Research on Variable Parameter Drilling Method of Ti-CFRP-Ti Laminated Stacks Based on Real-Time Sensing of Drilling Axial Force

Abstract

Ti-CFRP-Ti laminated stacks have been widely used in aviation, aerospace, shipbuilding and other industries, owing to its excellent physical and electrochemical properties. However, chip blockages occur easily when drilling into Ti-CFRP-Ti laminated stacks, resulting in a rapid rise of drilling temperature and an increase of axial drilling force, which may lead to the intensification of tool wear and a decline of drilling quality. Cutting force signals can effectively reflect the drilling process and tool condition, however, the traditional plate dynamometer is typically difficult in realizing the follow-up online measurement. Therefore, an intelligent tool holder system for real-time sensing of the cutting force is developed and constructed in this paper, and the variable parameter drilling method of Ti-CFRP-Ti laminated stacks is studied on this basis. Firstly, an intelligent tool holder system with high flexibility and adaptability is designed; Secondly, a cutting force signal processing method based on compressed sensing (CS) theory is proposed to solve the problem of high-frequency signal transmission; Lastly, the drilling experiment of Ti-CFRP-Ti laminated stacks is carried out based on the intelligent tool holder system, and the drilling parameters are optimized using a compromise programming approach and analytic hierarchy process (AHP). The comparison of results show that the optimized drilling parameters can effectively reduce the hole wall surface roughness and improve the drilling efficiency while ensuring a small axial force.

Numerical study on the heat effect on the drilling damage of Ti/CFRP stacks

“…Besides, the four kinds of drilling parameters of Ti are used to obtained different entrance and exit temperature in the machining area. 27 And based on this, the relationship between temperature and the drilling processing quality of Ti/CFRP stacks is analyzed. And the processing parameters of Ti are summarized in Table 5.…”

“…In this study, the constant drilling parameter of CFRP with rotation speed of 2000 rpm and the feed speed of 100 mm/min is chosen, which are common used in machining CFRP. Besides, the four kinds of drilling parameters of Ti are used to obtained different entrance and exit temperature in the machining area 27 . And based on this, the relationship between temperature and the drilling processing quality of Ti/CFRP stacks is analyzed.…”