Performance Evaluation of Uncoated Carbide Tool in High Speed Drilling of Ti6Al4V

Abstract

This paper presents the experimental investigation into the performance of the uncoated carbide tool when high speed drilling (HSD) of Ti6Al4V. Machining responses such as thrust force, torque, vibration, chip formation and surface integrity of drilled surface were evaluated at various cutting conditions. Results show that cutting speed and feed significantly influenced the above responses. Folded wavy type chips and curly type chips were produced under all tested cutting conditions. It was also found that the transition from aperiodic to periodic chip formation occurred as the cutting speed increases. In addition, improvement of the drilling performance was also recorded as a result of reduction of acceleration amplitude during peck drilling method was adopted. Observation on the subsurface of the drilled workpiece indicates a severe plastic deformation at all tested cutting conditions.

Machinability of Titanium Alloys in Drilling

“…As shown in Figs. 13 and 14, the thrust force decreases as cutting speed increases (Rahim et al, 2008). At the same time, results also showed that low torque values were obtained at the highest cutting speed.…”

“…Apparently, such reduction may attribute to better lubrication and shorter tool-chip contact length during drilling. Moreover, surface roughness measured by peck drilling is far better than conventional drilling method (Rahim et al, 2008).…”

“…It is believed that the natural frequency of measurement systems does not exceed the vibrating frequency. In another work by Rahim and co-workers (Rahim et al, 2008) showed that pecking drilling method significantly reduces the thrust force and torque. …”

“…13. Comparison of thrust force when drilling Ti-6Al-4V using cemented carbide tool under flood coolant condition (Rahim et al, 2008) Fig. 14.…”

“…14. Comparison of torque when drilling Ti-6Al-4V using cemented carbide tool under flood coolant condition (Rahim et al, 2008) Some researchers have tested several techniques in drilling of titanium alloys. A step feed drilling or intermittently decelerated feed drilling and vibratory drilling were conducted by Sakurai co-wrokers (Sakurai et al, 1992;Sakurai et al, 1996) to examine the cutting force and cutting characteristic of TiN coated cobalt HSS and oxide treatment nitridized cobalt HSS when drilling Ti-6Al-4V.…”