Types of Burrs by Machining Process

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Burrs are not “one size fits all.” Burrs come in as many different types as there are machining processes and methods. Identifying burrs allows you to address not only removal processes but also possibilities of preventing them from occurring in the first place. Examining the characteristics of the burrs will provide information that helps you find the best deburring solution.

This table provides some examples of burrs and their relation to specific machining processes.

ProcessBurr TypeMachining Methods
Removal MachiningCutting burrCutting (turning, boring, milling, drilling, reaming, broaching, gear cutting, etc.); Abrasive machining (cutting by grindstone, belt grinding, honing, superfinishing, ultrasonic machining, blasting, barrel finishing, brush finishing)
Shear burrPress punching, slitting, shearing
Without burrElectrolytic machining, electrolytic grinding, etching machining, chemical
Burr due to fused solidificationElectrical discharge treatment, laser treatment, blowout
Deformation MachiningBurr due to fused solidificationCasting, die casting, plastic molding, sintering, rubber molding, laminating
Burr due to plastic deformationDie forging, gear rolling, swaging
Addition MachiningBurr due to fused solidificationWelding, deposition, soldering
Coating burrPlating, painting, coating, metal flame coating

We can further break down cutting burrs into these subgroups:

Rollover Burrs
The most common type of burr, this is generally formed at exit, when the tool pushes/punches/pierces through and causes material to roll over the edge instead of shearing off.

Tear Burrs
Material tears or deforms instead of shearing off during machining.

Breakoff Burrs/Cut-off Burrs
Material falls off workpiece leaving a burr behind.

Poisson Burrs
The machined material bulges outwards when the tool is applied to the workpiece under a downward force. This burr can also occur on the edge of the workpiece when the tool removes a layer from the surface laterally.

Take a Look

The illustrations below provide visual representation of what how some of these burrs are formed, and what they may look like.

Fig. 2. Burr formation mechanism (a) Poisson burr (considering the cutting tool as a cylinder); (b) Rollover burr; (c) Tear burr; (d) Cut-off burr. Source: Adapted from [4].

 

 

 

 

 

 

 

 

 

 

 

Next week we’ll dig into how burrs are categorized. Combined, all this data on burrs can help you make the most informed choice when choosing a deburring method.

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