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The wire electrical discharge cutting can be used to separate parts from plateshaped workpieces or to make slots with various contours in electroconductive materials generally characterized by low machinability by conventional machining processes. The analysis of the wire electrical discharge machining process showed that there are many groups of factors able to affect the process results. The axiomatic design principles were used to define the conditions in which experimental research aiming to highlight the factors able to affect the sizes of technological interest in the case of wire electrical discharge machining. To evaluate the influence exerted by some input factors of the wire electrical discharge machining process, namely by the pulse on time, pulse off time, and by the average intensity of the discharge current, on some results of technological interest, an experimental research in accordance with the requirements of a full factorial experiment was designed and materialized. By processing the experimental results, it was possible to determine empirical mathematical models of power type function. [ABSTRACT FROM AUTHOR]

To develop the design activity in the case of a mechanical equipment for a machining process, certain initial conditions should be known and these conditions are sometimes called design requirements. Over the years, various methods were used in to elaborate the design requirements. Within the method of value analysis, better initial information is offered by the product or process functions. When the axiomatic design method is applied, the so-called functional requirements are taken into consideration. In the paper, the value analysis method and the axiomatic design method are used to highlight the design requirements in the case of a polyfunctional minimachine tool. One noticed that if the value analysis method is applied, some functions which are not technical attributes of the product or process are considered, in the case of applying the principles of the axiomatic design method only the requirements that could be materialized by a certain component of the desired product are considered. [ABSTRACT FROM AUTHOR]

In the industrial engineering field, there are several methods able to be applied in order to materialize a cut contour. Not in all cases, the removable rate of material and cutting accuracy are satisfactory and the costs are sufficiently low. In such situations, some nonconventional processing methods could ensure a fast and appropriate solution for cutting workpieces. Knowing that the surface roughness is a parameter of real interest in almost cases when the accuracy is considered, definitely it will decide the chosen manufacturing process. Due to its influence on the surface properties and on the number of subsequent machining operations, the required roughness value could be taken into consideration when selecting the cutting process. Among distinct nonconventional processes which can be applied, in the present paper, the laser beam procedure was established as being the right choice in order to accomplish certain objectives. A theoretical analysis showed that some of input factors for laser beam process are able to affect the sizes of the surface roughness parameters and could be represented by cutting speed, pressure of the gas sent to the processed area, the power developed in the contact area between the laser beam and workpiece, the process efficiency and the frequency of the laser beam. An experimental research was designed and developed, in order to highlight the influence exerted by the above mentioned factors on the size of the Rz surface roughness parameter. Using the experiments planning, it was developed a series of experiments, in order to show the intensity of effects exerted on the surface roughness by the process input factors. [ABSTRACT FROM AUTHOR]

The electrochemical machining with forced hydrodynamic depassivation allows the material removal from workpiece by electrochemical erosion. The products resulted as a consequence of the electrochemical reactions developed between the workpiece material and electrolyte are removed from the machining zone by forced circulation of the electrolyte. A theoretical analysis led to formulation of several hypothesis concerning the behaviour of some metallic materials when test samples presenting a conical surface are affected by the electrochemical machining process with forced hydrodynamic depassivation. In the paper, the results of some experimental researches developed on test samples from steel, bronze and aluminium are presented. By mathematical processing of the experimental results, some empirical mathematical models were established. The empirical models highlight the influence exerted by the gap size, by the size of angle corresponding to the conical surface and by the voltage applied to the two electrodes on the size of the final gap and on the quantity of material removed from the test piece, for a certain duration of the machining process. [ABSTRACT FROM AUTHOR]

The electrochemical machining process is based on the material removal from workpiece as a consequence of electrochemical reactions developed between the workpiece material and electrolyte, when both tool electrode and workpiece are found in an electrolyte and they are connected in the electric circuit of a direct current supply. Distinct factors could exert influence on the sizes of parameters of technological interest in case of electrochemical machining process. The paper presents the results of some theoretical considerations and experimental researches concerning the evolution of the work gap size and diminishing the test piece mass in case of using a conical active surface of the test piece and an aqueous solution of sodium chloride as electrolyte. The experimental results were mathematically processed and empirical mathematical models were determined. The empirical models and the graphical representations based on these empirical models illustrated the diminishing of the final gap size when the angle of conical surface increases and when the initial gap size is higher; the increase of voltage determines an increase of the final gap size. A similar influence is exerted when the test piece mass is considered as output factor. [ABSTRACT FROM AUTHOR]

The electrical discharge drilling could be applied in order to obtain cavities in workpieces made of materials difficult to be machined by classical machining methods. Distinct factors exert influence on the drilling speed. An experimental research was designed and developed by considering the depth of the cavity achieved by means of a tubular tool electrode. One used a machining scheme involving the achieving of the work movement by test piece to the tubular tool electrode clamped on the machine tool table. In this way, the influence exerted by the spurious electrical discharges facilitated by the presence in the work gap of the metallic particles detached from the two electrodes can be diminished. Empirical mathematical models were determined by mathematical processing of the experimental results and using specialized software. The empirical mathematical models proved a high influence exerted on the drilling speed by the peak current intensity. [ABSTRACT FROM AUTHOR]

Between the machinability by classical machining methods and use of nonconventional technologies there is a certain correlation. When the machining by classical methods is not possible or it is difficult to be applied, one can took into consideration the use of nonconventional technologies. The documentary research showed that that the empirical models corresponding to the tool wear, cutting forces and roughness of the machined surface, considered also as machinability indexes, take into consideration characteristics of the workpiece material. In order to improve the conditions of developing a machinability evaluation by drilling under constant force feed, a machining schema involving the work feed movement of the test piece from up to down, to the rotating drilling tool, was proposed. The experimental research led to a power type empirical mathematical model able to highlight the influence exerted by the rotation speed, drilling tool diameter and the force feed on the length of hole achieved in a certain time. [ABSTRACT FROM AUTHOR]

Different processing methods can change the physical–mechanical properties and the microgeometry of the surfaces made by such processes. In turn, such microchanges may affect the tribological characteristics of the surface layer. The purpose of this research was to study the tribological behavior of a test piece surfaces analyzing the changes on the values of the coefficient of friction and loss of mass that appear in time. The surfaces subjected to experimental research were previously obtained by turning, grinding, ball burnishing, and vibroburnishing. The experimental research was performed using a device adaptable to a universal lathe. Mathematical processing of the experimental results led to the establishment of power-type function empirical models that highlight the intensity of the influence exerted by the pressure and duration of the test on the values of the output parameters. It was found that the best results were obtained in the case of applying ball vibroburnishing as the final process. [ABSTRACT FROM AUTHOR]