The most common bulk forming process is closed die forging with flash. One goal of the industry is to reduce flash. For geometrically difficult parts like crankshafts flash reduction can be achieved by flashless preforming and flash-reduced final forging. The corresponding process design is challenging and defects like an insufficient cavity filling often occur in final forging. A controlled, moveable flash gap enables the alteration of the material flow, increasing the filling of the cavity again. In this paper, the flashless preforming for crankshafts and the influence of a controlled flash gap on cavity filling are described.
Forging, die design, material flow, FEA, flash land
In common forging processes for geometrically complicated parts such as crankshafts, an excess on material (flash) is technically needed to produce a good part, which results often in a material utilization between 60 % and 80 %. But the material costs in forging represent up to 50 % of the total production costs. By decreasing the flash ratio, the material usage and production costs in forging operations can be reduced significantly. For a crankshaft, the development of a new forging sequence was necessary, to achieve the reduction of flash. This development was performed for an industrial two-cylinder crankshaft, based on finite element analysis (FEA) simulations. The new forging sequence consists of three flashless preforming operations, an induction reheating followed by a multidirectional forging and the final forging. By use of this forging sequence the flash ratio was reduced from about 54 % to less than 10 %. Due to the huge reduction of the flash ratio, material as well as energy can be saved from now on, thus increasing the competitiveness of the company.
hot forging, FEA simulation, reduction of flash, multidirectional forging, resource efficiency
Compliance with punctual delivery under the high pressure of costs can be implemented in the forge industry through the optimization of the in-house tool supply. Within the Transfer Project 13 of the Special Research Department 489, a mathematical model was developed which determines the minimum inventory of forging tools required for the production, considering the tool appropriation delay.
production planning and -steering, production management, tool inventory reduction, servicelevel, fo
The more complicated a forging geometry is, the more flash is necessary to achieve a form filling and a part free of defects. Most small and medium sized enterprises (SME) forge many different parts in small and medium batch sizes and cannot afford the high effort to design more efficient forging processes. In the paper the development of a resource efficient forging process chain for crankshafts is summarized. The forging sequence consists of flashless preforming steps and a flash reduced final forging. The tools were designed to work on industrially used fast moving mechanical presses. The last of the four flashless preforming steps is a multidirectional forming of the crank webs and a pin offset. To keep the forging forces on a low level and enable a stable forging process, an induction reheating of the preform before multidirectional forging was designed. The crankshaft was successfully forged with a reduced flash ratio of less than 10 %.
forging, flash, induction heating, preform, crankshaft
The lecture introduced IPH – Institut für Integrierte Produktion Hannover gGmbH with its three fields of activity: forming technology, logistics and automation technology. Furthermore, research and consulting projects were discussed. In addition, Industrie 4.0 was presented as a major focus of current research.
industrie 4.0, automation technology, logistics
Increasing electricity price fluctuations through the augmented integration of renewable energies require dynamic tariff plans in order to conform the energy demand on the energy offer for achieving network stability. If time-variable electricity tariffs taking account into the specific needs of small and medium enterprises (SME) can be developed, energy costs can be reduced significantly by freedom degrees of an adapted manufacturing control.
energy costs, electricity tariff, manufacturing control, renewable energy
In this paper an approach for the integration of energy costs in manufacturing control algorithms is presented. The developed method is based on the Load-Oriented Order Release (LOOR) and considers fluctuating electricity prices due to the increasing supply of renewable energy in the power grid. The development allows particularly small and medium-sized enterprises (SME) to save energy costs by organizational methods of manufacturing control without capital-intensive investments.
manufacturing control, energy costs, load-oriented order release, job shop production
The concept of angular difference allows simultaneous measurement of the relative and absolute rotation angle as well as the torque. The torsion of a shaft resulting from torque gets determined via the difference of two angles and converted into correlating torque. Today’s measuring devices use encoder disks or additional torque shafts. An incremental or absolute structure of measurement of the encoder disks is applied to it. Torque shafts are used frequently to extend the twist angle as a result of torsion. Current methods of measurement for rotation angle and torque are described.
