How are CDs made?

Answer 1

Replicated CDs are mass-produced initially using a hydraulic press. Small granules of raw polycarbonate plastic are fed into the press while under heat. A screw forces the liquified plastic into the mould cavity. The mould closes with a metal stamper in contact with the disc surface. The plastic is allowed to cool and harden. Once opened, the disc substrate is removed from the mould by a robotic arm, and a 15 mm diameter center hole (called a stacking ring) is removed. The cycle time, the time it takes to "stamp" one CD, is usually 2-3 seconds. This method produces the clear plastic blank part of the disc. After the metallic layer is applied to the clear blank substrate, the disc goes under a UV light for drying and it is ready to go to press. To press the CD, first a glass master is cut using a high-power laser on a device similar to a CD writer. This glass master is a positive master. After testing, it is used to make a die by pressing it against a metal disc. The die then becomes a negative image: a number of them can be made depending on the number of pressing mills that are to be running off copies of the final CD. The die then goes into the press and the image is pressed onto the blank CD, leaving a final positive image on the disc. A small circle of lacquer is then applied as a ring around the center of the disc, and a fast spin spreads it evenly over the surface. The disc can then be printed and packed.

Answer 2

u burn it on iTunes