Chapter for clean-up and separating castings and mold

Chapter 1INTRODUCTION _____________________________________________________1.1 IntroductionInline knockout machine is a kind of machine widely used in foundries for clean-up and separating castings and mold box. Machine is suitable for the above purpose because of simplicity of structure, reliability and provision for adjustment in vibrating direction and amplitude of exciting force. Main components of Inline Knockout Machine mainly consist of torsion bar, vibrating frame, vibrating box, vibrating motors installed on both sides of the vibrating box, spring and support device. When it works, the two vibrating motors rotate synchronously in the reverse direction. The vibration force in the vibration direction is generated by two vibration motors and the excitation force in the vertical vibration direction is equal to zero resulting in a straight line or an approximately straight line motion.figFailure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 2The vibrating box may break in the long-term work, especially the sides of the vibrating box may suffer Fracture, and also vibrating frame may suffer fracture in its structure. The main cause of mechanical failure in vibrating screen is the vibration. Components like frame, vibrating box, spring dampers and bearings are affected by this. The vibration will crystallize the molecular structure of the metal causing what is known as metal fatigue to develop. The first sign that an operator has indicating that the fatigue in the body of the screen deck is almost at a critical stage in its development are the hairline cracks that will appear around the vibration’s point of origin. This work adopted components of inline knockout machine such as vibrating box, vibrating frame as the object to study and analyze the stress distribution and deformation under static loads, check the strength of vibrating box and analyze whether it will resonate by calculating the natural frequencies and mode shapes of the structure.1.2 Vibrating Screen Working PrincipleThe simplest Vibrating Screen Working Principle can be explained using the single deck screen and put it onto an inclined frame. The frame is mounted on springs. The vibration is generated from an unbalanced flywheel. Fig1.2.1. inline knockout machineFailure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 3The vibration pattern of the horizontal frit is back and forth and the inclined vibrating screen is round. There are different ways to produce the vibration itself. The horizontal screen uses a double balance system. A very erratic motion is developed when this wheel is rotated. A double counterbalance system is used in the horizontal screen. The counterbalance weight will alternately promote and retard the direction of vibration depending upon where within each revolution the weights come opposite each other. Fig 1.2.2. Counterbalance weight Eccentric shaft is used in the inclined vibrating screen. The vibration of an unbalanced flywheel is very violent. This causes mechanical failure and structural damage to occur. The four bearing system greatly reduces this problem.Failure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 41.2 Motivation Of The Present WorkInline knockout machine consist of component like torsion bar, vibrating frame, vibrating box, vibrating motors installed on both sides of the vibrating box, spring and support device. Vibrating box may be damaged during long-term operation. In particular, the sides of the vibrating box may break, and the structure of the vibrating frame may also break.The main cause of mechanical failure in vibrating screen is the vibration. Components like frame, vibrating box, spring dampers and bearings are affected by this. The first sign that an operator has indicating that the fatigue in the body of the screen deck is almost at a critical stage in its development are the hairline cracks that will appear around the vibration’s point of origin. Failure analysis of above components will give a closer theoretical look at the behavior of the above mentioned components.Failure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 5Chapter 2LITERATURE REVIEW ______________________________________________________2.1 Introduction2.2 Classification of Literature Review2.2.1 Classification AReport on major literature referred and studied. Literature review should include current thinking, findings, and approaches to the problem. Following citation format should be adopted. Generally there are two types of citation formats are adopted.Turner (1963) presented analysis of structures using stiffness matrix method. Patil and Kulkarni (1990) developed Sample Large-Angle-of-Attack Viscous Hypersonic Flows over Complex Lifting Configurations. Various research carried out in debris and referred from (Jadhav, 1990). Deshpande et al. (1998) revealed new development of analytical tools.CitationsInitially this work is proposed by Patil (2011)Initially this work is proposed by Patil and Kadam (2011)Initially this work is proposed by Patil et al. (2011)Failure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 6Boitumelo Ramatsetse 1 described in mineral processing industries vibrating screens operate under high structural loading and continuous vibrations. In this regard, this may result high strain rates, which may often lead to structural failure or damage to the screen. In order to lessen the possibility of failure occurring, theories and techniques for analyzing machine structures are investigated and applied to perform a