Candle Stick Drill Research Articles

Effect of eccentricity of twist drill and candle stick drill on delamination in drilling composite materials

Drilling is the most frequently employed operation of secondary machining for fiber-reinforced materials owing to the need for structure joining. Delamination is one of the serious concerns during drilling. Practical experience shows that an eccentric twist drill or an eccentric candle stick drill can degrade the quality of the fiber reinforced material. Comprehensive delamination models for the delamination induced by an eccentric twist drill and an eccentric candle stick drill in the drilling of composite materials have been constructed in the present study. For an eccentric twist drill and an eccentric candle stick drill, the critical thrust force that will produce delamination decreases with increasing point eccentricity ξ. The results agree with industrial experience. The need for control of drill eccentricity during drill regrinding has been proved analytically by the proposed models.

Taguchi analysis of delamination associated with various drill bits in drilling of composite material

This paper presents a prediction and evaluation of delamination factor in use of twist drill, candle stick drill and saw drill. The approach is based on Taguchi’s method and the analysis of variance (ANOVA). An ultrasonic C-Scan to examine the delamination of carbon fiber-reinforced plastic (CFRP) laminate is used in this paper. The experiments were conducted to study the delamination factor under various cutting conditions. The experimental results indicate that the feed rate and the drill diameter are recognized to make the most significant contribution to the overall performance. The objective was to establish a correlation between feed rate, spindle speed and drill diameter with the induced delamination in a CFRP laminate. The correlation was obtained by multi-variable linear regression and compared with the experimental results.

Taguchi analysis of delamination associated with various drill bits in drilling of composite material

This paper presents a prediction and evaluation of delamination factor in use of twist drill, candle stick drill and saw drill. The approach is based on Taguchi’s method and the analysis of variance (ANOVA). An ultrasonic C-Scan to examine the delamination of carbon fiber-reinforced plastic (CFRP) laminate is used in this paper. The experiments were conducted to study the delamination factor under various cutting conditions. The experimental results indicate that the feed rate and the drill diameter are recognized to make the most significant contribution to the overall performance. The objective was to establish a correlation between feed rate, spindle speed and drill diameter with the induced delamination in a CFRP laminate. The correlation was obtained by multi-variable linear regression and compared with the experimental results.

Comprehensive analysis of delamination in drilling of composite materials with various drill bits

Beside the twist drill, the effects of various drill geometries were rarely discussed in analytical fashion. This study presents a comprehensive analysis of delamination in use of various drill types, such as saw drill, candle stick drill, core drill and step drill. In this analysis, the critical thrust force at the onset of delamination is predicted and compared with the twist drill.