Proceedings of SerbiaTrib '13

Based on the cutting data of every tool path, thenumber of cuts NC i and furthermore the tool wearVB i at the end of a tool path (i) can be calculated,as demonstrated in this figure. The flank wear VB i-1developed in the previous tool path (i-1), is relatedto a number of cuts NC i-1 considering the cuttingdata of the actual tool path. The number of cuts NC idata of the actual tool path is added to the NC i-1and thus the flank wear VB i at the tool path (i) canbe determined. By this method the flank weardevelopment can be effectively predicted in allsuccessive cutting tool paths.7. AN APPLICATION EXAMPLE OF THEDEVELOPED METHODOLOGYThe analytical method for estimating the toolwear is applied in the case of a test part presented inFigure 10. Considering the initial and finalworkpiece’s geometry, the tool paths required toremove the raw material volume were defined usingthe commercial “OPUS-CAM” system [17].Figure 10. The employed test part and the tool pathsrequired for the material removalFigure 11. Determination of chip data along the toolpaths by a CAD/ CAM systemThe determined tool paths are presented in thelower part of Figure 10 too. The machining tookplace in forty z-levels. The raw material removalwas accomplished using up milling and downmilling as well. Both operations lead to the samefinal workpiece shape, but the tool wear behaviourin each case may be different.After the tool paths have been determined, the“Schnitte.dat” file is generated by OPUS, as shownin Figure 11. This file contains geometrical datarelated to the chips formed in each tool path. Morespecifically, the parameters illustrated in Figure 10,determined at certain distances from every tool pathinitial point are stored into the “Schnitte.dat” file.In the first column of the file, the tool position isdefined as a percentage p of the actual tool pathlength l i , whereas i is the number of the tool path.At every tool position, the angle φ ref of the first toolrake – workpiece contact, the corresponding entryangle φ ent at the maximum cutting edge penetrationinto the part material and the exit angle φ ex arestored. Moreover, in the following columns, theundeformed chip length l cu , the axial depth of cut a zand the chip width b are accumulated. The data ofthe “Schnitte.dat” file are further processed by thedeveloped Data - PREparation (DAPRE) software.Thus, various data, as for instance the entryimpact time per chip, the undeformed chip lengths,the tool –workpiece contact angle etc. can beprovided. Considering these data the coated toolwear evolution versus the number of cuts isdescribed and in this way, the conduct ofalgorithms for an analytical optimization of millingprocess towards attaining set targets is facilitated.18 13 th International Conference on Tribology – Serbiatrib’13