Many forged parts include piercings e.g. as bearings. The web of the forged pieces has to be pierced in an additional manufacturing step. By integrating this so far separately performed operation into the final forging step the process chain can be shortened. However, up to date there is no information available on how the process parameters influence quality relevant factors. Therefore, a combined forging-/piercing process is designed and performed. The results of previous research projects showed that the variation of the inserted mass and the forging temperature have a distinct effect on the dimensional and form accuracy of the work pieces. In this project different punch and work piece geometries and the influence of a different forming sequence on tool stress and the material flow was investigated. The punch and work piece geometry show no effect on form accuracy of the piercing while an inappropriate forming sequence leads to failure of the tool.
forging, flashless, precision, piercing
In the past, scientific analysis of development and production of large-scale products has not been conducted very often. In the joint project „Innovations for the production of large-scale products“, sponsered by two German ministries in the state of lower saxony, IPH – Institut für Integrierte Produktion Hannover gemeinnützige GmbH will make a contribution to reply scientific questions in consideration of development, production and recycling of large-scale products.
xxl-products, development, manufacturing, recycling
Cross wedge rolling is a method for reshaping cylindrical billets for getting a better mass distribution. Against the backdrop of rising material costs, this method is increasingly becoming the focus of many forging companies - but the high investment costs for tools and equipment prevents the economical benefit of the process. With flat cross wedge tools and corresponding rolling machines tooling costs can be reduced and the process is therefore interesting for small batches. Moreover, studies show that CWR is also applicable in warm temperature range.
warm forging, process chain, cross wedge rolling
Closer tolerances, reduced surface roughness, no scale and reduced decarburization can be realized by warm forging. However, the geometrical spectrum of warm forged parts is limited by flow stress. To overcome this geometrical limitation, innovative warm cross wedge rolling and forging processes are developed in the project presented in this paper. To investigate the effect of lower temperatures on process parameters, e. g. force, die wear and material properties in comparison to hot forming processes, Finite Element Analysis (FEA) and experimental tests using downsized model geometry were performed. In this paper the new warm cross wedge rolling process is explained and results of warm cross wedge rolling trials (e. g. work piece characteristics), FEA simulations of forming forces and material analysis are shown. The results of these analyses allow industrial application of warm cross wedge rolling for the first time.
warm forging, process chain, cross wedge rolling
Many forged parts include piercings e.g. as bearings. The web of the forged pieces has to be pierced in an additional manufacturing step. By integrating this so far separately performed operation into the final forging step the process chain can be shortened. However, up to date there is no information available on how the process parameters influence quality relevant factors. Therefore, a combined forging-/piercing process is designed and performed. The results of previous research projects showed that the variation of the inserted mass and the forging temperature have a distinct effect on the dimensional and form accuracy of the work pieces. In this project different punch and work piece geometries and the influence of a different forming sequence on tool stress and the material flow was investigated. The punch and work piece geometry show no effect on form accuracy of the piercing while an inappropriate forming sequence leads to failure of the tool.
forging, flashless, precision, piercing
A new tool design and die assembly developed at IPH has the ability to form flashless, near-net-shape forgings and pierce the workpiece all in one stroke. The tooling concept for the combined flashless forming and punching process was developed for rotationally symmetric parts. The die assembly is designed to fit into a standard forging press. The tool consists of an upper die, an upper punch (combined forming and punching die), gas-filled springs, a lower die, a lower punch and a release mechanism. The design of this forging sequence was facilitated by material-flow simulation programs using finite element analysis (FEA) techniques.To determine the influencing parameters forging trials have been made on Muller Weingarten PSH 265 screw press. The feasibility of a combined forming and punching process to produce near-net-shaped parts has been successfully demonstrated.
forging, flashless, precision, piercing
Saving resources becomes more and more important. Therefore the forging industry tries to develop processes with less flash than the conventional techniques or to avoid flash completely. Currently only simple parts like gears can be forged without flash. In a research project flashless forging processes for crankshafts were developed. In this paper the evolution of the flashless forging process and the process steps will be described. The collaboration research project "process chain for the production of precision forged high performance parts" has been conducted in the last few years at IPH and was funded by the German Research Foundation (DFG).
precision forging, flashless, crankshaft
Flashless precision forging is a special process of drop forging performed in closed dies. This process is distinguished by high quality and the ability to achieve a near net-shape part. Latest research results have shown that it is possible to forge a two-cylinder crankshaft without flash. This was realized using a multi-directional forging tool and a flashless precision forging operation. In this paper a new method for a three dimensional shrinking compensation is presented that facilitates the construction process
forging flashless precision near-netshape
Large-scale products (XXL-products), such as bearing rings for wind turbines, pose special challenges to the production technology. For example, the continuous growth of product dimensions puts challenges on forming technologies as they reach their technical limits. Scaling effects, that occur when scaling up, can include physical limits for a further upscaling. These effects have only been studied for small scale production processes so far. The consideration of such effects in the large scale production offers the opportunity to exploit the potential of metal forming processes and improve the calculation forecasts.
xxl-products, forging, flowproperties, scaling factor, scaling effect, ring compression test
As a result of increasing globalization in procurement an increased competition exists for production companies. In the field of sheet metal forming companies will therefore be required to produce proper quality products with short delivery times at high punctuality at lowest possible production costs.
sheet metal forming, experience recovery, equipment effectiveness
In a current research project at IPH – Institut für Integrierte Produktion Hannover gGmbH and Laser Zentrum Hannover e. V. the knowledge of die failure mechanisms during the forming of aluminium will be extended. Aspects of the analysis are minimization, quantification and forecasting of adhesion. Furthermore it will be analysed in what way the tools, laser-dispersed with aluminium oxide, decrease the adhesion.
