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CD MANUFACTURING CYCLE
PREMASTERING is the first step in the CD manufacturing process. It all begins with a customer providing the manufacturer with a digital format tape containing information (ie: music) stored in binary form.
CRC (Cyclic Redundancy Check): a mathematical process designed to detect possible errors occurring during digital data transfer.
P&Q Encoding: marking the beginning and the end of each track while calculating its duration.
MASTERING is the process of transferring digital information from a tape to a polymer film. The mastering process entails several distinct operations.
GLASS COATING: the process of applying a photosensitive or thermosensitive polymer layer (depending on the mastering system) onto a clean, polished glass-like surface.
DECODING: deciphering of information on the P&Q encoded tape. Decoding is done in conjunction with the writing process.
WRITING: transferring of digital information from the master tape to the polymer-coated, glass disc (Glass Master). This process eventually creates Data Pits.
FILM DEVELOPMENT: the process of developing the film (polymer layer) and forming the Data Pits -physical indentations which contain digital information. When scanned by a D/A (Digital to Analog) converter, Data Pits produce analog signals (ie: music).
DIRECT WRITING: an option to Writing and Film Development, this one-step process utilizes laser technology. Direct Writing permits transferring of digital information from the master tape to the polymer-coated, glass disc while simultaneously forming and finishing the Data Pits.
GLASS MASTER METALLIZATION: as a preparation for electroplating, a conductive layer is applied over the developed polymer film.
REPLICATION: is the actual process of CD manufacturing from electroplating to inspection and complete packaging.
ELECTROPLATING: formation of a negative copy of the Glass Master to form a Stamper. The electroplating process involves several steps. First, the Glass Master is immersed in an electroplating bath to produce a negative copy referred to as a Metal Master, or the Father. It undergoes further replication to ultimately produce another negative copy referred to as a Stamper, or the Son. The end product of the electroplating process is a rough, unfinished replication template.
STAMPER PREPARATION: to ensure high-quality molding, the back of the Stamper is polished and its outer and inner edges are trimmed. MOLDING: the mold containing the Stamper (negative copy of data pits) is injected with plastic melt at a high temperature and pressure to form a positive plastic copy of the Metal Master, known as the Raw Disc.
METALLIZATION: the process of sputtering a Raw Disc under vacuum producing an aluminum coating. The coating forms a reflective layer that allows a scanning laser beam to read the information from the CD.
SPINCOATING: the process of applying an ultra-violet sensitive lacquer layer over a metallized disc while spinning the disc at a high rate of speed. This process produces a smooth, thin layer of lacquer covering the metallized disc. The lacquer is then cured under an ultra-violet light. Spincoating provides a protective layer for the information on the disc. It also provides a smooth surface for printing.
QUALITY CONTROL: The compact disc is tested for signal strength and decoding errors in compliance with the Sony/Philips Red Book standards.
PRINTING: Silk screening or pad printing label information containing text and/or graphic elements onto the lacquered surface of the disc. Once the label is transferred to the disc, it is cured under the ultra-violet light. Depending on the production process, printing can be performed either in-line (usually for one or two color prints), or off-line (three or more colors).
INSPECTION: final check for possible physical defects resulting from any of the production steps.
PACKAGING: placing the compact disc (on a tray), along with information booklet, into a Jewel Box. The Jewel Box can be shrink wrapped, placed in a corrugated long box, or packaged in a blister PVC container.
DUPLICATED CD (CD-R)
CD-R is a one time recordable medium and are run directly from your mastered CD-R or Digital Audio Tape (DAT) at one or two times speed. The lack of computer checked mastering, makes this process dependant upon the supplied master. The reliability could be in question resulting from data errors from the original source equipment.