sensitivity study of a newly developed vibrating screen. Structural strength and stability of a vibrating screen is essential to insure that failure doesn’t occur during production. In this paper a finite element analysis (FEA) on a reconfigurable vibrating screen (RVS) is carried out to determine whether the structure will perform as desired under extreme working conditions at the different configurations of 305mm×610mm, 305mm×1220mm and 610mm×1220mm.This process is aimed at eliminating unplanned shutdowns and minimizes maintenance cost of the equipment. Each component of a screen structure is analyzed separately, stress and displacement parameters are determined based on dynamic analysis. In addition, a modal analysis was carried out for the first three (3) modes at frequency f of 18.756 Hz, 32.676 Hz and 39.619 Hz respectively. The results from the analysis showed weak points on the side plates of screen structure.Sergio Baragetti 2 An innovative design solution is presented in this paper; it allows the enhancement of structural Resistance and the dynamic performances of a vibrating screen for inert materials. The new design does not significantly affect the geometry of the traditional screens, keeping the same global dimensions and almost the same mass value. In fact the aim of this study was to design a new vibrating screen having almost the same dimensions but that could give a much higher dynamic structural resistance at frequencies and load amplitudes much higher than the nominal ones. Numerical finite element models were generated to investigate the structural and dynamic behavior of a standard vibrating screen. These analyses allowed the modification of the geometrical parameters of the traditional screen and to design the new one. Accurate three-dimensional FE models were so generated in order to evaluate the best design solution, in terms of dynamic structural resistance, able to reduce the stress values at the most stressed area. The fatigue resistance of all the components of the new screen was checked, with particular attention to the welding joints. Experimental full scale tests on a prototype of the new screen were carriedFailure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 7out in order to validate the numerical models and mostly to verify the structural integrity of the vibrating screen during the working conditions. Strains at the surface of the most stressed areas of the screen were measured in dynamic working conditions, at different frequencies and load amplitudes; these stress values were compared with the numerical ones in order to validate the numerical results. The new screen was patented.Zhao Yue-mina, Liu Chu-shenga3 The reliability is a key factor for the design and manufacture of large vibrating screen. In the paper, He presented a new large vibrating screen with hyperstatic net-beam structure. Dynamic characteristic of the vibrating screen was researched and dynamic simulation method of large screening machines was explored. He used finite element method (FEM) to analyze dynamic characteristic of large vibrating screen with hyperstatic net-beam structure. Multi natural frequency, natural modes of vibration and dynamic response of the vibrating screen were calculated. The structural size of stiffeners on the side plate was optimized under multiple frequencies constraints and an adaptive optimization criterion was given. The results show that the vibrating screen’s structural strength is increased and the natural frequency of bending deformation is enhanced. The modal frequencies are far from working frequency, and thus the structure is able to avoid resonance effectively and reduce the destructiveness. The maximum transverse displacement of the vibrating screen is 0.13 mm, the maximum difference in vibration amplitude of corresponding points is 0.44mm and the maximum dynamic stress is 16.63MPa. The structural optimization shows that the mass of the side plate is decreased by 194.50kg, the second and third modal frequency is increased by 1.73% and 2.91% respectively and a better optimal effect is received.Yongjun Hou, Pan Fang and Lian Zeng 4 In order to study the stress distribution of dual-frequency vibrating screen and ensure the screen box has sufficient strength and longevity, a finite element model of dual-frequency vibrating screen was built, and the stress, modes and fatigue life of the screen box were analyzed. The results indicate that, the stress concentration appears at the contacting parts between the crossbeam and the stiffener of motor seat, the crossbeam, L-type stiffening plate, baffle of material addedFailure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 8and screen box. The middle of crossbeam and the L-type stiffening plate are weaker parts of fatigue; they are easily fatigue failure under high frequency vibrationLiu Xinyong ,Cui Hongbin ,Cao Pengxian15 A simplified model of self-balance screen was constructed by using SolidWorks, and then imported into the Simulation to analysis its structure and modal. The stress distribution, deformation and structural natural frequency, mode shapes under static loads of the self-balance vibrating screen were calculated to provide theoretical basis for the following analysis of the dynamic characteristics and structure optimization design of vibrating screen.I.B. Eryu¨ rek, M. Ereke, A. Go¨ ksenli 6 In this paper the failure of the rear suspension spring is analyzed in detail. The rear axle suspension system of the truck and fractured flat spring is investigated. Fracture surface, mechanical and