Shaped CDs are produced in one of two ways. A special mold can be made and used to "stamp" CDs (or DVDs) as part of the precision injection molding process that is used to make CDs and DVDs. Because of the initial cost involved in setting up this process, it is usually used for mass production. For the same reason, this is generally restricted to the production of read-only CDs and DVDs (CD-ROM or DVD-ROM). Recordable CDs and DVDs (CD-R or DVD-R or DVD+R) are not generally available except in standard shapes including rectangular. The second method to produce a shaped CD or DVD is to produce a normal CD-ROM or DVD-ROM and cut it to the desired shape. This method works only for CD-ROM. It will not work for CD-R because the plastic used to produce CD-R tends to splinter when cut. It is important that two criteria be met for a shaped disc to function properly. First, the shape must be balanced to avoid problems when it begins to spin. Second, at least three points of the outer edge must touch either the outer 12 cm diameter rim of the player's tray where standard size discs fit or the inner rim where 8 cm diameter mini discs fit.
