The CD and DVD Replication Process

The commercial process by which CDs and DVDs are manufactured is generally known as Replication. This process produces mass quantities, typically 1000 units and above of read only discs and starts from the constituent elements that go to make up a CD or DVD. The duplication process also results in a read only disc, but starts from a pre-manufactured writeable disc and is a service typically provided by a disc duplication company such as Media Matters Technology. Pricing for replication is available via our online quote calculator.

There are typically seven stages to the manufacture of a CD or DVD:

Premastering
Mastering or Glass Mastering
Electroplating
Pressing
Quality Control
Printing
Packaging

Typically the source for the data to be replicated will be supplied on a master CD or DVD, the pressing plant will then check and validate the data supplied prior to mastering.

Also known as Glass Mastering, this operation is undertaken in a clean room environment, as any dust or other contaminants can cause failures in the finished product.

Glass is the preferred medium to hold the master disc image or “father” image. This is created after the glass has been thoroughly cleaned, a dye polymer is applied by spin coating, the spinning spreads the coating across the glass surface. This is then heated to dry both the glass and substrate in preparation for mastering.

A LBR (Laser Beam Recorder) is used to perform the mastering, typically at 8x speed, the LBR laser writes the information or more accurately creates pits of a certain length (depending on whether a CD or DVD is being created) into the substrate.

There two different  processes used to create the glass master, these are either  Photoresist Mastering and Non-photoresist (NPR) or Dye-Polymer mastering.

After mastering the glass master is transformed into a “stamper”, this is used to create the pressed discs. A layer of nickel is applied to the  glass master by electrolysis. This layer is then removed from the glass master, and is a negative of the CD image.

The CD or DVD can now be replicated. This is done by injecting liquefied polycarbonate in the mould, all the data contained on the negative “stamper” is then transferred to the plastic polycarbonate layer.

At this point the CD would still not be readable, but once a very thin layer of aluminium is laid over the polycarbonate via a vacuum process, the disc can read as the aluminium layer is reflective and will bounce the light back, allowing the information contained on the disc to be read.

The final part of the manufacturing process is for the disc to be covered in a layer of lacquer, this seals the disc and protects it from scratching and dust, the lacquer is also spin coated on to the disc and acts as the topside of the disc which can then be printed with a text or a graphic design.

Before a production run all elements of the process are tested,  then using a signal analysis machine sample discs can be tested

The final part of the manufacturing process before packaging, the top surface of the disc can be printed. For replication there are two types of printing available; Silkscreen or Offset.  Typically offset is used for higher quality photographic artwork using the CMYK colour process for the basic colours. Often a white base coat is applied as fifth colour and even a sixth colour can sometime be applied using a pantone colour ink for a specific colour.

Silkscreen printing is normally applied for more graphically based artwork.

The finished discs are now ready for packaging, this can vary from standard packaging products such as a CD jewel case or a DVD case to more basic requirements such as a plastic sleeve to fully customised and printed solutions.