CD Duplication

clear-discThe process of manufacturing compact discs, or more commonly known as CDs, is relatively similar to that of vinyl records, except with a greater amount of chemical intervention. Firstly, a glass master must be composed from an audio or video tape of the disc’s future content. The circle of glass is thoroughly cleaned using ionized water and a fine goat hair brush. To ensure its immaculate cleanliness, the disc is placed in a chamber equipped with a laser to detect any dust or other debris remaining on the
glass surface.

Now is where the chemical intervention comes into play. The glass must be thoroughly coated with a primer and photo-resistant material. After application, the glass with its new coatings are dried for 30 minutes in a specialized oven. Another coating is applied later, normally silver or vanadium.

cdreplication1Next, a process called electroforming is using to transfer the information from the original audio/video tape onto the surface of the disc. An electric current that interprets the tape’s information is used to apply a secondary metallic coating, this one made of nickel. As the disc soaks in a electrolytic solution (nickel solphamate), the current causes a nickel layer to be deposited on the CD master copy. The disc master is stamped out of the large metal coating, and used to manufacture millions of copies. This stamping process also results in a negative copy of the disc, which is referred to as the “father” (similar to the “mother” of vinyl records).

Although the glass master is used to create the CDs you have in your home, these copies are made of far different materials. The master is placed in a hollow chamber called a “die”. The replicated CDs, which are the ones to be distributed, are made of a poly-carbonate base, and their coatings are normally an acrylic layer and an aluminum layer.


Zelda Crist-1121


Zelda Crist
Solid State Contributor

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