What’s Deburring: The Secret to Smoother Metal Parts

Burrs are simply imperfections on metal surfaces left after CNC machining. These so-called “impurities” deteriorate the smoothness and beauty of the end part. So, there are all the good reasons for getting rid of them.

Deburring is the very process of eliminating burrs of a machined part’s surface. It removes sharp edges, scratches, ridges, and similar imperfections. Let’s review the process in detail and find out the method of deburring available.

What Causes Burr in Machining?

The machining process is the route cause of burrs appearing on most types of metals. Imperfections may occur at every stage of manufacturing because of material failure. The latter occurs when mechanical, electrical, and thermal stresses are applied to metal surfaces.

Here are the machining processes that usually cause tear burrs and other imperfections:

• Drilling.
• Engraving.
• Milling.
• Turning.
• Blanking.
• Punching.
• Laser Cutting.
• Plasma Cutting.
• Shearing.

Just for reference, surface roughness is connected to the probability of metal burrs occurrence to a moderate degree. The dependency is reversed. Heat-sensitive metals, on the other side, are prone to burrs because of the vulnerability of heated metal to physical stresses.

How Do You Deburr From Metal?

Depending on types of burrs, types of metal, and other factors, you may choose between several types of deburring:

1. Manual Deburring

In case you have only a few small-sized parts to finish, you may opt for manual deburring methods. This way, you’ll need to have deburring tools like knives, sandpaper, files, or any other polishing tools.

This method of deburring is regarded as a traditional one. It requires some expertise and typically leads to rather slow but satisfactory results. However, it does not deal with challenging deburring well.

2. Mechanical deburring

Mechanical deburring is somewhat the same as other polishing methods executed with the help of a CNC machine. It employs cutting, grinding, milling, or brushing tools to eliminate imperfections through direct contact.

Mechanical deburring is a perfect complementation of a conventional production process. It’s still a low-cost finishing method that can be performed over parts of varying sizes in bulk. Normally, manufacturers use it to remove burrs that are too large for other methods to handle.

It’s worth mentioning that the method is rather rough than precise. But it fully depends on the machine and deburring tool chosen.

3. Thermal Deburring

This deburring process involves using intense heat energy to remove inaccessible burrs. The working principle is placing a part inside a sealed chamber pressurized with a mixture of combustible gases. Then, the gaseous mixture covering the parts is ignited, causing combustion and causing heat. The latter oxidizes the burrs.

The neat part is that a heat attack does not deteriorate the components. It’s because of the very little mass of the gaseous substance and large area of impact. 

Usually, the method is inapplicable to heat-sensitive materials for obvious reasons. Yet, it perfectly remains some challenging burrs, stains on surfaces, and other imperfections of durable metals. 

4. Electrochemical Deburring

This method belongs to finishing processes that are normally executed over small components. Getting rid of burrs using other methods is impossible in such cases, because it’d deteriorate critical tolerances. 

Electrical deburring utilizes an electrode having a shape of an edge to deburr. Electrical current and an electrolyte are necessary to carry out such deburring. Types of everyday electrolytes are sodium chloride and sodium nitrate. Once exposed to the electrolyte thhrogh which the current is run, burrs start to deteriorate quickly. 

5. Waterjet Deburring

It’s another interesting, CNC-powered method to remove various types of burrs. The specialized piece of machinery is used here. Components are placed in a sealed chamber (deburring can be performed in an open-air environment as well) where pressurized water removes burrs and chips across the surfaces of parts. 

High-pressure water flow is optimal to use where there are hard-to-reach burrs. The method is absolutely perfect for removing imperfections from the internal surfaces of holes and taps. 

6. Abrasive and Micro-Abrasive Blasting

Well, blasting is a versatile material removal method overall. But it also may be used to remove burrs. The process involves using extremely fine abrasive media and a nozzle to create an abrasive jet. The latter targets and removes microns of material.

This is probably the most precise and repeatable method for deburring. Yet, it is pretty expensive. In most cases, this level of precision is not that necessary for deburring applications only. 

Why is Deburring Necessary?

After being cut, metals leave sharp, rigid edges, removing which is beneficial in the following ways:

• Helps to achieve superior surface quality. It may be crucial if the end product is for consumer sale. No one really wants to hurt their customers.
• Compliance with safety regulations. Some burrs easily can damage other industrial machines and are to be removed.
• Lover rejection rates. Actually, it’s often that parts that were not deburred properly do not meet the technical specifications set. In some cases, deburring is due after each machining process.

Deburring is easily considered a crucial phase of the sheet metal process chain.

Design Considerations and Cost-Saving Tips

1. Tool path planning and planning burr shape and access

Obviously, cutting tools themselves cause burrs while removing the material of a workpiece. It’s possible to optimize the design by ensuring that the tool path avoids the critical in-plane exit angles.

It’s hardly possible to prevent burrs from occurring. Yet, you still can minimize burr size variation by not changing cutting tools often. Besides, you may locate burrs on easy-to-access edges. This way, you’ll be able to remove burrs in the most cost-effective way.

2. Understand the material and components

For one, you may choose the more appropriate tools to perform machining operations in a way that burning is minimized.

On the other way, you should bear in mind that choosing the right deburring tools is crucial as well. The aggressiveness of the deburring method must correspond to the durability of the material.

3. Choose the Right Machine Setting

The directions of the workpiece, throughput time, and motor power are important considerations here. One metal is not the same as any other, so it’s crucial to choose and adjust the setting accordingly.

This way, you’ll achieve higher efficiency and greater cost-effectiveness of the deburring process. Even the conveyor belt speed may impact the cost of deburring a workpiece.

Conclusion

Every manufacturer is to get rid of burrs at any matter. The reasons are safety of goods intended for consumer sale, prevention of industrial machinery damages, reduction of rejection rates, etc. 

It’s worth choosing an optimal deburring method that corresponds to a particular component’s specificities. Combined with design optimization and propper setting, you’ll achieve the highest quality and cost-effectiveness of deburring.