External spray mist as a cooling strategy in bone milling

The growing proportion of the population comprising individuals of advanced age is accompanied by an increase in the number of patients affected by periodontitis. This may entail the use of bone replacement materials such as allogenic bone. Thermal damage of the workpiece is one of the greatest risks when machining bone. The use of cooling lubricant to prevent exceeding the critical temperature has not yet been previously investigated during bone milling. The aim of this paper is to develop a new cooling method using a spray mist of compressed air and NaCl solution. To ascertain the impact of the cooling lubricant on the machining of bone, technological investigations on path milling are being conducted. The results show a significant reduction in the workpiece temperature when applying NaCl solution as a coolant lubricant. The lowest workpiece temperature of T w = 25 °C was achieved for a rotational speed of n = 38000 min -1 , a cooling lubricant rate of Q k = 0.2 ml/s, a cutting depth of a p = 0.25 mm and a spherical milling tool with a diameter of d t = 1 mm. The employment of a novel external spray mist of NaCl solution and compressed air has proven to be a highly effective cooling method, resulting in a substantial reduction in process temperatures. In comparison with compressed air cooling, lower workpiece temperatures are attained. Moreover, the spray mist exhibits a wider cooling area and a more uniform distribution.