chemical properties and microstructure of the spring material is analyzed. A force acting on the spring is determined and strength calculations are carried out. Later, failure behavior and cause of fracture is revealed after carefully analysis of microstructure and results of calculations. At the end precautions to be taken to prevent a similar failure is recommended.2.3 Objectives of present work1. TO generate Numerical finite element models to investigate the structural and dynamic behavior of a vibrating screen.2. To study the stress distribution on the vibrating box and vibrating frame under current operating condition.3. To study the stress concentration on the vibrating box and vibrating frame under current operating condition.4. Resonable selection of vibrating screen working frequency.Failure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 9Chapter 3Working Conditions Of Inline Knockout MachineThe unit consists of the freely suspended screen and a shaft assembly carried by the box. Near each end of the shaft, an eccentric portion is turned. The shaft is counterbalanced, by weighted fly-wheels, against the weight of the screen and loads that may be superimposed on it. When the shaft rotates, eccentric motion is transmitted from the eccentric portions, through the two bearings, to the screen frame.Frame is mounted on vibrating box with the help of two steel angels. Two L shaped angular plates restricts the motion on screen. The vibrations are transferred from torsion bars to screen.Spring dampers are mounted as per the load to be applied on the vibrating screen, two on each side for damping purpose and grounded.Property Specification(mm) Wire diameter 19 Inner diameter 90 Outer diameter 128 Length 315 Pitch 39.37 Number of turns 8 stiffness 120.94 N/mm^2 *Stiffness values of spring is calculated by using above property and used in the modal analysis as one of the input value. Damping factor is also one of the property to be used in harmonic analysis.Failure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 10Stiffness of spring calculation –1.?=8pd^3N/gd^4=8*39200*(109)^3*8/76920*19^4=324.109mm2.k=p/ ?=39200/324.109=120.94 N/mm^2Failure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 11CHAPTER 4Modeling Of The ComponentFor the failure analysis of the knockout machine the main components to be considered are vibrating box and vibrating screen. During the cycle of process effect of vibration is mainly observed on the side plate of the box ,secondly the vibrating screen also suffers failure as result of frequent loading of mould boxes.The vibrating box is divided into two parts: Vibrating frame and screen frame. Screen is installed in the interior of screen frame. The box is located on the vibration damper using springs. Material enters into the upper ports of vibrating box and is discharged through the bottom ports during the working.Because of the complex of structure and too many parts of screen and screen frame, the finite element models of them are very difficult to be building by using the ANSYS. Because CAD is mature and operational software, it can quickly create virtual models of screen and screen frame. Therefore, the combination of CAD and ANSYS is very necessary for analyzing vibrating screen. The combination can improve the speed of changing model and the efficiency of analyzing vibrating screen .The CAD model was changed into a standard format which can is imported into ANSYS in order to get finite element model.CATIA allows the creation of 3D areas, from 3D images, sheet metal, compounds, shaped, made or pedaling areas up to the meaning of technical devices. The application provides advanced technological innovation for technical appearance. It provides tools to complete product meaning, such as functional specifications as well as kinematics meaning. CATIA provides an extensive variety of applications. CATIA v5 is able to read and produce STEP format files for reverse technological innovation and surface recycling.For the analysis purpose following 2 components are considered:-1. Vibrating box2. Vibrating screenFailure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 121. Vibrating Box- Vibrating box is main component of inline knockout machine which supports all other components such as frame, dampers ,torsion bar, angle plates etc. generally the box is combination of welding and bending process.Torsion bar is mounted by bolting a circular plate inside the box plate. The screen is mounted with the help of angle plate.one net like structure is present at the top of screen but is not considered in analysis.Fig 4.1.1-Isometric View Of Inline knockout MachineFailure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 13Fig4.1.2- Detailed Drawing Of Vibrating Box2.Vibrating Frame-Vibrating screen is the second part under consideration for analysis. Function of the screen is to support vibrating net.mold boxes and castings passes over this net. Vibrating screen act as a support for the vibrating box and doesnot allow them to scatter over the surface.Failure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 14Fig 4.1.3- Detailed Drawing Of Vibrating ScreenFailure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 15REFERENCESIEEE format: for students of Electronics/Digital system/ Power system/CSEASCE format: for students of Structure/Construction & managementASME format: for students of Automobile/Production/ Design/CAD-CAM-CAE/Heat PowerFailure Analysis Of Inline Knockout Machine Operating Under VibrationRIT Rajaramnagar 16Attach XEROX copy of approved synopsis