Efficient optimisation of machining processes based on technical specifications for surface roughness: application to magnesium pieces in the aerospace industry

Materials Forming, Machining and Tribology

Davim

2014

In the last decades, the interest for magnesium has increased notably. In particular, the need for weight reduction in the automotive industry has made magnesium a suitable material to replace traditional structural materials because of its low density. But, in addition, magnesium is also finding applications in different sectors as aeronautics, electronics, medical or sports. Thus, machining of magnesium is a topic of great interest for industry and researchers. In the present work, an introduction to the main topics on magnesium machining is presented. The text covers from general topics of magnesium to more specific ones related with the machining process. In this sense, an approximation to the properties of magnesium, magnesium alloys and metal matrix composites of magnesium, and some applications are presented to give a general overview of magnesium. After that, the machining of magnesium is covered addressing general issues and more specific particularities of magnesium machining, such as the ignition risk. To conclude, a brief review of some of the main experimental investigations on magnesium machining is presented, covering drilling, milling and turning processes. In these studies, the machining process is assessed using indicators such as surface finish, temperature or tool wear.

Section: Turningmentioning

confidence: 99%

Machinability of Magnesium and Its Alloys: A Review

Carou

Materials Forming, Machining and Tribology

Davim

2014

“…On the other hand, this approach would allow, if necessary, for an increase in the degree of complexity of the geometry of the test pieces from solid knowledge about the joint behaviour of the individual materials depending on the results that were obtained. We have previous experience in the machining of both materials, both in continuous turning (horizontal and facing) [47][48][49][50][51][52][53][54][55][56][57][58][59][60] and in intermittent turning [56][57][58][59][60]. The geometry of the specimens raised in the present study is a natural evolution of the geometries and materials previously studied separately that have just been mentioned.…”

Section: Methodsmentioning

confidence: 96%

“…Statistical analysis of the data. The statistical methodology carried out in order to analyze the results of the experimental design is briefly described in [54]. The variability of the surface roughness is modelled through the analysis of variance (ANOVA) over the average roughness values, Ra, identifying the most influential factors and interactions on the surface finish.…”

Section: Methodsmentioning

confidence: 99%

Experimental Study for Improving the Repair of Magnesium–Aluminium Hybrid Parts by Turning Processes

Villeta

Valencia

et al. 2018

Metals

Self Cite

Abstract:One of the lightest metallic materials used in the aeronautics, aerospace, and automotive industries, among others, is magnesium, due to its excellent weight/strength ratio. Most parts used in these industries need to be made of materials that are rigid, strong, and lightweight, but sometimes the materials do not simultaneously satisfy all of the properties required. An alternative is to combine two or more materials, giving rise to a hybrid component that can satisfy a wider range of properties. The pieces machined in these industrial fields must satisfy stringent surface roughness requirements that conform to the design specifications. This work shows an experimental study to analyse the surface roughness reached in hybrid components made up of a base of magnesium alloy (UNS M11917) and two inserts of aluminium alloy (UNS A92024) obtained by turning. Its purpose is to determine the influence of the factors and their possible interactions on the response variable, the surface roughness Ra. The study is carried out using a design of experiments (DOE). A product of a full factorial 2 3 and a block of two factors 3 × 2 was selected. The factors identified as possible sources of variation of the surface roughness are: depth of cut, feed rate, spindle speed, type of tool, location with respect to the specimen (LRS), and location with respect to the insert (LRI). Data were analysed by means of the analysis of variance (ANOVA) method. The main conclusion is the possibility to carry out the repair and maintenance of parts of magnesium-aluminum hybrid components by dry turning; that is, without cutting fluids and, therefore, in the most sustainable way that the process can be carried out. In addition, different combinations of cutting parameters have been identified that allow these operations to be carried out in an efficient manner, reducing mechanization times and, therefore, also the direct and indirect costs associated with them.

“…From another side, Sayit et al [18] also identified a negative effect of the feed rate in discontinuous turning on the surface roughness, evaluating feed rates from 0.11 to 0.32 mm/rev. When using feed rates up to 0.1 mm/rev, the surface roughness values are below a range suited for aerospace and aeronautic fields (0.8<Ra<1.6 μm) [36]. However, when machining with the highest feed rate (0.2 mm/rev), the surface roughness is clearly above the aforementioned range.…”

Section: Surface Roughnessmentioning

confidence: 91%

“…For the feed rate selection, work by Villeta et al [36] is taken into account, though slightly higher values of the feed rate are selected. Thus, feed rates from 0.05 to 0.2 mm/rev are selected.…”

Section: Methodsmentioning

confidence: 99%

Experimental investigation on finish intermittent turning of UNS M11917 magnesium alloy under dry machining

Carou

Int J Adv Manuf Technol

Lauro

et al. 2014

An experimental investigation on finish intermittent turning of UNS M11917 magnesium alloy under dry machining is presented. The objective of the study is the analysis of the chip morphology, surface quality and temperature when varying cutting conditions. The intermittent cutting process is analysed using three different workpieces (one continuous and two discontinuous). The experimental plan is based on full factorial designs. Main results of the investigation include the identification of the feed rate as the most important parameter to explain the surface roughness, while no clear influence was found for the cutting speed and slot width. The maximum temperature measured on the tool during the tests was below 50°C in all of the tests. These low temperature values are explained by the low machining times, depths of cut and cutting speeds used. Thus, for the range of the cutting parameters tested, finish operations can be performed using dry machining under safe conditions. In addition, it was identified that the increase of the depth of cut and feed rate led to higher maximum temperatures, while the increase of the slot width led to lower values. Finally, the morphology of the chips can be classified as segmented chips, including the arc, elemental and spiral chips. Thus, in terms of machining, these chips can be considered as favourable, but, in terms of ignition, these chips are more likely to ignite.