concept of angular difference, rotation angle, torque
This paper is concerned to technology trends in logistics and shows a user interface which is focused on voice commands for using it with automated guided vehicles (AGV). Furthermore a multimodal human-machine interaction (HMI) will be presented, which gives the user the possibility to communicate and control an AGV due to information from a speech recognition system and an electroencephalograph (EEG). It will be shown, which potentials based on the merging between the acoustical voice signals and the non-invasive recording of the brainwaves from the EEG-Headset are available. By the detection of the cognitive and emotional state of the user from the signal curves by the EEG like attention or mental effort, an intelligent HMI should be realized. As a result of this, dialogues between humans and machines could be used more efficient and wrong inputs, like for example the request for a reconfirmation if an inattention is detected, could be reduced. First perceptions will be shown in this paper. In conclusion there will be a prospect of upcoming studies in the future.
driverless transport systems, driverless transport vehicles, voice control, eeg
The lecture introduced IPH – Institut für Integrierte Produktion Hannover gGmbH with its three fields of activity: forming technology, logistics and automation technology. Furthermore, research and consulting projects were discussed. In addition, Industrie 4.0 was presented as a major focus of current research.
research and development, industrie 4.0, automation technology, logistics
In the context of industry 4.0 cognitive technical systems are systems that can adapt functionality flexibly and completely personalized to the specific needs of an operator or a product. Due to a wide range of intelligent sensors technical systems have the cognitive ability. In this presentation, examples of cognitive system from the intralogistics are shown.
intralogistics, cognitive system, sensor technology, industry 4.0
Pistons for combustion engines are usually made of aluminum. But increasing requirements on efficiency and performance can be met by use of steel pistons that will probably spread in the automotive industry in the next years. The pistons are forged and an expensive machining process is necessary to finish them. In the usually unidirectional forging process it is not possible to pre-forge some areas, such as the pin bores as they represent an undercut. By the help of a multidirectional forging operation it is possible to forge undercuts. This process is distinguished by a pre-forging of the pin bores and an improved material usage. Furthermore, the following machining operation will be simpler due to an easier positioning of the part. Currently, the forging tools are under development. Once they are finished they will be tested in an industrial environment on an eccentric press. The tools and parts will be analyzed concerning the quality of the parts, the die wear and the economic efficiency of this new process.
piston, steel, forging, pin bore, undercut, multidirectional
Forging companies are often suppliers of the automotive industry, which has, by the implemented principles of Just-In-Time production, particularly high demands on the logistics performance of their suppliers. Moreover, the cost pressure in this industry is very high, so forging companies are striving to minimize their logistics costs. One of the factors influencing these logistics costs is the amount tools in a company’s tool inventory. Since the tooling costs have a high percentage of the product costs, strategic positioning between logistics performance and costs in the forging industry holds great potential. However, while a too low number of tools may cause delays in production and more frequent setting-ups caused by division of production lots and a concomitant increase of setting-up times of up to 30%, a possible consequence of too high tool inventories is the increase of process uncertainty by a prolonged and more stray tool circuit pass-through time. A structured approach to the positioning of the tool supply between logistics performance and costs is presented.
production planning and -steering, production management, tool inventory reduction, servicelevel, fo
In this paper the comparison of simulations of cross wedge rolling processes with real trials using flat cross wedge tools is presented. The investigated materials are titanium and bainitic grade steel. First simulations were used to find the suitable parameter combinations for the investigated materials. Afterwards tools were manufactured with these parameters and additionally with some variations to investigate a field of parameters around this range of parameter values. The purpose of these tests is to find geometrical and process parameters with which a stable cross wedge rolling process for bainitic grade steel and titanium is possible.
