A machine and process useful for processing a delicate workpiece, e.g., an implantable medical device, includes a carrier having a mandrel and wheels. The workpiece is positioned on the mandrel, which is free to roll by gravity on rails which cooperate with the wheels to self-align the travel of the carrier. The carrier can move the workpieces through a series of processing steps by gravity feed and without human intervention. A laterally movable carriage receives the rolling carriers and moves the carrier for processing, and returns the carrier to the rails to again roll by gravity to another processing substation for additional processing. An elevator, which can including processing units itself, is positioned along the rails to receive carriers and raise them so they can continue to roll for further processing.