The economic use of forming processes requires sound knowledge in terms of tool and process design. A forming process depends on many process parameters, which must be taken into account during development. Even small deviations from the ideal parameters can result in a forming process no longer being economically viable.

Due to its many years of experience in the field of technological process design, the IFUM is a reliable partner for the redesign and optimisation of forming processes. With our know-how, we support you in designing your forming process to suit the component in question, to be cost-efficient and according to your individual requirements. This can be done both on a theoretical basis, with the help of a simulation and on a practical basis via various practical tests.

The IFUM provides support in the development of new forming tools and forming processes. The range of services that the IFUM provides includes the design and construction of forming processes, the development of individual tool concepts and the development of new and innovative process routes. Furthermore, feasibility analyses can be carried out and processes can be examined in terms of their scalability.

geführt werden und Prozesse in Bezug auf ihre Skalierbarkeit untersucht werden.

In terms of quality assurance and minimisation of rejects, the IFUM supports in the metrological recording and monitoring of the desired forming processes. The IFUM has various equipment for process monitoring and process control and is available to give advice with its know-how regarding the suitable measurement technology. The implementation of application-specific sensor technology in new or existing tool systems is also one of the IFUM's fields of activity.

The IFUM provides support with its know-how in the optimisation of existing forming processes, ranging from the adaptation of tools, to the analysis and optimisation of suitable process parameters. With the help of the institute's own presses and press tools, the IFUM is also able to carry out forming tests with different component geometries. In addition to new tools or tool coatings, new materials and/or lubricants can also be tested.

By quantifying friction, it is possible to draw conclusions about the tribological system in forming processes.

In the field of hot forging, cylinder or ring crush tests are carried out for this purpose. The IFUM is equipped with automatic spraying devices, in order to ensure reproducible lubricant application.

In the field of sheet metal forming, a strip drawing line with and without deflection is available, with which the friction conditions can be experimentally determined both at drawing radius and at flange drawing areas. For this purpose, a sheet metal strip is pulled either through flat jaws or over a cylindrical test specimen. Depending on the forces that act, the coefficient of friction can be determined for the material pairing being tested.

In production processes, the tribological system in the forming process is mainly evaluated by examining the tool wear.

The IFUM is able to examine wear mechanisms, such as thermal shock, in isolation or to investigate the entire load configuration in the industrially relevant series forging process with a fully automated forging cell. The loaded tools are measured optically at regular intervals with our measuring macroscope and the surface roughness is measured. Following the investigations, the metallographic examination of micrographs and the evaluation of microhardness curves take place.

In the field of sheet metal forming, the wear test stand provides a device with which the wear occurring on the drawing radii of a forming tool can be experimentally simulated and analysed. Here, the drawing process is simulated by cyclically drawing a slit strip over the quarter-circle radius of a test specimen. The contact tension can be adjusted both by adjusting the tensile force and by changing the specimen geometry for the specific case under investigation. Thus the wear progress can be measured and analysed reproducibly over the course of the stroke.

With the help of optical and tactile measurement technology, wear-critical areas can be identified, causes pinpointed and countermeasures verified.

The topographical and geometrical measurement of components and tools is an important evaluation criterion in forming technology. The optical measuring macroscope VR3200 from Keyence is available at the IFUM for topographical measurements. The measuring device enables the detection of three-dimensional surface contours and roughness profiles. For the complete geometric acquisition of component and tool contours, the IFUM has an Atos 2 400 measuring system from the company GOM. With this, 3D CAD models of a scanned component geometry can be generated, which enables a comparison with the ideal geometry of a component. The measuring systems thus provide the basis for quality and process evaluations of forming processes.

An Atos 2 400 optical 3-D scanner from GOM is available at the IFUM for three-dimensional measurements of small and medium-sized objects for quality control and reverse engineering.

The system can be used for the measurement and inspection of parts such as sheet metals, tools and dies, turbine blades, prototypes as well as injection moulded and pressure die-cast parts. The resolution is 0.14 mm. Further technical specifications of the measuring system are listed below.

An optical measuring macroscope VR 3200 from the company Keyence is available at the IFUM for carrying out dimensional measurements in 2D, as well as contour measurements of components. 3D measurements can be carried out with the VR 3200 up to a height of 10 mm (± 5 mm) in the widescreen mode. Numerous measuring tools can be used for angle measurements, height measurements or cross-section measurements. Measurements of the area can also be carried out. Parameters such as area, circumference, diameter and roundness can be determined automatically. Surface roughness measurements can also be performed with the measuring system in accordance with the DIN EN ISO 25178-2 standard. Some technical specifications of the VR3200 are listed in the table below.

The geometric accuracy and the surface quality of sheet metal components, as well as the wear of the tools used are determined on the one hand, by the process parameters and on the other by the static and dynamic interactions between the press and the tool.

A qualitative description of the machine characteristics is of particular importance for both the press manufacturer and the user. For the press manufacturer, it is possible to carry out an evaluation of new developments, in comparison to predecessor machines on the basis of such data. In addition, it is possible to track the changes in the properties of a machine (static and dynamic) over the period of use. For the user, the parameters provide differentiated information for the purchase decision as to whether a machine is suited for a particular application.

