Laser Focus World www.laserfocusworld.com
Preservation of the surface quality from parts 4 to 12 suggests
that the tool has not degraded during the μ-LAM process.
To analyze the quality of the machined surface aesthetics, a
digital camera along with a high-intensity fiber-optic light was
used to pick up any “spoking” effect or fracture occurrence. For
part 18 in the group, there is no visible damage seen on the surface and the part is aesthetically perfect (see Fig. 3).
In addition to Si, the μ-LAM process also improves productivity for other crystals and IR materials (see Table 2). μ-LAM
is also an enabling technology, producing high-quality, large-di-ameter Si optics and all sizes of
CaF2 optics compared to zero
acceptable parts using conven-
tional diamond turning alone.
Recently, μ-LAM technology
has made some groundbreak-ing progress in machining optical-quality tungsten carbide
(WC) using a diamond-turn-
ing process. While favored in
the glass molding industry, as
it performs well under high
temperature and high-pres-
sure applications, WC is an extremely hard material (about 3X
harder than Si) and, therefore, has never been successfully dia-mond-turned to an optical quality surface. The status-quo process to manufacture WC optical molds is to grind and polish
them in an arduous 3–4 hour per-part process.
Micro-LAM has developed a process incorporating μ-LAM
technology that can manufacture an optical-quality WC mold
via laser-assisted diamond turning, taking minutes vs. hours.
The quality of these μ-LAM-produced lenses is also well within
the required specifications that eliminate the need for post-pro-
cessing steps such as polishing (see Fig. 4).
For a 17-mm-diameter WC part, machining time is 90 seconds. With a required Sa spec for this < 5 nm part, the μ-LAM
process yielded roughness values of 2 to 2. 5 nm.
With a less-than-eight-month payback, the μ-LAM system is
proving its worth for many IR optical materials and crystals,
with productivity improvements up to 500%, machine efficiency increases up to 200%, and improved part quality. μ-LAM
processes are also being developed for ultrahard materials such
as silicon carbide (SiC), sapphire, spinel, glass, and some selected metals used in the optics and aerospace industries.
Deepak Ravindra is CEO, Sai Kumar Kode is lead process engineer,
and Chris Stroshine is global sales manager, all at Micro-LAM, Portage,
MI; e-mail: firstname.lastname@example.org; www.micro-lam.com.
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The quality of these
lenses is also well
within the required
eliminate the need
steps such as