The strength/density ratio of aluminium can be increased significantly by the integration of ceramic particles in the metal matrix, so called Aluminum MMC. Because machining of MMCs is very expensive due to the high hardness of the ceramic particles precision forging of Aluminum MMCs allows the high quantity production of near net shape components with a strength/density ration. The paper describes the development of a precision forging sequence for a demonstration made of Aluminum MMC.
aluminium metal matrix composites, flashless forging, FEA
In a research project by the Institut für Integrierte Produktion Hannover (IPH) and the Institute of Metal Forming Siegen the basics for hydroforming titanium tubes were investigated. The aim of this research project was to develop a multi-stage process chain for hydroformed parts made of titanium. First the method-specific material properties as well as the tribological system were examined. The results were combined in a simulation model which enabled the process development. Finally, the developed process chain was successfully tested using a real component and the trials were compared with the simulation results.
hydroforming, FEA, titanium
Due to high mechanical loads the die cavity shows high wear in warm forging processes. Within this paper the ability of a hydrogenated amorphous carbon doped by 40 % chromium as wear protective coating for bulk forming processes will be analysed. Therefore billets with temperatures between 650 and 1200 °C have been forged on this layer. Thereafter the layers are analysed and the wear behaviour is evaluated.
coating, forging, forming
The early detection of defects in forging processes offers economic benefits. For example, workpieces that are forged incorrectly can be discharged from the process chain immediately and thus do not cause additional process costs, i. e. in a subsequent heat treatment. The development of a novel process monitoring using electrical current allows the identification of forging defects and underfillings.
forging, process monitoring
The higher mechanical loads in warm forming processes lead to increased mechanical wear of the dies. Using hard Diamond-like Carbon (DLC)-coatings can reduce this main disadvantage of warm forging. By an adequate doping of DLC with elements the temperature stability of these coating can be increased. Especially in areas with high relative movement the analysed coatings show advantageous behaviour compared to not coated dies.
diamond-like carbon (DLC), warm forming, bulk forming, wear
Forged parts have geometrical fluctuations for example caused by die wear. The investigation of a controlled, movable flash gap by FEA for compensation purpose showed how far the material flow can be varied during the forming operation. A potential to improve forging results is derived.
forging, die design, material flow, FEA, flash land
Hydroforming is often used to conduct forming of thin-walled hollow parts made of tubes. In order to form thick-walled hollow parts made of Aluminum a process has been developed, to form such parts. These parts are in a heated state. The forming has been made by help of an active fluid medium on a hydraulic deep-drawing press. For investigation purpose an example process has been designed for a trial part. This process has been analyzed by FEA and verified by laboratory tests.
hydroforming, forging, tubes, aluminium, FEA
Recent research dealt with the basic forgeability of aluminium-matrix composites produced under laboratory conditions. These research projects concentrated on metallurgy and, by deriving flow curves, on formability. In contrast to laboratory conditions, the industrial use requires large batches of raw materials and takes place under real conditions. Those conditions have not yet been analysed. This paper describes the combination of mechanical advantages of aluminium-matrix composites and a flashless forging process. The advantages can be outlined as higher part strength, compared to conventional forging parts with the same weight. Newly derived flow curves demonstrate formability and were used to evaluate basic forging parameters. The first forging trials in a conventional forging process using a high forging rate resulted in broken parts and therefore required a reduced deformation rate. The matrix slug material provides a higher deformation rate but has to be reduced, due to the use of MMCs. Using a conventional forging press (e.g. screw press) causes material failures likes cracks, because forging Al-MMCs requires a reduced forming speed of 20 mm/s. Reducing the forming speed, hydraulic presses are recommended. FE-analysis of the newly developed flashless forging process is described and depicts the basic forming operations (spreading, elongating and climbing) of the material in the forging die. Altogether a new strategy for a flashless forging process layout with Al-MMC is shown.
