How Does an Impact Crusher Crush Hard Rocks？

Impact crushers break down hard rocks by repeatedly impacting them with high-speed hammers or blow bars, causing the material to shatter and break into smaller pieces. The material is fed into the crushing chamber, where a rotor with attached hammers or blow bars spins rapidly, flinging the material against impact plates or breaker blocks. This process repeats until the material reaches the desired size and is discharged. 

Here's a more detailed explanation:

1. Rotor and Blow Bars/Hammers: Impact crushers feature a rotor that spins at high speed. Attached to the rotor are either blow bars or hammers. 

2. Impacting the Material: As the rotor spins, the blow bars or hammers forcefully strike the material fed into the crushing chamber. 

3. Shattering and Further Reduction: The impact of the blow bars or hammers causes the rock to shatter and break into smaller pieces. These smaller pieces are then propelled towards impact plates or breaker blocks, where further size reduction occurs through impact and abrasion. 

4. Discharge: The process continues until the material is reduced to the desired size, at which point it is discharged from the crusher. 

5. Types of Impact Crushers: There are two main types: Horizontal Shaft Impactors (HSI) and Vertical Shaft Impactors (VSI). HSI crushers are more common and can be used in both primary and secondary crushing stages, while VSI crushers are often used for secondary or tertiary crushing to produce finer materials.