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Debate over new CD formats spurs machine & resin development.

No one knows which of the competing standards for higher-capacity computer and video discs will win out. But suppliers of molding, printing, and metalizing equipment - as well as resins - are already gearing up with new technology.

What will the next generation of higher-density compact discs look like? And what materials and equipment will be required to make them? Those questions brought over 5600 attendees to the recent fourth annual Replitech International show in Santa Clara, Calif. That figure represents a 25% increase over last year's crowd. Although a spate of announcements in recent months - including some at the show itself - have clarified the specifications on several proposed new formats for computer and video discs, the competition between these incompatible formats is far from resolved.

While plenty of questions remain, three things seem certain: CD manufacturing is in for some changes, though perhaps not radical ones. Materials and equipment suppliers are not sitting still, but rather are actively developing new products for making next-generation discs. And whichever high-capacity format wins out, CD manufacturers will benefit from expanded market opportunities.

HIGHER-DENSITY FORMATS

The concept of higher data density in CDs has been discussed in the computer industry for some time. But for the time being, attention is fixed on competing proposals for entertainment video-disc formats.

Last December, Sony Corp. of Japan and Philips Consumer Electronics N.V. of the Netherlands jointly announced specifications for a single-sided, 5-in. Multimedia Compact Disc (MMCD) that stores 135 min of film at tv-studio quality. According to a Philips executive, 95% of all movies can be recorded on this single-layer disc. But for movies with extra-long playing times, Philips/Sony offers a dual-layer MMCD. The latter is a single-sided disc based on "2-P" technology developed by 3M Co. of St. Paul, Minn., which doubles disc capacity to approximately 7.4 gigabytes (GB).

The construction of a single-layer MMCD is similar to today's standard CD. The dual-layer version starts with the same molded substrate, onto which is sputtered a special semi-reflective layer developed by 3M (see accompanying diagram). Next a liquid uv-curable resin is applied over the semi-reflective layer. A stamper containing the pit pattern for the second information layer is pressed onto the liquid resin, which is hardened by uv radiation before the stamper is removed. Finally, a conventional aluminum reflective layer is sputtered over the second information layer, and a standard liquid protective coating is uv-cured on top of the aluminum.

In January, one month after the Philips/Sony announcement, the SD Alliance - which is headed by Toshiba of Japan and Time Warner Inc. of N.Y.C. and includes at least six other consumer-electronics and home-entertainment giants - announced plans for another higher-density standard, which is not compatible with MMCD. Called Super Density (SD), it's based on a double-sided 5-in. disc with enough storage capacity for two full-length feature films (270 min of playing time). The double-sided disc is essentially two CDs bonded to each other back to back.

To further complicate the situation, the SD Alliance later announced that it would offer a wide range of higher-capacity CD products tailored to different application needs. Actual specifications were introduced at the show. The most basic version would be a single-sided SD digital video disc (DVD) with 5 GB capacity - 7.5 times as much as conventional CDs. There's also a single-sided DVD with 9 GB capacity. Then there are two-sided SD discs with 10 and 18 GB capacity (5 or 9 GB on each side). That's not all: SD-R is a recordable, two-sided, write-once disc with 4 GB per side. And SD-Rewritable is the first rewritable disc, which has 2.66 GB per side.

What does all this mean to disc manufacturers? Most CD replicators agree that the one-sided, single-layer MMCD (or SD-DVD) would be the easiest option to produce. Explains Bert Gall, general manager of licensing standards for Philips in Eindhoven, the Netherlands, "The single-layer MMCD is based on relatively small changes from existing CD technology." The main difference is smaller pits - and a lot more of them.

The key question concerns dual-layer versus dual-sided manufacturing. Replicators are a bit uncomfortable with 3M's 2-P dual-layer/single-sided process because they haven't seen it used commercially, whereas dual-sided SD production has been demonstrated at the WEA manufacturing plant in Olyphant, Pa. According to Richard Marquardt Jr., v.p. of Warner media manufacturing and distribution at WEA, SD disc manufacturing will be based on the system used to make conventional CDs. A dual-layer SD manufacturing line will have two presses that feed into a single line that metalizes both discs, then puts a back-coating on each and bonds them together.

