MM Science Journal | www.mmscience.eu ISSN 1803-1269 (Print) | ISSN 1805-0476 (On-line) Special Issue | HSM 2019 15 th International Conference on High Speed Machining October 8-9, 2019, Prague, Czech Republic DOI: 10.17973/MMSJ.2019_11_2019045 MM Science Journal | 2019 | Special Issue on HSM2019 3019 HSM2019-013 CHATTER AVOIDANCE IN MILLING BY USING ADVANCED CUTTING TOOLS WITH STRUCTURED FUNCTIONAL SURFACES J. Baumann 1 *, E. Krebs 1 , D. Biermann 1 1 Institute of Machining Technology, TU Dortmund University, Germany * Corresponding author; e-mail: Jonas.Baumann@tu-dortmund.de Abstract The productivity of machining processes is often limited by the occurrence of dynamic effects. The presented approach intends to counteract tool deflections, and thus to damp and disrupt chatter vibrations by using milling tools with defined functional structures on the flank faces at the minor cutting edges. The potential of process stabilization is evaluated by analyzing the operational behavior of three variants of surface structures in experiments, in which an aluminum alloy was machined. An increase of the process stability and productivity of up to 60 % could be achieved. Keywords: Cutting tools; Chatter avoidance; Surface structures 1 INTRODUCTION The aerospace and automobile industry as well as many other branches face an increasing demand of highly load- resistant and lightweight components. To fulfill both requirements complex geometries and aluminum or titanium alloys have to be applied [Gonzalo 2006]. Many workpieces are designed as structural components where high amounts of material removal of up to 95 % have to be realized in performant machining processes [Brecher 2007]. The economic application of cutting processes is limited by the material removal rate under the restrictions of the production accuracy and quality at minimal costs. Such goals could be archived by increasing process parameters like feed velocity and tool engagement [Denkena 2011, Tönshoff 2014, Denkena 2016]. The maximization of these parameter values is limited by the performance of the drives of machine tools or disturbing effects, which can appear during the machining process [Dietrich 2016]. Thermal effects and static deflections can be compensated when modern control systems are used, whereas dynamic effects like chatter require preventive actions and specific process strategies [Hirsch 2012]. Various chatter suppression techniques were developed, but almost all of them require significant constrictive measures or specific adaptions to the process conditions, which also constitute considerable efforts [Munoa 2016]. This motivates the development and analysis of a new universally applicable approach, which combines a cutting-edge modification and application of surface structures on the flank faces at the minor cutting edges (figure 1). While all present applications of structures on the functional surfaces aim at a reduction of cutting forces or tool wear, the presented investigation introduces a new technique to avoid disturbing dynamic effects. Fig. 1: Process stabilization approach. 2 STATE OF THE ART The presented work covers scientific topics from process dynamics, tool optimization and surface structuring. The state of the art on these fields is presented in this section. 2.1 Process dynamics Early scientific works, regarding dynamic effects in turning processes were published since 1946 [Arnold 1946, Cook 1955, Hölken 1957, Cook 1959, Tlusty 1963, Merrit 1965]. Until 1961 the mechanism that is responsible for the occurrence of dynamic effects in machining processes was not sufficiently identified [Andrew 1961], although the regenerative effect in milling processes was already described starting in 1953 [Hahn 1953, Tobias 1956, Tobias 1961, Danek 1962, Peters 1963]. Later the regenerative effect was identified as the critical mechanism which leads to the occurrence of dynamic deflections in cutting processes [Altintas 2000, Tlusty 2000, Weck 2006]. Investigations on the impact of environmental and