Ainhara Garay

Mondragon University | Mu · Machining

Critical aero-engine components such as turbine discs must withstand severe cyclic stresses, which can eventually lead to low cycle fatigue (LCF) failures. These components are made of difficult-to-cut alloys and machining conditions that are employed in the last stage of the manufacturing chain must be correctly defined to avoid the generation of...

Aerostructures withstand cyclic mechanical loads and therefore, their design must fulfil surface integrity and fatigue strength requirements. This paper studies the effect of pneumatic machine hammer peening on surface integrity of 7050-T7451 aluminium alloy. Specimens were hammer peened using two different stepover distances (0.07 and 0.35 mm) and...

This paper addresses problems of predicting chip formation in high strain machining conditions. A complete physical model of chip formation requires both plasticity and chip/tool friction models. Friction models are commonly partly phenomenological, with friction coefficients measured from the conditions in which the models are applied. This paper'...

Employing cutting fluids in machining processes, especially for difficult-to-cut materials, improves machinability through prolonged tool life, improves surface integrity and chip evacuation. However, like oil and water-based cutting fluids are hazardous to the environment and workers' health, alternative solutions are required. Liquid Nitrogen (LN...

Within the framework of industry 4.0, the aim is to develop collaborative human-machine environments in order to achieve greater adaptability to the variability of cutting processes by making efficient use of available resources. For this, the use of the existing information in the data obtained from the cutting processes is fundamental. The contro...

Broaching is a widely used finishing operation for the manufacturing of transmission gears which are commonly made of steel AISI 1045. Therefore, there is a high interest for industry to understand the metal cutting process and modeling could shed light on it. In the present work, an innovative methodology to establish a hybrid model based on the c...

A new method for measuring temperature in the rake face of a tool during dry orthogonal cutting using thermography is presented. In addition, a new technique is also used to calibrate the infrared camera. Using this technique, real temperature values from camera response are directly obtained without the need for emissivity correction. Emissivity i...

Measured forces, chip geometry and tool temperatures from machining a mill annealed Ti6Al4V at cutting speeds mainly from 1 to 100 m/min, but in some cases down to 0.1 m/min, are reported, as well as mechanical testing of the material. Finite element simulations with inputs the measured flow stress, and subsequently a small high temperature strain...

The performance of aeronautic critical components is strongly dependent on its fatigue behavior, which is directly linked to their surface integrity condition. Broaching operation is a machining operation extensively used for the manufacturing of some features due to the good dimensional quality and surface integrity condition obtained. Thus, the c...

The guarantee of surface integrity has become a primary objective for researchers when analysing the reliability of machined aircraft aluminium alloy structural parts in high-speed machining. This work studies the effect of cutting speed on the surface integrity of face milled 7050-T7451 aluminium workpieces. First, 7050-T7451 aluminium workpieces...

Nickel-based alloys are widely employed in the manufacturing of aero-engines. These alloys are difficult to machine, and tensile residual stresses are generated during machining. These tensile residual stresses can negatively affect the performance of aero-engine components. Nevertheless, residual stresses can vary due to thermal or mechanical load...

Cryogenic machining together with minimum quantity lubrication (MQL), is claimed to be a promising alternative to flood cooling in industrial applications since it avoids the use of large amounts of cutting fluids and it improves the functional performance of machined components through its superior surface integrity characteristics. In this paper,...

This paper analyzes the effect of tool wear on residual stresses when turning. Inconel 718 discs were machined for prolonged periods at several cutting speeds, feed-rates and depth of cut. Tests were interrupted to measure and relate tool wear with the subsequent residual stress measurements. The discussion of experimental results is supported by o...

Nickel based alloys are extensively used in the aerospace industry due to the excellent corrosion resistance and high mechanical properties that are maintained up to elevated temperatures (600–800 °C). However, these superalloys are classified as difficult-to-cut and therefore modelling and simulation of the machining processes has become a key in...

Titanium alloys are widely employed in many aerospace components due to their high strength-to-weight ratio, good corrosion resistance and fatigue properties, maintained at relatively high temperatures. Nevertheless, machining these materials efficiently has become a challenge in a sector that demands high productivity rates and minimal manufacturi...

In manufacturing aeronautical critical components, such as turbine discs commonly made of Inconel 718, surface integrity is crucial to ensure their fatigue life. Among the machining processes used, the drilling operation is one of the most critical as overheating can occur causing thermal damage to the hole. The amount of heat dissipated could dete...

Infrared radiation thermometer is used to measure the temperature of tool during dry orthogonal cutting of titanium alloys. The accuracy of measured temperature depends on several parameters such as the experimental setup , physical acquisition data system and physical characteristic of the tool. These parameters are identified, their uncertainty e...

Tool life is usually measured by end tool life tests, however, such experiments are costly and time consuming. Establishing correlation between these tests and shorter and cheaper tests is consequently of great interest. Experimental results from dry orthogonal cutting tests are reported and a good correlation between temperature reached at the too...

Tool life is usually measured by end tool life tests, however, such experiments are costly and time consuming. Establishing correlation between these tests and shorter and cheaper tests is consequently of great interest. Experimental results from dry orthogonal cutting tests are reported and a good correlation between temperature reached at the too...