Most MMCD applications will likely use single-layer discs for several years to come, predicts Philips' Gall. Yet he defends the practicability of dual-layer technology: "Experiments at 3M have shown the feasibility of the dual-layer technology applied to MMCD. Philips, Sony and others - including equipment manufacturers - have started their own experiments and will report progress within the next couple of months."

An important question for replicators is cost. WEA's Marquardt says, "To replicate SD discs, the mold must be modified, which costs about $20,000. A bonding machine must also be purchased for about $50,000 to $70,000. The spin-coating process may be eliminated. The biggest cost is a second molding machine, which costs about $250,000."

To produce Philips/Sony's single-layer MMCDs, the additional investment in CD replication lines is expected to be minimal, says Gall. For dual-layer MMCD discs, an additional station is needed for the semi-reflective layer and the second information layer (which involves spin-coating, stamper pressing, and uv curing). Gall estimates the additional investment to be in the range of $250,000 to $500,000.

Replicators are also concerned about cycle times. WEA's Marquardt says 4-sec cycles have been achieved with the Toshiba/Time Warner SD format. He adds that because the 0.6-mm SD disc has only half the mass of plastic in a conventional 1.2-mm disc, cooling times should be faster and cycle times lower than for conventional discs.

At the show, Marubeni America Corp. demonstrated molding of SD-DVDs on a Meiki injection press. According to sales director Toshio Koike, the molder was running at a cycle rate of 3.9 sec/disc.

Gall says Philips/Sony single- and dual-layer MMCD discs are expected to have cycle times the same as or slightly longer than those for standard CDs. "I doubt that thinner discs will lead to shorter cycle times," Gall cautions.

The debate over higher-density disc specifications is not likely to continue much longer. All parties involved - and that includes Hollywood studios and the computer industry - want to see new discs and disc players on the market by next year. Many industry experts feel that SD has the upper hand in Hollywood and MMCD has support from the computer industry, although the format sponsors deny this view.

NEW MATERIALS REQUIRED?

Higher-density CDs call for smaller pit structure and, in the case of SD, a thinner disc. There has been a lot of speculation regarding use of acrylic or polyolefins in place of polycarbonate for the new discs, but no decision has been made yet. Patricia Keenan, GE Plastics' industry manager for media and data storage, says, "I expect polycarbonate will continue to be the leading product in this industry for the near future. We are evaluating all of the new high-density formats and working with replicators and equipment manufacturers to help develop an overall systems solution - which may include new mate, rial, processing, or stamper technology."

Bayer Corp.'s optical-disc market manager Ramesh Pisipati says of the new higher-density discs, "This format places particularly stringent requirements on the injection molding process for substrates. Pit replication with smaller pits is a challenge, especially toward the outside diameter. Good pit replication with these smaller pits requires higher melt and mold temperatures, which requires increased thermal stability of the resin. These higher temperatures also result in higher temperature of the disc as it is removed from the mold cavity. In order to minimize the resulting distortion, the disc may be remain in the mold longer." He concludes that a resin with a broader processing window may be required.

In fact, Bayer has already developed an improved polycarbonate for this market, called Makrolon MAS 140. According to Pisipati, it has proven successful in traditional CD manufacturing and can handle the various new formats expected to come to market soon.

ANOTHER NEW CD TECHNOLOGY

Although high-density CDs have been taking a lot of the limelight, specifications for another CD format were also introduced by Philips/Sony in the week before the show. So-called "enhanced CDs," also known as "CD-Plus," are geared toward music recording. The Recording Industry Association of America (RIAA), Apple Computer Inc., and Microsoft Corp. worked closely with Sony and Philips to define this specification.

CD-Plus combines normal CD audio tracks with CD-ROM data in one disc. The audio tracks can be played on any existing CD audio player. In addition, video clips, liner notes, and photographs can be viewed on multimedia PCs with CD-ROM drives. Many industry leaders feel future music albums will be released in parallel formats - conventional CD and CD-Plus. Thus, replicators will have another new manufacturing opportunity.

