İş Parçası Dinamiğinin Frezeleme Kararlılığına Etkisinin İncelenmesi

Frezeleme operasyonlarında tırlama titreşimleri üretkenliği olumsuz yönde etkileyen en önemli faktörlerden biridir. Kesme parametrelerine, Tezgâh/İş mili-takım tutucu-takım sistemi ve/veya iş parçası dinamiğine bağlı olarak ortaya çıkan bu titreşimler Tezgâh/İş mili ömrü, iş parçası yüzey ve boyut kalitesi, takım aşınması vb. gibi açılardan kritik bir önem taşımaktadır. Bu çalışmada frezeleme işleminde iş parçası dinamiği dikkate alınarak hem teorik hem de deneysel kararlılık analizleri yapılmıştır. İş parçası frekans tepki fonksiyonu temel faktör olarak değerlendirilip, her talaş kaldırma adımı için kararlılık diyagramları oluşturulmuştur. Tek serbestlik dereceli deney düzeneği üzerinde gerçekleştirilen frezeleme testleri ile de talaş kaldırmayla ortaya çıkan iş parçası dinamiği değişiminin kararlılık sınırlarına etkisi irdelenmiştir. Teorik ve deneysel çalışmalar neticesinde iş parçası dinamiği değişiminin kararlı ve kararsız kesme bölgelerinin değişimine yol açtığı gözlemlenmiştir. Elde edilen sonuçlar esnek iş parçalarının frezelenmesin de iş parçası dinamiğinin süreç verimliliği üzerinde kayda değer bir oranda etkisinin olduğunu ortaya çıkarmıştır.

Investigation of Workpiece Dynamics Influence on Milling Stability

Chatter vibrations are one of the most important factors that negatively affects the productivity in the milling operations. Those vibrations, which occur depending upon the cutting parameters, the Machine/Spindle-tool holder-tool assembly and/or the workpiece dynamics, have a critical importance in terms of the Machine/Spindle life, the workpiece surface and dimensional quality, tool wear etc. In this study, both theoretical and experimental stability analysis have been performed by taking into account the workpiece dynamics during the milling process. Stability lobe diagrams have been created for each material removal step by considering the workpiece frequency response function as a fundamental factor. Effect of the workpiece dynamics alteration arising due to the material removal on the stability limits has been examined with the milling tests performed on a single degree of freedom experimental setup. As a result of the theoretical and experimental work, it has been observed that the variation of the workpiece dynamics leads to change in the stable and unstable regions. The obtained results have revealed that the workpiece dynamics has remarkable influence on the process efficiency in the milling of the flexible workpieces.

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