Chain-die Forming is a new approach of making sheet metal products, which is proposed and developed recently. This new approach is expected to replace conventional roll forming method in the future because Chain-die Forming has the advantage of nearly zero redundant strain components during forming. The term ‘redundant strain’ is usually used by researchers of roll forming method to describe the strains which do not contribute to the final formed profile; instead, they are responsible for the harmful product defects like edge wave, flare, chamber, etc. But with Chain-die Forming, such ‘redundant strains’ can be reduced or eliminated because of its super large visual ‘rolls’.
The roll size of roll forming has been proved that has inverse relation with the redundant strain, especially the longitudinal membrane strain. However, it is not economical to deploy super large rolls in conventional roll forming lines as it will result in cost rise on rolls and more space will be required to contain larger roll forming lines. This conflict is well resolved by the Chain-die Forming method, which uses a chain running on a track board having large enough working radius to reduce or eliminate redundant strains. The chains, or track board, cannot deform blanks directly. Die blocks are made and attached to the chains to form products.
Numerical simulations and experiments are conducted to explore the potentials of Chaindie Forming. The simulation results as well as experiments have all proved that the Chaindie Forming method can significantly reduce longitudinal strains and improve product quality as well. The simulation results are also compared to roll forming and stamping, and conclusion has been made that the Chain-die Forming process is more like stamping than roll forming.
As the Chain-die Forming method uses die blocks instead of roll to form product, it is possible to use non-identical die blocks to make products with non-uniform cross section profile. One example of such products is structural part of motor vehicle, which is conventionally produced by hydro-forming or stamping. The exploration about making structural part of vehicle by Chain-die Forming is also successfully investigated by FEA approach, which provides important advices about product and die design.
An additional FEA study to Millipede Forming is also carried out to deepen the understanding of sheet metal forming process as well as the principles employed by the Millipede Forming on how to optimize forming process to gain better product quality.