Drilling unit for fittings
The drilling heads of CNC machines mostly have many drilling spindles which are arranged in a regular hole grid with a respective distance of 32 mm. The drive of the drill mostly runs via a common gear which isn't often designed for the relatively strong forces when drilling cup hinges.
Cup hinges mostly need a vast hole with a diameter of between 26 and 40 mm for the actual cup hinge as well as two smaller holes for the locking sleeves or screws. These three holes are usually not arranged in one line and not of 32mm distance from each other.
If cup hinge drillings are to be made ragularly, three separate cycles with single drills are necessary with a normal drilling gear. Also, most drilling gears are being overstrained with time by large cup hinge drillings.
Hence for regular cup hinge drillings mostly separate, firmly installed units are used. Alternatively many manufacturers offer changing units.
The firmly installed units have the benefit of very few cycle times, as they can be immediately used without changing time. Although changing of the drilling pattern is only possible through considerable effort, e.g. when using different hinges with other cup hinges.