrors, such as ballistic missile warning, astronomy and space telescope,deep space detector, satellite device mirrors require higher imaging quality, making the manufacturing technology of large aperture and high precision mirror to be particularly important. Si C as a new generation of mirror material, it has excellent physical and mechanical properties. However, the Si C has high hard brittle characteristics, it is difficult to machining, the machining of Si C mirror by arc-shaped envelope grinding method with an arc-shaped grinding wheel has the advantage, at present,the precision grinding with arc-shaped metal bonded diamond grinding wheel is an important machining method of the large aperture Si C mirror. But due to the demand for large aperture size and the hard and brittle characteristics of Si C, the loss of the arcshaped diamond grinding wheel in the grinding process is large, and at the same time the arc-shaped profile of arc-shaped grinding wheel is easy to wear and damage, this makes a bad impact on the Si C mirror precision, the arc-shaped diamond grinding wheel needs to timely and accurate dressing, so the on-line dressing technology of arc-shaped of grinding wheel is crucial.Therefore, this paper focuses on the on-line dressing technology of arc-shaped metal bonded diamond grinding wheel in grinding large aperture Si C mirror. A new method of arc envelope partial sphere of electron discharge dressing grinding wheel based on biaxial rotation generating motion is proposed, and an on-line dressing device of arc-shaped metal bonded diamond grinding wheel in grinding large aperture Si C mirror is developed, it realizes the on-line electron discharge dressing of arc-shaped metal bonded grinding wheel, and solves the difficult problem of on-line dressing of arc-shaped grinding wheel, to improve the quality and efficiency of large aperture Si C mirror machining, to give a strong support for advanced manufacturing technology in the space optical.First of all, this paper analyzes the advantages of arc-shaped grinding wheel and the principle of the arc envelope grinding method with arc-shaped grinding wheel, it has the advantages of high utilization rate and long service life. By establishing a threedimensional space mathematical model, analyzing and deducing the principle and formula about the new method of arc-shaped envelope sphere of electron discharge dressing grinding wheel based on biaxial rotation generating motion. The structure of grinding wheel arc-shaped profile is analyzed, and the law of the angle between the rotation axis of the dressing electrode and the rotation axis of the grinding wheel is analyzed, then they are determined.Secondly, the arc-shaped radius of grinding wheel is analyzed and determined; By analyzing and calculating, designs the grinding wheel, the cup dressing electrode and online electron discharge dressing device,by assembling them, then the on-line dressing device of the arc-shaped metal bonded diamond grinding wheel for grinding large aperture Si C mirror is developed. The removal law of grinding wheel dressing and the variation law of the arc-shaped grinding wheel radius in grinding is studied, and the arcshaped grinding wheel dressing condition in the process of grinding is predicted and calculated.Finally, experimental studies about the surface topography and the arc-shaped profile precision of electron discharge dressing the arc-shaped grinding wheel are done. The effect of various discharge parameters on the surface topography of electron discharge dressing the grinding wheel is explored. The on-line dressing device of the arcshaped grinding wheel is used to grind the large aperture Si C mirror, and the dressing effect of the arc-shaped grinding wheel was detected and verified. The experimental results show that the electron discharge dressing method based on the arc-shaped envelope sphere can be used to realize the on-line dressing of arc-shaped metal bonded grinding wheel.