An impact crusher is a machine that breaks down materials through high-speed rotational force applied by hammers (blow bars) mounted on a rotor. It is widely used in mining, construction, and recycling industries to reduce large rocks or waste into smaller, usable sizes.

Working Principle:
Material enters the crushing chamber via a feed hopper. The rotor spins at 500-1000 RPM, transferring kinetic energy to the blow bars. These hammers strike the material, propelling it against impact plates (curtains). Fragmentation occurs through repeated collisions and inter-particle friction. Output size is controlled by adjusting the gap between the rotor and impact plates or modifying the rotor speed.

Components:

  • Rotor: The central rotating shaft equipped with blow bars.

  • Blow Bars: Replaceable manganese steel or alloy hammers.

  • Impact Plates: Secondary crushing surfaces.

  • Adjustable Grates: Control final particle size.

Applications:

  • Crushing limestone, granite, and aggregates in quarries.

  • Recycling concrete, asphalt, and demolition waste.

  • Raw material preparation in cement plants.

Advantages:

  • High reduction ratio (1:10-1:20).

  • Cubical product shape (ideal for concrete mixtures).

  • Energy-efficient with lower fines generation.

Types:

  • Horizontal Shaft Impactors (HSI): Primary/secondary crushing.

  • Vertical Shaft Impactors (VSI): Producing finely shaped sand.