In-situ Measurement of Residual Stress and Thermal Deformation of Substrate after Laser Drilling

This study has successfully integrated an advanced laser drilling machine (LDM) and a photo-elastic (PE) system to measure the residual stress of acrylic substrates after drilling manufacturing. The full-field distribution of fringe denotes the strain concentration of the specimen after hole drilling, and we collect massive data based on a self-built system of measuring the photo-elasticity effect of the samples. The work uses the self-developed PE system, contains parameters during manufacturing, and yields quantitative sensor fusion results promising the preventative maintenance of the LDM. The diagnostic maintenance system can achieve this through signal processing and artificial intelligence algorithms. In particular, edge computing architectures can effectively diagnose faults in real-time. The appearance of contours caused by machining is traditionally measured with a surface profile meter, but now we are experimenting with measuring shapes and residual stresses through photo-elasticity. This paper introduces the sapphire substrate for the emerging material and compares its properties with those of acrylic specimens. We have constructed a 5G experimental field and verified the developed architecture and methods, and well-developed technologies have been promoted in the industry. The measured results and data can cooperate with upcoming 5G communication and utilize the advantages of enhanced mobile broadband (eMBB), massive machine type transmissions (mMTC), and ultra-reliable and low latency communications (URLLC). This work applies the domain knowledge of PE and the advantage of 5G technology, providing a diagnostic maintenance system for the laser drilling machine.