NEW REPLICATING EQUIPMENT

Even though the format question is far from solved, several machinery suppliers introduced new products at the show that reportedly are designed for the new formats and can improve production of conventional CDs as well.

Netstal Machinery introduced the 66-ton Discjet 600 molding system, said to be designed specifically to handle advanced disc technology. Discjet 600 incorporates DSP Graphtrack, a relatively new graphical user interface first introduced on Netstal's HP Series machines. The controller offers closed-loop features with stepless programming of mold-filling and hold-pressure profiles, said to be a prerequisite for pit shaping and the optical features of higher-density formats.

The injection unit has a new low-mass design that increases precision of movement, as well as a hydraulically controlled nozzle. Hydraulic system pressure has been increased from 2030 to 3050 psi, resulting in smaller oil volume and smaller valves.

Discjet 600's new three-tiebar hydraulic clamping system is said to provide precision guidance and high stiffness. The opening and closing movement of the short molding stroke (2.3 in.) is performed by a special clamp plunger. Separate cylinders provide the longer stroke (12.1 in.) required for stamper changing. The system is designed for fast movement with a minimal use of energy. It is capable of straight injection or injection-compression. The machine also has a 50% smaller footprint than its predecessor, the Netstal Disc 60, says market-development engineer Robert Hayes. Prices of the two machines are similar.

Discjet 600 was integrated into at least two complete replication lines at the show. First Light Technology introduced the Uniline 3000, which reportedly can be used to produce all optical-disc formats but was designed with higher-density discs in mind. According to company president Art LeBlanc, "Uniline 3000 allows two independently operated molding systems to deliver substrates to the downstream equipment while maintaining process control. Problems usually arise when discs from two molding systems merge into one downstream production line. We solved that problem through temperature stabilization of the discs prior to downstream processing."

Uniline 3000 includes a new-generation metalizer for high-density disc formats that reportedly offers improved sputtering rate, uniformity, and target life. "Dual vertical cathode capability allows the metalizer to process dual-layer discs requiring both reflective and semi-reflective layers, thereby eliminating the need for two production lines to manufacture one order," LeBlanc adds.

Other features of the Uniline 3000 are the A.I.D. iNSPECt Series q-c tester, clean-room processing, and a single control system for all machine functions.

Another new replication line integrated with Netstal's Discjet 600 is the MCL 3000 Plus from Multi Media Masters & Machinery. Cycle times during the show were below 4 sec. The line reportedly can produce approximately 18,400 good discs per day with an average production run of 1000 discs.

"Increased reliability of the system is achieved through use of significantly fewer moving parts," notes Michael Hill, president of the company's American operations. Greater utilization of the system is said to be achieved through an integrated cooling buffer before the metalizing step, which allows the injection machine to continue to run during routine preventive maintenance of the downstream system. After maintenance is completed and the MCL 3000 Plus is restarted, it can use up the buffer discs because it runs faster than the injection molding machine.

The CD-20900 CD-ROM Replication System also was shown for the first time at Replitech by Krauss-Maffei. The system includes the company's newest 44-ton C-Series disc molding machine with hydraulic damp and special "non-opening" mold of K-M's own design. Business manager Artie Riegger notes that an 88-ton C-Series machine for higher-density products has the same dimensions as the 44-tonner. Krauss-Maffei guarantees a cycle time less than 4.3 sec in continuous production to Philips/Sony Red Book specifications. Riegger adds, "If the two-sided disc offering from the SD Alliance becomes the format of choice, only a slight modification to the mold and take-out transfer chute would be necessary."

A new molding system said to be designed for higher-density discs was shown for the first time by Nissei America. The DVD Molding System was shown producing 0.6-mm PC discs conforming to the Toshiba/Time Warner SD-DVD standard. The system is based on the MO40E3H 40-ton injection-compression molding machine. Digital servo-valve hydraulic control is said to provide position accuracy of 0.01 mm (0.0004 in.) and response-time accuracy of 1 millisec, both of which permit high-speed injection with high reproducibility. The machine is also said to have a small footprint, increased clamp rigidity, ultra-precise temperature control, and extra plasticating speed.

