This paper presents a novel desktop device for lapping thin-walled micro groove of a specimen used in optical equipment,
the device is aimed to remove metamorphic layer (about 1μm thick) formed on the groove’s upper surface as well as
ensure its thickness accuracy. It adopts the way of macro/micro motion combination, the macro-motion table uses stepper
motor and ball screws to realize motion in large stroke, high speed and the micron level positioning, the micro-motion
table uses the electrostriction appliance to actuate the flexible four bars mechanism to realize the small stroke, low speed,
and the submicron level positioning. The system uses the strategy of two ways of feedback, the macro/micro motion
table uses the precise linear grating as close-loop position feedback, and the sensing holder uses the eddy current
transducer as the force and deformation feedback of the elastic fixture. The most novel aspect is the first proposed idea of
realizing automatic feeding by elastic recovery of the fixture, whose structure has been delicately designed. In order to
ensure small lapping force and relatively high natural frequency, both static and modal analysis of the fixture has been
done by ANSYS, the results was in good accordance with experiments. Lapping experiments have showed that this
device can remove metamorphic layer efficiently as well as obtain good surface quality at the same time.
Atmospheric Pressure Plasma Processing (APPP) using inductively coupled plasma has demonstrated that it can achieve comparable removal rate on the optical surface of fused silica under the atmosphere pressure and has the advantage of inducing no sub-surface damage for its non-contact and chemical etching mechanism. APPP technology is a cost effective way, compared with traditional mechanical polishing, magnetorheological finishing and ion beam figuring. Thus, due to these advantages, this technology is being tested to fabricate large aperture optics of fused silica to help shorten the polishing time in optics fabrication chain. Now our group proposes to use inductively coupled plasma processing technology to fabricate ground surface of fused silica directly after the grinding stage. In this paper, form control method and several processing parameters are investigated to evaluate the removal efficiency and the surface quality, including the robustness of removal function, velocity control mode and tool path strategy. However, because of the high heat flux of inductively coupled plasma, the removal depth with time can be non-linear and the ground surface evolvement will be affected. The heat polishing phenomenon is founded. The value of surface roughness is reduced greatly, which is very helpful to reduce the time of follow-up mechanical polishing. Finally, conformal and deterministic polishing experiments are analyzed and discussed. The form error is less 3%, before and after the APPP, when 10μm depth of uniform removal is achieved on a 60×60mm ground fused silica. Also, a basin feature is fabricated to demonstrate the figuring capability and stability. Thus, APPP is a promising technology in processing the large aperture optics.