Sheet-based punching machines

Sheet metal cutting is a common operation performed by mechanical engineering companies to produce metal parts from sheet metal. Its purpose is to partially or completely separate areas of the sheet to obtain the desired shape and/or to prepare them for other operations such as bending or stamping.

Depending on the size of the part series to be produced, several processes can be used.

• Small production runs: wire EDM is generally used to make openings in the strip during press tool development. At this stage of tool development, when only the forming stations are tested, wire EDM eliminates the need for strip-cutting stations. This is a thermal process.

• Small and medium production runs: oxycutting, traditional plasma cutting, fine-jet cutting, laser cutting and abrasive waterjet cutting are all "sheet metal" techniques. They are used to cut sheet metal and, in the case of the last three techniques, for precision cutting. Oxycutting, plasma and laser cutting are thermal processes. Abrasive waterjet cutting is an abrasive process.

• Medium and large production runs: press cutting is the oldest sheet metal cutting process, and is still by far the most productive. Most of the metal parts that make up an automobile are cut using this process: visible, or "appearance" parts (hoods, fenders, body sides, rafters...), and more or less hidden structural parts (side members, middle feet, hinges, steering columns...). This process is also used in the hardware industry (washers, door and window mechanisms, etc.), household appliances (washing machine drums, hoods, etc.), construction (gratings, scaffolding parts, etc.), electrical and electronic components (car radio housings, connections, printed circuit supports, etc.).

Most of the time, stamping accompanies a forming operation such as stamping or bending. In some cases, it is the only or main operation performed (as in the case of washers or flat connector parts).

It is this latter process that we present in this article. We will, however, exclude fine cutting, which remains a technique in its own right [1] .