The arm of an excavator mainly includes the boom and the dipper, which play a key role in the excavator. The boom, also known as the boom or the jib, is a longer arm connected to the frame, which is mainly responsible for supporting and moving the other parts of the excavator. The dipper, also known as the forearm or the second arm, is a shorter arm connected to the bucket, which is mainly used to control the digging and loading actions of the bucket.
In addition, excavators can also be equipped with different types of arms, such as extended arms, rock arms, etc., to meet the needs of different working environments. Extended arms are suitable for working environments in confined spaces, while rock arms are suitable for tasks that require high-intensity excavation. These different types of arms also differ in design and material. For example, the rock arm is made of high-strength manganese steel material and filled with a mixture of iron sand and cement to increase weight and durability.