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How does the geometry of the carbide tips affect chip removal in a saw blade?

by lorraine•

How does the geometry of the carbide tips affect chip removal in a saw blade?

As a supplier of carbide tipped saw blades, I’ve been deeply involved in the industry for years. In my experience, the geometry of carbide tips is a crucial factor when it comes to chip removal in saw blades. Let’s delve into this topic step – by – step. Carbide Tipped Saw Blade

The Basics of Chip Formation and Removal

Before we discuss the impact of carbide tip geometry, it’s essential to understand the basic principles of chip formation and removal during the sawing process. When a saw blade cuts through a workpiece, the material is sheared off by the cutting edges of the carbide tips. This sheared material forms chips. Efficient chip removal is vital because if chips accumulate in the cutting area, they can cause several problems. These include increased cutting forces, higher temperatures due to friction, and a decrease in the quality of the cut surface. In extreme cases, chip clogging can even lead to premature blade wear or breakage.

Different Geometries of Carbide Tips and Their Effects on Chip Removal

Tooth Shape

One of the most obvious aspects of carbide tip geometry is the tooth shape. There are several common tooth shapes, such as flat – top, alternate top bevel (ATB), and triple chip grind (TCG).

  • Flat – top teeth: Flat – top teeth are relatively simple in design. They are often used for cross – cutting softwoods. When cutting, the flat top of the tooth shears the material. However, the chips formed are relatively large and may not be easily removed. The lack of a specific shape to guide the chip can lead to chip jamming, especially in denser materials. This is because the flat surface doesn’t provide a clear path for the chips to move away from the cutting area.
  • Alternate top bevel (ATB) teeth: ATB teeth are characterized by alternating bevels on the top of each tooth. This design is very effective for both cross – cutting and ripping operations. The beveled edges help to direct the chips out of the cutting area. The alternating pattern creates a kind of "scooping" effect, pushing the chips up and out of the kerf. This results in better chip removal compared to flat – top teeth, reducing the chances of chip clogging and improving the overall cutting efficiency.
  • Triple chip grind (TCG) teeth: TCG teeth have a unique geometry with a flat center and two beveled edges on each side. This design is ideal for cutting hard materials such as laminates, plastics, and abrasive woods. The center flat section first breaks the surface, and then the beveled edges shear the material. The resulting chips are small and easier to remove. The multiple cutting edges also help to spread the cutting forces, which further aids in efficient chip formation and removal.

Rake Angle

The rake angle is another important geometric parameter of carbide tips. It is the angle between the face of the cutting edge and a line perpendicular to the workpiece surface.

  • Positive rake angle: A positive rake angle means that the face of the cutting edge slopes forward in the direction of cutting. This type of rake angle reduces the cutting force required to shear the material. As a result, the chips are formed more easily and tend to curl. The curled chips are more likely to be ejected from the cutting area, improving chip removal. However, a very large positive rake angle can make the cutting edge less strong, increasing the risk of chipping or breakage, especially when cutting hard materials.
  • Negative rake angle: A negative rake angle has the face of the cutting edge sloping backward. This provides a stronger cutting edge, which is suitable for cutting hard and abrasive materials. But the chips formed with a negative rake angle are often more difficult to remove. They tend to be more compact and may not curl as easily as chips formed with a positive rake angle. This can lead to increased chip clogging, and additional measures may be needed to ensure proper chip removal, such as using a more aggressive tooth shape.

Clearance Angle

The clearance angle is the angle between the flank of the cutting edge and a line perpendicular to the workpiece surface. A proper clearance angle is essential for preventing the flank of the tooth from rubbing against the workpiece.

  • If the clearance angle is too small: The flank of the tooth will rub against the workpiece, generating excessive heat and increasing the friction. This can cause the chips to stick to the tooth and the workpiece, making chip removal difficult. It can also lead to premature wear of the carbide tip.
  • If the clearance angle is too large: While a large clearance angle reduces friction, it can also weaken the cutting edge. The tooth may break more easily under cutting forces, and the increased space between the tooth and the workpiece may not effectively guide the chips out of the cutting area.

Practical Considerations for Chip Removal in Different Applications

Woodworking

In woodworking, the choice of saw blade with the appropriate carbide tip geometry is crucial for achieving high – quality cuts and efficient chip removal. For example, when making cross – cuts on softwoods, an ATB – toothed saw blade with a positive rake angle can provide excellent results. The ATB teeth direct the chips out of the kerf, and the positive rake angle reduces the cutting force, allowing for smooth and fast cutting.

On the other hand, when ripping hardwoods, a TCG – toothed blade may be more suitable. The TCG geometry is better at handling the denser material and producing small, easily removable chips. The negative rake angle often associated with TCG teeth provides the necessary strength to cut through the hard wood.

Metal Cutting

In metal cutting applications, the requirements for chip removal are even more demanding. The chips formed when cutting metals are usually harder and more difficult to break. Saw blades with special carbide tip geometries are used. For example, some blades have serrated or segmented carbide tips. The serrations help to break the chips into smaller pieces, making them easier to remove from the cutting area. The rake and clearance angles are carefully designed to balance the cutting force and the strength of the cutting edge, ensuring efficient chip removal while maintaining the durability of the blade.

Conclusion

In conclusion, the geometry of carbide tips has a profound impact on chip removal in saw blades. Tooth shape, rake angle, and clearance angle all play crucial roles in determining how easily chips can be formed and removed from the cutting area. As a carbide – tipped saw blade supplier, I understand the importance of choosing the right geometry for different applications. Whether it’s woodworking, metal cutting, or other cutting tasks, the proper geometry of carbide tips can significantly improve the cutting efficiency, reduce blade wear, and enhance the quality of the cut.

TCT Router Bits If you are in need of high – quality carbide – tipped saw blades and want to discuss your specific requirements for chip removal and other cutting performance, I invite you to contact me for a procurement discussion. We can work together to find the most suitable saw blade solutions for your needs.

References

  • "Machining Science and Technology" by P. K. Rao
  • "Cutting Tool Engineering" magazine, various issues on saw blade technology
  • "Handbook of Machining with Cutting Tools" by E. O. Ezugwu and Y. Yamane

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