move a wafer carrier 24 contained within the smif pod 20 the arm 18 includes pivoting shoulder 181 elbow 182 and wrist 183 joints to allow a complete range of motion in the horizontal direction the arm 18 includes an upper arm 185 which extends between the shoulder joint 181 and the elbow joint 182 and a forearm 187 which extends between the elbow joint 182 and the wrist joint 183 an arm vertical drive 26 permits the arm 18 to raise and lower the wafer carrier 24 vertically the vertical drive 26 includes a second motor 261 which turns via a belt and pulley linkage a lead screw 262 the lead screw 262 is affixed to the bulkhead 12 via a mounting block 263 a bearing assembly 264 affixed to an arm carriage 265 allows the lead screw 262 to drive the arm carriage 265 up and down in a prior configuration of the pod loader interface 10 the arm carriage 265 travels up and down along two guide rails 266 the arm carriage 265 is affixed to an upper end of the articulated arm 18 so that the arm 18 moves up and down with the carriage 265 in the presently preferred configuration of the pod loader interface 10 the arm carriage 265 travels up and down along a single guide rail and the second motor 261 is a stepper motor that employs closed loop feedback the arm carriage 265 also supports a third motor 267 which provides the impetus for the horizontal travel means of the articulated arm 18 the third motor 267 also.