| SiC and Zerodur is material often used in spacing optics.This material is hard and brittle,difficult to manufacture.With the increasing size of optics,the effectiveness of optics manufacture has become a key problem in optics system.As an important part in optics manufacturing process,lapping in computer controlled optics surfacing(CCOS)use time-invariant tool influence function(TIF)and features with low removal rate and edge effect,this had a bad impact on the subsequent process.The structure of lathe is no longer suit for optics lapping as the size become larger.High effective lapping method for large optics is an extreme important problem in optics manufacturing.1.Lapping with varied pressure is proposed to increase the efficiency.With varied lapping pressure,the transforming distance between the pad and workpiece changes the abrasive number participating in lapping,as well as the pressure on each abrasive.It results in varied proportion of movement pattern of abrasive and corresponding removal pattern.Removal mechanism and nonlinear removal rate with varied lapping pressure distinct from Preston’s equation is deduced through the collective removal behavior of abrasive.Bio-inspired from handwork lapping,surface characteristics of error profile and pressure distribution along the trajectory is obtained.The results point out that pressure-variant lapping contributes to further decrease the process time,and thus to make a computer controlled lapping process more efficient.The platform for large optics robot lapping is established.Varied pressure is realized through voice coil motor.The reduction of the process time was observed to approximately 30% using a combination of the dwell time method with pressure-variant tool influence function compared to stable pressure lapping.2.Arc length edition of Preston’s equation is proposed to obtain tool influence function with arbitrary trajectory.Trajectory with no edge across is deduced to solve the problem of edge effect.3.Compliant lapping would be a develop direction for optics lapping.Work status is derived from force sensing to understand the lapping situation and better arrange the process parameter.Force and position frame from contact force serves as theoretical foundation for compliant lapping,and tracking of unknown surface with high speed demonstrates the effectiveness of this idea. |
