Particle fracture and debonding during orthogonal machining of metal matrix composites

This paper investigates the particle fracture and debonding during machining of metal matrix composite (MMC) due to developed stress and strain, and interaction with moving tool by finite element analysis. The machining zone was divided into three regions: primary, secondary and tertiary deformation zones. The tendency of particles to fracture in each deformation zone was investigated. The findings of this study were also discussed with respect to the experimental results available in the literature. It was found that particles at the cutting path in the tertiary deformation zone fractured as it interacted with tool. In the secondary deformation zone, particles interacted with other particles as well as cutting tool. This caused debonding and fracture of huge number of particles as those were moving up along the rake face with the chips. No particle fracture was noted at the primary deformation zone. The results obtained from finite element analysis were very similar to those obtained from experimental studies

Effect of cooling methods on dimensional accuracy and surface finish of a turned titanium part

In metal cutting, the choice of cooling method influences the deformation mechanism, which is related to the dimensional accuracy and surface finish of the parts. The deformation mechanism of titanium alloys under machining conditions is known to be very different from that of commonly used industrial materials. Therefore, the effect of cooling methods on dimensional accuracy and surface finish in machining titanium is of particular interest. This paper investigates experimentally and analytically the influence of cooling method and cutting parameters on two major dimensional accuracy characteristics of a turned titanium part—diameter error and circularity, and surface finish. Data were analyzed via three methods: traditional analysis, Pareto ANOVA, and Taguchi method. The findings indicate that the cooling method has significant effect on circularity error (contribution ratio 76.75 %), moderate effect on diameter error (contribution ratio 25.00 %), and negligible effect on surface finish (contribution ratio 0.16 %)