Utilizing internal icing force to reduce delamination in drilling composite tubes

Thanks to the superior mechanical properties and corrosion resistance, composite materials have been increasingly utilized in industries over the past decades. Drilling is indispensable for building load carrying structure of composites. Owing to the peculiar property of composite laminates, delamination defect is often produced at the exit of drilling, which leads to serious concerns of reliability and safety. This research presents an innovative method of utilizing the internal expansive force during water icing to suppress delamination in drilling on wall of composites tubes. The experimental results demonstrate the delamination extent can be reduced by 40% on average, while the drilling feed rates can be elevated more than 400% when maintaining the same level of delamination extent. The effects are enhanced with increasing feed rates. Being more advantageous than the previous method of applying electromagnetic media inside the tube as back-up, the water icing is both clean and easily remolten as well as recycled leaving little environmental concerns after use. It requires no attention of cleaning the drill bit. The proposed innovative method is effective and inexpensive for industry. (C) 2015 Elsevier Ltd. All rights reserved.