Process for producing burr-free workpieces by blanking, in particular in a counterblanking tool

摘要

The present invention relates to a process and a device for producing burr-free workpieces by blanking using a counterblanking tool. The counterblanking tool has an upper tool and a lower tool which include respectively an upper blanking die and a lower blanking die and an upper punch and a lower punch. The counterblanking tool further includes a ram plate which moves one of the upper and lower tools towards the other of the upper and lower tools. The ram plate moves in a continuous ram stroke during which a blanking strip from which a workpiece is to be blanked is clamped between the upper and the lower tool. During the initial portion of the blanking operation, the blanking dies remain in place while a first one of the punches, travels further and a second one of the punches travels back until a limit stop is reached. During this travel the first punch cuts partly into the blanking strip. After movement of the punches is stopped, one of the blanking dies travels against the limit stop and pushes the other of said blanking dies so that the dies slide along the punches and the second one of the punches cuts the workpiece out from the blanking strip. Thereafter the ram stroke is stopped and reversed so that the tools are separated and the workpiece is pushed out of the counterblanking tool.