What is Burrs in Machining: Complete Guide 2025

Burrs come from machining process and methods. The identification of the type of burr is important for burr minimization. Burs characterization helps in providing information for the best deburring process. The deburring process helps in removal and preventing burs from occurring again. More information about identification removal, and prevention of CNC burring is explained in this article.

What is a Burr in Machining?

Burrs in metal are unwanted material projection on machined parts. Any cutting or material removal method results in the byproduct having ragged and bumpy edges. These are sharp pieces and often attached to the workpiece and named burrs.

What Causes Burrs in Machining

Burrs in metal are generated by machining processes like grinding, milling, drilling or turning. Thermal stresses during machining also forms burrs in metal. It is present on the edge of sharpened tool or as a raised part over the surface. burs forms in many types and this raised one is formed by hammer striking.

Definition of burrs

Image taken from International Standard ISO 13715.

Burr Formation Mechanisms

Burr formation is a complicated phenomenon. It is formed by large plastic deformation of workpiece. The type and characterization of burr depends on the type of machining process. Process parameters, tool geometry and tolerances, tool edge quality, tolerance, and surface finish of workpiece.

Identifying and Classifying Burrs

In deburring process and CNC burring, burr identification is the most important step.

Visual Inspection

It involves inspecting burrs with help of naked eye without any microscope and non-destructive method.

Image taken from: Gillespie, L. K. The Battle of the Burr: New Strategies and New Tricks. Manuf. Eng. 1996, 116 (2), 69–78.

Burr Classification Systems

The classification standard of ISO 13715 is for undefined edge quality and shape. The burr classification can be in 5 classes.

Tuofa CNC specializes in high quality deburring processes and CNC deburring for bur minimization with high energy polishing, and micro precision surface finish. We have proven ability to provide customized deburring polishing to our customers on any kind of material by maintaining material integrity and quality of services.

Advanced Burr Prevention Strategies

There are few strategies in deburring processes and for burr minimization.

Tool Path Optimization

Burr minimization can be occurred by selecting appropriate tool geometry and material, tool path design and proper process planning.

High-Pressure Coolant

Application of high- pressure coolant of 1000PSI in machining process improves the tool life and good for burr minimization in CNC deburring.

Minimum Quantity Lubrication (MQL)

It increases tool life and gives a better surface finish with tolerances and edge quality of workpiece.

Material Considerations

Proper material selection with respect to tool material is important in burr minimization. Material thickness is also important. For example, thin material is more prone to burring.

Types of Burrs

Burrs can be classified based on machining process and based on locations

Based on Machining Processes

• Shearing Burrs

Compressive forces on the material results in plastic deformation of edges and their elongation which creates burrs.

• Drilling Burrs

Sharp edges are produced during drilling process, and they protrude from their origin.

• Milling Burrs

Burr formed from thermal cutting and a rough edge formed on the workpiece.

• Turning Burrs

Edges formed during turning of material and create burrs on the surface.

• Grinding Burrs

Rough edges formed on the workpiece during grinding of material.

Types of machining burrs

Characteristics and Examples

Rollover Burrs:

It occurs when the workpiece is pierced, sheared or punched. The machine pulls the part and makes it bent or rollover.

Poisson Burrs:

This occurs when material bugles outward or sideways. Machine tool has a downward force.

Breakout Burrs:

This occurs when the workpiece part is separated from the material before the finishing of cut.

Types Based on Location

Ther are two types of burrs based on location.

Primary Burrs

This is the large cut occurs by mode and direction of tool.

Secondary Burrs

These are the remaining material at the edge after deburring processes. This occurs after the breakage of primary burrs.

Effects of Burrs on Machined Parts

Burrs in metal affect the machined parts in many ways.

Impact on Functionality

Burrs in metal affect the processing condition like feed rate and tolerance. It also affects the surface finish and quality control of machined parts.

Surface Quality Concerns

Quality control of surface finish is one of the major concerns in manufacturing. Burrs affect these and aesthetics of machined parts.

Effects on Product Life Cycle

Wear and tear resistance is greatly affected in machined parts by burrs formation. Product lifespan and durability are also vulnerable to burring.

Methods for Burr Removal

Manual Deburring

It is one of the deburring processes in which burr minimization occurs by scraping or buffing the bur out of the metal price by hand. The hand tools are used in manual deburring processes such as files or scrapers and the technique is manual filing or scraping.

Mechanical Deburring

In these deburring processes, deburring is used by cutting, grinding, milling or tuning to remove burrs. This occurs by direct contact with burrs. It is used if burrs are heavy or strong,

Thermal Deburring

Thermal deburring processes involve combustion of metal for a short period of time. This occurs in pressure chamber and burrs are removed by thermal energy.

Electrochemical Deburring

In this CNC deburring, workpiece is anode and deburring tool is cathode. In the presence of current, electrolyte creates an anodic reaction which removes the burr from the burr in metal surface.

Tuofa's Deburring Expertise

Tuofa is an expert in CNC deburring which includes mechanical, thermal and electrochemical deburring processes. Our skilled labor and expert staff have proven capability to perform manual deburring with the help of high-quality hand tools and advanced techniques

Choosing the Right Deburring Method

It is the most important part in the CNC deburring to choose right deburring processes.

Factors to Consider

1. Material Type: if you want to perform efficient deburring processes, material information is most important. It includes hardness, surface finish, tolerances, feed rates, speed and etc.
2. Burr Location: the location of burr like primary or secondary burr is important to access edge quality, and its condition
3. Precision Requirements: tolerances and edge quality in quality control are vital. They help in functioning properly the machined parts.

High pressure water jet CNC deburring

Comparative Analysis of Deburring Techniques

Cost Considerations

The deburring cost as per the IQS directory, is 30% of its production cost for a high-tolerances parts. In other industries, it is 15-20% of the production expenses.