forging, flashless, aluminium, matrix, composite, characterization, upsetting, FEA, simulation, tool
In automotive industry, parts made of aluminum alloys are used with increasing frequency. During forging operations for the production of aluminum long flat pieces, defects like folds can appear. Especially internal folds are of interest, which are only evident in the fiber orientation and have a negative effect on the dynamic mechanical properties of the forged part. In forging, the forming operation can be realized either from one direction (uni-directional) or from several directions (multi-directional). The boundary conditions for multi-directional forging are described in this article. For a given tool geometry, multi-directional forging permits the realization of fold-free forgings, which has been shown to be not possible with uni-directional operations. A newly developed method based on Finite-Elements-Analysis (FEA) simulation helps with the design of the forming process and the determination of the appropriate tool geometry. A new algorithm integrates the computer-aided identification of internal folds. For a given process and tool geometry, the area with internal folds is adjusted, until the simulation shows no fold formation. It is shown, that by using this model, a dependable assessment and correction of forging tools and forming process and thus the realization of a fold-free forming are possible.
multi-directional forging, aluminum forging, internal folds, finite-elements-analysis, algorithm, to
A smart option to increase the energy yield of wind turbine generators is to increase its height. There is an exponential increase of the usable wind energy at enlarging the tower’s height, but also an exponential increase of the tower’s weight. The application of lightweight design concepts in the production of wind turbine tower sections may lead to weight reduction while keeping the tower’s stiffness at an equal level. Here the results of a study for lightweight concepts and their implementation on towers and a guiding systematic approach are being presented. The investigated design solutions proved successfully in bionic, aerospace and automotive applications. FEA simulations were used to compare the different structures and to estimate their feasibility. The investigation’s main result is a lightweight structure which provides weight reductions up to 20 %, by using lower wall thicknesses.
forging, genetic algorithm, preforming optimization
In order to achieve higher energy yields of wind turbine generator, the most expedient approach is to enlarge the tower height. By increasing the height the usable wind energy increases exponentially, but also does the tower weight. Therefore in a research study several constructional designs for lightweight tower design have been investigated. The design considered several design solutions which proved successfully in bionic, aerospace and automotive applications. FEA simulations were used to compare different structures and to estimate their feasibility. The best-fit identified constructional design is based on trapezoidal sheet. The developed design enables a weight reduction up to 20 % in comparison to standard towers.
xxl-product, large-scale, xxl, wind turbine, wind power, lightweight construction, tower constructio
A smart option to increase the energy yield of wind turbine generators is to increase its height. There is an exponential increase of the usable wind energy at enlarging the tower’s height, but also an exponential increase of the tower’s weight. The application of lightweight design concepts in the production of wind turbine tower sections may lead to weight reduction while keeping the tower’s stiffness at an equal level. Here the results of a study for lightweight concepts and their implementation on towers and a guiding systematic approach are being presented. The investigated design solutions proved successfully in bionic, aerospace and automotive applications. FEA simulations were used to compare the different structures and to estimate their feasibility. The investigation’s main result is a lightweight structure which provides weight reductions up to 20 %, by using lower wall thicknesses.
xxl-product, large-scale, xxl, wind turbine, wind power, lightweight construction, tower constructio
For a systematic complaint handling the 8D method has been established. However, so far there are no adequate measurement and evaluation techniques to assess the quality of an 8D report. As a consequence it can not be guaranteed at any time that the complaint processing is carried out correctly and efficiently. In a research project of the FQS, the Institute of Metal Forming (IFUM) and the IPH - Institute of Integrated Production gGmbH an automated metric system for measuring and evaluating the quality of 8D reports was developed. To determine the metrics algorithms are used for text mining. Also manual reviews are used to realize the required range of reviews efficiently and reliably.
