Modelling of Thrust Force during Drilling of Fibre Reinforced Plastic Composites

Delamination during drilling of composite materials is critical problem. Thrust force acting on workpiece being drilled plays a key role in delaminating the composite, therefore its modelling is of great importance. This work presents with example, step-by-step procedure to capture complex drilling dynamics via a mathematical model. A glass fibre reinforced plastic composite material is drilled at constant feed rate. The corresponding thrust force time response is recorded. Third order transfer function between thrust force and feed rate representing the system is identified using system identification toolbox of Matlab®. This transfer functions is then converted into corresponding state-space model. Good match is observed between thrust force response from state-space model and experiments.