DVD continues to be a hot topic at Replitech, the replication industry’s main trade show. In September 1996, IMM reported on the excitement brewing over the format’s pending introduction. Now, three years later, DVD has clearly arrived.

In fact, since DVD’s national roll-out in August 1997, more than 1.5 million players have been shipped, reports Film & Video magazine’s Ed Eberle (see “DVD@NAB: Has the Future Arrived?” March 1999). DVD’s real coming of age, says Eberle, came in the last quarter of 1998, with more than 250,000 players sold nationally in December alone. “Total sales of DVD hardware in 1998 represented almost $5 billion in retail sales,” Eberle writes. “There are currently more than 40 DVD-Video player models marketed under 30 different brand names.” Also, major and independent studios sold more than 1.3 million DVD disks between January and mid-February 1999, he adds. By the end of 1999, predictions suggest that the installed base of DVD consumer players will reach between five and seven million. And each of these consumers is expected to buy at least 25 DVD titles within the year, indicates Eberle.

With the evident acceptance of DVD technology among consumers, both raw materials suppliers and equipment manufacturers are rising to meet new challenges in production and design. Scott Parent, director of Product Development and Engineering at Steag First Light in Saco, ME, noted in his address to attendees at Replitech ‘99 that “DVD will have an accelerated ramping schedule where worldwide manufacturing may reach four billion units a year in less than half the time observed in the CD market,” which ramped up over a 20-year time frame.

Though relatively small, the recording media market is a demanding one—evidenced by the variety of developments in manufacturing process, materials, and end-use packaging being exhibited at the show.

Mold and Equipment Enhancements
Steag First Light introduced its second generation Uniline DVD replication system. The new system is 51 percent smaller than the original Uniline DVD system and incorporates many new hardware and software features, providing versatility in producing DVD-9, -5 and -10, plus CD-Audio/ROM with fast cycle times and high yields.

The optical disk industry has long struggled with the problem of increasing productivity. Traditionally, CD and DVD manufacturing has used a one-at-a-time production method. But with the introduction of Axxicon’s two-cavity disk mold at Replitech ‘96 (see September 1996, IMM, p. 116) new possibilities emerged. Axxicon has installed a number of dual-cavity molds for the production of DVD-5 and -10, and CD-Audio/ROM disks (Figure 1). The dual-cavity mold shown this year, developed with Arburg, allows the simultaneous production of substrates for the A and B sides under identical molding conditions. Optical disk manufacturers believe that this will result in better quality and consistency as well as double the production of a single machine.

At the show, Arburg showcased its Twindisc 270S (Figure 2) using the Axxicon dual-cavity mold to produce DVD-5 and -10. With a total cycle time of about 4.5 seconds, the production time for one disk is under 2.25 seconds.

A new SD35E all-electric disk molding subsystem from Sumitomo Plastics Machinery includes the machine, mold, and takeout robot designed for molding DVD, CD, CD-ROM, CD-R, and MO disks. The SD35E provides shot weight accuracy and repeatability resulting in a typical deviation-to-mean ratio of less than .02 percent, which means greater productivity and lower scrap rates.

Additionally, the all-electric SD35E means more cost-efficient operation with the machine’s five energy-efficient servomotors, which draw power only as needed for significant, quantifiable energy savings. Specialized disk molding features include a temperature-controlled platen, a disk-oriented screw assembly, a gate mechanism in the moving platen, and a two-zone temperature-controlled nozzle.

Sumitomo also offers a custom-designed CD/DVD mold with four independent cooling circuits for faster cycle times; specialized coatings to ensure long life of the mold and mirror block; ease of maintenance; and interchangeability of key parts and easy adaptation to either CD or DVD molding.

Another all-electric injection molding machine—the Elektra Disco—was introduced by Ferromatik Milacron. Designed for CD-ROM production, the machine reportedly has a cycle time of less than four seconds. As with other electrics, considerable cost savings are reported in the elimination of hydraulic oil and the necessary auxiliaries.

GE Plastics offered its Process Optimizer software to help customers optimize their disk manufacturing process to increase productivity. The software rigorously defines operating limits and process settings based on statistical predictions that can be easily examined in very few runs, which minimizes downtime and accelerates customer manufacturing improvements.

New Materials for All Occasions
New materials and processing programs continue to be at the center of CD and DVD manufacturing. As formats become more sophisticated, processing must stay in stride to answer new challenges. In response to the new, high-density formats, Bayer, Dow, and GE Plastics have all developed new materials, which promise high-quality alternatives with improved performance, low birefringence, low moisture absorption, and even a weapon against piracy.

