Surface Quality Improvement in Machining an Aluminum Honeycomb by Ice Fixation

Abstract

A honeycomb structure is widely used in sandwich structure components in aeronautics and astronautics; however, machining is required to reveal some of its features. In honeycomb structures, deficiencies, such as burrs, edge subsiding, and cracking, can easily appear, owing to poor specific stiffness in the radial direction. Some effective fixation methods based on a filling principle have been applied by researchers, including approaches based on wax, polyethylene glycol, iron powder, and (especially) ice. However, few studies have addressed the optimization of the cutting parameters. This study focused on optimizing the cutting parameters to obtain a better surface roughness (calculated as a roughness average or R a ) and surface morphology in the machining of an aluminum alloy honeycomb by an ice fixation method. A Taguchi method and an analysis of variance were used to analyze the effects and contributions of spindle speed, cutting depth, and feed rate. The optimal cutting parameters were determined using the signal-to-noise ratio combined with the surface morphology. An F-value and P-value were calculated for the value of the R a , according to a "smaller is better" model. Additionally, the optimum cutting parameters for machining the aluminum honeycomb by ice fixation were found at different levels. The results of this study showed that the optimal parameters were a feed rate of 50 mm/min, cutting depth of 1.2 mm, and spindle speed of 4000 r/min. Feed rate was the most significant factor for minimizing R a and improving the surface morphology, followed by spindle speed. The cutting depth had little effect on R a and surface morphology. After optimization, the value of R a could reach 0.218 μm, and no surface morphology deterioration was observed in the verified experiment. Thus, this research proposes optimal parameters based on ice fixation for improving the surface quality.

Study on milling flatness control method for TC4 titanium alloy thin-walled parts under ice fixation

“…Dhananchezian and Pradeep Kumar 15 used low-temperature cooling method to machine TC4 titanium alloy, and the cutting temperature was reduced by 61%–66%, the surface roughness value was reduced by 36%, and the cutting force was reduced by 35%–42%. Shokrani et al, 16 Wang et al, 17 and Fengbiao et al 18,19 proposed a milling method with low-temperature liquid nitrogen cooling, which successfully achieved efficient machining of titanium alloy, aluminum alloy honeycomb material and nickel-based alloy honeycomb material, and the surface quality of the workpiece was effectively improved and machining defects were effectively suppressed. However, this processing method requires a continuous flow of liquid nitrogen to the processing area to prevent the ice from melting, and is costly and wasteful.…”

Optimization of the cutting tool geometry when milling aluminum honeycomb structures

“…The components of the cutting forces which have been determined by the numerical model allow determining the resulting cutting force given by the following relation [13]: 1 4…”

“…In addition, the signi cant vibrations of the thin walls of the honeycomb represent the source of several problems such as the deformation of the walls, the burrs as well as the poor surface quality generated [3]. Milling is the most widely used material removal forming process in the production of mechanical parts (automotive, aerospace) [4]. In this regard, the Numerical studies show that the morphology of the chips and the wear of the cutting tools are closely linked to the machining conditions [5].…”

Development and Characterization of a Thermoforming Apparatus Using Axiomatic Design Theory and Taguchi Method

“…The signal-to-noise (S/N) ratio is particularly utilized in the Taguchi method to study the influence of each factor [37]. Because the uniformity, the typical of interest in this investigation, should be as close as possible to zero, a "smaller the better" formula is employed for the S/N ratio calculation as follows [39], [40]:…”