aluminium forging, wear, wear coatings
In standard sheet metal forming processes the subsequent welding is executed outside the forming press. Because of that spatial separation complex handling and transferring operations are being required which result in a deterioration of the joint accuracy. 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 (CD) stud welding with tip ignition was developed and tested. Due to its high-speed capability, low insertion of energy and high process reliability, this technique is particularly suitable for the integration in sheet metal working tools. The new technology produced top quality CD arc stud welding along with high process stability and robustness in long-term tests.
sheet metal, capacitor discharge arc stud welding, cd arc stud welding, tip ignition, follow-on tool
While merely solutions for integrated resistance welding have been known until now, a tool technology in a reliable process for the functional integration of initial contact capacitor discharge (CD) arc stud welding was developed in a research project. This technology is particularly well-suited to integration into sheet metal working tools, amongst other reasons, because of its high joining speed, low energy input and high process reliability. In endurance tests, this new technology can be used in order to manufacture high-quality stud welds with a high robustness to disturbing variables at the same time, not least due to the fact that the extraction of welding spatter was tried out for the first time.
sheet metal, capacitor discharge arc stud welding, cd arc stud welding, tip ignition, follow-on tool
To realise integration, a new modular tool concept was developed in a research project. However, negative process effects like weld splatters occur. As a counteraction the control of process parameters, an extraction system and mechanical solutions were developed. Focus of this research project was to demonstrate process stability and reachable numbers of strokes. Welding tests with a developed joining step within a progressive die showed good joining results and high process stability. Welded studs were examined by reverse bending experiments and achieved maximum values pointing to the sheet material were used. Disturbances were introduced reliably detected by process monitoring of the voltage and current curve progression as well as the bolt movement. The analysis of the measurements showed the robustness of the automated welding process. Welding emissions were efficiently removed by suction from the shielded welding area in the tool without compromising on joining qualities.
sheet metal, capacitor discharge arc stud welding, cd arc stud welding, tip ignition, follow-on tool
Warm forged parts have advantages in comparison to conventional hot forged parts: Closer tolerances, reduced surface roughness, no scale and reduced decarburization. However, the geometrical spectrum of warm forged parts is restricted by high flow stress. To overcome this geometrical limitation new rolling and forging processes are developed in the European research project "DeVaPro - Development of a Variable Warm Forging Process Chain". The focus is on the layout of a warm preforming operation by cross wedge rolling followed by an intermediate heating and warm final forming in conventional dies. To get an idea of the effect of lower temperatures on process parameters, e.g. force, die wear and microstructure as opposed to hot forging processes, FE-simulations and experimental tests with a model are performed. In this paper a new warm cross wedge rolling process is introduced and results of experimental tests e. g. mechanical characteristics and microstructure are shown.
warm forging, process chain, cross wedge rolling
Warm forged parts are distinguished by good surface properties and high dimensional accuracy. In comparison to hot forging the maindisadvantage is the high wear of the forging dies because of the higher mechanical load. Diamond-Like Carbon (DLC) coatings are anti-adhesive and extremely hard (up to 3500 HV) and are thus suitable as wear protection coatings. The suitability of these kind of coating is examined by simulation and experiments at the IPH – Institut für Integrierte Produktion Hannover gemeinnützige GmbH. For this purpose, a modular test rig was developed, which enables the detection of relevant process parameters, e.g. as the die temperature. The project aims at a reduction of die wear and a wa to demonstrate the wear process, depending on the process parameters.
DLC, coating, warm forging
The complaint processing in the customer-supplier relationship is costly and time consuming and often incorrect. At the Institute of Metal Forming and Metal Forming Machine Tool (IFUM) will together with the IPH - Institute of Integrated Production Hannover gGmbH developed a measurement and evaluation system to improve the quality and reduce costs in the processing of complaints involving the 8D method.
processing of complaints, method of valuation, cost reduction, 8d report
The processing of complaints involving the 8D method is sometimes very costly and time consuming and often error-prone. Against this background, an automated metric system for measuring and evaluating the quality of processing of an 8D report is presented in the article. On the one hand text mining algorithms are used to determine the metrics. On the other hand manual reviews are used to realize the required bandwidth at reviews efficiently and reliably. The metric system was implemented in software and is designed to enable companies in various industries to reduce the expense of an effective fault management significantly, to shorten response times in the event of a complaint and to benefit from a long-term avoidance of errors.
quality management, complaint management, 8d report, data mining, text mining
In comparison with the conventional forging with flash, precision forging helps to reduce the amount of raw material. Beyond this no additional step for flash removal is needed. In this paper the development of a three step process for a two cylinder crankshaft with flange and pin is described and afterwards compared to a four step process. It shows that the three step process lowers the number of faults saves time and forces. These advantages are due to the innovative tool concept which is shown in this paper.
cross wedge rolling, bi-directional forging, crankshaft forging without flash
Sheet metall parts with small dimensions and high quantities are usually manufactured very economically in a progressive forming process. If these parts require welded joining elements, these elements must be joined on separate welding stations. The handling of the separated components causes high costs. The integration of a thermal joining process simplifies the manufacturing of such components significantly. As part of an EFB research project a welding step including welding head and tool supply of the joining components to the tool integrated stud welding process was developed at the IPH. Emissions are removed from the welding area by means of suction while the tool is closed to protect the tool against contamination. To ensure the quality of welding process parameters current, voltage and distance are permanently monitored. Investigations of welding results from long-term tests with introduced disruptive effects showed a high process reliability and sustainability of compounds as well as a stable and reproducible process. Overall, it was shown that a thermal joining process safely integrate in sheet metal forming by stud welding and that potentially occurring disruptive effects are manageable.
sheet metal, capacitor discharge arc stud welding, cd arc stud welding, tip ignition, follow-on tool
