Verification of influence of coating to the lifespan of mills

For application of new cutting tools into the praxis or for determination of their further development it is necessary to know their cutting properties. They are also important from the view of their economical handling. Beside that these properties serve as good and complex indicator in system of quality and reliability of cutting tools. Paper describes problems of tool wear and verification of tool lifespan. It is focused to testing of HSS grooving mills. At the beginning it brings theoretical knowledge from the field of HSS and describes advantages and disadvantages of long-term experiment. In practical part it describes the test that was used for HSS grooving cutters. Tests were realized as long-term experiments which are more accurate but more time demanding with higher consumption of material. During measuring of tool wear the cutting needs to be interrupted so we could cut in discrete intervals. Three types of HSS grooving mills were used with two jags and diameter of 6 mm. One type was coatless and two other types with coating AlTiN and AlTiSiN. As machined material there was steel STN 17 241, EN X5CRNi 18-10, that is austenitic chromium-nickel steel with very good corrosion resistance, cold plasticity and weldability. Experiment was realized on CNC machining center HAAS VF- 1B, that is located in laboratory of Cracow Polytechnics. Published graphs show that after use of coatless HSS steels labeled as „A“ the lowest lifespan was reached, as the mills lasted in action for shortest time. After use of mills with coating AlTiN S labeled as „B“ the influence of coating was observed in achieving of double lifespan. Longest action and thus best lifespan, what can be seen on graph C, was reached after use of HSS mills with coating AlTiSiN labeled as „C“, with threefold time period in comparison to coatless „A“ mills.Príspevok sa zaoberá overovaním životnosti frézovacích nástrojov. V experimente boli použité tri druhy HSS drážkovacích fréz s dvoma zubmi, s priemerom 6 mm. Jeden druh bol bez povlaku a ďalšie dva druhy boli povlakované špeciálnymi povlakmi. Experiment bol vykonávaný formou dlhodobých skúšok trvanlivosti, ktoré boli štatisticky spracované a následne vyhodnotené