Breakthrough of regenerative chatter modeling in milling by including unexpected effects arising from tooling system deflection

Abstract

Conventional twist drilling is a widely used machining process for creating holes in aerospace and automobile structures. Drilling at room temperature can sometime affect the quality of machined holes due to increased thermal effects on the workpiece. Thermal effects can be a cumbersome when machining composites and fiber metal laminates due to their different thermal expansion coefficients, which may introduce additional stress in the structure. Thermal machining effects can be minimized using coolants supplied either directly or indirectly to the cutting tool-workpiece interaction zone, to remove away part of the generated heat. The use of coolants adds extra costs for handling, disposal, and environmental impact. Therefore, environmentally friendly cooling technologies are replacing conventional cooling methods to reduce costs and impact on the environment. In addition, the selection of machining parameters has great influence on the hole quality. This paper investigates the impact of drilling parameters and two modern cooling technologies namely cryogenic liquid nitrogen and minimum quantity lubrication on the hole perpendicularity error of fiber metal laminates commercially known as GLARE® (Glass Laminate Aluminum Reinforced Epoxy). It was also found that applying cryogenic liquid nitrogen or minimum quantity lubrication does not lead to an improvement in hole perpendicularity error in GLARE® laminates.

Cutting force prediction based on a curved uncut chip thickness model

“…The results of Young have been extended by Wang and Mathew [18] and later by Arsecularatne et al [4,19] to tools with nonzero inclinations angles by introducing equivalent cutting edges to trace back the calculation to classical models. Regenerative machine tool vibrations are predicted based on these approaches by Totis and Sortino [20] and by Kuster and Gygax [21] for internal turning, and by Totis for milling operations [22], too. The predictions have been deeply studied in the literature, experiments are performed and compared to the theoretical models by Lazoglu et al [23], Atabey et al [24,25], Kaymakci et al [26], and by several other researchers.…”

Upgraded Kalman Filtering of Cutting Forces in Milling

“…In the light of these considerations, the following Shearing and Ploughing stationary cutting force model was adopted, where , , and [N/mm ] are the shearing coefficients in the tangential, radial, and axial directions, respectively, whereas , , and [N/mm] are the plowing coefficients in the tangential, radial, and axial directions, respectively. This kind of model is a simplified version of well established cutting force models that can be found in literature [ 30 , 31 ]. Eventually, the components of the resultant force can be simply derived as follows, …”