The liner material can change the stress state of the movable jaw plate.

The backing liner behind the movable jaw plate serves as a force-transition component of the jaw crusher. Many production sites only focus on the wear resistance of the jaw plate tooth surface, while overlooking differences in force conduction caused by liner material selection. The liner fits directly between the movable jaw body and the back of the jaw plate. Liners with different stiffness and toughness alter the load transfer path, stress distribution and cushioning effect, which further affect the stress state and failure mode of the jaw plate.

When high-hardness, high-rigidity metal liners are adopted, their deformation is minimal. Crushing loads are transmitted rapidly and directly to the movable jaw body. Such liners barely provide deformation compensation. If minor unevenness exists on the back of the jaw plate or the supporting surface of the movable jaw, point-concentrated load will form at contact points and raise local stress on the rear side of the jaw plate. Under continuous impact loads, stress concentration points tend to expand inward, triggering rear cracks that gradually spread toward the tooth surface and eventually lead to jaw plate fracture. This type of liner applies to working conditions with precisely machined supporting surfaces and stable incoming impact, and it imposes strict requirements on assembly flatness.

Liners with favorable toughness and certain deformation allowance produce slight elastic deformation under load. They can adaptively fit tiny gaps on supporting surfaces, disperse localized concentrated stress and achieve even stress distribution on the back of the jaw plate. Upon impact, the liner absorbs part of the impact energy, lowering the peak transient load transferred to the jaw plate and reducing the risk of tooth tip chipping. However, accumulated deformation may cause plastic collapse of the liner, thinning its thickness and shifting the supporting position of the jaw plate. The clamping angle changes accordingly, rebalancing load distribution and aggravating uneven tooth surface wear. Regular inspection and timely replacement of liners are required.

Softer liners deliver stronger cushioning and notable impact attenuation. Nevertheless, they undergo rapid compressive deformation under long-term alternating extrusion and feature a short service life. Once the liner collapses, the jaw plate becomes loose and wobbles, continuously shifting the force direction during crushing. This accelerates wear of the jaw plate, fastening bolts and movable jaw body, making them unsuitable for coarse crushing of large lumps and high-frequency impact scenarios.

Liner selection shall be determined comprehensively based on incoming material characteristics and equipment assembly precision. Rigid liners focus on stable force transmission, while tough liners prioritize stress equalization. Hunan Xiangjian Machinery Technology Co., Ltd. can provide matched combination schemes of liners and movable jaw plates according to on-site crushing conditions to reduce abnormal cracking and uneven wear of jaw plates. If abnormal rear cracking or rapid one-sided wear of jaw plates frequently occurs at your site, you may share equipment parameters and material conditions to discuss suitable selection solutions.