New for 1999 from GE Plastics is Lexan OQ1050 polycarbonate, which the company touts as being “a new global platform . . . for CD and DVD applications as well as for advanced recordable/rewritable formats.” Initially available in Europe and Asia, the resin is scheduled for global rollout in 2000. The resin boasts increased flow for low birefringence and fast cycle times, plus improved optical clarity and resin purity. Lexan OQ1040L resin is especially formulated for DVD manufacturers who need a higher-flow optical-quality polycarbonate. And Lexan OQ1030L, first introduced in 1997, has been refined with an improved particulate level and viscosity consistency, making it usable for DVD, CD-ROM, CD-Audio, and CD-Recordable media.

Dow Plastics’ newest material promises to not only offer superior qualities for DVD with respect to molding, but also was developed as an answer to the piracy problems that continue to plague the CD and DVD industry. Polycyclohexylethylene (PCHE) resin (Figure 3) was tested successfully for DVD applications in cooperation with Axxicon.

“PCHE performed to all our expectations in the molding process,” said Merijn Voets, manager, Development and Engineering, Axxicon. Following the successful bonding and metallizing on a DVD production line at Advanced Optical Disc in Vianem, The Netherlands, playable PCHE DVDs were produced.

Axxicon’s trials on equipment currently used for molding DVD disks indicated that PCHE resin can be incorporated into existing manufacturing processes. PCHE resins have a distinctly low specific gravity, high dimensional stability and rigidity, and very low inherent moisture, important in maintaining the extreme flatness of the disks.

Dow also hopes that by monitoring the supply of PCHE, the industry can prevent unauthorized replicators from obtaining the material, thereby eliminating the illegal production of disks. The company is proposing an independent legal entity that would track the supply of polymers similar to the way the supply of paper used for currency is monitored.

Bayer Corp. showcased its Makrolon DP1-1265 polycarbonate resin (Figure 3), which was introduced two years ago for the DVD market. Ramish Pisipati, Optical Memory Industry manager for Bayer’s Plastics Div., says that molders are achieving cycle times under 4 seconds using the material. “Molding is still the slowest step in the optical memory disk production process, so gains in cycle time are reflected throughout the process.”

Old Material, New Application
Polymethylmethacrylate (PMMA) had its day in the sun in the optical media industry during the days of the Laserdisc. It was an ideal material for molding a thin, large diameter disk because of its extremely low birefringence. It is also less expensive than polycarbonate.

Because of its tendency to undergo dimensional changes when exposed to moisture, specifically when the moisture is absorbed from only one side as in CDs, PMMA could not take advantage of this market. However, DVDs, like Laserdiscs, have two surfaces exposed to moisture and are symmetrical, making PMMA a good alternative.

To that end, two companies have begun promoting PMMA for DVD use. Cyro Industries’ Acrylite DQ501 acrylic molding compound, developed in conjunction with Rohm GmbH, offers high light transmittance, storage capacity, surface hardness, and elastic modulus. It also has low birefringence, optical purity and clarity, and precise mold surface reproduction at a lower material cost than polycarbonate.

Elf Atochem North America has also introduced a new acrylic resin into the DVD market (Figure 3, p. 33). Called Plexiglas VOD-100, the new material offers reduced viscosity for improved replication and superior optical properties. It also has reduced birefringence and increased light transmission.

“When molding with polycarbonate, replicators must balance three processing parameters: birefringence, disk flatness, and signal quality,” explains Don Hone, Market Development manager of the Autoglas Div. of Elf Atochem North America. “Often they can improve one of these, but only at the expense of one of the others.”

Switching to Plexiglas acrylic resin “allows replicators to remove birefringence from the processing equation,” says Hone. DVDs made from the Plexiglas acrylic resin are also more scratch resistant than those made of polycarbonate.

DVD Prompts Packaging Alternatives
The polystyrene jewel box remains deeply entrenched as the packaging of choice for CDs, but the advent of DVD has given molders new opportunities to explore alternatives.

Alpha Enterprises, a media packaging manufacturer with molding facilities in North Canton, OH and Tucson, AZ, offers its new Trimpak, molded of polypropylene. Half the height and weighing 1.2 oz less than a jewel box, Trimpak can fit easily into brochures or mailing envelopes.

Compact Disc Packaging Corp. in Farmingdale, NY introduced its new Pull Pack CD/DVD packaging design (Figure 4). Pull Pack has the same outside dimensions as the jewel box; however, it has a pullout drawer, which delivers the disk and pulls out the leading edge of the booklet for easy accessibility.

The case is molded in two pieces from polystyrene and sonic welded together. The disk shelf is molded from medium impact polystyrene, and the drawer mechanism is molded from polypropylene. The durability of the product makes it ideal for the rental and institutional markets such as video stores, libraries, and technical research facilities. The package is molded in China.