During the last decades in the theory of machining nonmetallic materials some serious advances have been achieved in the field of applying fundamental scientific approaches to the grinding and polishing technologies for
high-quality precision surfaces of electronic components, optical systems, and decorative articles made of natural and synthetic stone [1–9]. These achievements include a cluster model of material removal in polishing dielectric workpieces [1–3, 6–7] and a physical-statistical model of formation of debris (wear) particles and removal thereof
from a workpiece surface [8–10]. The aforesaid models made it possible to calculate, without recourse to
Preston’s linear law, the removal rate in polishing nonmetallic materials and the wear intensity for bound-abrasive
tools. Equally important for the investigation of the workpiece surface generation mechanism and formation of
debris particles are the kinetic functions of surface roughness and reflectance of glass and quartz workpiece
surfaces, which have been established directly in the course of polishing. During the in situ inspection of a
workpiece surface by laser ellipsometry [11] and reflectometry [12] it was found out that the periodic change of
the light reflection coefficient of a workpiece surface being polished is attributed to the formation of fragments of
a deposit consisting of work material particles (debris particles) and tool wear particles [13, 14]. The subsequent studies of the mechanism of interaction between the debris particles and wear particles in the tool–workpiece
contact zone, which were carried out based on classical concepts [15, 16], yielded some unexpected results. It was demonstrated that electrically charged debris and wear particles, which are located in the coolant-filled gap
between a tool and a workpiece, move by closed circular trajectories enclosed in spheres measuring less than one fifth of the gap thickness. This implies that the probability of the debris and wear particles reaching the tool and
workpiece surfaces and, especially, getting localized on the surfaces is extremely low, which contradicts the results of experimental examination of these surfaces. Based on the quantum-mechanical description of the process of scattering of the debris and wear particles that are as small as 3–4 nm in the tool–workpiece contact
zone, the mechanism of formation of a workpiece microrelief and the mechanism of formation of a debris-particle deposit on the tool surface were clarified [17–21]. However, the mechanism of formation of the deposit fragments and their discrete arrangement on the workpiece surface in the process of polishing with a bound-abrasive tool has
not been studied yet.
Problems of efficiency and quality improvement of diamond-abrasive finishing of optical materials by tools with bounded polishing powders, including diamond powder, are considered. The dependences of the particle number on the diffusion angle and coordinate of the contact have been derived in the studies of the dynamics of collision and diffusion of slime particles. The coordinate dependence of the flat surface roughness of glass K8 optics in fine diamond grinding has been described. Interaction and dispersion of deterioration particles in a contact zone of the tool and the processed sample in the course of polishing is described and the dispersion structure of deterioration particles of the tool on slime particles and on deterioration particles is explained oscillatory. It is shown a that differential dispersion section of deterioration particles on slime particles is not less than on deterioration particles and is maximum at corners of dispersion close to 0° and 180° on the central sites of a contact zone. Coordinate dependence of the full dispersion section of deterioration particles of the tool and dependence of microprofile height of the processed surface on circular zones radius are calculated.
Problems of improving efficiency and quality of diamond-abrasive finishing of optical materials by tools with bounded
polishing powders, including diamond powder, by means of the improvement of the machining technology and application
of new tools with functionally oriented designs and characteristics of working layer are considered. A model has
been proposed of the slime particle formation and directional removal as well as of the generation of a high-quality surface
in diamond-abrasive finishing of optical materials taking into account the peculiarities of the mass transfer in the
contact zone and statistic character of the distribution of slime particles by size. The dependences of the particle number
on the diffusion angle and coordinate of the contact have been derived in the studies of the dynamics of collision and
diffusion of slime particles. The coordinate dependence of the flat surface roughness of glass K8 optics in fine diamond
grinding has been described. Interaction and dispersion of deterioration particles in a contact zone of the tool and a processed
sample in the course of polishing is described and the dispersion structure of deterioration particles of the tool on
slime particles and on deterioration particles is explained oscillatory. It is shown, that differential dispersion section of
deterioration particles on slime particles no less than on deterioration particles as much as possible at corners of dispersion
close to 0 and 180° on the central sites of a contact zone. Coordinate dependence of full dispersion section of deterioration
particles of the tool and dependence of microprofile height of the processed surface on circular zones radius are
calculated. Conformity of experimental and theoretical microroughness profiles of a polished surface on a quartz sample
is shown.
It is demonstrated that the removal rate in polishing optic materials decreases exponentially with increasing bond energy in
these materials and the polished surface roughness depends on the ratio of natural frequencies of molecular fragments on the
tool and workpiece surfaces. The dependences of polished surface roughness on the slime particle size, permit an optimal
choice of powders for a bound-abrasive polishing tools, which will ensure a required polished surface quality. The dependences
of the polished surface microprofile parameters on the coordinate of a zone under study, which were described
by periodic functions, do represent the effects that occur in the tool-workpiece contact zone. The optical monitoring
system, the device for giving of the technological environment in a zone of contact of the tool and a processed detail and a
technique of adjustment of the machine tool for finishing processing of precision optic surfaces are described. The relation of intensity
of the beam reflected from a surface, to intensity of a falling beam allows to estimate a reflexion index in situ. Increase of
reflexion index in process of roughness decrease is established. Possibility of active quality assurance of precision surfaces
in the course of processing is shown.
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