CD Replication and Duplication

CD Replication and Duplication

CD replication and CD duplication are both methods of making multiple copies of a compact disc but there are some essential differences between the two processes. Below you will find a summary of what the difference is between CD replication and CD duplication, and some information about what is involved in these two processes.

The difference between CD replication and CD duplication

CD Replication: refers to the manufacture of more than 500 CDs. The process of CD replication entails pressing the data deep inside a CD. In CD replication (also known as manufactured CD) a glass master is created from the available data and then a ‘stamper’ is made from the glass master. This stamper is then utilized in pressing the discs with injection molding consisting of raw polycarbonate plastic. CD replication provides CDs that are as good in quality as those available in record stores.

CD Duplication: refers to the manufacture of less than 500 CDs. In CD duplication (also known as burned CD) the data is burned onto the new CD using a laser. This process is used by small time CD copiers and is considered inferior than CD replication. CD duplication produces more bad CDs that have a higher percentage of unusable data than a manufactured CD.

The Process of CD Replication

Glass Master: Making a glass master is the first stage in the process of CD replication. This is a very important and complex stage and requires tremendous talent and advanced technology. Once a pre-mastered CD is received from the customers, this process begins.

Glass mastering is done in a class 1000 clean room. Technicians have to wear specialized face masks, footwear, and clothes so as to reduce the instances of small particles, which may spoil the CDs.

The blank glass master is stripped of its old photo-resist from the top and is then given a final washing and cleaning with de-ionized water. This blank glass master is then dried thoroughly before proceeding further. A spin coating technique is used to cover the top surface of the blank glass master with a new photo-resist layer of 150 microns thickness. The homogeny of the layer is tested by infrared beams after which it is baked for half an hour at 80 degrees C and is ready for exposure to laser light.

Laser light is then focused on areas in the photo-resist surface where pits have to be developed. After this is done the photo-resist covering is removed from these areas and the newly created pits are visible. Care has to be taken to see that the pits are made all the way down to the glass and are not only on the top surface. The glass is not affected by this process.

Stamper: The top surface of the glass master containing the pits is then made metallic either using silver or nickel. At this stage the glass master is played to check for any mistakes and if there aren’t any then a reverse image is stamped into the ‘stamper’. This stamper is subsequently used to stamp data deep into the CD which will have the entire final binary information needed to play the disc.

Outer shell: The final replicated CD is then put into its packaging which can either be a wallet, a jacket cover or a jewel case cover.

CD replication should be done under ISO 9002 conditions else there can be defects in the CD and this might result in it not playing satisfactorily.

Recently many companies have started making copy protected CDs, which mean that they cannot be replicated or duplicated. New technology and software is being developed all the time, which will all essentially help to reduce and eventually stop manufacturers from being able to carry out CD replication. These efforts are being made to stop CD piracy but how successful they will be remains to be seen.

CD piracy is becoming a big issue both in the United States and the rest of the world hence the reasoning behind these copy protected CDs. It is hoped that this crime can be dramatically reduced and eventually eliminated altogether by taking measures such as this in the future production of CDs.