Control Metal Flow Research Articles

Design and optimization of multi-stage manufacturing process of stirling engine crankshaft

Crankshafts are among the most important parts in internal combustion engines, of which stirling engine is a useful example. Manufacturing process of a crankshaft, is considered as a three-step forging process using preform, due to the complexity in geometry. The most challenging step of the multistage forging process is to avoid stress concentration and to create uniformity of strain by controlling metal flow. In the present study, the final part was achieved under three manufacturing processes namely: upsetting, hot and cold forging. The models used in each manufacturing process are designed by CATIA software. A finite element simulation on the basis of Cockcraft–Latham damage criterion was developed in DEFORM software. Using experiment design by Taguchi method, The optimization of manufacturing processes were carried out by MINITAB software in two steps, in which the optimization objectives are considered as force, damage and strain uniformity, and; input variables are taken as part-mold friction, pressing velocity and process temperature. In order to find the most effective parameter of each manufacturing process, analysis of variance was conducted on the results, in which, the most effective parameters in the upsetting, hot and cold forging processes were temperature, friction and temperature, respectively.

충격압출 공정에서 초기 슬러그 디자인이 사각 배터리 케이스의 이어링에 미치는 영향 분석

In the current paper, the effects of initial slug design on the earring of an Al rectangular battery case manufactured by impact extrusion were studied. During impact extrusion, non-uniform metal flow between the long and the short sides of the battery case leads to earring, which is subsequently trimmed. Process parameters such as friction, aspect ratio of the battery case, the die shape and the forming temperature tend to induce earring because they cause greater non-uniform metal flow. Large aspect ratio of the battery case and high friction between slug and die can greatly affect the earring of a rectangular battery case. To make a rectangular battery case without earring, it is necessary to control metal flow uniformly during impact extrusion. One of the ways to reduce the earring is to control the metal flow of slug at the initial upsetting stage. To analyze the effects of the initial slug design on earring, FE analysis was conducted using DEFORM 3D. Two types of initial slug designs were evaluated where volume was removed along either the width or thickness directions. The results show that the initial slug design can be effective in adjusting the uniformity of metal flow.

State-of-the-art of plate forging in Japan

The state-of-the-art of plate forging processes for forming complicated parts without cutting and finishing in Japan was reviewed. For cups having comparative large thickness and plates having complicated cross-sectional shapes, plate forging is more useful than conventional billet forging due to due to comparatively small change in shape. In plate forging, forging processes such as upsetting, extrusion and ironing are included in the sequence of conventional stamping composed of shearing, bending and deep drawing in order to control metal flow in plates. Plate forging has the advantages of higher performance, larger productivity, lower cost, etc. Plate forging processes are classified into desired functions of products, local thickening, local thinning, formability improvement and forming of gears and plates.

Loading state in local loading forming process of large sized complicated rib-web component

Purpose – The purpose of this paper is to explore the basic loading state in local loading forming process of large-sized complicated rib-web component, which is important for understanding process characteristic, controlling metal flow and designing preformed geometry of the local loading forming process. Moreover the analytical models for different loading states are established to quickly predict the metal flow. Design/methodology/approach – Through analysis of geometric characteristic of large-sized complicated rib-web component and the deformation characteristic on planes of metal flow by local loading method, a representative cross-section is put forward and designed, which could reflect the local loading forming characteristics of large-sized complicated rib-web component. Finite element method (FEM) is used to analyze the stress and metal flow, and the analytical models of metal flow are established by using slab method (SM). Findings – Three local loading states and one whole loading state are fo...

Precision forging of spur gear by flow control forming method

In order to reduce the final forging load of spur gear precision forging, several alternative die designs that use a ring billet are put forward. The influence of different designs on metal flow and load requirements is examined through finite element simulation and experiments. A new precision forging technology is then developed, which includes a two-step forging process to control metal flow in the die cavity. Well-shaped products can be forged successfully by using a lower forging load than that of conventional forging.

Finite Element Analysis and Experimental Study of an Electromagnetic Shell Part with Flow Control Forming

In this paper, an electromagnetic shell part was studied with the design of die, simulation and the flow control forming (FCF) method. The important technology of FCF was the design of cavity die to control metal flow. The simulation results indicate that pyramidal faces of cavity die exerted a significant influence on qualities of parts. The simulation results also revealed that the effective stresses of the sheet were inhomogeneous and the distributions of the equivalent stress were lamellar with obvious gradients. Experimental results show that steel sheet (08Al) could be formed in one step into intricate shapes at room temperature. This confirmed that FCF is a safe, clean and practical method for the near net forming of parts.

