Considerations to make around jaw liners

Watching a jaw liner to the crushing application is a crucial factor behind achieving maximum liner wear life.

“Having the correct liner profile will boost cost efficiency,” says Jarrod Adcock, crushing product manager at Superior Industries.

As a member of Superior’s rockface-to-loadout solutions team, Adcock assists aggregate producers with overall plant productivity. This begins with well-designed primary circuits and ongoing assistance with aftermarket wear parts.

Adcock shares a few pointers operators should know when selecting a liner that’s ideal for the characteristics of their feed material and the desired product size.

Pinpointing manganese percentage

Constructed of manganese steel or other alloys, jaw liners form a protective layer to the inside of the crushing chamber to prevent excessive wear to the crusher body from the material being processed.

The given feed material type will dictate the optimum percentages of manganese required.

“Superior’s application engineers help producers pinpoint the manganese percentage they need, as an operation may be able to access a lower manganese content, and be far more cost efficient,” Adcock says.

He stresses that some operations might equate higher manganese content with longer liner life. But if their material is not hard enough to work harden the liners, they could simply be throwing money away.

Choosing the right liner configuration

Additionally, while a standard liner may cover many applications, Adcock says it’s important to consider the variety of application-specific liners available.

“Superior offers five different liner configurations – from a standard flat tooth liner to a wavy sharp tooth liner, and also a corrugated, bellied-filled, or anti-slab liner,” he says.

As an example, Adcock says the anti-slab liner is engineered for concrete recycle or slabby-laminated material applications. Its uneven tooth height generates less “slabby” product from the flat slab of material that enters the jaw. The protruding teeth, or ridges, of the anti-slab liner help to initially break up the material versus a standard flat tooth liner that will chew up material longer before reducing it to a size that passes the closed-side setting.

For rounded or slippery-type rock, Adcock says a sharp tooth liner may be the best choice. He says it offers moderate spacing between each tooth to really grab the rock and help pull it down through the machine.

Alternatively, the tooth height and spacing on the corrugated liner is designed for all-purpose applications such as shot rock and gravel.

Lastly, for applications with varying feed gradations (i.e., portable crushing), a bellied and filled-ends liner helps to maintain a high position of crushing while providing maximum liner life.

Gauge liner wear

An industry rule of thumb on proper liner usage is defined as wearing the jaw liner surface evenly along the length of the liner and utilizing 50 to 55 percent of the original liner weight.

While there are several factors that may determine when to change out a set of liners, one of them is looking at the tooth height. During maintenance, measure the distance between the peaks and valleys of the teeth. If the distance is less than 3/8 in., the liners should be replaced.

Adcock stresses that if liner replacement is delayed, operations lose the advantages of the liner design. Both tooth height and corrugation are required to properly crush the material, as the configuration provides voids for material to fall into.

When that corrugation wears away, there is a lot more force that is generated down into the crusher. This can potentially cause damage such as toggle plate breakage or decreased bearing life.

Avoid downtime and damage

As Adcock plainly describes, downtime is money at the end of the day.

“If the producer optimizes liner performance, that means less downtime,” he says. “And if they do not change the liner in time, damage can occur to other components, resulting in lost production and additional labor, parts and maintenance costs.”

Related: How liners can reduce operating costs

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Carol Wasson is a veteran freelance writer for the aggregate and construction equipment industries.