The Dreaded Burr: How Workpieces Are De-Burred

In the manufacturing industry, it’s not uncommon for workpieces to have one or more burrs after being machined. Machining operates can change the shape, size and other physical characteristics of a workpiece. Milling, for example, cuts away material from a workpiece using a rotating cutting tool. Stamping, on the other hand, involves compressing a workpiece between a die set.

When workpieces are machined, it often creates surface imperfections known as burrs. Burrs typically look like raised strands of metal and occur on areas of a workpiece that were directly exposed to a machining tool. Some burrs are harmless, but others can cause serious headache for manufacturers. As a result, many manufacturers seek to de-burr their machined workpieces.

The 3 Types of Machine-Created Burrs

Machining operations typically create one of three types of burrs, each of which features a different shape.

  1. Rollover: The most common type, rollover burrs resemble pieces of shaved, curled metal.
  2. Poisson: When excess material forms at the end of a workpiece and extends laterally, it’s called a poisson burr.
  3. Breakout: Finally, breakout burrs are characterized by a blossoming shape that “breaks out” from the workpiece.

You may discover other types of burrs, but most machine-related burrs consist of rollover, poisson or breakout.

De-Burring Processes

When burrs form, manufacturing companies must remove them from the workpiece using a de-burring process. There are actually several de-burring processes, each of which is designed to remove burrs.

Manufacturing companies perform manual de-burring by scraping or buffing down burrs using one or more tools. Scrubbing the surface of a workpiece with a piece of sandpaper, for example, is considered a manual de-burring process. It’s not a particularly fast or effective way to remove burrs, but it’s simple enough that anyone can do it.

A more modern and advanced way to remove burrs from a workpiece is electrochemical de-burring. With electrochemical de-burring, burrs are exposed to a solution consisting of salt or glycol. An electrical current is then applied to the solution, which dissolves the burrs. Electrochemical de-burring is highly useful for removing burrs in hard-to-reach places, such as cracks and crevasses within a workpiece.

There’s also mechanical de-burring, which involves the use of a machine to grind burrs off a workpiece. Mechanical de-burring was invented in the 1960s and has since become a popular method for removing burrs. The de-burring machine quickly and efficiently grinds off stubborn burrs, leaving behind a smooth surface on the workpiece.

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