August 14, 1995
From Entertainment Correspondent Dennis Michael
ANAHEIM, Calif. (CNN) -- Compact disks can carry music, of course, but that's just a start. Now there are computer programs and games on CD-ROM, or CD based players like 3DO, Sony's Playstation, and Sega Saturn. Soon home video also may be making its home on the shiny circle. The fascinating process of CD-ROM manufacturing turns information into silvery disks, ready for the buying. The method is similar to the making of music CD's.
Compact disks by the thousands, every day, in every format, are turned out by Disk Manufacturing Inc. in Anaheim. First, the music, game, or program is prepared for conversion into a stamping negative in product engineering. Then, plastic disks are simply stamped, one every five seconds or so. The pits that hold the information are on clear plastic disks, but are invisible to the human eye, and more important, unreadable by the laser without a reflective surface. So a layer of aluminum vapor only a few molecules thick is added in a "sputtering" chamber. A layer of lacquer is added, then spun to an even thickness and cured. Now it's a compact disk and it's ready to be inspected.
"We're looking for defects down in the micron range, which is very, very small," said Kevin Christiansen, a quality assurance worker. "A maximum defect is about the size of a half-typed period. The microscope allows us to get right down in there and look very closely."
Small defects matter. That's why DMI factory workers wear dust-resistant clothing. Now that the factory is turning out thousands of CD-ROM's, this is even more important. The tolerances are finer than for music CD's. "Actually, in an audio disk, you can drill a 16th of an inch hole through it and you may not even pick up that defect because of the interleafing of the digital data," said Tom Brown, DMI general manager. But if you did the same thing to a CD-ROM, "you'd have a much bigger problem," he said.
The factory's computers check each disk and quality assurance workers constantly inspect the output. Once the disk has a side that the laser can read, it needs a side that the user can read. Art can be supplied by the customer -- DMI prints disks for a wide variety of distributors -- or DMI will help with design. Once silkscreens are created and colors are chosen, the disks are individually silk-screened with ink that also cures in seconds under ultra-violet light. And, again, computers check every individual disk.
DMI's factory is a new facility. Right now it's turning out more than 65,000 disks a day, 24 hours a day, seven days a week. By the end of the year, that capacity will more than double, feeding the nearly endless demand for media on compact disk.
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