Critical Thickness and Dynamic Stiffness for Chatter Avoidance in Thin Floors Milling

Abstract

A common problem in the aeronautical industry is the chatter vibration due to the lack of dynamic stiffness in the milling of thin walls and thin floors. The present work proposes a method for chatter avoidance in the milling of flexible thin floors with a bull nose end mill. It allows the calculation of the thickness previous to finish milling or the minimum dynamic stiffness that the floor must have to avoid the chatter vibration appearance. To obtain these values, the stability model algorithm has been inverted to estimate the thickness or the dynamic stiffness required in a floor to allow a stable milling. This methodology has been validated satisfactorily in several experimental tests.

Influence of Axial Depth of Cut and Tool Position on Surface Quality and Chatter Appearance in Locally Supported Thin Floor Milling

“…Secondly, it is noticeable that chatter appearance is higher for lower material removals; namely, it affects more cutting zones. As Campa et al [32] have stated, this phenomenon happens in the milling of thin floors with bull-nose end mills, and it is related to the fact that low depths of cut also involve low lead edge angles, that ease chatter appearance.…”

“…In another case, Campa et al [32] milled various blocks of aluminum without back support from 30 mm thickness to 1 mm, employing a bull-nose end mill of 16 mm diameter, a feed of 0.05 mm/tooth, and depths of cut higher than 5 mm, as well as a parallel strategy (instead of helicoidal). The final average roughness was between 0.3 mm and 1.4 mm in absence of chatter.…”

Evaluation of Thin Wall Milling Ability Using Disc Cutters

“…An attempt to analyze the problems related to the generation of thin parts or components of thin-walled parts by machining, as different researchers have approached them, highlights the fact that the main objectives pursued were the following: The identification or generation of software capable of analyzing the behavior of the workpiece material when the problem of generating thin walls by chipping arises [ 32 , 33 ]; The influence of the rigidity of the technological system or some of its components on the possibilities of generating thin walls by chipping [ 10 , 11 , 12 , 13 , 34 , 35 , 36 , 37 , 38 ]; Highlighting the connections between the vibrational or dynamic processes in general, specific to the realization of thin walls by cutting, and some aspects of the characterization of the surfaces generated in this way [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]; The use of the finite element method for modeling some aspects related to the generation by cutting thin walls [ 31 , 33 ]; The evaluation of the size of the cutting forces that occur when thin walls are obtained by cutting and revealing the correlation between the cutting forces and the deformation of the thin walls [ 2 , 12 , 35 , 53 , 54 , 55 ]; The identification of solutions that lead to the reduction of the deformation of thin walls generated by ...…”

Measurements of Forces and Selected Surface Layer Properties of AW-7075 Aluminum Alloy Used in the Aviation Industry after Abrasive Machining

“…Analysis of amplitudes in cutting provides the source of data regarding the generation of vibrations during machining, which is essential with respect to thin-walled workpieces [14]. The issues emerging in the machining of thin-walled elements, e.g., the shape and dimensional accuracy, the cutting forces, and the surface roughness, have been extensively described in the literature [15,16,17].…”