Metal Burrs: Formation, Types & Tips

Machined metal components are vital in many industries and applications, but the process of machining leaves behind some imperfections. Some of these imperfections present on the surface of the components are called metal burrs.

The guide below captures information about the different types of burrs and how they can be removed. So, let's read.

What are Metal Burrs?

Metal burrs are a result of metal machining; a burr is the rough edge or ridges on the metal component. The main reason which leads to creating a burr is the process of manufacturing, and due to the tools involved in the process, these burrs are formed. Most of the burrs appear due to the cutting process of sheet metal.

How are Metal Burrs Formed?

Burrs are mostly created due to the machining processes like milling, drilling, grinding, engraving, or turning. The burr appears in the form of lines on the component and creates a raised edge. It looks as if a hammer has been struck on the surface of the metal, leading to these burrs.

5 Different Types of Burrs

There are five different types of burrs, and each type is discussed below:

1. Poisson Burr

Poisson burr is a type of burr wherein the material is deformed due to the perpendicular direction of loading. When compressive forces act on the material, it leads to create such burrs on the edges and deform it. When the cutting process takes place, the cutting tool strikes the component, and the cut edges are deformed due to compression.

2. Roll-over Burr

Rollover burrs are pieces of metal that are bent from the cutting path. When the cutting tool moves and cuts the component, some material ends up rolling, and the material folds through the cutting edge.

In cases where the material is malleable, the rolled chip doesn't leave the part. The depth of the cut also leads to the rollover burr, as the deeper it is, the thicker the rollover burr.

3. Tear Burr

The tear burrs are side burrs that are formed when the component has its cut path formed rather than cutting completely. It takes place during the punching process, and a sharp edge is left through the contour of the punched hole.

4. Cut-off Burr

Cut-off burr is formed when the leftover material from the cut falls off from it. It can be either positive or negative and is mostly observed in either automated screw machine components or saw cuts. These burrs can be prevented if appropriate support from both sides is provided.

5. Thermal Burrs

Thermal burrs are also known as slags. They are created when molten metal hardens after laser or plasma cutting or welding. Heat causes stress, and once cooled, these slags come out of the base metal and can be chipped off through brushing or grinding.

Effects of Metal Burrs

Metal burrs have some effects that cannot be ignored and are discussed in the section below.

Safety Concerns

Metal burrs cause safety concerns and have a risk of injuries because of the sharp edges, which can lead to cuts and cause severe injury.

Quality and Performance

Burrs play a significant role in the product’s performance. Even if it is just a tiny burr, it may lead to issues with the parts not fitting perfectly. These burrs could lead to a malfunction in equipment in automotive, aeroespacial, and other applications where safety is significant.

Aesthetic Considerations

Burrs can impact the aesthetic value of any component. Industries that have aesthetics as a priority may not accept these components with burrs.

Economic Impacts

In situations where burrs are not properly managed, the risk of increased cost of production and wastage of labor and materials causes an economic impact.

Deburring Tools and Methods

In case components develop burrs during machining, and you want to know how to remove burrs, this section below will help you.

Manual Deburring

Manual deburring is a very old method that requires skills to get the desired results. It is suitable for small-scale operations and uses sandpaper and polishing equipment to get rid of burrs.

Pros

• It is highly flexible
• Does not require high investments in equipment.

Contras

• Not suitable for large quantity
• It is limited to simple and small burrs.
• Cost-effective only if the quantity of components is small.

Punch Deburring

Punch deburring uses punching devices like dies, which include fine blanking dies and sizing dies, which offer better efficiency compared to manual methods.

Pros

• It is more productive than manual deburring methods.
• It has improved efficiency.

Contras

• It is not suitable for complex shapes.
• It requires special tools.

Hole Deburring

Hole deburring is meant to remove burrs of inner holes. The tools used are the ones that can easily enter and exit the hole without causing any damage. The tools have a tapered tip, which helps create chamfers.

Pros

• It is an affordable and speedy process.
• It can create excellent surface finish.

Contras

• It is suitable for holes only.
• Requires specialized tools.

Brushing

Brushing involves using sandpaper after cleaning the surface. It is also automated as it can be mounted on machine tools. Components that have complex shapes may find this method suitable.

Pros

• It is quick and economical.
• It can work with complex components.
• It offers automated processes.

Contras

• It requires multiple brushes to achieve effectiveness
• If you want to enhance the efficiency, a tool changer may be required.

Electrochemical Deburring

Electrochemical deburring is a process that helps to remove burrs from small-sized parts. The process can reverse the metal plating and remove the material using electrodes and sodium electrolytes.

Pros

• It is a highly precise process.
• The deburring process can be opted for multiple parts in one go.
• It doesn't lead to any tool wear in affected areas.

Contras

• It is limited to small-sized components.
• It may require custom tools.

Tumbling

Tumbling consists of using abrasive and liquids in a vibratory barrel which helps to remove burrs without damaging the surface. This process can be used for metales but is most suitable for ceramics and plastics.

Pros

• It is less aggressive and highly efficient.
• Helps remove other imperfections apart from burrs.

Contras

• It requires special machinery.
• Different mediums are needed for different applications.

Grinding and Rolling

Rolling and grinding are ideal ways to get rid of burrs when you need a high-quality finish. It is a flexible process and offers quick burr removal.

Pros

• It is a quick and easy process.
• Offers a high rate of production.

Contras

• It is suitable for small-size products.
• The process may require secondary finishing.

Thermal Deburring

Thermal deburring is a method which uses combustion and removes burrs from components. It consists of using a fuel and oxygen mixture and removing burrs without causing any damage to the components.

Pros

• It is a versatile and quick process.
• It leads to the process of multiple components.
• It offers a high rate of production.

Contras

• Certain components need protective measures.
• The removed material becomes oxide and may need additional processes.

Tips for Preventing and Controlling Metal Burrs

There are different ways you can control and prevent metal burrs, and some of these are as follows:

• Adjust the feed rates and speed so that burr formation can be reduced during the process of machining.
• Use sharper tools that are coated.
• Climb milling helps to minimize burr formation compared to traditional milling.
• Use coolants, which reduce heat and burrs.
• Do deburring methods as discussed above to eliminate the burrs.

Conclusión

Deburring is a very important aspect to consider for machined components so that their aesthetics and performance are not compromised. If you are in search of machined components having no burrs on their surface, you get in touch with us on DEK. We will offer you machined components of high quality and excellent surface finish free from burrs.

Preguntas frecuentes

Which manufacturing methods leave a burr?

There are different methods of manufacturing that leave a burr, such as milling, drilling, turning, etc.

Which material properties affect burr formation?

Burr formation is impacted by ductility, toughness, and hardness of the material.

Can burr formation completely be prevented?

Burr formation can be minimized but not eliminated completely.

What is the best deburring method?

There are various methods for deburring; the best ones are manual, electrochemical, mechanical, and thermal deburring.