The IFUM offers static and dynamic press measurements in accordance with DIN 55189 and VDI 3145. In addition, the table and ram deflection can be recorded. If a measurement with GOM Pontos is not feasible for reasons of visibility or accessibility of the object in question, conventional solutions using tactile or laser-optical measuring equipment are also available. Based on many years of experience, the results can be compared and evaluated.

A range of high-performance material testing machines are available at the Institute of Forming Technology. Depending on the required area of application or desired sample geometry, we offer individual consultation and selection of a suitable test procedure. An overview of the conventional flow curve recording options in our test field is shown in the following tables. A wide range of extensions can also be arranged upon consultation with the IFUM.

Tensile load (Sheet metal forming)

¹  convective heating in thermal chamber or thermal container

²  conductive resistance heating

³  inductive heating

The Institute for Forming Technology has the powerful DIL805 dilatometer from TA Instruments at its disposal for conducting structural analysis. Depending on the required application, the standard quenching unit (805A), as well as the pressure (805D) and tension (805T) units can be used at the Institute. With these set-ups, a wide range of experiments can be carried out to characterise thermal material effects, such as the investigation of phase transformation behaviour within heating experiments (time-temperature austenitisation diagrams (TTA Diagrams)) or within quenching experiments (time-temperature transformation diagrams (TTT Diagrams)). Heating takes place via an inductive heating unit, whereby the temperature is monitored via thermocouples. In addition, the linear expansion can be continuously determined via push rods. After the test has been carried out, the samples used in this process can be evaluated in our experienced and well-equipped metallography.

The following table shows the boundary conditions for feasible tests. After a consultation, these tests can be individually adapted and optimised for different sample types. The cooling and heating rates can be adjusted upon agreement.

In the process design phase, precise knowledge of the material-specific deformation capacity or the damage development in the material is very helpful. At the Institute of Forming Technology and Forming Machines, there are many possibilities to investigate damage characterisation or to determine the deformation capacity, as well as possibilities for parameterisation and validation of damage models, which are continuously in further development. In addition to conventional Nakajima and Marciniak tests for recording FLCs, butterfly tests can be carried out with a specimen geometry developed at the IFUM, whereby stress ranges from shear to uniaxial tension can be recorded, thanks to a variable test device.

The TI 950 TriboIndenter from Hysitron enables the mechanical and tribological characterisation of materials on the nanoscale. Thanks to feedback control, the transducer-based system allows diamond specimens of defined geometries to be pressed into the material under investigation, with a maximum load of 10 mN in either a load-controlled or a displacement-controlled manner. The diamond tip can be positioned on the sample surface with a lateral accuracy of approx. 10 nm. Complete loading and unloading cycles (force-penetration curves) are recorded, which can then be used to draw conclusions about the mechanical properties of the sample via corresponding models. The system can be fully automated and can process several samples in succession based on a script. At the IFUM, this system is used for the mechanical and tribological characterisation of a wide range of materials. In addition, at the institute it is also possible to combine the TI 950 TriboIndenter with the x-Sol 800 heating unit. This allows nanomechanical characterisation experiments to be carried out a temperature range up to 800 °C.

Main areas of research:

• Characterisation of joining zones of similar and dissimilar material combinations
• Determination of flow properties
• Recording of property maps and distributions (such as modulus of elasticity and hardness values)
• Carrying out wear measurements at the nano scale (nanowear)
• Determination of tribological properties of surfaces and coatings

The Institute of Forming Technology has access to a large number of simulation programmes and modern hardware, for the numerical simulation of a wide range of processes from fields including sheet metal forming, solid forging, as well as biomedical technology. Our many years of experience in the field of material characterisation, modelling and process simulation enable us to address complex, innovative research and industry-specific issues. The focus always lies on the holistic coupled simulation of all process steps, such as heating, forming and a possible heat treatment, but also on the analysis of the tool loads resulting from the processes, as well as the wear prediction. Below is an overview of the possibilities of numerical process simulation available here at the Institute of Forming Technology and Forming Machines.

The simulation of solid forming processes has been one of the IFUM's core competences for many years. Based on a wealth of experience from numerous successful academic and industrial projects, as well as the latest and application-oriented analysis methods, a wide range of issues from the field of solid forming can be considered. For this purpose, the IFUM has software programmes such as Simufact Forming or Forge NxT at its disposal, which allow a detailed investigation of cold, semi-hot and hot forming processes, as well as heat treatments.

We always attach importance to a holistic view of the process chains. In this way, the influences on the quality of a forged part, for example, can be identified on the basis of the continuous virtual process chain of heating, preforming, finished forging, deburring, cooling and tempering.

Thanks to a simulative process analysis, the forming process can be designed efficiently in terms of equipment requirements and material utilisation. Furthermore, the products can already be examined virtually for defects such as wrinkles or critical areas and the fatigue strength of the tool. In addition to product-related analysis, we also use process simulation to assess and optimise tool life.

