The process of gluing two DVD substrates together to form a finished disc.  This process is critical to the quality of a DVD.  Improperly bonded discs could become delaminated.  The thickness of the bonding layer is critical with dual layer DVDs (DVD-9 or DVD-18), as it provides the separation between layer 0 and layer 1.  Centering alignment of the 2 substrates is critical in order to prevent eccentricity or shrinking of the center hole size.  Hot melt glue is used in some low-cost DVD manufacturing operations, but is not useable for dual layer discs.  Ultraviolet cured bonding resin is used by high quality DVD manufacturers.