INVESTIGATION OF THE CALCULATION PLOUGHING FORCE AND THE EFFECT OF FRICTION COEFFICIENT IN MACHINING OF ALUMINUM 6061-T6

Öz

In metal cutting operations, the ploughing force, which occurs due to the effect of edge radius of the tool that is an essential factor in terms of tool wear, prediction of flow stress, chip formation mechanism, surface quality and finite element modeling of metal cutting operations. In the literature, the ploughing force was estimated based on the periodic force in steady state metal cutting operations. However, periodic force does not occur in most metal cutting operations. In this article, the ploughing force was estimated by integrating uncut chip thickness to zero value by using extrapolation method. After estimating the ploughing force by this method, the Coulomb friction coefficient can be calculated and the precision of the assumption is compared. The estimated ploughing force is more homogeneous when plotted against uncut chip thickness, and the Coulomb friction coefficient is quite accurate to friction value which found in the literature. Hereby, the assumption is acceptable to estimate the ploughing force by using extrapolation method and the calculation of the Coulomb friction is valid in metal cutting operation which periodic force does not occur.

Anahtar Kelimeler

• Aluminum Al6061-T6,Metal Cutting,Ploughing Force,Coulomb Friction Coefficient

Alüminyum Al6061-T6‘nın İşlenmesinde Sürtme Kuvvetinin Hesaplanması ve Sürtünme Katsayısının Etkisinin Araştırılması

Öz

Metal kesme işlemlerinde, takım kenar yarıçapının (edge radius) etkisiyle ortaya çıkan sürtme (ploughing) kuvveti takım aşınması, akış geriliminin tahmini, talaş oluşum mekanizması, yüzey kalitesi ve metal kesme işleminin sonlu elemanlar yöntemi ile modellenmesi açısından önemli bir değişkendir. Literatürde, sürtme (ploughing) kuvveti kararlı hale (steady state) gelmiş metal kesme işlemlerindeki periyodik kuvveti temel alarak tahmin edilebilmiştir. Fakat periyodik kuvvet çoğu metal kesme işlemlerinde ortaya çıkmamaktadır. Bu makalede, sürtme kuvveti kesilmemiş talaş kalınlığını (uncut chip thickness) ekstrapolasyon yöntemi ile sıfıra yakınsayarak tahmin edilmiştir. Sürtme (ploughing) kuvvetinin bu yöntem ile tahmin edilmesinden sonra Coulomb sürtünme katsayısı hesaplanılarak yapılan varsayımın doğru olup olmadığı karşılaştırılmıştır. Tahmin edilen sürtme (ploughing) kuvveti, kesilmemiş talaş kalınlığına karşı çizildiğinde daha homojendir ve Coulomb sürtünme değeri literatürde bulunan sürtünme kuvvetleriyle oldukça yakın çıkmıştır. Bu yüzden, periyodik kuvvetin oluşmadığı metal kesme işlemlerinde, sürtme (ploughing) kuvvetini ekstrapolasyon yöntemi ile tahmin etmek ve Coulomb sürtünme değerini hesaplamak kabul edilebilir görünmektedir.

Anahtar Kelimeler

• Alüminyum Al6061-T6,Talaşlı İmalat,Sürtme Kuvveti,Coulomb Sürtünme Katsayısı

Kaynakça

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