Removing single-point diamond turning marks using form-preserving active fluid jet polishing

The rapid development of optical instruments has necessitated the efficient manufacturing of a wide variety of optics with high form accuracy and ultra-smooth texture. Single-point diamond turning (SPDT) has the advantage of high efficiency in form generation because it can directly produce optical surfaces with sub-micrometer form accuracy. However, the inevitable residual turning marks affect the performance of the optical surface by causing diffraction and generating stray light. Thus, there is great interest in developing economical and efficient post-treatment methods for diamond-turned surfaces with wide applicability and superior form-preserving capability. In this study, an active fluid jet (AFJ) polishing technology for removing diamond turning marks was developed and investigated. A turning mark removal (TMR) simulation model in the AFJ polishing was developed based on the material removal characteristics and fluid–structure interaction (FSI) analysis. Spot polishing tests were carried out through orthogonal experiments to study the effect of the polishing parameters on the material removal rate of the turning marks and verify the proposed model. Accordingly, the optimal combination of parameters was obtained. To evaluate the form-preserving ability of the method, a spiral polishing test was conducted, whose results showed that the value of material removal that is suitable for eliminating the turning marks without destroying the surface form can be determined by from the changes in the surface profiles and microtopography. Hence, a form-preserving process can be realized by adjusting the dwell time and tool path in the AFJ polishing process. Finally, the practicality of the AFJ polishing method was demonstrated on an aluminum surface. The experimental and theoretical results prove that AFJ polishing technology can enable form-preserving post-treatment of diamond-turned surfaces. • A simulation model is established to describe the removal of turning marks. • The machining parameters are investigated to achieve efficient form-preserved AFJ polishing. • Form-preserving AFJ polishing is applied to remove turning marks of optical components.