Deburring

With a wide range of deburring tools from handheld to machine tools, the Cromwell range is designed to take care of all your tooling needs. With big name brands such as Noga, Dormer and Kennedy you'll be sure to find the right tools for your application.

What is deburring?

Simply put deburring is the process of removing imperfections from the surfaces of metal workpieces once they have undergone machining. Even the most precise methods of machining don't always produce perfect results and can leave rough edges and protrusions known as burrs.

Why do workpieces need deburring?

Burrs whilst looking insignificant not only mar the look of the finish on a workpiece but also can compromise the overall performance of the finished component, especially if that part is designed to work in high precision instruments and machinery.

There are different types of burrs that occur during machining:

• Rollover burrs - These are the most common types of burrs. They are tiny bits of curled metal projecting up from the workpiece. Much like a chip that hasn't fully detached.

• Poisson burrs - These occur when too much of the machined materials collects at the end of the workpiece. They typically extend sideways.

• Breakout burrs - These form an upswelling shape. They often look like they are pushing out of the surface.

How are burrs removed?

Burrs can be removed in many ways, and thankfully they are not too difficult to get rid of. the tooling used varies from method to method.
• Hand deburring - This is a manual way to get rid of burrs and imperfections and uses a specialist deburring tool comprised of a blade and a tool holder. The burrs are scraped off the surface using the blade, the process is easy enough but takes a while to do as it is a meticulous process, so doesn't always yield the best productivity.

• Mechanical deburring - Deburring in this method uses a machine with an abrasive tool known as a rotary burr which is used to grind the burr off the surface. It is costlier due to the equipment involved but yields much higher productivity rates and, consequently is the go-to method in industrial machining operations.

Other methods of deburring include thermal deburring in which combustive gasses are used to basically burn the burrs off of the surface and is ideal for hard-to-reach areas. There is also Electrochemical deburring, where a mixture of salt and glycol is used to conduct energy through the surface, removing the burs with blasts of energy, leaving the rest of the workpiece unscathed.

Types of deburring tools

Depending on the method used there are a few different tools you can use to deburr surfaces.

• Hand deburring tool - This is a simple manual tool comprised of a blade and an ergonomic handle. The blade is usually interchangeable to allow for different blades to be switched depending on the application. Common blades are a swivel blades that is commonly used to deburr curved edges and the insides of holes, as its curved profile and freely moving head allows for the contours of curves. Other blade types include countersink blades, shaped to match the indentation of a countersink as well as triangular scraper blades that are designed for straight and angular edges. Some blades feature protective coatings designed for use with particular kinds of hardened metals.

• Rotary burrs - Rotary burrs come in many shapes, sizes and materials and are used in machining applications to remove burrs quickly and efficiently. They are usually manufactured from hard materials such as tungsten carbide and some feature hardened coatings to grind tough materials effectively. Common coatings used are aluminium oxide, ceramic and diamond. Machine deburring can be wet or dry, in wet applications a coolant is usually used to stop potential ignition from the grinding process as some metallic dust is flammable and the grinding process can produce sparks.

FAQ

Why is deburring important?

Deburring is an important process for several reasons. Firstly, the overall aesthetic of the workpiece can be marred but the look of unsightly burrs, secondly burrs can be health hazards to the worker involved in manufacturing the piece. Burrs tend to be sharp and jagged so cuts and grazes can be a risk if left. Finally, in the manufacture of precision components burrs left undealt with can cause all kinds of issues such as mechanical failure due to burrs getting caught or exposing flaws in the surface resulting in cracks etc causing the component to fail. In certain industries involving things like high pressures, excessive heat, and heavy loads this can be a major health hazard.

How do I use a hand deburring tool?

Hand deburring is relatively simple. Firstly, select the blade that is most suitable, e.g., a swivel blade for curved edges, countersink blade for countersinks etc. and load it into the handle section. Hold the workpiece in you non preferred hand or on a bench or vice. Once secured line your tool up with the work this will help reduce the risk of a false start! Once lined up you can then turn the tool in a clockwise direction whilst applying pressure to remove the burrs.