A.I. Fernández-Abia

Application of a Force Sensor to Improve the Reliability of Measurement with Articulated Arm Coordinate Measuring Machines

A study of the operator contact force influence on the performance of Articulated Arm Coordinate Measuring Machines (AACMMs) is presented in this paper. After developing a sensor capable of measuring the contact force applied by an operator, a ring gauge has been used to analyse the relationship between the contact force and diameter and form errors measured with the AACMM. As a result, contact force has been proved as one of the main factors influencing the AACMM performance. A probe deflection model based on the Finite Element Method (FEM) has been also proposed in order to obtain the AACMM probe deflection caused by contact force. This allows measurement correction by comparing them with reference values, specifically, a ring gauge. Experimental test results show a significant measurement improvement that minimizes diameter error. Finally, an uncertainty evaluation for the contact force sensor and AACMM measurements with and without probe deflection model has been carried out in order to validate the ability of the sensor and the methodology followed.

A cryo lubri-coolant approach for finish milling of aeronautical hard-to-cut materials

Use of heat-resistant alloys is growing worldwide in aeronautical turbo-machinery industry. One of the most used materials is Inconel 718. This material is featured by high resistance to corrosion and oxidation while keeping good mechanical properties at high temperature. However, low machinability of this material results in poor material removal rates and premature tool wear, among other drawbacks. Consequently, mineral cutting fluids are injected in the cutting zone in order to improve machining. However, todays environmental consciousness leads us to propose the cryoMQL technology as an ecological alternative. In order to achieve better results when milling Inconel 718, a CO2 cryogenic regulation system and a nozzle adaptor have been developed to use cryoMQL and a comparative analysis is performed with regard to other coolant alternatives.

Tools for Teaching-Learning of Manufacturing Engineering Using Content Management Platforms

This paper presents the methodology that is being applied at present time for teaching and evaluation of different courses in the area of manufacturing processes engineering at the University of León. The context is delimited to the use of content management systems and continuous evaluation of learning. In particular, the Moodle platform is used for structuring the contents and for the continuous evaluation of courses in the scope of materials science, manufacturing processes and automation of operations. An analysis of the changes and challenges derived from the adoption of this methodology in the different courses in which has been applied is presented. These changes have been slightly different as a function of the compulsory or optional character of courses, as well as depending on the number of students enrolled in them.

Estimation of Cutting Forces and Tool Wear Using Modified Mechanistic Models in High Performance Turning

In this chapter a model for prediction of cutting forces when turning austenitic stainless steels following the approach of mechanistic models is presented. Mechanistic models, also called semi-empiric, use empiric laws based on the tool geometry and coefficients obtained by experimentation. These coefficients implicitly pick up characteristic data about part and tool materials or tool geometry. Therefore, a series of machining tests is required to calculate these coefficients for each pair tool-workpart, commonly known as characterization tests. This chapter is structured as follows. In Sect. 3.1 a model for prediction of cutting forces without considering the effect of tool wear is presented. This model allows to estimate with reasonable precision the cutting forces. This model can be used, for example, in the scope of machine-tools and fixtures design or optimization of cutting tool geometry. In Sect. 3.2 this model is extended to include the effect of tool wear. So, the model can be used in the scope of monitoring techniques. Both models were developed for turning AISI 303 austenitic stainless steels at high-speed cutting conditions.

Management of Manufacturing Engineering Seminars in the Context of New Educational Trends

A methodology for seminars developing in manufacturing engineering is presented. Often, when planning similar seminars, it is noted that seminars have a very limited duration. A normal way to overcome this limitation is to prepare the seminar educational documents, at students disposal, before the seminar date. In this point, ICT tools used for virtual teaching, like eXe-Learning, become a significant advancement. However, in this paper is not only considered the elaboration of seminar materials for students, but also a whole educational strategy for seminars developing in manufacturing engineering is stated.

The influence of cutting speed in austenitic stainless steel machining: Study of specific force coefficients

Although the turning process has been widely studied and is well-known, some limitations exist in the processing of certain materials due to an absence of their characterization. Such is the case of austenitic stainless steels, which in spite of being materials of great economic and technological value, their behavior in machining is still not well understood in some aspects. In industry there is not enough reliable and up-to-date technological data about austenitic stainless steels, especially when considering the state of the art in technology development where cutting speeds are higher and higher. In this paper a mechanistic model for cutting force prediction is developed; expressions for the specific coefficients of cutting are determined that characterize the behavior of austenitic stainless steels turning at high cutting speeds using coating tungsten carbide tools.

A Mechanistic Model for High Speed Turning of Austenitic Stainless Steels

Behavior of austenitic stainless steels is not well known and these materials are still considered as difficult to machining materials. Moreover, the continuous increment of cutting speeds and other cutting parameters derived from last technological advances in tool material makes it more difficult to understand the behavior of these materials in high performance machining. A mechanistic model is presented in this paper for cutting force prediction of austenitic stainless steels turned at very high cutting speeds (up to 750 m/min). The developed model allows the estimation of cutting forces in turning when the cutting action occurs on the side cutting edge and nose radius edge for general turning tools. A tool-part geometrical model is proposed and the cutting force coefficients have been calculated by means of characterization tests.