The present invention relates to a method at the material processing by the use of high kinetic energy, comprising a piston which is driven from a start position by a hydraulic system pressure (pS) by means of a drive chamber in order, by only one stroke, to transfer high kinetic energy to a blank/tool to be processed, whereafter there is a risk that a rebound of the piston will occur, and the method comprises that a step is taken in connection with said stroke performed, which step prevents said piston from making a rebound with an essential content of kinetic energy in order to avoid negative effects as a result of a rebound, whereafter the piston is returned to said start position by means of a second chamber, wherein said step comprises that a valve means closes the driving connection between the system pressure (pS) and the piston, wherein said step comprises that said valve means is controlled by a pilot valve controlling the entire striking progress, and that said second chamber is pressurized with the system pressure (pS) during the entire striking progress.