Abstract: The numerical control (NC) incremental sheet metal forming process is a flexible forming process, this process is very suitable for the small-lot, varied and complex sheet metal product. The thickness change laws of the truncated cone and vertical wall cylinder by NC incremental sheet metal forming on NC machine are researched. The thickness of the deformed region is measured, the data is analyzed. It is shown that the thickness of the deformed region in NC incremental forming of the sheet metal conforms to the sine law. The ultimate forming thickness is different for the different material. The ultimate forming thickness is related to the raw thickness, the thinning is larger for the larger thickness of the raw sheet. A vertical wall cylinder must be formed with multi processes. The thickness change is different for the different tool paths. A vertical wall cylinder of uniform wall-thickness can be formed by NC incremental forming process with parallel line type multi tool-paths. The fender forming is guided by the thickness change laws. The thickness change laws are verified by the fender forming and have an effect on the NC incremental forming of the complicated components.

Key words: Flexible process, Incremental forming, Sheet metal forming