Cutting apparatus, tray, and transport system

A cutting apparatus comprising:

• a cutting unit having a spindle with a cutting blade mounted on the spindle;
• a chuck table having a holding surface used for holding either a workpiece unit that includes a plate-shaped workpiece supported on an annular frame by a tape or a tray shaped similarly to the annular frame, wherein the holding surface is connected to a suction source such that the suction source is configured and arranged to apply a negative pressure to the holding surface to hold either the workpiece unit or the tray thereon;
• a processing feed unit that has a drive source and moves the chuck table along a processing feed direction;
• an indexing feed unit that has a drive source and moves the cutting unit along an indexing feed direction perpendicular to the processing feed direction;
• a rest area used for placing a receptacle that houses the workpiece unit or the tray;
• a transport unit configured to transport the workpiece unit or the tray between the rest area and the chuck table, the transport unit having a first holding pad that holds the workpiece unit or the tray;
• a sub-chuck table that is disposed sideways of the chuck table and that includes a holding surface that is at a height different than the holding surface of the chuck table, and wherein the holding surface of the sub-chuck table is used for holding a board for use in adjusting the cutting unit;
• and
• a board transport unit configured to transport the board between the tray held on the chuck table and the sub-chuck table,
• wherein the board transport unit includes:
• a second holding pad that holds the board, and
• an air-driven actuator that is supported, together with the cutting unit, on the indexing feed unit and moves the second holding pad, between a position where the second holding pad contacts the board held by the sub-chuck table and a position above the holding surface of the chuck table and the holding surface of the sub-chuck table, along a direction perpendicular to the processing feed direction and the indexing feed direction.