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How to Choose Excavator Bucket Teeth

Excavator bucket teeth are the primary wear parts at the front end of the working mechanism on construction machinery. They typically consist of a tooth root and a tooth tip, which are assembled and secured to the very front of the bucket using a pin and a retaining ring.

Classification of Excavator Bucket Teeth by Application Environment:

Excavator bucket teeth are broadly categorized into three main types: rock teeth (used in iron ore and various types of stone quarries), earthmoving teeth (used for excavating loose materials such as soil, sand, and gravel), and cone teeth (used in large-scale open-pit coal mining). However, the shapes of bucket teeth vary by excavator brand, each with its own distinctive features.

The Functions of Excavator Bucket Teeth:

1. Protecting the bucket. As everyone knows, bucket teeth are wear parts. Take the common 20-ton excavators in China as an example: a single bucket tooth costs only a few dozen yuan, while a bucket itself costs at least several thousand yuan. Since buckets experience significant wear during operation, the bucket teeth play a major role in protecting them.

2. With a small contact area, they allow for easier penetration into materials, resulting in smoother operation and higher efficiency.

3. Under special operating conditions (particularly when working with rock or in low-temperature environments), they protect the entire machine when encountering hard objects, reducing the impact on hydraulic components and power transmission parts.

 Selection of Bucket Teeth

Currently, domestic bucket teeth materials are generally categorized into cast and forged types, with differences in their adaptability and suitability for specific operating conditions. Since the composition of cast teeth can be freely adjusted (by adding more wear-resistant metal elements), original equipment manufacturers (OEMs) typically select cast bucket teeth for factory installation. Forged bucket teeth, on the other hand, feature higher impact toughness and are less prone to fracture; consequently, their market share in aftermarket parts is increasing year by year.

Cast Bucket Teeth: Casting is the process of pouring molten metal into a mold cavity shaped to match the part, allowing it to cool and solidify to form the final part or blank. A drawback of castings is their susceptibility to porosity and sand holes, resulting in mechanical properties that are generally inferior to those of forged teeth.

Forged bucket teeth: This process involves applying pressure to special metal billets using forging machinery to shape them through extrusion at high temperatures. This refines the grain structure within the forged piece and induces plastic deformation, resulting in specific mechanical properties. Forging improves the metal’s microstructure, ensuring that the forged bucket teeth possess excellent mechanical properties, enhanced wear resistance, and a longer overall service life.

Selecting Bucket Teeth

When selecting bucket teeth, it is crucial to consider the specific working environment of the excavator to determine the most suitable tooth profile. For general earthmoving tasks such as digging soil and loose sand, flat-tip earthmoving bucket teeth are recommended. For excavating hard, blocky rock, RC-type bucket teeth are typically used, while TL-type bucket teeth are generally preferred for excavating blocky coal seams.

V. Maintenance and Recommendations for Extending the Service Life of Bucket Teeth

1. During operation, an excavator bucket is typically equipped with five bucket teeth. The outermost teeth have a shorter service life than the inner ones. Depending on working conditions and the operator’s habits, the wear rate of the outer teeth is generally 25%–35% higher than that of the inner teeth. Therefore, the author recommends swapping the positions of the inner and outer teeth after a period of use to extend the overall service life.

2. When operating, excavator operators should ensure the bucket is positioned perpendicular to the work surface during digging to avoid breaking the teeth due to excessive tilt angles.

3. Operators should avoid placing excessive stress on individual teeth, particularly when encountering large rocks. Some operators may attempt to pry rocks apart with a single tooth; this practice is incorrect and can easily cause the tooth to break.

4. Generally, wear at the base of the teeth is significantly less than at the tips, but this does not mean the base teeth will never need replacement. The normal clearance between the base and the tip should be between 0 and 2 mm. If this clearance is exceeded, excessive play between the two during operation will cause abnormal wear, ultimately leading to tooth breakage due to concentrated stress.