Research Group Sheet Metal Forming

Contact

Name

Laura Conrads

Group Manager

Phone

work
+49 241 80 25110

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The Sheet Metal Forming group examines conventional sheet metal forming processes, such as deep drawing and bending, next to innovative processes: the combination of stretch forming and Incremental Sheet Forming is suitable for the economic production of small series. In addition, the Finite Element method is applied to design and optimize sheet metal forming processes numerically.

 
 

Local Heat Treatment of Strain-Hardened Steels

Locally and globally heat-treated crash boxes after crash test Copyright: ILT Locally and globally heat-treated crash boxes after crash test

Current lightweight design strives for high strength steels, which at the same time offer sufficient formability. To tailor the properties of low alloy steel accordingly, strain hardening combined with a subsequent local heat treatment presents a promising alternative. This approach can be used to locally increase the formability of semi-finished parts as well as to adapt the property distribution of the sheet metal at best to the function of the final part. In the joint research project of the Institute of Metal Forming and the Fraunhofer Institute for Laser Technology, a crash box serves as an example part. Local softening strategies, which increase the energy absorption capacity, are developed, at first, by means of FE simulations. Dynamic impact tests of real crash boxes confirm that the deformation path can be reduced by 28 % compared to a globally heat-treated crash box and thus weight can be saved.

For further information, please contact Laura Conrads.

  Improving the crash behaviour
 
 

FE Simulation of Multi-Stage Bending Processes

Bending center of a stamping and bending machine Copyright: Phoenix Feinbau GmbH & Co. KG Bending center of a stamping and bending machine

The stamping and bending technology is used for the production of complex bending parts, for example for the electric industry. The process design is mainly based on expert knowledge and experimental testing. Aim of the cooperation project with Phoenix Feinbau GmbH & Co. KG is the development of precise FE models to describe multi-stage bending processes and the springback behavior of the produced parts. One key aspect is the identification of material data of high-strength spring steels by means of an inverse modeling approach under bending conditions. Experimental investigations are further carried out to implement the FE boundary conditions correctly. The validated FE models are then applied to examine and evaluate different influencing factors on the final parts in stamping and bending processes.

For further information, please contact Chris Mertin.

 
Manufacturing of an Outer Skin Component of a Shelby Daytona Cobra Coupé
Springback simulation of multi-stage bending processes
 
 

Flexible Forming of Sheet Metal Components

Production of Airbus A320 inspection cover superimposed with plot of geometric accuracy Copyright: IBF Production of Airbus A320 inspection cover superimposed with plot of geometric accuracy

Many application parts contain elements which are made by flanging or hole flanging operations. The production of these flanging elements by means of Incremental Sheet Forming, short ISF, can be easily integrated into the production process on the Flexible Sheet Metal Processing Center. Thus, the entire process chain of the component production can be carried out in the same clamping. The advantages of this process integration are demonstrated by a component based on the inspection cover of the Airbus A320. First of all, the curved preform of the target geometry is created within a very short period of time by stretch forming. In ISF, a hemispherical forming tool successively forms the remaining areas of the component. After trimming, the high process limits of ISF are finally used to set up the flange and hole flange elements.

For further information, please contact Marvin Laugwitz.

 
Process Combination of Stretch Forming and Incremental Sheet Metal Forming
Process combination of Stretch Forming and Incremental Sheet Metal Forming
 
 

Car Body Production of a 1964 Shelby Daytona Cobra Coupé

Car body of 1964 Shelby Daytona Cobra Coupé Copyright: American Muscle Motorsports & Services Car body of 1964 Shelby Daytona Cobra Coupé

The 1964 Shelby Daytona Cobra Coupé was not to be seen in the historical racing sport for decades despite its many successes. Back then, only six original Shelby cars existed. The company American Muscle Motorsports & Services wanted to make the dream of bringing this legend back to the racetrack come true. Using the process combination of stretch forming and Incremental Sheet Forming, the Institute of Metal Forming, short IBF, was able to offer a flexible and cost-effective manufacturing technology for the production of the Shelby's car body. Due to the digital process chain developed at the IBF, planning and process design was accelerated considerably compared to a manual production. The subsequent production took place in the Flexible Sheet Metal Processing Center of the IBF and the body was delivered to the customer after a few weeks. So, the Shelby will soon be back on the road in historical racing.

For further information, please contact Roman Schmitz.

 
Manufacturing of an Outer Skin Component of a Shelby Daytona Cobra Coupé
Manufacturing of an outer skin component of a Shelby Daytona Cobra Coupé
 
 

Integrated CAx Process Chain

Production using integrated CAx process chain Copyright: Ahrens+Steinbach Projekte Production using integrated CAx process chain

In prototyping and small batch production, conventional manufacturing processes, such as deep drawing, are usually not economically applicable. Flexible processes with low tooling effort, such as stretch forming and Incremental Sheet Forming, short ISF, are a promising alternative to realize parts within a very short time. In addition, the goal "first time right" is pursued to save resources. Therefore, reliable and precise planning tools and models are needed. The integrated CAx process chain, developed at the IBF, enables the process planning in a CAD-CAM environment with corresponding interfaces to FE models and digital image correlation tools. Numerical simulations of stretch forming or ISF provide digital geometries that can be compared with the target geometry. In so doing, iteration cycles during the prototype production are performed virtually while material-intensive and time-consuming experiments are avoided.

For further information, please contact Roman Schmitz.

 
Digital Process Planing for Flexible Sheet Metal Forming
Digital process planing for Flexible Sheet Metal Forming
 
 

Self-Supporting Freeform Structures

Freeform structure made of individual pyramids and triangles Copyright: Sebastian Helms Freeform structure made of individual pyramids and triangles

In architecture, elaborate facades or roofs with an extraordinary design usually require massive substructures. A resource-efficient alternative for the realization of complex freeform structures was developed in a joint project of the Chair of Structures and Structural Design and the Institute of Metal Forming: By means of targeted tessellation and folding, thin sheets are enabled to create a powerful, self-supporting facade system without needing any substructures. The reproduction of individualized shapes requires a large number of single parts and flexible manufacturing processes. Incremental Sheet Forming allows for the economical production of these facade concepts. The presented facade consists of 140 individual pyramids and 234 individual triangles made of stainless steel. With a weight reduction of 48 % compared to conventional construction methods, the high lightweight design potential opens up new possibilities for modern facade structures.

For further information, please contact Lisa-Marie Reitmaier.

 
 

Leveling Strategies for Heavy Plates

Digitized heavy plate before leveling Copyright: AG der Dillinger Hüttenwerke Digitized heavy plate before leveling

Flatness is an essential quality feature in the production of heavy plates. To achieve the required flatness, the plates are hot-leveled. The applied process control is usually based on expert knowledge. The aim of the cooperation project with the AG der Dillinger Hüttenwerke is the development of tailored leveling strategies in order to predict the optimum leveling process required for different flatness defects. At first, correlations between flatness defects and process as well as material parameters are identified. For this purpose, an efficient and robust flatness characterization coupled with database analysis is used. Afterwards, the influence of different flatness defects on the leveling result is examined and evaluated in finite element simulations of the leveling process. Hence, suitable leveling strategies can be derived.

For further information, please contact Marvin Laugwitz.