In this research, experimental studies were based on drilling with solid carbide tools and the material used was Al7075. The study primarily focused on investigating the effects of machining parameters (cutting speed, feed rate, diameter of the tool) on the thrust force (F z ) and the cutting torque (M z ) when drilling an Al7075 workpiece. The experimental data were analyzed using the response surface methodology (RSM) with an aim to identify the significant factors on the development of both the F z and M z . The application of the mathematical models provided favorable results with an accuracy of 3.4% and 4.7%, for the F z and the M z , respectively. Analysis of variance (ANOVA) was applied in order to examine the effectiveness of the model, and both mathematical models were established and validated. The equations derived proved to be very precise when a set of validation tests were executed. The importance of the factors' influence over the responses was also presented. Both the diameter of the cutting and the feed rate were found to be the factors of high significance, while cutting speed did not affect considerably the F z and M z in the experiments performed.

Apart from experimental research, the development of accurate and efficient models is considerably important in the field of manufacturing processes. Initially, regression models were significantly popular for this purpose, but later, the soft computing models were proven as a viable alternative to the established models. However, the effectiveness of soft computing models can be often dependent on the size of the experimental dataset, and it can be lower compared to that of the regression models for a small-sized dataset. In the present study, it is intended to conduct a comparison of the performance of various neural network models, such as the Multi-layer Perceptron (MLP), the Radial Basis Function Neural Network (RBF-NN), and the Adaptive Neuro-Fuzzy Inference System (ANFIS) models with the performance of a multiple regression model. For the development of the models, data from drilling experiments on an Al6082-T6 workpiece for various process conditions are employed, and the performance of models related to thrust force (Fz) and cutting torque (Mz) is assessed based on several criteria. From the analysis, it was found that the MLP models were superior to the other neural networks model and the regression model, as they were able to achieve a relatively lower prediction error for both models of Fz and Mz.

Noncircular gears are used in several technological applications in order to enhance the performance of different mechanical instruments (flow meters, bikes, internal combustion engines, etc.)• The mathematical models for manufacturing elliptical and oval gears are included.• The algorithm of the mathematical models is implemented using MatlabTM.• Simulations are carried out, and the method is implemented in a real WEDM machine.• Two pairs of elliptical and oval gears are obtained applying this method.

The concept of the sustainable development which is defined in terms of the triple bottom line (economic, environmental and social) is becoming increasingly important. Until now, however, the social aspects have been under-investigated in comparison to environmental and economic aspects. From the product design point of view there is an emergency for development tools and methodologies that are directly linked with the social pillar of sustainability. The research has as main target to discover the future role of designers and engineers to address sustainability as well as emerging priorities from societal to environmental challenges. Furthermore, the present paper presents a model named sustainability push & pull, which is focused on the cultivation of sustainable behaviour to the citizens. The key issue is the users/citizens participation during the product design process, playing an active role to the product development. The whole work was based on a framework which was built according to the direct communication between users and designers. Focused on this target, two new design for X methodologies a) Design for Promoting Sustainable Principles through user education and b) Design for Green Usability developed following the guidelines of the proposed User Assessment Tool. The research garnered responses from 72 participants who answered detailed questions during the whole design process. Data analysis was accomplished according to the data analysis process proposed by Miles and Huberman. The positive view to the whole process made clear that the used methodologies are friendly and very interesting for both the users/citizens and designers. The results from both the questionnaires and interviews show that it is also very educating while the proportions of knowledge about sustainability were grown up.

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