Cutting gap

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The cutting gap (also shear gap ) is the distance between the upper and lower blades measured at right angles to the cutting plane during shear cutting , i.e. the lateral distance between the cutting edges moving past each other.

When cutting sheet metal, the size of the optimal cutting gap depends on the sheet thickness and the strength of the material. It is usually a maximum of 5% of the sheet thickness (0.5% for fineblanking). This should be strictly adhered to with complex materials such as aluminum sheet . A small cutting gap is technically more complex, but results in a significantly lower edge indentation and thus a better quality of the cut surfaces. In the case of aluminum, however, this leads to a built- up edge and "tinsel" formation (sheet abrasion). A large cutting gap, which can occur through tool wear, causes increased burr formation on the cutting edges of the workpieces. As a rule, the gap is designed in such a way that the cracks, starting from the upper and lower blade edges, converge and do not run past one another. The surface quality that can be achieved here is rather poor, but the dimensional accuracy is sufficient and the economy is at its highest. Cutting force and work, tool wear and the stress on all components are then lowest.

The size and position of the cutting gap therefore influences the service life and the number of possible cuts until the tool is worn. When it comes to shear cutting, one speaks of the tool life of the cutting tool. Too large a cutting gap prevents cutting and causes the workpiece to be squeezed off with strong burrs.

In summary, the size of the cutting gap has an impact on:

  • the burr height on the cut part, indentation and conicity of the cut surfaces
  • the surface quality of the cut surfaces
  • Dimensional accuracy of the cut part
  • the required cutting force
  • the wear of the cutting tool and the possible tool life

Individual evidence

  1. ↑ Willy Schal (Ed.): Manufacturing technology. Volume 2, Handwerk und Technik, 9th edition Hamburg 2002, ISBN 3-582-02313-3 , pp. 100f