Temporary sources and explosive celestial bodies in the universe can only be observed through their high-energy radiation, for example X-rays. The multilayer nested Wolter-I type focusing mirror is widely used in X-ray astronomical telescopes. The electroforming replication process can achieve batch high-precision production of Wolter-I type focusing mirrors, with the process flow of mold ultra-precision turning, ultra-smooth, coating, electroforming, and demolding. The fabrication of molds accounts for a large proportion in the process, and the molds accuracy and surface quality directly determine the optical performance of the mirrors. We built the DRL2000 ultra-precision lathe for mold turning of mission EP (Einstein Probe) and eXTP (enhanced X-ray Timing and Polarimetry mission). The swing straightness error of the guide rail was separated and compensated through trial cutting and reverse measurement methods to achieve a turning generatrix accuracy of peak-to-valley (PV)<0.2μm. An in-situ measurement device has been built based on the ultra-precision lathe. After adjustment the system measurement error can be controlled within 0.1μm. The corresponding spiral measurement path and coaxiality error separation method were studied and verified through experiments. An offline measurement device was built and based on it, an optical lever measurement method was preliminarily validated. Finally, a division method of medium-low frequency error and medium-high frequency error was proposed.
With the vertical fluctuation of small amplitudes, the quasi-planar freeform surface is essentially a plane superposed by microstructure with several micrometers. In practical, it’s widely used to improve the optical performance. However, its form accuracy highly depends on the processing iteration with all kinds of computer controlled optical surfacing (CCOS) technology. This paper presents an automatic characterization method for the quasi-planar freeform surface by atmospheric pressure plasma processing (APPP). Firstly, the principle of APPP and fabrication of the typical quasi-planar freeform surface are introduced. Based on this, an automatic characterization method is developed to eliminate the misalignment between the measured and designed surface, which serves for the form error evaluation and removal generation of next processing step. Finally, the simulation and experiment were conducted to demonstrate the effectiveness of the proposed method, which indicates that it can provide the reliable feedback for the fabrication of quasi-planar freeform surface.
Over the past few years, atmospheric Inductively Coupled Plasma (ICP) has aroused extensive attention in optical fabrication field since its chemical etching-based processing mode does not mechanically damage work-pieces. However, the principle of chemical etching will inevitably bring some processing temperature while maintaining the efficiency. This makes the ICP jet easily cause thermal damage to the ultra-thin or low thermal conductivity optical elements, even cause the element to crack seriously. Therefore, this paper proposes a velocity-region dual adaptive path planning algorithm, which reduces the processing temperature by limiting the moving velocity of a single path, and achieves the removal of excessive peaks through Repeated traversals.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.