Straightening Out The Lines

TAPEDISC Business Magazine, October 1998, Knowledge Industries Publications, White Plains, NY

Assembly lines are delicately balanced systems. They're not just machines; they're complex assemblies of devices, people, rules and procedures. Change any one element, and the entire balance of profit and loss can be altered, especially in a business with margins as tight as CD and DVD manufacturing

Rarely is the equation's delicacy more evident than when new technologies come into play. All of a sudden, old and settled practices are suddenly up for evaluation. Is it better to have more human intervention or less? Should production lines flow in a smooth, relentless stream or is it better to let discs sit for a while, and, in a way, rest, as time eases the stresses and strains caused by the manufacturing process.

Manufacturing CDs and DVDs is a relatively complex and incredibly precise process. Traditionally, CD - and especially DVD - production lines have not moved in smooth streams. Discs have traveled the road to replication in uneven spurts, sometimes waiting for minutes and even hours between the various steps.

Molten plastic is injected against a stamper; given time to cool; coated with a highly reflective layer of metal; sprayed with a protective layer of lacquer; and then printed with a label. For DVD, things get considerably more complex because DVDs have far more exacting tolerances than CDs and can have multiple layers as well.

With all the molding, spraying, cooling and drying going on, it's obvious that discs can't zip down the production line in an endless stream. The crucial questions facing the optical media industry are how long the wait between steps should be, and whether humans should be part of the process of moving things along. People and in-production CDs don't get along too well. No matter how hard humans try, they are inevitably accompanied by dust and dirt, which are enemies of efficient CD replication. Production lines that keep things moving without intervention are known as in-line systems. The replication industry uses the word "batch" to describe systems that require waits between steps, and significant human intervention.   top

Historically, optical media have gone into production via batch technology and gradually shifted to in-line systems. "Everyone I'm aware of has been willing to start running with off-line and to switch later to the in-line process," says John O'Sullivan, an engineer at GE Plastics Optical Media Development Center (OMDC). OMDC was opened to test new optical media equipment, as well as different processes, such as batch versus in-line (TDB, May 1998). One result: at any point in time there are large populations of batch and in-line systems in operation.

As is inevitable for a topic that reaches to the industry's core, in-line vs. batch can prove a contentious subject. Industry members sharply dispute how many batch systems are in operation and whether switching to in-line is worth the cost in many situations. Karl Schneck, president of the Optical Disc Manufacturers Association (ODMA), throws his vote behind in-line systems. "I really can't imagine why you would do batch in CD-ROM."

There are manufacturers, however, that do. When Technicolor Media first opened its production lines, "we took a more conservative position," says Randy Higgison, vice president, optical media manufacturing and engineering. "We purchased a semi-inline process," he says. "Our molding machines are separate, but our lacquer and metalizing are in one in-line position," he says.

Existing Equipment = Less Expensive

Industry experts say there are a number of factors involved in the in-line versus batch equation, among the most important include: installed base and accepted practices. Many different factors can have an impact on the production line equation. Existing business methods may not be as efficient as new developments, but the known and comfortable is often cheaper to adapt to than the fresh and new. And, using existing equipment, even if it is inefficient, is cheaper than starting up an entirely new production line.  top

That's certainly the case with a lot of longtime CD manufacturers, Higgison says. "In facilities that have been around since the mid-to-late '80s, I'm sure a lot of people are still using some of that older equipment," he says. "Newer facilities that started up in the last four or five years tend to lean towards the in-line system," he says. "The older equipment is still operating in the batch mode."

A Second Opinion

Manufacturers of in-line systems contest by saying that not only are there no extra costs involved in moving to their technology, in-line production facilities can actually be cheaper than off-line ones. "There are actually no extra costs. It's lower cost; because on a typical batch system; you've developed a lot of work into the process," says John Stroud, sales manager-Latin America at Saco, ME-based First Light Technology, Inc.

.

Replicators agree that, at least when it comes to production costs, In-line systems do offer fairly significant cost savings compared to off-line ones. "In-line processes help you a lot with the costs of operation. You can save as far as labor costs and it saves the turn time," explains Higgison.

One significant area of savings is in clean room facilities. "With off-line, you need a certain level of clean room facilities and people who are in a specific type of suit moving the discs," Stroud says. Clean rooms are expensive to build and even more costly to maintain. With in-line systems, all that work takes place in a sealed box that humans never enter while discs are being produced. "If the clean room is integrated into the machine, you can have one operator running that machine and he never handles any discs," he says.

Still, many batch systems have an advantage in-line simply can't match — they're paid for. Innovation carries a price many companies are unwilling to pay. "The older facilities have equipment that has already been paid for," one manufacturer says. In those cases, "you don't have the depreciation and such -not with the batch system.  top

Inspection And Yield Rates

Bad news travels faster with in-line than with off-line systems, and that's good news for replicators. "In general the main advantage of an in-line process is the immediate feedback of what's going on," Schneck says. It's difficult to examine off-line discs until an entire batch has gone through the production process; the CDs or DVDs simply aren't complete enough to be tested.

In in-line systems, testing can actually be built into the production process, explains Schneck. "There are a lot of things that obviously can go wrong with your production process, but with an inline process, you can get to a stage where you can do your testing a lot quicker than by batching," he says. "If I manufacture by batching, I may not find out if I had a problem until I did all 120,000 discs; but if I had an in-line process I would know before I did 50-to-100 discs," he says. "Just for yield purposes your in-line process would be more beneficial."

DVD Technology

When it comes to making certain kinds of DVD discs, manufacturers are finding they prefer to follow a batch process. That's especially true with DVD-9. Making DVD-9 means bonding two halves together. Manufacturers say that if discs aren't allowed time to cure, warping, or "radial tilt," can result.

"Our data shows that aging is really critical for DVD-9 replication in order to avoid changes in radial tilt," Higgison says. "We cannot do DVD by bonding it right after metalization and molding." Discs need to sit for anywhere from 12-to-24 hours. Though he's heard of successful in-line DVD-9 process, Higgison isn't sure of their yield rates.

First Light executives say they've basically solved the tilt problem. "Through thermal management of the discs while they are bonding, we've been able to eliminate tilt as a factor. We really have not had an issue with tilt in the systems we have in the field," says Wesley Phillips, First Light's director of sales.  top

It will be some time before the DVD industry makes the transition to in-line technology, however, believes Phillips. "In looking at it worldwide; a lot of people bought batch systems just so they could say they did DVD," he admits. "At this point, I would say that batch systems are probably 75 percent of what's out there; but I think that's going to change rather quickly," predicts Phillips.

Others agree, and think the shift will happen across the board. "Obviously the ultimate goal, and people are beginning to do this now, is to move from any kind of off-line process to an in-line process," O'Sullivan says. "The more you integrate actives together, the faster things are going to move. You get increasingly quick throughput by having everything integrated on-line."

There are still others that prefer somewhat of a combination between the two. "My preference for CD, if we were to get the equipment today, would be to go full in-line," Higgison says. "The molding, metalization, lacquering and inspection would be on one line; the printer would be off-line with both label and inspection included. Most of the vendors I've dealt with have gone towards the in-line process minus the printing. To me, that would be the ideal configuration." A factory in a box is infinitely preferable to one spread out over a vast shop floor, and it looks as if the optical media industry is headed in such a direction.   top

Tony Seideman (Tseideman@aol.com) is a freelance writer for the consumer electronics industry.