VSI Sand Makers
Professional Manufactured Sand Making & Aggregate Shaping

Rock-on-rock: Material is ejected from the rotor at high velocity and impacts a self-formed bed of the same material lining the peripheral guard plates. No metal-to-rock contact occurs, which gives the best particle shape (highly cubical), minimal iron contamination, and the lowest wear cost — ideal for hard abrasive rock like granite, basalt, and quartzite. The trade-off is slightly higher fines content.

Rock-on-anvil: The peripheral guard plates are replaced with fixed metal anvils. Material ejected from the rotor strikes the anvils directly, delivering a more aggressive breakage that produces higher throughput and tighter, more consistent grading. Best suited for medium-hard or low-abrasion materials like limestone and dolomite. The trade-off is faster anvil wear and a marginally less optimal particle shape.

VSI sand makers handle granite, basalt, limestone, river pebble, quartz, dolomite, and recycled construction aggregate. Maximum feed size ranges from 30 mm (VSI7615) to 50 mm (VSI1145) — material must be pre-crushed by a jaw or cone crusher in earlier stages. The VSI supports two feed methods: full centre feed (all material enters through the rotor, primarily used for rock-on-anvil sand production) and centre feed with cascade (material splits at the distributor cone — part enters the rotor, the rest falls around the chamber perimeter to form a protective material bed — this is the standard configuration for rock-on-rock combined mode). Highly abrasive materials should always use rock-on-rock mode to control wear cost.

There are three complementary approaches: (1) Add a wheel sand washer or spiral sand washer downstream — this is the most effective method, removing excess fines, clay particles, and dust to produce clean, well-graded sand that meets concrete specifications. (2) Slightly reduce rotor speed — lower impact velocity reduces over-crushing and fines generation without significantly affecting the target output size. (3) Use closed-circuit configuration with a vibrating screen — returning oversize material for re-crushing while separating the desired fractions ensures 100% product gradation compliance.

Yes — this is one of the most common applications for VSI in rock-on-rock mode. By reducing rotor speed and operating in centre feed with cascade configuration, the VSI primarily rounds off needle-shaped and flaky particles from the upstream cone crusher without fully reducing material to sand size. The result is premium cubical aggregate with significantly lower needle-flake content — ideal for highway surface course, asphalt concrete, rail ballast, and high-grade concrete where particle shape directly affects strength and workability.

Liner life depends heavily on material abrasiveness and throughput. Rock-on-rock mode using chromium carbide blocks on granite typically achieves 100,000–200,000 tonnes per liner change. Rock-on-anvil metal anvils may need replacement at 50,000–100,000 tonnes for moderate abrasion material. SUNREX maintains stock of common wear parts for all VSI models for fast dispatch.