Advanced Materials Research Vol. 837

Abstract: This paper presents a program for modeling and optimization of the arc welding process. Interface of the program is divided: time-synchronized monitoring multiple welding robots, a quick calculation options are various parameters, quickly replace the original design parameters (sequence of welding, etc.), the high degree of reliability modeling of welding defects, overheated regions, distortion and residual stresses in structures, intuitive visualization and control mechanism of the modeling process. Process variables are easy to evaluate quickly by changing the welding parameters, leading to systematic optimization of fusion zones, heat-affected zones, residual stress, and distortions. The software provides tools for reporting display of distortion, temperature distribution, residual stresses, and curve progression of physical factors on fixed measuring points. As a production process tool, simulation offers an interface to RoboCad, as well as an export interface to robots. Welding paths can be simulated in real speed, direction, and inclination, and the program is capable of tracking different heat sources (Goldak model, volume sources, surface heat sources with Gauss distribution, and combinations of this). This paper presents RobotStudio simulation of welding of parts. Optimum welding parameters are set using Simufact.welding modeling.

Abstract: In the context of the competitive actual environment, the production need to adapt to the preferences of the consumers, this represents the essential goal for all manufacturers. The production flexibility can be achieved by designing and marketing of new products or/and modify existing products in short time and at low cost. The technique presented in these article addresses of manufacturers and designers who made glass products unique or small series, adapted to consumer demands. In recent decades, digital fabrication methods are developed in various fields (aeronautics, shipbuilding, automotive, construction, architecture, industrial design and so on) and gained great popularity due to relevant advantages over the traditional production methods. Sculptural surfaces (also called free form surfaces) of the product with aestethetic requirements and/or functional role can be achieved through various technologies RP & M (Rapid Prototyping and Manufacturing). The Rapid Prototyping technologies can be grouped unto two major categories. First one refers to additive processes RP. From this point of view there are over 40 different types such as: stereo lithography (SL), Laminated Object Manufacturing (LOM), Selective Laser Sintering (SLS), 3D Printing (3DP), Solid Ground Curring (GSC) and Fused Deposition Modelling (FDM). The second one consists of subtractive Rapid Prototyping. Subtractive Rapid Prototyping (SRP) is one of the methods used for processing digital models into physical objects used for RP and for Rapid Tooling (RT). It is difficult to say what method is the best RP/RT; every one of them has advantages and disadvantages. The choice of the appropriate method depends on many factors, such as: product geometry, material type, dimensional accuracy, surface roughness on finished product, and so on. The starting point of this work consists in three photographs that are digitally processed to achieve the expansion of 2D in 3D structure. The expanded model is imported into computer-aided manufacturing (CAM) software. The parameters required to processing on Computer Numerical Control (CNC) machine are set, in order to obtain the shape of the casting mold. The schedule of heat treatment for glass is adapted according to the characterics of glass, mold material and the type of kiln. Rheological behaviour of glass has a key parameter in processing glass. The steps of kiln casting process (temperature ramps, heat treatment time) are choose at some values of viscosity (also called viscosity points ) related with glass type and size of object. The presented method can be successfully used in the manufacturing process offering to companies the possibility of increasing the capacity of new product development.

Abstract: The cutting of the threaded surfaces using whirling thread cutting devices is considered as one of the most productive cutting methods. From all the whirling thread cutting methods that one which utilise an inner point of contact had became the most utilised, because of the advantages which characterise the cutting process in this case:

Abstract: Among the processing methods by cold flow, toothing by intermittent blow is one of the most widespread. The gear-cutting by cold generation by intermittent blow is a processing method which extended continuously especially in the last 30 years. This enabled on the one hand, a better knowledge of the properties of toothed surfaces, and on the other hand the emphasis of the relationships between the superficial characteristics and the exploitation (use) properties of these products (frictional, fatigue etc.), as well as of the optimization of the technological processing parameters of these surfaces. The present paper presents a determination study on the depth of the hammer-hardened coat in the cold teething process by intermittent blow for a tooth of the generated teeth.

Abstract: This paper presents an integrated platform, based on collaborative environment, which can improve the design and prototyping activities. Collaborative activities in supporting product development and design during all product life-cycle, needs a Digital Factory framework. Demonstration of prototyping in real-time where are available changes in geometry, constraints, or other parameters can be based on virtual and augmented platforms. The mechanical and non-mechanical design needs, or any other virtual experiment can be experimented in virtual laboratory where researchers located in different geographical zones, can work on the improvement of product, by sharing resources and research results. Key words: Collaborative platform, virtual prototyping, virtual laboratory, conception, business strategy

Abstract: The paper aims to highlight the pressure and velocity variations on power lines created by water flowing through a cylindrical valve. Drain valve is typical cylindrical bottom of the dam or hydroelectric penstocks. Varieties of dimensions of these valves allow different analyses of the dynamics within them. The valves are able to access water from both sides and different ways of filling and closing action items. This paper presents a method to analyse the influence of parameters on physical-mechanical construction or operation and hence derive dynamic optimal design of these types of valves. Refer to the more intermediate positions of the piston sealing and visualization power lines and areas of turbulence for each position.

