Design and evaluation of a modified drilling method

The aim of the study was to develop a modified drilling method (MDM) for a bench drilling machine to enhance the drilling task performance. The MDM and the present drilling method (PDM) were evaluated for the subjects of varying age groups (21-30, 31-40 and 41-50 years) while performing the drilling task for different work durations (3, 6 and 9 min) in the sitting and standing working postures. The performance parameters used were metal removal rate (MRR) and perceived discomfort score (PDS). Drilling load required to perform the task and endurance time were also determined for both PDM and MDM. Thirty male subjects were selected to perform the drilling task on a mild steel block at a drilling speed of 700 rpm. The results of the study showed that there was an increase in MRR by more than 140% using MDM. PDS was also reduced appreciably at different body segments using the proposed system. The results of the study further revealed that there was a substantial decrease in the drilling load required to perform the task and a considerable increase in the endurance time.