Maschinelle Oberflächeneinglättung

Mechnical surface smoothing for the efficient die and mold production

 

Motivation

German die and mold makers have to face increasing international competition. To stay in the market, a continuous technological and economical process optimization has to be ensured. Due to the use of more complex geometries and high-strength materials in car production, the demands on deep drawing dies increase simultaneously.

Scheme hammer peening and deep rolling
Figure 1: Scheme hammer peening and deep rolling

Objective

It is the aim of this project to reduce the conventional process chain in die and mold production. Therefore, the potential of deep rolling and hammer peening is analysed to automate the manual polishing work completely. As a result of the achieved surface layer hardening it is also of interest whether this effect can increase the load capacity of tool coatings. Furthermore, different process extensions are analysed.

Process chain in die production [Ford Forschungszentrum Aachen GmbH]
Figure 2: Process chain in die production [Ford Forschungszentrum Aachen GmbH]

Approach

With the help of experimental and numerical approaches, the basic understanding of the two methods is supposed to be extended. The derivation of time- and direction-dependent material behavior is done by FE-simulations. At the same time experimental analysis helps to identify the process parameters for maximum attainable surface smoothing and hardness increase. Based on this knowledge, in the second work package deep rolled and hammer peened samples are coated to analyze the load capacity of the hardened surfaces. Afterwards wear behavior of the most promising samples is tested in the combined strip drawing test. Another work packages deal with the potential of process extensions of the mechanical surface treatment. In this respect nanoparticles and alloying elements are rolled and hammered into the surface layer to evaluate the influence on wear behavior. The treatment of real deep drawing tools of industrial partners completes the project.

Milled and hammer peened structure in direct comparison
Figure 3: Milled and hammer peened structure in direct comparison

Acknowledgment

The PTU would like to thank the following companies for the supporting of this project:

  • BMW AG
  • Tatasteel
  • Daimler AG
  • Volkswagen AG
  • Ford Forschungszentrum Aachen GmbH
  • FILZEK TRIBOtech
  • Hans Berg GmbH & Co. KG KWL
  • Konstruktion und Werkzeugbau Löcker
  • Oerlicon Balzers
  • VST Seidel GmbH&Co. KG
  • Siebenwurst Werkzeugbau GmbH Zwickau
  • ECOROLL AG
  • Zeller und Gmelin GmbH&Co. KG