Burr

What is a Burr?

A burr is a sharp, raised edge that forms on the corners of a machined workpiece during machining. Burr formation is a common phenomenon in metalworking and can present challenges for both workpiece quality and workplace safety. Burrs are undesirable because they can compromise the functionality and appearance of a workpiece, and pose a safety hazard when handling the parts.

Factors Affecting Burr Formation

Several factors influence burr formation, including:

• Tool: The condition, sharpness, and geometry of the tool significantly affect burr formation. A dull or improperly selected tool increases the likelihood of forming burrs.
• Material being machined: Softer materials, like aluminum, are more prone to burr formation than harder materials, such as steel.
• Machining method: Different methods, such as drilling, milling, and turning, can impact burr formation in various ways.
• Machining parameters: Cutting speeds and feed rates can either increase or decrease burr formation.

Methods for Removing Burrs

Burr removal is an essential part of the machining process, and there are multiple methods for accomplishing it:

• Manual removal: Traditional methods, such as filing, hand scrapers, and air tools, are still widely used in many machine shops. However, these techniques are time-consuming and require precision. They also tie up machinists' time and can present the risk of accidents.
• Automated CNC machine tools: In modern machining, burr removal is often handled by automatic CNC machines. Advanced CAM software, such as Mastercam, offers fully automatic toolpaths for burr removal, reducing the need for manual labor and increasing efficiency.
• Special tools and automated systems: Specialized tools and automated systems, such as rotary brush machines, can also be employed for burr removal. These provide efficient and consistent surface finishing.

Preventing Burr Formation

Burr formation can be prevented by optimizing machining methods:

Arc movements: Adding small arc movements around external corners in toolpaths can help reduce burr formation.

Machining strategies: In certain situations, switching from climb milling to conventional milling can help minimize burrs.

Optimizing machining parameters: Optimizing cutting speeds, feed rates, and depths of cut can reduce burr formation and improve machining quality.

Summary

Burrs are a common problem in machining processes, but there are effective methods to both prevent and remove them. Automated CNC machine tools and advanced CAM software make burr removal easier, saving machinists time and increasing productivity. High-quality, burr-free parts not only ensure superior product quality but also enhance workplace safety during handling. Taking these factors into account is essential for optimizing the machining process and achieving the best possible results.