Proceedings of SerbiaTrib '13

Table 4. Chip shape during processing with MQLtechniqueDepth a [mm]1.52.02.5Cuuting speedv c [m/min]210Feed f [mm/rev]0.224 0.280 0.400Some chip shapes during machining of the samesteel C45E, with the same tool, using MQLtechnique are shown in Table 4. Chips are dark,which indicates that in the machining area a largeramount of heat is generated and dissipated throughthe chips. It can be concluded that MQL techniqueprovides good effects of lubrication, but the badeffects of cooling the machining zone. Based on achip shape, it can be concluded that the use of MQLtechnique provide favourable shapes of chip for allanalyzed machining conditions.The technological areas for both techniques oflubrication and different depths of cut are shown infigures 12 and 13. They are based on the assessedchip suitability. From the analysis of thetechnological areas, it can be concluded that MQLtechnique offers a wider field of machining.Previous studies have shown that differenttechniques of lubrication have a great impact on thewear of tools as well. In our study the measuredparameters of tool wear were as follows: concentricwear (VB) and wear on the secondary surface oftool (VB'), and crater wear - see table 5 and 6. Thisparameters has direct impact on the machiningprocess, and thus on the machinability. Criterion oftool wear was VB = 0.3 mm. Tool life in the case ofMQL technique was for about 33% longer (see Fig.14). The parameters of the surface roughness -mean height of roughness (Ra) and maximumroughness (Ry) were measured depending on themachining time. As regimes for machining themean values of the obtained technological areashave been adopted: a = 2.0 mm and f =0.280 mm/rev, cutting speed v c = 320 m/min(Figure 14 and 15).Table 5. Tool wear during machining with conventionalCLF dosingTime T [min]Machining lenghtL c [m]0.93 2723.75 1286Secondary rakeTool wear on tool facePrimaryrakeClerance7.23 2080Figure 12. Technological areas for depth a = 1.5 mmFigure 13. Technological areas for depth a = 2.5 mmFigure 14. Comparative diagram of tool wear fordifferent techniques of CLF dosing296 13 th International Conference on Tribology – Serbiatrib’13