In addition, Nissei says the integrated swing-arm robot provides a disc take-out cycle of less than 0.3 sec. The mold was designed using resin flow analysis and incorporates an in-mold runner/sprue-removal mechanism.

Marubeni America had its new Semi-Line system running at the show. Referring to the speed of the post-molding line, Koike says, "The system runs below a 1.6-sec cycle time versus the 2-sec cycle times offered by other manufacturers." The Semi-Line system incorporates the Meiki molder as well as a Singulus metalizer and A.I.D. q-c tester.

A CD replication system from Nobler Technologies also made its debut at the show. The Optiline occupies less than 10.8 sq ft and is entirely designed and manufactured by Nobler, providing a single contact for all service and support. Use of common parts throughout the system also facilitates maintenance. The system can replicate two rifles simultaneously and is designed to provide a consistent yield of greater than 95%.

UPGRADED PRINTING SYSTEMS

With the disappearance of the "long box" audio CD package a couple of years ago, printing quality on the disc itself has become even more important than it was in the past. In CD-ROMs as well, high-quality printing helps increase perceived value of products that have a much higher retail price than audio CDs. Screen printing is still the technology of choice for most replicators, although offset printing is gaining some ground, despite its higher cost.

Dubuit of America introduced an offset printer while also offering improvements to its three-color screen printer. The new 528 offset printer combines offset and screen printing. It has four offset print heads with intermediate curing to keep colors from mixing. It also has flat cliches instead of round ones to provide quick and easy changeover, says sales manager Michael Taylor. The printer can also be equipped with up to three screen-printing heads to permit operation as an independent three-color screen printer. It prints up to 3600 parts/hr.

Taylor also notes that improvements to Dubuit's three-color screen printer include increased printing speeds up to 4500 pph; capability for code, label, and post-print inspection; an optical screen registration system for quick and easy setup; vacuum management; and a full network of sensors that follow the disc from start to finish.

New from Autoroll Machine Corp. is the SRS 800 static read-side inspection and sorting system. "What makes SRS 800 so different is that it functions on the unload side of the printer and inspects 70 parts/min without spinning the disc, which cuts equipment costs," says president Bill Karlyn.

In addition, Autoroll's Rotoflex 566 screen printer has many new features, including simultaneous printing of two different jobs, automatic table-position calibration, AutoVision barcode/catalog-ID verification, and integration with a label-inspection device and the SRS 800 data-inspection system.

For the first time at Replitech, Apex Machine Corp. showed its HSCD-1 printer, which offers a combination of offset and letterflex printing. "Our machine prints and dries each color, eliminating the offset blanket in the middle," says CEO Bob Coningsby III. "The process is simpler, easier, and therefore less problematic. Our system can print a picture as does an offset printer, but it is half the price."

The HSCD-1 is a modular, linear-format system designed to provide full-color process printing on CDs at speeds up to 100 parts/min. Simple plate-mounting technology reportedly allows a complete copy changeover in 5 min.

Kammann Machines introduced the K-15.0 offset printer, which combines screen printing and offset so that four-color process printing can be achieved with 300-line screen resolution. The machine can run as an offset printer or two-color screen printer. It can print 50-60 parts/min, and changeover times are 15-20 min, according to company sources.

RELATED ARTICLE: New Alliance in Disc Metalizing

Leybold Technologies, Enfield, Conn., plans to spin off its disc metalization business and form a separate company in cooperation with a former competitor, Denton Vacuum, Inc., Cherry Hill, N.J. Subject to FTC approval, the new company will focus on developing products for the next-generation CDs, according to company sources. It will be called Singulus Technologies and will have its corporate headquarters, manufacturing, R&D, and engineering together at a new site in Alzenau, Germany. American sales and marketing headquarters will remain in Enfield, Conn.
COPYRIGHT 1995 Gardner Publications, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1995, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

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Title Annotation:compact disc
Author:Block, Debbie Galante
Publication:Plastics Technology
Date:Aug 1, 1995
Words:3002
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