8d-report, claims management, complaint, quality management
This paper describes the development of a warm cross wedge rolling process with one area reduction. The paper also includes results of finite element analysis (FEA), experimental trials with a downsized work piece and the adaption to the industrial work piece in original size. In the FEA simulations tools with serrations on the side have been used. The downsizing method is explained and the difference between FEA, downsized and originally sized work piece with the focus on forming forces, temperature distribution and defects are presented.
warm forging, cross wedge rolliing
A suitable technology for pre-forming of highly loaded forgings is the cross-wedge rolling. With little effort, investigations are now carried out using a new module for cross-wedge-rolling with flat dies. To expand the existing geometric limitation of warm forged steel components, the cross-wedge-rolling at temperatures between 650 °C and 950 °C was investigated. In addition, first studies with aluminum using the new module are described.
warm forging, cross-wedge-rolling
The early detection of defects in forged parts offers economical advantages due to the possibility of sorting them out of the process chain. The aim of the presented research project is the development of a forging process monitoring without sensors. In the process electric current is flowing through the forged part. The quality of the forged parts is measured by the electrical signal. Typical defects of forgings like underfilling and wrong temperature of the billet show characteristic signals and therefore can be detected. These parts are sorted out of the process chain. The user of the forging machine is able to adjust the forging process immediately.
forging, process monitoring
The implementation of process monitoring technologies in manufacturing processes allows significant cost and time savings. An online process monitoring of die cavity filling in warm forging processes could not be realized until now. Important process parameters for example billet volume, billet temperature or lubrication could only be observed after forging. This paper describes the implementation of an online process monitoring system based on electricity.
forging, process monitoring
To produce preforms for complex long flat parts with an unsteady mass distribution along the longitudinal axis rolling processes, like cross wedge rolling, can be used. Tools for cross wedge rolling processes can be constructed as roller or flat, both with wedges. In the collaborative research project "SFB 489 - Process chain for the production of precision forged high performance parts" the subproject "Innovative machine and tool technology for precision forging" deals with the development of a flashless forging process for a two cylinder crankshaft with pin and flange. This process is developed by IPH - Institut für Integrierte Produktion Hannover. The first preform of the developed forging sequence is produced by a cross wedge rolling process on the basis of flat with wedges. To consider the mass distribution of the two cylinder crankshaft in the preform for a rolling process four mass concentrations for the crank arms and mass concentrations for pin and flange are needed.
crankshaft, cross wedge rolling (CWR), forging sequence, preform, rolling process
Lightweight design of cars is one way to reduce fuel consumption and increase the range of cars. This is an important factor to attain the EU limit values for CO2 emissions for vehicles and thus to avoid penalties for exceeding these limits as of the year 2012. The growing number of uses for high-strength steels or lightweight structures are adequate means to reduce weight. At IPH - Institut für Integrierte Produktion Hannover gGmbH a method to produce hollow profiles made of aluminum was developed. This method, called hydroforging, combines flashless forging and tube hydroforming. It allows the production of thick-walled hollow aluminum profiles with undercuts without the need for complex tool kinematics. The forging is supported by an active medium. A tool concept has been developed using the drives of a hydraulic press with die cushion. With this tool, various part geometries shall be produced and analyzed. To produce the tools' interior pressure and the forming pressure, liquid tin as an incompressible active medium is used. The forming is initiated by upsetting the aluminum profiles and supported by the active medium, so that the profile is pushed against the cavity of the dies. The process was designed based on simulations and will be verified by practical experiments. This paper describes the development of the forging process with an active medium.
hydroforming, forging, tubes, aluminium, FEA
Sheet metal parts often have to be connected by fasteners. Fasteners like bolts are mostly welded individually after the forming process and outside the working tool. This spatial separation of production steps requires complex handling operations and has negative impact upon the positioning accuracy of the fasteners. Every executable manufacturing step inside the sheet metal working tool shortens the process chain significantly. Furthermore, using a combined process the precision of position and orientation of fasteners improves. The challenges of integrating the welding process into the sheet metal working tool are handling the emissions and associated pollutions of the tool as well as creating a reliable monitoring-system for the welding-process. Within the scope of a research project, a reliable technology for the integration of condenser discharge stud welding with tip ignition was developed and tested. It complements existing solutions for integrated resistance welding processes.
sheet metal, capacitor discharge arc stud welding, cd arc stud welding, tip ignition, follow-on tool
