abrasives that have been bound in a solid matrix can offer several
potential advantages over loose abrasive processes with pitch or
polyurethane laps for finishing of optics. These advantages include
polishing efficiency, temperature stability, cost of consumables,
and compatibility with CNC generating machines. Unfortunately, little
has been published on bound- abrasive polishers, and very few commercially
available products exist.
polishing laps are used to study material removal for transparent
ceramics as a function of load, coolant, and lap composition.
are four performance criteria for the successful development of
a bound abrasive polisher:
The polisher must maintain its physical integrity during use at
moderate to high velocities (thousands of rpm), in an aqueous
environment, and under light to moderate load;
The polisher must release particles of polishing abrasive at a
rate that promotes efficient removal of glass from the work piece
surface, but not so rapidly as to cause excessive tool wear, or
so slowly that the tool surface "glazes" over with a
solid film of binder;
The polisher must be manufactured in such a way that it exhibits
reproducible performance under constant operating conditions;
The initial surface figure quality of the fine ground part must
not be so severely degraded that it cannot be easily improved
in fine finishing with processes like MRF.
conduct research on compositions and manufacturing techniques for
developing bound abrasive polishing tools. Our long term objective
is to produce tools for use on COM CNC machines to remove grinding
tool marks (e.g., cutter marks) on optical glass surfaces in a pre-polishing
stage prior to fine finishing with MRF. Another objective is to
eliminate sub-surface damage and pitting from deterministically
micro-ground polycrystalline optical ceramics like ALON and spinel.
Our strategy is to conduct screening experiments manually with pin
laps and/or pellet laps on candidate systems (polisher abrasive
and epoxy host, part type/shape-flat, coolant type, and load), followed
by the manufacture and testing of contour or peripheral ring tools
using CNC machine platforms.
alumina pin lap (far left), and a square-faceted epoxy lap
(left) filled with nanodiamonds and alumina. Grain decoration
on the surface of an ALON part (below).
L. Gregg, A. E. Marino, J. C. Hayes, and S. D. Jacobs ,“Study
of Grain Decoration in ALON Using Bound Abrasive Polishers,” in
Optical Manufacturing and Testing V , edited by H. P. Stahl
(SPIE, Bellingham, WA, 2003), Vol. 5180, pp. 47-63.
E. Gillman and S. D. Jacobs, "Bound-Abrasive Polishers for
Optical Glass," Appl. Opt. 37, 3498-3505 (1998).
E. Puchebner and S. D. Jacobs, "Development of New Bound Abrasive
Polishers for Final Finishing of Optical Glasses," in Optical
Manufacturing and Testing, V. J. Doherty and H. P. Stahl, eds.,
Proc. SPIE 2536, 256-264 (1995).
Ng et al., "Evaluation of Bound Abrasive Media for Fabrication
of Ring Tool Polishers," in Optical Fabrication and Testing,
Vol. 13, 1994 OSA Technical Digest Series (Optical Society of America,
Washington, DC, 1994), pp. 114-116.