Several FE programmes are available to the institute for the numerical representation of sheet metal forming processes. These include the simulation programmes LS-DYNA from DYNAmore, Abaqus FEA from Simulia and Simufact Forming from MSC.Software. With these programmes, conventional processes such as deep drawing, thermomechanical processes such as mould hardening and novel processes such as thick sheet forming, or even shear cutting processes can be reproduced realistically.

In order to be able to represent the respective process exactly, detailed material data and material models, as well as damage models are required, which can also be recorded and created at the institute according to the process route under consideration. Depending on the application, a wide range of questions can be answered in this way.

The IFUM has extensive experience in the field of process simulation of fibre-reinforced plastics, from successfully completed to ongoing research projects. These include simulations of individual processes, such as the forming or thermoforming of organic sheets, UD tapes/laminates and sandwich composites or the impact extrusion of glass mat reinforced thermoplastic (GMT), as well as simulations of coupled processes, such as an organic sheet forming with impact extrusion/injection moulding of reinforcing ribs or UD tape laying with downstream impact extrusion. The aim of the process simulations is to support the areas of tool design, tool development and process design as well as process optimisation by analysing the process-specific thermomechanical material behaviour. In the case of coupled process simulation, the fluid-structure interaction between plastic and plastic or metal and plastic is also taken into account. Meaningful simulations require, on the one hand, suitable material parameters to parameterise the thermomechanical material models (Link to FVK characterisation) and, on the other hand, validation on the basis of real tests, which can also be carried out at the Institute.

Depending on the forming process, material and the objectives, different simulation programmes are used, which are listed in the following table.

The overall objective of the Collaborative Research Centre 1153 "Tailored Forming" is the realisation of novel process chains for the production of load-adapted hybrid solid components using pre-assembled semi-finished products. Possible material combinations of these hybrid semi-finished products are steel-steel, steel-aluminium or titanium-aluminium combinations. Numerical simulation plays an important role in the efficient design of innovative processes and process chains. The process chains under consideration and the hybrid semi-finished products that are used give rise to a large number of issues. The focus is always on a holistic consideration of the individual processes. For example, the development of the intermetallic phase is already numerically predicted for the production of semi-finished products by extrusion, taking into account the thermomechanical load spectrum. In the forming of hybrid semi-finished products with very different properties, one challenge lies in the adjustment of the different flow behaviour through targeted inhomogeneous heating concepts. With the help of numerical simulations, both the inductive heating and the resulting temperature distributions as well as the material flows of the different materials can be efficiently analysed and optimised. Thus, by using numerical simulations, even complex interlinked process chains can be designed and process errors such as cracks in the joining zone during forming, or an unfavourable growth of intermetallic phases during heating and cooling processes can be avoided. 

One objective of the numerical design of forming processes is to ensure safe process control and to minimise process errors. A typical component error in the forging process is the formation of forging folds, which lead to a reduction of the mechanical properties at this point, and have an influence on further process steps. By topologically inspecting all boundary nodes and the selected meshing of the forging component, wrinkles can be identified in the virtual process development phase. This possibility is offered by various commercial finite element software packages. The wrinkle detection in Simufact Forming was co-developed at the IFUM and is implemented from version v.16.

In the process design phase, knowledge of forming limits and damage developments in the material is very helpful. In this way, the potential of existing and also innovative materials can be fully realised, through precise knowledge of the limits of deformation. The Institute for Forming Technology and Forming Machines has many years of experience in the parameterisation, further development and implementation of damage models, especially for sheet metal forming. Thus, the appropriate damage model can be selected for each and every process, taking into account the material selection and process boundary conditions. In addition to conventional forming limit diagrams, which can also be recorded isothermally at very high temperatures using newly developed test methods, the focus is on the use of stress-based damage models. These allow the description of the damage development, taking into account the stress state in the material and thus allow, for example, a realistic representation of the damage in high-strength steels, where conventional forming limit diagrams reach their limits.

In addition to the components, one focus is on the analysis and prediction of tool life under thermomechanical stress. In particular, forging tools or tools from special processes such as thixoforging are subject to extreme thermal and mechanical stress, which leads to crack formation and ultimately tool failure. By parameterising and implementing models such as the Coffin-Manson-Basquin approach or the Sehitoglu model, the service life of tools can be estimated taking into account the locally acting load. In this way, processes can be optimised in a targeted manner and efficient planning of production and set-up times can be implemented. The required material data can be determined at the Institute of Forming Technology and Forming Machines under a variation of the thermal and mechanical load spectrum in cyclical tests, so that a realistic representation is possible.

Numerical wear calculations are of great interest in the context of process simulation of a forming operation. By considering the hardness development of hot-working steels in operation, an improved wear prediction for forging tools and a better planning of batch sizes and tool set-up times can be achieved. In addition, more accurate predictions of the tribological behaviour can be used to derive optimisation measures in the die design. The Institute of Forming Technology and Forming Machines is involved here both in the further development and implementation of wear models and in the experimental characterisation of the material behaviour of tool steels under variable cyclically applied thermomechanical loads.