Tool wear damage caused by abundant emulsion in milling operation of PH stainless steel

The use of cutting fluid in milling operations causes increase of temperature variation oil the tool and may cause decrease of tool life. However, sometimes its use is necessary due to possible deleterious influence the temperature increase may have oil the workpiece. Therefore, it is important to make fluid less harmful for the tool. In this work, two alternatives were tried: the application of emulsion internally to the tool, forcing it to get closer to the cutting edge and the use of an emulsion with higher concentration, trying to increase the lubrication and decrease the fluid cooling capacity. These alternatives were experimented in the face milling operation of stainless steel used in the aeronautic industry (where workpiece damage must be avoided) and were compared to the usual was of fluid application (externally to the tool and with lower concentration) and also to dry calling, in two different cutting speeds. Tool wear damage was analyzed. The main conclusions were: a) dry cutting generated longer tool lives than Cutting with emulsion no matter the way of application and the fluid concentration; b) tool wear mechanism which caused the end of tool life was attrition for dry cutting and cracks and chippings of thermal origin for cutting with emulsion, again, no matter the way of fluid application and the fluid concentration.