1. GP-cone crusher parameters/cubicity
Effect of: -stroke -reduction ratio -"width" of the feed material -application example -closed circuit for product shape

2. Stroke and flakiness index
During the crushing stroke the material is crushed
and its density increases. Bigger stroke gives higher
density and bigger interparticular crushing action.
It moves stones between others and cuts flaky
grains into smaller and cuts corners of the grains
improving their shape.
GP300 MF, c.s.s. 20 mm, feed 5-50 mm ,Granodiorite

3. Crusher reduction ratio
If the crusher setting is same with two different feed size,
the reduction ratio is bigger with the coarser feed.
Nowadays crushing ratio is calculated using either 80 or 50 % size on the crusher feed and discharge

4. The "width" of the feed material
Wide feed fraction gives better shape for crushed aggregates than
narrow one. Narrow feed is and wide feed mm.
12-15 mm fraction size is so called support fraction, it fills room
between larger stones increasing the density and bringing more
effective crushing stroke improving the product shape

5. Do we loose capacity?
Not necessarily, finer feed gives also higher throughput

6. Closed circuit
In the closed circuit feed change from narrow to wide fraction improves
the shape of aggregates. Also the closed circuit increases crushing stages, same grains are crushed more times giving better shape. Smaller is the screen mesh size, better quality for the final product.
GP100 MF, feed granite rock mm
c.s.s. 12 mm, screen mesh size 12 mm

7. Hur utnyttjar vi våra krossar för optimal kubisitet?
Två tänkvärda diagram

8. Basic concepts for Closer look on Cubicity /Stroke relation
NOMINAL STROKE, nSTR
- Difference between CSS and OSS
HORIZONTAL STROKE, hSTR
- The horizontal movement of a point at mantle (picture 1.).
RADIAL STROKE, rSTR
- The radial movement of a point at mantle (the curve length).
See picture 1.
EFFECTIVE STROKE, eSTR
- Effective stroke direction is against angle bisector between mantle mantle and concave. Effective stroke corresponds to the stroke which is possible to utilise after considering crusher dynamics Effective stroke is less than or equal to nominal stroke (picture 2.).
UTILISED STROKE, uSTR
- Utilised stroke direction is against angle bisector between mantle and concave. Utilised stroke is same as real compression movement effected on aggregate. Compression movement is function of Cavity type, Eccentric shaft speed and Nominal stroke. Utilised stroke is always less than or equal to effective stroke. (picture 2.).

9. Choke zone concept CHOKE ZONE
- Choke zone is the smallest crushing zone in closed side volume Inter-particle breakage can occur only above choke zone.
Choke zone controls the capacity of the crusher (picture 1).
VOLUME RATIO OF CRUSHING ZONES, DV
- The ratio of crushing zone volumes between two sequential zones.