Burr

A burr is an unwanted protrusion of material on workpiece edges that arises during thermal or mechanical machining processes.
Burrs affect edge quality, subsequent processes and the further processing of sheet metal components.

Formation of burr

Burrs form when material is plastically displaced, raised, or not completely separated during the cutting or machining process. The extent of the burr formation depends, among other things, on the manufacturing process, the material, and the process parameters used.

Typical causes of burr formation

  • thermal separation processes
  • mechanical processing
  • tool wear
  • unsuitable process parameters
  • material deformation at the cut edge

Impact on subsequent processes

Remaining burrs can impair stable subsequent processes and negatively affect the function of components. Coating, assembly, and welding processes, in particular, are sensitive to uncontrolled material protrusions.

Possible effects

  • increased risk of injury
  • assembly problems
  • uneven coatings
  • unstable subsequent processes
  • increased post-processing effort

Deburring as a process step

In the deburring process step, material protrusions are removed in a controlled manner to create reproducible edge conditions and stable conditions for subsequent processing steps.

Depending on the initial condition and required edge quality, further processing steps such as edge rounding or surface finishing follow.

Related process step Deburring sheet metal

Difference between primary burr and secondary burr

Primary burrs form directly during the cutting process. Secondary burrs, on the other hand, can only form in subsequent processing steps such as edge rounding.

Technical differences

  • Primary burr: occurs immediately during separation or cutting
  • Secondary burr: results from material displacement in subsequent processes
  • Primary burr: often sharp-edged material protrusion
  • Secondary burr: frequent material dumping near the surface

FAQ

Why do burrs need to be removed?

Remaining burrs can impair edge quality, affect subsequent processes, and negatively impact workplace safety.

In which processes does burr form?

Burrs are created during thermal and mechanical machining processes such as laser cutting, punching, milling or drilling.

Further topics

Deburring sheet metal Process for the controlled removal of material protrusions. Primary burr Excess material that arises directly during the separation process. Secondary burr Material build-up that can occur in subsequent processing steps. Edge rounding of sheet metal Process for generating a radius-like transition between surface and edge.