Abstract: In kinematic couplings, clearances are inevitable for their operation. The size of these clearances but as a consequence of use, causes a malfunction of the mechanism to which it belongs. The law of motion of driveline changes, big clearances, non-technological system causes vibration, leading to discomfort, uncertainty, and thus reach its degradation. In the paper we shall make a few of geometric and mechanical type considerations about the clearances in the linkages, linkages planes with joint rotation links. Based on mathematical algorithm developed and applied crank mechanism, the model presented in [1], this paper scientifically developed mathematical model, proposing mathematical models to study the influence of the size of the clearance in general dynamic calculation mechanisms. Mechanism considered is crank connecting rod mechanism with clearance cinematic coupling between rod and crank rotation. The paper makes a study of the influence on the dynamic behavior of the crank rod mechanism at high speeds, but also general method algorithm is developed and accurate method to assess the dynamic behavior of multi-body mechanism. The first case is considered a constant angular speed motor and thus determine the elemental expressions that establish the mechanism position, velocity and acceleration expressions in the two directions heads elements. Finally we obtain the expression of the normal reaction force, as well as position expression that defines its angle. With reaction force can specify phase (contact, flight, impact) [1], the behavior of the journal. For the case of general method - the method multi-body - the exact method are established liaison relationships between the parameters , write matrices , inertia matrix. Use Lagrange equations, if non-holonomic constraints. Matrix differential equation of motion is written and it can be solved numerically using Runge-Kutta method of order four. Of the iterative method, we obtain the parameters used in calculating the reaction force expression that can be evaluated accurately in journal bearings behaviour. Any would be their source of appearance, they usually produce unwished effects during the mechanisms functioning.

Abstract: Processing through volumetric cold plastic deformation (cold rolling) with flat wedge tools is a procedure used in mass production to process profiles (circular, threads, grooves, teeth) on revolution pieces. Complex profiles obtained by cold plastic deformation with flat wedge tools have important advantages: material economy, high productivity, continuous fibre, superior mechanic properties, low values of the roughness parameters, low costs. In recent years, the simulation of processes of volumetric plastic deformation by the finite element method is used to obtain the optimization of the deformation process and the improvement of the product quality even from the design stage. By numerical simulation there is observed the evolution during the process of different parameters such as: stress and deformations in the deformed body, mode of material flow, final shape and sizes of the product etc. Therefore, it becomes possible to analyse the process even from the design stage by identifying the problems which can appear and their influence on some characteristics of the product obtained: geometry, state of deformations and stress.This paper presents the experimental determination of the deformation force at the processing of complex profiles with flat wedge tools and the influence of the friction coefficient between tool and semi-product on its value; influence established by simulating the deformation process. The process also has been simulated by means of finite element calculations using the Abaqus/Explicit code. The material behaviour is described by using a 5-parameter strain-hardening law and by accounting for thermal effects at high strain-rates. The comparison between the values and the variation of the deformation force recorded experimentally and at simulation allows establishing the optimal value of the friction coefficient and validating the numerical model developed.

Abstract: Conveyor belt is one of the most common types of continuous handling equipment used for moving rocks of various sizes horizontally or inclined. From researches done in the exploitation of mineral resources and rocks and from the Strength of Materials calculations in this paper is observed above the conveyor sizing and other elements of the transporter requires knowing how belt traction forces (tensions thereof) varies on the conveyor length. In all cases the operation of the conveyor belt must be provided without engaging the slip phenomenon and limiting its displacement (between sets of rollers) so conveyor can operating at optimum parameters. The materials that make up a conveyor belt can be divided into two categories: materials for coating plates or outer shell and a resistance part, areas with inserts that can be textile and steel cables. Because the bands are subjected to tensile efforts and wear phenomena we determine the maximum strength they can operate without going into permanent deformation regime. Conveyor belt dimensioning calculations and other elements of a conveyor varies depending on its length and the carrier operating situations. We can see, also, that sizing conveyor belt and other conveyor components require knowledge of how belt traction forces (tensions thereof) varies along the length of the conveyor. The tensions from the conveyor belt will be study for the climb section and for the descend section. It mentions that the specific resistance to motion of the belt on full branch, consisting of resistances due: current material deformation, rotation rollers camps because pressing rubber layer and roll belt and belt bending. Since current material strength due to deformation and bending belt represents a large percentage of total specific resistance to motion, it follows that resistance decreases with decreasing displacement belt between rollers and increase with the effort in belt, respectively. This explains that resistance decreases with increasing length of conveyor (especially when its initial stretch is great), and with increasing conveyor tilt too. Also, we observe, from the values of forces calculated in the paper, that the resistance to rotation of the roller bearings decreases with increasing load on the roll, hence the values adopted for specific resistance to movement can be more larger on the empty branch than on the full. Knowing how to calculate resistances to motion of the belt, you can fix that occur belt efforts through the points made on the contour method, starting point of the drum motor development and ending point of winding it. These movement resistances calculated for empty and full branches are needed to precisely determine the installed power of the conveyor belt.

Abstract: Today, among the basic requirements to be fulfilled by an automobile, those relating to environmental protection and recyclability are of great importance. This paper aims to present a new technological solution to recover rare metals - Platinum, Palladium and Rhodium - from automotive used catalysts, based on hydrometallurgical method of solid-liquid extraction. Following the theoretical and experimental researches, were established the technological sequences which must be carried for recovering precious metals from used automotive catalysts, in the pilot phase. The proposed technology has been applied for a quantity of 10 kg of used automotive catalysts of ceramic monolithic type, at the end of the recovery process and selective separation, resulting the following recovery efficiencies: 95 % for Platinum, 95 % for Palladium and 92 % for Rhodium. Finally, there were highlighted the main advantages of hydrometallurgical processes: versatility, economicity, high efficiencies and relatively low costs.