2010 Full-Line Drill Catalog - Desanto

Guhring is heavily engaged in the subject of minimalquantity lubrication and occupies one of the top positions inthis technology. In addition to the suitable MQL geometry,our priority lies especially in the optimal delivery of thecoolant in the vicinity of the tool holder. Therefore, wehave developed a suitable MQL shank end for our cuttingtools and a suitable MQL coolant delivery system for theapplication with our tool holders.The coolant delivery has also been subject to an indepthanalysis. The result is the recently developed MQL deliverysystem consisting of a one-piece delivery pipe, with athin-walled stainless steel pipe glued-inside and a MQLadjustment screw. The advantages of this solution are:ToolholdersBecause an extremely low volume of lubricant is appliedwith minimal quantity lubrication, the delivery of theselow coolant quantities to the effective area is of utmostimportance. Hereby, the geometric design of the shankend is of main significance for a secure delivery of thelubricant.In a comprehensive series of tests we have thoroughlyinvestigated different geometric designs of the shank endand subsequently determined the optimal design. TheGuhring developed conical shank end optimally satisfiesthe relevant MQL conditions:In comparison to entirely dry machining, MQL canconsiderably reduce machining temperatures. The result islonger tool life and increased process reliability. Thermographicexperiments at Guhring showed that coolingwith dry air reduces the temperature at the tool point bymore than 200 degrees. The addition of a few millilitres ofneat oil per hour, hence MQL, resulted in an even lowertemperature thanks to the reduced friction.ChipToolWorkpiecewithout Air MQL431°C196°C145°Cwithout Air MQLEffective coolingGuhring has determined the heat development at the drill point when applied without cooling or with internal cooling with air or MQL respectively. WithMQL, the temperature of the tool and subsequently the transfer of heat to the workpiece is considarably reduced.272