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La aleación de aluminio AA3003 proveniente de colada continua posee una microestructura que afecta significativamente su uso potencial en aplicaciones de ingeniería. Este trabajo estudia los efectos de la homogeneización sobre la microestructura del AA3003 con trabajo en frío. Se estudiaron seis condiciones combinando las variables: condición inicial (con y sin homogeneizado) y cantidad de trabajo en frío. Se evaluaron todas las condiciones mediante microscopía óptica y electrónica de barrido, combinadas con técnicas de electrones retrodispersados y espectroscopía de dispersión de rayos X. Los resultados sugieren que, para ambas condiciones iniciales, las fases secundarias presentes son Al6(Mn,Fe) y -Al(Mn,Fe)Si. La homogeneización causó la disolución y precipitación de los dispersoides, la esferoidización de las partículas primarias y permitió que la variación del tamaño de las partículas secundarias fuese mínima durante el trabajo en frío. Además, se obtuvo que las fases secundarias están compuestas de partículas primarias y secundarias, que difieren en su contenido de Fe y Mn, lo que resulta en una relación Mn/Fe más baja para las partículas primarias (0,57 para la condición recibida y 0,80 para la condición homogeneizada), mientras que los dispersoides tienen una mayor relación Mn/Fe (1,56 después de la homogeneización). La homogenización aumentó la ductilidad y redujo la probabilidad de agrietamiento del material durante el trabajo en frío, lo cual se evidenció en los resultados obtenidos de resistencia, dureza y ductilidad.//The aluminum alloy AA3003 produced by a direct chill continuous casting process has a microstructure that significantly affects its potential use in engineering applications. This work studies the effects of the homogenizing heat treatment on the microstructure of AA3003 with cold working. Six conditions were studied, combining the variables initial condition (with and without homogenizing) and amount of cold working. All conditions were evaluated by means of optical and scanning electron microscopy, in combination with backscattered electrons and energy dispersive X ray spectroscopy techniques. Results suggest that for both initial conditions, the secondary phases present are Al6(Mn,Fe) and -Al(Mn,Fe)Si, which vary in number, size, and shape. The homogenization caused the dissolution and precipitation of dispersoids, in addition to the spheroidization of primary particles, and minor variation of the size of secondary particles during cold working. Secondary phases are composed of primary and secondary particles, which differ in their Fe and Mn content, resulting in a lower Mn/Fe ratio for the primary particles (0,57 for the as-received condition and 0,80 for the homogenized condition), whereas the dispersoids have a higher Mn/Fe ratio (1,56 after the homogenization). Homogenization increased ductility and reduced the likelihood of cracking during cold working. This was evidenced by the results obtained for strength, hardness, and ductility.

In this paper an application of simulation for preventive evaluation of feasibility and costs in turning is presented.

In this paper a comparison of injection molding technologies for production of micro - optical devices is presented.

There is a strong interest both in mining and quarrying industry for the development of mechanical components such as jaws and mills made of high wear resistance materials. Hadfield steel is particularly resistant to abrasion wear and it is suitable for such an application. In recent years, a new metallurgical procedure has enabled the production of Hadfield steel with dispersion of Ti(C, N), which further increases the wear resistance of the material but severely reduces its machinability. In this work, a comparison of commercial tool grades and geometries for machining special Hadfield steel is presented. Specifically, surface roughness, chip form and tool life obtained by applying the selected tools were investigated and discussed. Some suggestions for tool selection are finally presented.

Single crystalline sapphire wafers are used as a substrate for semiconductor applications like gallium nitride-based white LEDs. In optimization of the manufacturing chain, rotational grinding can play a mayor role by substituting the conventional lapping process and reducing cost intensive efforts in downstream polishing steps. Due the material properties and in particular the hardness of sapphire, however, grinding process development is difficult. For this reason, the measurement of in-process variables like contact zone temperatures is of significant interest. In this paper, a concept and experimental setup for IR-based temperature measurement that utilizes the optical properties of sapphire is presented. The system behaviour of the realized test setup is examined in calibration tests. The results of successfully performed grinding tests are presented to prove the feasibility of the measuremnt concept.

The development of software for preventive estimation of cutting forces and cutting conditions of complex turning operations has been discussed in this paper. The aim of this software was to support the preventive process design and optimization, in terms of cutting conditions, chip control, cutting forces, workpiece dimensions and surface roughness for complex turning operations. The modeling of the workpiece was based on the quadtree technique which allows complex workpiece shapes, optimized computer memory management and very fast elaboration time. Also, the modeling of cutting forces has been discussed in this paper. The software was tested for development of parts programs for high-quality automotive components evidencing good prediction capabilities with short elaboration time on a conventional desktop computer.

Cutting force measurement in machining is a key issue for tool geometry optimization, tool condition monitoring, workpiece material machinability testing and other activities. In this work, the development of an innovative rotating dynamometer for cutting force measurement in milling is discussed. The device is capable to measure the forces acting on each cutting edge separately with a good dynamic response. Static and dynamic behavior of a simplified single-edge device was first investigated by means of static calibration procedure, pulse tests and preliminary cutting tests. Afterwards, pulse tests and cutting tests were performed on the complete measuring device clamped on a milling machine in order to evaluate the dynamic behavior of the system in operating conditions.

Nowadays, the interest for cutting force models is moved to their application in the indirect tool condition monitoring (TCM) systems. Hence, the reliable modelling technique becomes an imperative. In this study, a comparison of the application of linear regression and evolutionary algorithms, namely genetic programming, for modelling the cutting forces in face milling was done. Face milling trials have been realized and some results are discussed.

A spring-damper-mass model of the tooling structure with rotating dynamometer is presented. The proposed mathematical model proves the effect of cutting parameters on the frequency-transfer response of the measurement chain, i.e. on the cutting force signals behavior. Milling experiments have been carried out to investigate the effect of the cutting parameters on the measured cutting force signals. The obtained experimental results are in good accordance to the model prediction.

Recent developments in the field of tool condition monitoring have evidenced that, even for simple geometries of cut, it is necessary to estimate carefully the uncut chip thickness and the tool engagement for better understanding of the relationship between cutting parameters and cutting forces. In the past, the finite element method was applied to estimate the engagement between the tool and the workpiece. However, the results were not satisfactory, due to the exponential grow of a number of elements. A new approach based on lumped parameters method for tool engagement evaluation is presented. The lumped parameters are organized in a fractal structure in order to limit the number of elements needed for the calculation of the interference between the tool and the workpiece. The new approach is very promising for the simulation of tool engagement and the estimation of cutting forces where the cutting geometry is complex, for example in ball-nose end milling of mould and dies. The main issues of the new approach are presented and some preliminary results of its application for cutting force estimation in milling are illustrated.

The knowledge of cutting forces gives an important information that can be used both for theoretical and practical purposes. The aim of this research has been to investigate the influence of cutting parameters, i.e. cutting speed, feed per tooth and depth of cut, on the cutting forces in face milling by applying Kistler 9123C rotating dynamometer. The analysis of generated signals was done by using a statistical approach and the estimation of the mean of cutting forces are proposed. Face milling trials have been realized and some results are discussed.