cross wedge rolling, bainitic grade steel, titanium, finite element simulations
The production ramp-up is often a critical period for manufacturing companies. It is essential to prepare an efficient plan and to monitor consistently the abidance of this plan. With a maturity level model and key figures the quality of a ramp-up can be described. Therefore, the values of the key figures are categorized into maturity levels. By different aggregation levels a target-actual comparison can be made based on one key performance indicator.
production ramp-up, maturity model, aggregation logic, ramp-up management
Elimination of waste is the basis of the Toyota production system as well as any other lean implementation. Visual Management supports the process of waste elimination within the company. It helps to detect deviations from standards that indicate problems which should be solved by the means of continuous improvement processes. The article describes the basics of Visual Management and introduces selected methods such as 5S. In order to show practical implementation aspects a use case of Siemens AG is presented.
visual management, lean production systems, lean management, waste elimination
In multi-site assembly, problems such as defective tools require assembly control to react promptly in order to avoid negative consequences, such as deferred deliveries or additional costs. A method is presented which uses statistical online simulation based on structured assembly plans to quickly identify and evaluate possible options for dealing with a problem. Furthermore, the structure and procedure of a purpose-built simulation system is shown in this article.
assembly control, simulation, production planning and control, failure management
Reducing die wear is an effective way to decrease costs within bulk forming processes. Therefore, specific tool materials and heat treatments as well as special coatings are used to prolong the lifetime of the tools. Diamond-like carbon (DLC) coatings show high hardness and superior frictional behavior. However, these coatings seem to be inappropriate for hot forming due to degradation processes at elevated temperatures. But for warm forming, due to the lower temperature input into the cavity DLC might be an appropriate coating. Friction influences the shear stresses on the cavity surface and is therefore an important factor for reducing die wear. Hence, the frictional behavior of DLC coatings within warm forming will be analyzed within this paper by using the ring compression test. An amorphous hydrogenated carbon coating and six metallic doped amorphous hydrogenated carbon coatings (Cr, V and W each in two variants) are compared to CrN and no coating. Firstly, nomograms are graphed by the use of Finite-Element-Analysis. Thereafter two test series are carried out varying forming temperature and lubrication. The results show that DLC coatings with and without metallic doping are able to reduce friction in warm forming. Within the investigations an amorphous hydrogenated carbon doped with 15 % chromium shows the lowest friction factor and is able to reduce the friction factor compared to no coating by up to 64 % within warm forming.
diamond-like carbon (DLC), friction, warm forming, bulk forming, ring compression test
The challenge in developing a hydroforming process for Tailored Hybrid Tubes is to provide feasible forming conditions for both the steel and the aluminum part of the semi-finished hybrid material. The aim of these investigations is to develop one-stage tube hydroforming processes for steel-aluminum-joints. Therefore, the effects on the materials’ forming behavior, especially the flow stress, of the parameters alloy, thickness, forming rate and seam design are being investigated. Forming tests were carried out on sheet metal specimens of joined steel and aluminum to investigate the impact of the varied parameters and to analyze the joint area’s forming behavior. Based on the results of the forming tests an FEA-simulation will be set up in order to design a hydroforming process for Tailored Hybrid Tubes of laser joined steel and aluminum. Eventually the hydroforming process of Tailored Hybrid Tubes shall be executed for a sample part.
hydroforming, automotive, laser brazing, laser soldering, steel-aluminum, car body, engine downsizin
Hot forging dies are subjected to high mechanical, thermal and chemical loads. These loads can lead to die failure and therefore are one of the main cost factors in forging industry. The billet temperature is the process parameter mainly influencing the loads in forging processes. In warm forging the billet temperature is much lower than in hot forging. Warm forging becomes more and more important due to the advantages against hot and cold forging. This paper describes an analysis of FE-simulations of the change in loads on forging dies and the effect on the die life time by changing from hot to warm forging processes. Furthermore a method is presented which enables a calculation of thermal stresses in forging processes.
warm forging, hot forging, thermal stresses, tool wear
