Journal of Modern Processes in Manufacturing and Production
Year:2010 | Volume:1 | Issue:1|Papers Count:8

Extrusion of Width and big sections always has had technical and economic problem s. One way to solve this problem is utilizing extrusion dies with larger dimensions in their external sections than the initial billets. The shape of the die for such a process is such that it could allow the material to flow sideways as well as in the forward direction. For this aim, a new formulation according to Upper Band Theory is suggested and acceptable velocity field is introduced.According to this way, extrusion process of width sections is analyzed by this formulation for the first time. Then extrusion pressure according to the various variables of the process is calculated. Upper bound Results show production of these sections will be affordable. In the next stage, this work is fulfilled by Abaqus Software. Finally results are compared and show a good agreement between Upper bound and Finite Element analyses.

A modeling technique for simulating the nonlinear post buckling behaviour of laminated composite plates with cut out and subjected to axial compression is developed. The present progressive damage model capable of predicting the interaction effects between the post-buckling behaviour and the various failure modes of compressively loaded openhole plates. Due to the large bending deformation, resulting in buckling caused by transverse loading, the geometric nonlinear analysis becomes important. Various failure modes such as fiber breakage, matrix cracking are modeled by degrading the material properties. The final failure load of the structure is found using the geometric nonlinear progressive analysis based on degenerated shell element, comprising three basic steps, stress analysis, failure analysis and material property degradations rules. The present results are found to compare well with those available in the literature.

In this study, sheet steel forming was implemented by means of expansive power emanating from chemical reactions of a cement based material without application of hydraulic devices. At first, enthalpy changes of the material were calculated based on thermodynamic rules. To validate the method, an experimental device was designed & manufactured.The expansive material formed sample steel sheet with 1mm thickness & 120 mm diameter into semi-spherical shape via temperature & expansive power. Forming is successfully performed without any wrinkling due to the concurrence of temperature & hydrostatic pressure of the material.

The purpose of this work was to calculate temperature of grinding surface of workpiece during creep feed grinding using temperature histories and Inverse heat conduction and to predict surface temperature using Fuzzy Logic. Because of inaccessibility of cutting zone and pouring of cutting fluid, there is no possibility to measure temperature of grinding surface experimentally. So temperature of grinding surface should be estimated using temperature measuring of a point below grinding surface in distinct time-steps, taking advantages of special analytical methods and putting them together with heat conduction subjects. In this research temeperatures of three points of workpieces made of cobalt based superalloy was measured using three thermocouples which were located 2mm below grinding surface. Then the temperature of grinding surface was calculated making use of Inverse heat conduction and experimentaly recorded temperature histories. Afterwards a model was developed to predict temperature of grinding surface utilizing experimental data and Fuzzy Logic. Comparison of results showed that suggested model were capable of predicting temperature of grinding surface within an average error of about 3%.

Condition monitoring of the machining process is very important in today's precision manufacturing, especially in the Electrical discharge Machining (EDM). This paper introduces a Fuzzy-based Algorithm for the prediction of surface roughness (Ra), in the EDM process. In this system discharge current (I), pulse duration (Ti), are the input variables and output is Ra. Fuzzy model provides a more precise and easy selection of EDM input parameters for the required surface roughness, which lead to better surface validity and decreases the machining cost.

Electrochemical turning (ECT) is one of the electrochemical machining techniques. This method uses a nozzle instead of conventional tool that delivers electrolyte to machining gap. This method is electrochemical jet turning (ECJT). A mathematical model for ECJT has been presented in this research and its accuracy has been studied by doing different experiments.

A new method for increasing LDR in deep drawing is application of anti-lock braking system (ABS) on blank holder. In this method, instead of applying a constant force on blank and control the metal flow, the ABS system holds and releases the blank several times (20 to 50 times) which results increasing LDR. This study investigates the effect of different parameters of ABS on improving the conditions of drawing and increasing LDR The results of steel sheet (ST14) with 0.5 mm thickness shows that for each velocity of punch there is an optimum frequency for ABS. The best condition for applying force of blank holder is create a constant gap and a variable gap with ABS system.

One of the disadvantages of conventional milling tools is to produce a large amount of heat in cutting zone and so making the tool warmer. As a result, the tool would be worn and its life time would be reduced. Therefore, in long time machining, it is essential to change inserts and tools, continiously. A milling tool with self rotary cutting inserts was designed and manufactured that enables inserts to turn around their axes (which is different from tool axis). This rotation causes the heat to dispread in whole cutting edge and increase tool life time. In this paper, the process of design and manufacturing of rotary milling tool is expressed. The surface finishing of machined Aluminium workpiece is perused with the ‘Full Factorial’ statistical experiment design. Milling Tool with Self-Propelled Cutting Inserts is manufactured for the first time in Iran and was docketed by the No.51358.