This will count as one of your downloads.
You will have access to both the presentation and article (if available).
Recent advancements in MRF technology have improved the polishing performance expected for astronomical optics in low, mid and high spatial frequency regimes. Deterministic figure correction with MRF is compatible with most materials, including some recent examples on Silicon Carbide and RSA905 Aluminum. MRF also has the ability to produce ‘perfectly-bad’ compensating surfaces, which may be used to compensate for measured or modeled optical deformation from sources such as gravity or mounting. In addition, recent advances in MRF technology allow for corrections of mid-spatial wavelengths as small as ~1mm simultaneously with form error correction. Efficient midspatial frequency corrections make use of optimized process conditions including raster polishing in combination with a small tool size. Furthermore, a novel MRF fluid, called C30, has been developed to finish surfaces to ultra-low roughness (ULR) and has been used as the low removal rate fluid required for fine figure correction of mid-spatial frequency errors. This novel MRF fluid is able to achieve <4Å RMS on Nickel-plated Aluminum and even <1.5Å RMS roughness on Silicon, Fused Silica and other materials. C30 fluid is best utilized within a fine figure correction process to target mid-spatial frequency errors as well as smooth surface roughness 'for free' all in one step.
In this paper we will discuss recent advancements in MRF technology and the ability to meet requirements for precision optics in low, mid and high spatial frequency regimes and how improved MRF performance addresses the need for achieving tight specifications required for astronomical optics.
Classically, Magnetorheological Finishing (MRF) is implemented in production to correct low order errors generated by conventional polishing techniques on planos, spheres, on- and off-axis aspheres and freeform optics achieving figure errors as low as 1nm RMS while using careful metrology setups. MRF is also used routinely to turn a sphere into an asphere or freeform, or to print high resolution wavefront corrective patterns on optical surfaces to compensate for system errors or bulk material inhomogeneity.
Recent advancements enable correction of mid-spatial wavelengths as small as ∼1mm and smoothing of surface roughness to ∼1Å RMS. Using these new developments combined with correction of low order form error have improved MRF performance to manufacture higher precision optics with respect to the mid- and high-spatial frequency regimes.
Efficient mid-spatial frequency corrections utilize optimized process conditions; raster polishing with a small tool size. Furthermore, a novel MRF fluid, called C30, can finish surfaces to ultra-low roughness (ULR) and its low removal rate is optimal for fine figure correction of mid-spatial frequency errors. C30 MRF fluid is able to achieve <1.5Å RMS roughness on Silicon, CaF2, Fused Silica, glass and other materials. It is best utilized within a fine figure correction process to target mid-spatial frequency errors as well as smooth surface roughness ‘for free’ all in one step.
These expanded capabilities of MRF technology are well suited for producing high precision optics to be used for industrial, medical or semiconductor optics.
Fine figure correction and other applications using novel MRF fluid designed for ultra-low roughness
View contact details
No SPIE Account? Create one
