Impact Crushers

A jaw crusher compresses material between two angled plates, one fixed and one moving, breaking it under sustained pressure. An impact crusher relies on kinetic energy, accelerating feed into breaker bars and plates where it fractures on contact rather than under continuous force. Jaw crushers tend to perform better with highly abrasive or very hard stone because the compression-style wear surfaces hold up longer under that kind of stress. Impact crushers produce a more cubical product and handle a broader range of material types efficiently, but wear rates increase sharply with highly abrasive feed. The right choice depends on your material's hardness, abrasion index, and what the finished product specification requires for shape and gradation.

A primary impact crusher handles the first stage of size reduction, taking the largest raw feed sizes and breaking them down to an intermediate size for downstream processing. A secondary impact crusher processes that intermediate material into a more refined output with tighter gradation control. The Mega-Slam™ is our primary HSI, and the Grand-Slam™ handles the secondary stage. The two machines differ in feed opening dimensions, rotor size, breaker plate configuration, and the degree of output size precision they are designed to deliver.

Impact crushers are designed for dry material processing. Wet or sticky feed can accumulate on rotor components and breaker plates, reducing throughput and driving wear beyond acceptable levels. If your material carries significant moisture or surface stickiness, it may need to be predried before entering the crushing circuit, or a different size reduction method may be more practical altogether. Our testing facility can evaluate a sample of your material and identify any processing complications related to moisture content before you make an equipment decision.

On an HSI crusher, the primary wear components are the blow bars, which are mounted on the rotor and absorb the direct force of incoming feed, and the breaker plates that line the crushing chamber wall. On the V-Slam™ VSI, the main wear parts are the rotor tips and the anvil ring or rock shelf. Replacement intervals depend on material hardness and abrasiveness, as well as feed rate. The practical signal for replacement is regular dimensional measurement of blow bars and breaker plates against the manufacturer's minimum thickness specification. Running worn blow bars does not just reduce crushing efficiency. It allows feed to contact the rotor body directly, which can cause significantly more expensive damage. Stedman's 24-hour parts department stocks wear components, so replacement parts are available without extended lead times when your schedule requires fast turnaround.

Breaker plates are suspended in the crushing chamber at adjustable angles relative to the rotor. Moving a plate closer to the rotor path increases the intensity and frequency of impact events, which produces a finer output. Widening the gap between the plate and the rotor allows material to exit the chamber earlier in the process, resulting in a coarser product. This means output gradation can be shifted during operation without changing wear parts or stopping the machine for a hardware swap. For operations that need to produce more than one product specification from the same machine at different times, breaker plate adjustment is the primary control mechanism.

Yes. Impact crushers are used throughout mining for mineral liberation, ore processing, and sized product preparation. The determining factor is not the industry but the material itself. Softer, more friable minerals process efficiently in impact crushers. Materials with a high silica content or Bond Work Index that indicates extreme hardness will cause wear rates that make impact crushing uneconomical, regardless of the industry. We have test reports covering a wide range of mining-related materials and can assess your specific ore or mineral feed against that history to give you a direct answer rather than a general one.

Our impact crushers operate across aggregate quarrying, asphalt recycling, energy, brick and clay, mining, food processing, agricultural processing, distilleries, fertilizer production, and herbs and spice processing, among others. Size reduction is a processing requirement in a wide range of industries, and the common thread is that the material needs to be friable and compatible with the high-velocity impact forces our machines generate. If you are unsure whether your industry or specific material is a fit, the most direct path is to submit a sample for testing at our Aurora, Indiana facility.