placed in the machine 10 step 52 and the clamping sequence started step 54 step 50 in addition to obtaining a baseline reference is useful in performing a basic cleaning function for the machine as the clamping plate is driven through its entire range of motion dried paint dirt and grime or other obstructive material present in the screw threads may be dislodged consequently even in embodiments wherein the baseline reference is taken in another manner it is preferred from time to time to drive the clamping plate through its entire range of motion as a u201c cleaning cycle u201d the machine may be advantageously programmed to perform the cleaning cycle after a specified period of idle time such as 10 minutes once the machine is started it is advantageous at step 56 to ensure that various safety protocols have been met for instance for safety purposes machines of this type are typically provided with a door and one safety protocol may and should be that the door must be fully closed before clamping and shaking begin other safety protocols may include checking the line voltage and current availability of the electrical supply a self diagnostic of the microprocessor or its programming and so on these safety protocols are well known in the art and form no part of the present invention if a safety protocol is.