Punch burr is a term frequently used in manufacturing technology. It refers to the burrs that are created when punching metal sheets.
During punching, a punch burr is created when the punch penetrates the sheet metal.
The severity of the punch burr varies depending on the material and process conditions. The design of the tools for different materials and material thicknesses also has a significant influence on the punch burr. The punch burr appears on the same side as the punch.
The burr height is typically measured with a micrometer. The plate thickness is measured near the hole and at the edge of the hole. The difference between these two measurements indicates the height of the burr.
There are standardised tolerances for different material thicknesses:
> Plate thicknesses up to 0.6 mm: burr height 0.15 mm
> Plate thicknesses from 0.7 to 1.5 mm: burr height 0.17 mm
> Plate thicknesses from 1.6 to 3 mm: burr height 0.20 mm
> Plate thicknesses from 3 to 6 mm: burr height 0.25 mm
> Plate thicknesses from 6 to 12 mm: burr height 0.50 mm
> Plate thicknesses over 12 mm: burr height 0.50 mm
Up to 10% of the perforated surface or the number of holes may fall outside these tolerances. Special agreements are necessary for higher requirements, such as decorative applications.
Punching burrs can have functional and aesthetic effects on the component.
Punch burrs also impair the appearance of the component. This is particularly relevant for visible components. In addition, sharp burrs can pose safety risks as they can cause injuries.
Various methods are available for removal. Mechanical methods include grinding, brushing and shot blasting.
Thermal processes such as laser and plasma deburring offer precise and effective solutions. Chemical finishes, such as pickling and electrochemical removal, also contribute to burr removal.
The choice of method depends on the material, thickness and intended use of the component.
A burr that forms when punching metal sheets. This burr forms on the exit side of the punch when the material is deformed by the pressure of the punching tool. Its formation is a natural part of the punching process and varies depending on the material, punching tool and process conditions. It can be particularly pronounced in thicker materials or if the punching parameters are incorrectly selected.
There are several removal methods, including mechanical, thermal and chemical processes. The choice of method depends on factors such as the type of material, material thickness and the intended use of the component.