A computer numerical control machine tool with a machine head having one or more process tools. The machine head is moveable with respect to a workpiece. A position sensor system detects the position of the machine head relative to the workpiece. A controller coupled to the position sensor system provides closed loop control of the position of the machine head relative to the workpiece. The position sensor system includes an ultrasonic probe. Also a method of controlling the position of a computer numerical control machine tool.

Drilling apparatus and method, the apparatus comprising: a first robot (10); a first member (30) (e.g. a pressure foot) and a drilling tool (38) both coupled to the first robot (10); a second robot (12); and a second member (52) coupled to the second robot (12); wherein the apparatus is arranged to press the members (30, 52) against opposite sides of a part to be drilled (2, 100) (e.g. an aircraft panel) so as to hold the part (2, 100) and prevent deflection of at least a portion of the part (2, 100); and the first member (30) and the drilling tool (38) are arranged such that the drilling tool (38) may drill into the portion of the part (2, 100) of which deflection is opposed from the side of the part (2, 100) pressed against by the first member (30). The robots (10, 12) may be robotic arms.

Provided are an alignment jig, a side track buffer system including the same, and an alignment method using the same. The alignment jig includes a horizontal jig fixed to a bottom plate of a side track buffer to extend in a horizontal direction to a lower portion of the transfer rail, and a vertical jig fixed to the transfer rail to extend downward in a vertical direction so as to be adjacent to a top surface in the horizontal direction. A separation distance between an intersection point of the vertical jig and the horizontal jig and a central portion of the bottom plate is detected as a buffer separation distance, and a buffer frame is horizontally moved automatically or manually to allow the buffer separation distance to match a reference separation distance, so that the side track buffer is installed in an accurate position.