Evaluating the effect of micro-lubrication in orthopedic drilling.

Achievement of low temperature, thrust force, and clean operating zone under with/without irrigation-assisted drilling is still a challenge in orthopedic surgery owing to substantial bone-tissue damage that extends the healing time. In order to mitigate the above challenges, a new micro-lubrication technique-a low-pressure cold mist impinged on the tool-bone joint interface and penetrating well into the bone surface to improve the cooling/lubrication efficiency-has been proposed in bone drilling. In this study, the aims are to characterize the effect of micro-cooling/lubrication on temperature and thrust force at different levels of cutting speed, feed rate, drill diameter, and coolant flow rate. For that purpose, a fresh calf bone was drilled through commercially available drill tool on three-axis mini-machine. The response surface methodology was applied to get the design of experiments, and the analysis of variance at p-values < 0.5 was used. Moreover, the empirical models were developed to examine the simultaneous effect of all the parameters on performance measures. The employed cooling-lubrication technology has shown a percentage reduction in temperature ranging from 34.3% to 48.3%, and 26.8%-35.9% under irrigation with respect to without-irrigation mode. For cutting force, these reductions are 13%-47.6% and 14.5%-44.2%, respectively. Furthermore, analysis of variance has highlighted the cutting speed and feed rate as the two most prominent parameters for temperature and thrust force under all the drilling modes. Relatively high-pressure cold mist in micro-lubrication has offered a lower temperature, thrust force, and clean operating zone under micro-lubrication mode than with/without-irrigation modes. Henceforth, the micro-lubrication technique has been found as a suitable cooling technique for drilling of bone in the viewpoint of temperature and thrust force.