Research on local loading method for an aluminium-alloy hatch with cross ribs and thin webs

Complex-shaped rib–web parts are widely used in aviation and aerospace industry, but they are very difficult to manufacture by conventional forging method. Through studying deformation characteristic of whole loading by FEM simulation and experimental research in the process of forging 2014 aluminium-alloy hatch, which is a typical rib–web component, the causes of various forging defects have been analyzed. Based on the analysis of whole loading a local loading method is put forward, the forming process of rib–web hatch has been investigated and the rib–web part has been fabricated with good forming quality. The results indicate that local loading forming process is a reliable method to form the rib–web forging because local loading method can predict and control metal flow direction effectively, change metal flow from the long distance into short distance, which may eliminate various forming defects, such as overlap, breaking of rib and disturbance of forging flow line. Transitive die plate and bolster plate are helpful to realize local loading, which can control metal flow and improve forming quality. The reasonable design and utilization of transitive die plate and bolster plate are crucial to ensure the forming quality of rib–web parts.

Near net shape forming process of a titanium alloy impeller

The complex components such as the impellers are difficult to manufacture because of their complicated shapes and high requirements of mechanical properties. In order to form the titanium impeller precisely two forming schemes with two die devices were designed. Three-dimensional finite element method (FEM) was used to simulate the forming process of the impeller and study the metal flow laws. Several key factors such as the loading scheme, die structure and billet shape were studied in detail. The simulated and experimental results show that the titanium alloy impeller with radial twisted blades can be precisely forged with the isothermal enclosed die forging technology. The local loading technology can control metal flow, so the forgeability of the impeller blades can be improved and the flaws such as underfill and flash can be avoided.

Characteristic Evaluation of Extrusion Parameters on Direct Extrusion Process of 3003 Al Alloy Used for Automotive Condenser Tubing

Environmental regulations in the refrigeration technology make the harmful refrigerants such as CFCs (chlorofluorocarbons) and HCFCs (hydro-chlorofluorocarbons) replaced by eco-refrigerants such as CO2 , and the substitution of CO2 increases the pressure of multi-void condenser tube. As a result, the stiffness of the conventional 1000 series Al alloys can be open to question. The present study is mainly aimed at developing a direct extrusion process and neocondenser tube material for the application of eco-friendly refrigerants with higher working pressure than the conventional CFC and HCFCs refrigerants. The mechanical properties and burst strength for condenser tube were greatly affected by the large grains formed by brazing condition. As a result of the burst testing, 3003 Al alloy proved to be more suitable than 1100 Al alloy for the application of condenser tube to eco-friendly refrigerant usage because 3003 Al alloy can be durable in the heat exchanger required high pressure of working. Furthermore, optimum dies design has to be introduced for control metal flow and metal welding during direct extrusion process.

자동차용 허브 클러치의 유동제어에 관한 실험적 연구

This paper suggests the new technology to control metal flow in orther to change of the cold forging from conventional deep drawing forming. This technology can be summarized the complex forming, which consists of bulk forming and sheet forming, and multi-action forging, which be performed double action press. The proposed technology is applied to hub clutch model which is part of auto-transmission for automobile. The purpose of this study is to investigate the material flow behavior of hub clutch through control the relative velocity ratio and the stroke of mandrel and punch using the flow forming technique. First of all, the finite element simulations are applied to analyse optimal process conditions to prevent flow defect(necking defect etc.) from non-uniform metal flow, then the results are compared with the plasticine model material experiments. The punch load for real material is predict from similarity law. Finally, the model material experiment results are in good agreement with the FE simulation ones.

Finite element analysis of a multi-stage axisymmetric forging process having a spring-attached die for controlling metal flow lines

In this paper, a computer simulation technique for the forging process having a spring-attached die is presented. A penalty rigid-viscoplastic finite element method is employed together with an iterative force-balancing method, in which convergence is achieved when the forming load and the spring reaction force are in equilibrium within the user-specified allowable accuracy. The force balancing is controlled by adjusting the velocity of the spring-attached die. To minimize the number of iterations, a velocity estimating scheme is proposed. Two application examples found in the related company are given in order to emphasize the significance of metal flow lines for quality control and to investigate the effects of spring-attached dies on the metal flow lines as well as the decrease in forming load.

A die forging design approach for controlling metal flow way and its application in practice

In this paper a novel idea about die forging process design in relation to metal flow is presented. The purpose is to almost completely fill a die cavity before flash starts to form. The paper shows that preform design is the way to realize this situation. The paper describes a method in which metal flow is simulated using UBET in reverse sequence to that occurring in practice. The successful application of the method in production is shown.

Metal Flow Control in Cold Simultaneous Forward/Backward Extrusion

AbstractIn order to display the merits of the cold combined forward-backward extrusion process, some simple devices were developed and tested for the control of simultaneous extruding speeds in the two directions. Among them, application of a supporting traction to the emerging product through the orifice of the larger extrusion resistance was found promising. The potentiality of this method was evaluated theoretically for the axisymmetric forward-backward can extrusion using a modified upper bound approach. Results of experiment with aluminum specimens proved the validity of this extrusion process in controlling metal flow and that of the analytical method in predicting the prevailing traction.