Custom developed computer numerical control interface
Many CNC (Computer Numerical Control) milling machines are commercially available today, but none offers an open-source interface designed for research applications. The work reported in this thesis has retrofitted a 25-year-old manual milling machine, which has previously been modified into a CNC mill, but whose interface is no longer functioning, into a functional CNC mill. New components have been incorporated as necessary, to produce an open-source CNC mill capable of use in research and as a standard CNC mill. The original milling machine has inconsistent backlash due to cheaper methods of construction, ranging up to 0.049-inch per axis. The thesis has implemented software compensation, capable of producing most CNC paths with only 0.015- inch of inaccuracy with a 99%-confidence interval. Though the final mill does not have all the built in functionality of a commercial mill, it is designed with research application in mind, and as such, it is intended as a platform for future research to be mounted upon. The open-source interface will allow many forms of integration within a flexible manufacturing environment and easy future customization as necessary.
Motion control, Control system, CNC, Computer numeric control, 2½D, Backlash, Common object model, Confidence interval, Drift, G-code, NC-file, PI control system, PID control system, Visual basic for applications, Working envelope, Encoder, Servo motor control