An add-on online measurement system is developed in this research to enhance the product accuracy and productivity of the machining process. For these purposes, a sensor that can detect location error in X, Y and Z directions has been designed with sub-micron resolution. Using this online measurement system, some potential applications for CNC machines have been explored. First, the possibility of reduction of mounting or remounting error of the workpiece on a CNC machine has been investigated. In comparison to the conventional methods, our results show that a factor of 2 accuracy enhancement can be achieved. Second, the system is applied to compensate for the error due to tool bit uncertainties. In particular, the error induced by tool bit change is examined and substantial improvement...[ Read more ]

An add-on online measurement system is developed in this research to enhance the product accuracy and productivity of the machining process. For these purposes, a sensor that can detect location error in X, Y and Z directions has been designed with sub-micron resolution. Using this online measurement system, some potential applications for CNC machines have been explored. First, the possibility of reduction of mounting or remounting error of the workpiece on a CNC machine has been investigated. In comparison to the conventional methods, our results show that a factor of 2 accuracy enhancement can be achieved. Second, the system is applied to compensate for the error due to tool bit uncertainties. In particular, the error induced by tool bit change is examined and substantial improvement of accuracy is achieved with the aid of our system. The tool change normally introduces an average error about tens of microns and it can be almost completely compensated by our system. Finally, the possibility of using our system as a cost-effective means for inspection the machined parts has been investigated. While our system may not be quite as accurate as a regular CMM (Coordinate Measuring Machine), the inspection can be accomplished much easier with our system as the rough location of all the coordinates of the machined parts are already known from the machining process. Therefore, the measurement can be done with significantly less effort, and the cost of quality inspection of the machined parts can be greatly reduced.