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The ball vibroburnishing process of external cylindrical surfaces involves workpiece rotation, while a ball is being pressed and forced to roll on the cylindrical surface, simultaneously, achieving an axial vibration. Experimental research was designed in accordance with the principles of a full factorial experiment with six independent variables at two levels on the test pieces made of two distinct steels, the medium-carbon steel 1C45 and the low-carbon alloy steel 18CrMn4-4. The frequency and amplitude of the vibration motion, ball diameter, radial rolling force, workpiece peripheral speed, and feed rate were considered as process input factors. The process output parameters were the surface roughness parameter Ra, Vickers microhardness of the surface layer measured at a certain distance from the hardened surface, and the hardened layer thickness. Through mathematical processing of the experimental results, power type functions were determined as empirical models. Worth mentioning is the fact that significant influence is exerted by the vibration amplitude on the size of the surface roughness parameter Ra, as well as the vibration motion frequency on the surface layer Vickers microhardness. Keywords: Ball vibroburnishing, Asperity generation, Process input factors, Surface roughness, Surface layer Vickers microhardness, Hardened layer thickness

One of the machining methods able to ensure a high material removal rate in the case of obtaining threaded surfaces is the whirling machining. In order to obtain a high accuracy of the machined surface and low values of the surface irregularities, an adequate selection of the machining parameters is necessary. A geometrical analysis of generating the surfaces in case of applying the whirl threading was developed. Geometrical and kinematical conditions were considered and software was used in order to modelling the process and to highlight the influence exerted by some process input factors on the machining errors and height of the surface irregularities.

In the present study the authors propose an experimental framework in order to perform FEA analyses upon a 3D model of a connecting rod. The study presents some of the technical issues that have been overcome by choosing the right software tools and the differences in terms of results that they may produce, it shows the setup used in the analyses including its constraints and loads, the proposed algorithm that imposed the number of analyses as well as their type, and the way the analyses were conducted in order for the results to validate or invalidate a optimized model. Because the connecting rod's 3D model presents a high level of complexity in terms of the number of free forms surfaces contained within the geometry, the authors propose a procedure by which they divide the geometry in areas of interest and in doing so can determine the most critical and the most affected areas under a given load for each FEA analysis. This procedure allows a virtual perspective of the modality through which the considered part gets affected and behaves under a given load in terms of distribution of stress and deformation, results that are consistent with its overall behavior.

In the technical literature there are some studies which use measured signals in order to compensate the errors caused by vibrations [1, 2], by the cutting force [3], by the deflections of the technological system [4], and others. Also, the technical literature presents some studies [6, which give few measurement techniques in order to measure the error which appears into the turning process and also, some methods to compensate or eliminate the consequences produced by those errors. In such conditions, this study propose to establish a possible methodology that can make the measurement of the radial deviation which corresponds to a work piece obtained into a turning process. The novelty of this study comes from the method of measurement used and from the measurement stand which provide the values of the radial deflection for the processed work piece, during the process. The experimental procedure assumes the existence of an experimental stand which allows to measure the distance between a sensor and the considered work piece. In such conditions, the mathematical algorithms used will transform the received electrical signal into a physical displacement. The obtained results suggest that the signal provided by the experimental stand and which it is used for measure the distance between a sensor and the considered work piece, allows to establish, with accuracy, the values for the radial deviations of the work piece. Also, this fact can offer a graphical representation of the shape which corresponds to the real profile of the processed work piece.

The vibro-burnishing is a process by means a ball or a roller or other tool active surface is pressed and moved, inclusively by applying a vibratory motion, along the surface to be finished, generating a specific microrelief. A device for vibro-burnishing adapted on a universal lathe was analyzed by means of some principles corresponding to the Axiomatic Design theory. The analysis was developed by adopting some simplifying assumptions and it proved an adequate design, by considering some functional requirements and design parameters specific to the device.

The phonic pollution is a problem of interest in the mechanical workshops. Various solutions could be applied in order to diminish the intensity level of the sound generated by various noise sources. The research presented in this paper aimed to highlight some aspects concerning the measuring of the sound intensity level in a mechanical workshop and some possibilities of decreasing the sound intensity level by using fences made of distinct materials. The sound intensity level corresponding to the use of a universal lathe was experimentally measured by means of an adequate apparatus. The results of experimental research were mathematically processed and some empirical mathematical models were determined. The analysis of the experimental results and empirical mathematical models highlighted the influence exerted by some factors on the sound intensity level and some possibilities of diminishing the phonic pollution by using various phonic fences.

Stamping of the bearing cages ensures a high enough productivity and consistency with the requirements of a large series manufacture. The roughness of stamped surfaces is one of the parameters for assessing the quality of the cages, which in its turn determines the behaviour in service of the bearings. A large number of input factors corresponding to the stamping process exert influence on roughness parameters. An experimental research has been conceived and developed to assess the influence exerted by the thickness of the blank and the clearance between the active elements of the die on the value of the surface roughness parameter Ra. The mathematical processing of experimental results allowed the identification of empirical mathematical models and graphical representations were designed to offer additional information concerning the influence of the two input factors in the stamping process on a quality parameter of the bearing cage.

The advantage of the technological assisted design consists in easy modification of the machining technologies for obtaining machine alternation, tool changing, working parameters variation or the modification of loads to which the tools are subjected. By determining tool movement inside machining and by using tool related moving speeds needed for both positioning and manufacturing we are able to compute the required machining time for each component of the machining operation in progress. The present study describes a cost optimization model for machining operations which uses the following components: machine and its operator related cost, set-up and adjustment, unproductive costs (idle state), direct and indirect costs. By using manufacturing technologies assisted design procedures we may obtain various variants for the technological model by modifying the machining strategy, tooling, working regimes or the machine-tool that are used. Simulating those variants allows us to compare and establish the optimal manufacturing variant as well as the most productive one.