During surgical interventions where bone machining operations are involved (drilling, sawing, etc.), bone tissue may be damaged by the mechanical and thermal loads, and thus, working conditions should be selected in order to reduce or avoid this problem. In this study, with the purpose of reducing the damage induced when drilling, an analysis and i...

Surface integrity (SI) and, particularly, the residual stress profile, has a great influence on the fatigue life of machined aeronautical critical parts. Among the different cutting parameters that affect the final SI, tool geometry is one of the most important factors. In particular, tool nose radius determines the surface roughness, as well as th...

Inconel 718 is commonly used in critical components such as turbine discs, where turning, drilling, milling and broaching are common machining operations. In these components, fatigue life should overcome standard values and, for this reason, working conditions in finishing operations are carefully chosen taking into account surface integrity issue...

Surgical procedures that affect the human body's bone structure, often entail cutting, drilling or screwing operations of bone. The post-operative success of these procedures is largely dependent on the degree of damage introduced by the process. In this article, the influence of the rotational velocity, feed per tooth and two drill bit type on wor...

During surgical interventions, bone tissue may be damaged by the achieved high cutting efforts and thermal damage, which should be avoided. In this study, a new surgical drill bit with two types of cutting edges is proposed and tested, reducing tissue damage. Large part of the material is removed by brittle crack propagation, and surface is finishe...

Machining behaviour of Ti-5553, Ti-6Al-4 V mill-annealed (MA) and Ti-6Al-4 V solution treated and aged (STA) alloys was studied in different interrupted cutting operations using PVD coated cemented carbide tools. Single tooth face milling was employed to study the wear behaviour and tool life of the coated tools that were further inspected using sc...

Orthogonal tests on cylindrical workpieces were carried out to analyze the effect of heat treatment on the machinability of newly developed Ti54M titanium alloy in comparison with Ti64. This paper focuses on the comparison of forces and temperature of the tool during dry orthogonal cuttings of Ti64 and three different heat treated Ti54M alloys. F...

Orthogonal cutting force measurements and single-point tool life tests were conducted in order to analyze the sensitivity to heat treatment on the machinability of three titanium alloys: Ti6Al4V, Ti-5Al-4V-0.6Mo-0.4Fe (TIMETAL® 54M), and Ti6246. The Ti6246 alloy showed the highest tool wear rates and the higher cutting forces in all the heat treatm...

Surgical procedures that affect the human bone structure often entail drilling operations of bone. The post-operative evolution of these interventions is conditioned largely by the damage generated during the operation. The aim of this study was to determine clearly the influence of the cutting conditions on temperatures and forces when drilling bo...

Surgical procedures that affect the human bone structure often entail drilling operations of bone. The post-operative evolution of these interventions is conditioned largely by the damage generated during the operation. The aim of this study was to determine clearly the influence of the cutting conditions on temperatures and forces when drilling bo...

The objectives of the Promach project were, on the one hand, determination of microstructural effects on machinability improvement technologies for engineering steels at the same strength level, and, on the other hand, definition of a steel design procedure to minimise running costs of mechanical components of strength above 900 MPa. Steels with im...

Titanium alloys are increasingly employed in the aerospace sector. Thus a better understanding of its behavior during machining process is needed in order to improve the productivity and reduce manufacturing costs. When machining titanium alloys, tool wear is associated to diffusion and attrition mechanisms, and thus stresses and temperature on the...

High-speed milling is used across industries from aerospace to electronics. Tool wear can be affected by cutting interruptions in milling that lower tool–chip interface temperatures but also cause thermal and stress cycling. Micro-thermal imaging was used to determine the temperature during interrupted cutting of titanium alloy Ti6Al4V and AISI 414...

Resumen La aleación Ti-5Al-4V-0,6Mo-0,4Fe (TIMETAL ® 54M) es una nueva aleación α+β con propiedades similares a la comúnmente empleada Ti-6Al-4V pero con maquinabilidad mejorada. En trabajos previos los autores contrastaron este mejor comportamiento [1, 2] relacionándolo con la diferente microestructura de ambos materiales. Con objeto de estudiar m...

Single-point turning tests of cylindrical bars were undertaken to analyse and compare the machinability of Ti6Al4V, the most common titanium alloy, and TIMETAL® 54M, a newly developed alloy with similar mechanical properties as Ti6Al4V but with better machinability. Conventional cooling and uncoated WC–Co tool inserts were used in the study, becaus...

Chip Formation process is a complex process, although significant improvements have been reached in the last years, some issues, such as serrated chip formation or residual stresses, remain still obscure. Modelling the chip formation process by finite elements allow us to take into account the non-linear behaviour of the cutting phenomenon, and hen...

Near-beta titanium alloys like Ti555.3 are increasingly being used in aeronautics replacing in some critical applications the most common Ti6Al4V. However, these near-beta titanium alloys have a poor machinability rating which needs to be overcome so as to maintain at least the same productivity levels as in Ti6Al4V.This paper presents the machinab...