How Feed Particle Size Distribution Affects Force Distribution on Jaw Plate Tooth Surfaces

In the ore crushing operation of jaw crushers, the force distribution across the tooth crests and valleys of movable jaw plates directly determines the overall crushing efficiency and service life of the jaw plates. Fluctuations in feed particle size distribution alter the contact pattern between materials and tooth surfaces, load transfer paths, and stress concentration positions, making it a key variable easily overlooked during working condition tuning.

When the feed contains a high proportion of large-sized materials, individual material chunks are large and leave wide filling gaps inside the crushing chamber. During crushing, loads are primarily borne by the tooth crest regions. The tops and edges of tooth crests come into direct contact with large material chunks, sustaining high-frequency impact loads and elevated compressive stress. The instantaneous stress peak rises notably, with loads concentrated on the small contact area of the tooth tops. Meanwhile, tooth valley regions only bear a small amount of lateral compressive force due to insufficient material embedding depth, accounting for a relatively low share of the total load. Under this force distribution, failure modes such as impact chipping and plastic deformation tilting of tooth crests are common. The overall wear shows distinct local concentration characteristics, which shortens the total service life of the jaw plate.

When the feed has a high proportion of medium and fine-sized materials, the material packing density is high and the material layer inside the crushing chamber features good continuity. The effective contact area between materials and tooth surfaces increases significantly. Loads originally concentrated on tooth crests are dispersed across the entire tooth surface. More materials embed into tooth valley regions, which then bear greater compressive load and shear friction. The force difference between tooth crests and valleys narrows, resulting in a more uniform overall stress distribution. However, fine-grained materials exert a stronger micro-cutting effect, and the abrasive wear rate of tooth valley regions rises accordingly. Long-term operation easily leads to premature flattening of tooth valleys and blurring of tooth profiles, which further weakens the crushing engagement effect and undermines the stability of discharge particle size.

When the feed has a continuous particle size gradation with a reasonable proportion of coarse and fine particles, materials of different sizes form a layered filling structure inside the crushing chamber. Coarse particles in the upper layer carry the main crushing load from tooth crests, while fine particles fill the gaps in tooth valleys to form a buffer layer. At this point, tooth crests bear the primary impact and compressive crushing force, and tooth valleys perform auxiliary compression and material support functions. The force distribution shows a gradient change with a low stress concentration coefficient, representing a relatively reasonable stress state. Under this working condition, the jaw plate wears uniformly overall, has a more stable service cycle, and maintains good crushing efficiency.

In field production, the tooth profile parameters and operating parameters of jaw plates can be adjusted in response to changes in feed particle size distribution. For feeds with a high proportion of coarse particles, jaw plates with larger tooth pitch and gentler tooth top transitions are recommended to disperse impact loads on tooth crests. For feeds with a high proportion of fine particles, optimizing the arc structure of tooth valleys can improve wear resistance. Hunan Xiangjian Machinery Technology Co., Ltd. provides targeted selection and customized solutions for movable jaw plates based on on-site feed gradation data. For more product details, please visit https://www.xjgmg.com.