Publication: Talaşlı üretiminde kesme işleminin sonlu elemanlar modeli ile incelenmesi
Abstract
TALAŞLI ÜRETİMDE KESME İŞLEMİNİN SONLU ELEMANLAR MODELİ İLE İNCELENMESİ Bu tezde FEM prosedürü ile yapılan kesme işleminin simülasyonundan elde edilen sonuçların deney sonuçları ile kıyaslanarak teklif edilen modelin doğruluğunun araştırılması amaçlanmıştır. Talaş kaldırmada kesme hızı, talaş açısı ve ilerleme miktarı gibi parametrelerin optimizasyonu ile kesme kuvvetlerinin azaltılması, kesici takım-iş parçası ara yüzeyinde ortaya çıkan ısının düşürülmesi veya ortamdan daha hızlı uzaklaştırılması ve sürtünme kuvvetlerinin azaltılması işlemleri kesici takım ömrünü uzatma yönünden önem taşımaktadır. Modelde kesici takım malzemesi olarak X8CrNi12 ve iş parçası olarak C45 girilmiş, bu malzemelerin (0 – 1200) sıcaklık C ve (0-80 s-1) birim şekil değiştirme hızlarına ait veriler tablolar halinde modele bağlanmıştır. İş parçası ve kesici takım malzemelerinin her ikisi içinde deforme edilebilen ve viskoplastik malzeme modeli seçilmiştir. Deneylerde ise aynı malzemeler kullanılarak vargel tezgahında değişik kesme hızı, kesme derinliği ve ilerleme altında kesme işlemi gerçekleştirilmiş ve kesme anında kesici uca gelen kuvvetler kesici takım üzerine bağlanan strain gage’ler ile ölçülmüştür. Elde edilen simülasyon sonuçları deneylerle karşılaştırılmış ve kullanılan modelin verimliliği görülmüştür.
FEM MODELING OF CUTTING PROCESS IN MACHINING In this thesis the cutting has been simulated using FEM procedures and the simulation results with respect to the cutting force have been compared to those of obtained from experiments. Chip removal process which is affected by several parameters such as cutting speed, chip angle and feed rate can be optimized by FEM simulations to reduce the cost of machining. Thus cutting process in a shaper machine is simulated with MSC.Marc and MSC.Superform. The work piece material and the cutter material were C45 and X8CrNi12, respectively. The stress-strain curves of the materials at elevated temperature, which were linked to solver, were obtained from software library for the temperature range of 0 to 1200 °C and strain rate range of 0 to 80 s-1. A viscoplastic material model was also selected for workpiece and cutter as both were deformable. In experimental part of the study, the same materials were used as wokpiece and cutter material with different cutting speeds, cutting height and feeds. The strain values which were caused by cutting force at the tool tip were measured with strain gages. A simple analytical calculation based on the beam bending was utilized to find the cutting force at the tool tip. The results of the simulations are compared to the experiments and the discussion directed to the effectiveness of the model.
FEM MODELING OF CUTTING PROCESS IN MACHINING In this thesis the cutting has been simulated using FEM procedures and the simulation results with respect to the cutting force have been compared to those of obtained from experiments. Chip removal process which is affected by several parameters such as cutting speed, chip angle and feed rate can be optimized by FEM simulations to reduce the cost of machining. Thus cutting process in a shaper machine is simulated with MSC.Marc and MSC.Superform. The work piece material and the cutter material were C45 and X8CrNi12, respectively. The stress-strain curves of the materials at elevated temperature, which were linked to solver, were obtained from software library for the temperature range of 0 to 1200 °C and strain rate range of 0 to 80 s-1. A viscoplastic material model was also selected for workpiece and cutter as both were deformable. In experimental part of the study, the same materials were used as wokpiece and cutter material with different cutting speeds, cutting height and feeds. The strain values which were caused by cutting force at the tool tip were measured with strain gages. A simple analytical calculation based on the beam bending was utilized to find the cutting force at the tool tip. The results of the simulations are compared to the experiments and the discussion directed to the effectiveness of the model.