Influence of Cutting Speed on the Hob Wear in Hobbing with the Minimum Quantity

In the paper the influence of cutting speed on the hob wear in gear hobbing when minimum quantity lubrication (MQL) cutting fluid supply method was applied, is described. Gears made of C45 steel were cut with the use of the hobs made of HS6-5-2 high-speed steel. For comparison, some tests with flood cutting fluid supply mode were performed. The investigations were carried out for four cutting speeds with constant feed rate and the full depth of tooth spaces. The tool wear was measured in a direct way, as the width of the flank wear land (VBC parameter). The results of the investigations were presented in the form of the diagrams of the distribution of tool wear on consecutive hob teeth vs. time, and also as the diagrams of the tool wear changes for the most loaded hob's tooth. By the use of the Taylor's equation the influence of the cutting speed on the hob tool life T period was determined. Based on the results obtained it was found that the MQL method can be an alternative solution for the cutting fluid supply in hobbing.