Defect evaluation of the honeycomb structures formed during the drilling process

In this paper, a comprehensive experimental investigation was carried out to precisely characterize the delamination and uncut fiber in the drilling process. A digital imaging procedure was developed in order to calculate the damage resulted from the drilling process. A novel method is proposed in this article based on image intensity to verify the obtained results. A full factorial experimental design was performed to evaluate the importance of the drilling parameters. Among other process parameters, feed rate, cutting speed, and tool diameter are the principal factors responsible for the delamination damage size during the drilling. The drilling process was assessed based on two proposed incurred damage factors, specifically the delamination factor and uncut fiber factor. Experimental results demonstrated that the feed rate was the paramount parameter for both delamination and uncut fiber factors. It was observed that both factors increased with an increase in the feed rate. Additionally, by increasing the tool diameter, the delamination and uncut fiber factors significantly increase. The effects of the cutting speed on damage factors were not linear. The minimum delamination factor and uncut fiber factor were obtained at the cutting speed of 1500 and 2500 r/min, respectively.