What are the recording methods of CD/DVD/Blu-Ray

[Neo]

There are several different methods available to make one or multiple copies of existing CD/DVD/BDs ranging from single CD/DVD/BD recorders to specialized devices that automatically duplicate and label discs and, for large runs, commercial mass replication. Options are distinguished by cost, speed, convenience and capability.

2. Computer CD/DVD/BD Recorders

   

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   By far the quickest and least expensive way to duplicate a disc is to copy it using a computer outfitted with a CD/DVD/BD recorder combined with off the shelf writing software. In addition to creating discs from scratch, many basic writing software packages will duplicate most standard CD/DVD/BD formats. Specialized copying software is also available with more sophisticated capabilities such as the ability to simultaneous duplicate to multiple recorders. But remember that the ability of a system to copy specific disc formats depends upon the individual capabilities of the software, reader and recorder used. It is therefore advisable to check with the respective manufacturers for specific information.
   
   Typically, discs are duplicated DVD to DVD/CD to CD/BD to BD by using the computer’s CD/DVD/BD-ROM drive as the master source feeding the copying recorder. In cases where a separate reading drive is not available the master is first downloaded to the computer hard drive using the reading ability of the recorder and later written back to a blank disc using the same recorder. Employing the computer’s hard disk as an intermediate copying step is also a common tactic used when dealing with poor quality source discs or other situations where computer systems are not fast enough to keep up to the speed set on the recorder.
   
   
3. CD/DVD/BD Duplication Systems

   

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   For copying larger numbers of discs various dedicated CD/DVD/BD duplication solutions are available including machines that function by themselves or with the assistance of operators. These configurations can either sit as standalone units or may be attached as computer peripherals. The most common devices are hand-fed tower systems that employ a number of CD/DVD/BD recorders linked together for simultaneous duplication from either a master CD/DVD/BD or from a hard drive. Also widely used are automated products incorporating robotic disc handling systems that mechanically load and unload one or more recorders. Sometimes disc label printers are included to produce a handful or even dozens of finished discs per hour. In addition to large commercial solutions many CD/DVD/BD duplication systems are compact and affordable and within reach for personal and office use. A number of companies also offer commercial CD/DVD/BD duplication services to perform short run work in quick turnaround times.
   
   
4. CD/DVD/BD Mass Replication

   

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   In contrast to CD/DVD/BD duplication which is usually performed on a small scale at the desktop level, CD/DVD/BD mass replication is typically used to make huge quantities of discs such as commercial DVD movies and software CD/DVD/BD-ROMs. These prerecorded (pressed) discs are manufactured from a mold in a factory setting and are created using a complete series of industrial processes including premastering, mastering, electroplating, injection moulding, metallization, bonding, spin coating, printing and advanced quality control. In addition to manufacturing discs, many replication companies offer companion services including packaging, printing, distribution and fulfilment.
   
   The first stage in producing CD and DVD discs is injection moulding, which uses the stamper to create the plastic discs or substrates containing the pits.
   
   Optical grade polycarbonate is first 'baked' to remove any moisture and is injection moulded in a high pressure moulding machine (press) using the stamper mounted in the mould fixed to the press. This mould is in two parts and provides a cavity which ensures that perfectly moulded discs are produced with the correct dimensions every time. One half of the mould contains the stamper (to form the pits) while the other half contains the mirror block to ensure a smooth surface.
   
   The hydraulic press applies a force to the two halves of the mould which are closed. Molten polycarbonate is then injected into the cavity and held in place by the applied pressure while the disc cools and solidifies. During cooling the centre hole is punched. After cooling, the press opens and the pressed disc is transferred by robot arms to a conveyor to allow the disc to cool before the next stage. The centre hole with sprue (formed by the injected polycarbonate) is discarded or re-cycled.
   
   Successful moulding of CDs which meet the CD specification, requires stable processes with the machines setup correctly. Moulding parameters which can affect the resultant CD include stamper geometry, mould temperature, polycarbonate temperature, compression force and cycle time.
   
   Cycle times for injection moulding of CDs have decreased substantially and are now around 3 seconds for the latest presses and moulds.
   
   DVD vs CD Moulding
   DVD moulding is similar to CD moulding but with some important differences.
   • Two pressings are needed for each final DVD disc
   • Each half disc (substrate) is 0.6mm thick instead of 1.2mm
   • The thinner disc also requires different moulding parameters, such as a shorter injection time and higher mould temperature.
   • Redesigned or new moulding machines are needed with injection compression where the mould is kept slightly apart until most of the polycarbonate has been injected.
   • Cycle times tend to be longer than for CDs.
   The quality of the final disc, including tilt and jitter, is critically dependent on the moulding process.

[Face]

great...
thank you bro.
I am really interest in hardware technologies....

thank u & carry on your lessons...