Replacement of jaw crusher wear parts

A jaw crusher is a machine used in the crushing of heavy-duty materials such as granite, ores, and minerals. Over time, the wear and tear caused by the constant crushing and grinding of these materials can cause damage to the components of the jaw crusher, specifically the worn parts.

Jaw crusher wear parts are designed to withstand the tough conditions that crushers face, such as abrasive materials and heavy impacts. These parts include jaw plates, cheek plates, toggle plates, and other components.

Wear parts replacement refers to the process of replacing the damaged or worn components of the jaw crusher with new parts. The replacement of these parts is crucial in maintaining the performance and efficiency of the jaw crusher.

The frequency of wear parts replacement depends on the type of material being crushed, the operating conditions of the crusher, and the maintenance practices followed by the operator. Generally, wear parts need to be replaced at regular intervals to ensure optimal jaw crusher performance.

Proper maintenance and timely replacement of wear parts can help extend the life of the jaw crusher and reduce downtime, saving both time and money for the operator.

The replacement of jaw crusher wear parts includes:

• Jaw die replacement
• Cheek plate replacement
• Pitman eye protection plate replacement
• Feeder hopper liner replacement
• Toggle plate seat replacement

Before performing any maintenance or repair work, make sure that the crusher is stopped and locked out. Crusher jaw dies are made from Manganese steel which work-hardens. For different materials and applications, there are different jaw die profiles to obtain the best possible capacity to jaw die cost ratio.

Before lifting any wear parts, check the weight of the component and ensure that the lifting equipment being used is adequate to lift the weight. In addition, familiarize yourself with all the special tools provided with the crusher specifically for replacing the wear parts.

Jaw die selection

There are several different jaw dies available for your jaw crusher. For profile details and application, guidelines contact your plant representative. The type of jaw die must be selected according to the feed material and desired end product. Because of many different applications and variables, one jaw die profile is capable of performing in many applications. If you are experiencing problems with your existing application or would like to improve the application, contact the Qiming Casting engineer. When inquiring about the correct jaw die profile, the following information must be provided:

1. Feed size and gradation
2. Feed type and characteristics
3. End product gradation
4. Capacity required
5. Options; intermediate plate, spacer
6. Crusher setting

Jaw die work hardening

Because the wear and work hardening does not occur evenly in the crushing cavity, it is recommended that the following measures are taken to maximize the useful life of the jaw dies:

• When using 2-piece jaw dies, and to optimize the wear profile, flip the upper and lower jaw dies after the first 50 to 200 hours. The hardness of the feed material will dictate when to rotate the jaw dies.
• Flip the upper and lower jaw dies after every 400 to 500 operating hours (200 hours if the material is very hard) to properly work harden the jaw dies.

Cheek plate replacement

Before lifting the cheek plate, check the condition of the lifting hole in the plate. A lifting hole is acceptable when the lifting tool locks into the cheek plate and does not come loose in any position. If the lifting tool comes loose from the

cheek plate, do not try to lift the plate.

The lower cheek plates will normally wear before the upper cheek plates. When the lower cheek plates are replaced, a small shelf may form between the upper and lower cheek plate. This shelf may slow down the material movement through the crusher.

Cheek plate removal

To remove the cheek plate, proceed as follows:

1. Loosen the lock nuts approximately 12 mm (1/2”) and pull the cheek plate away from the side plate, so that the cam of the lifting tool can be rotated into the locked position.
2. Lock the lifting tool.
3. When the lifting tool is engaged and locked to the cheek plate, remove the lock nuts, washers, and bolts.
4. Lift the upper cheek plate out from the crusher.
5. Follow the above procedure for the removal of the lower cheek plates.

Cheek plate assembly

To assemble the cheek plates, proceed as follows:

1. Insert and lock the cheek plate lifting tool into the cheek plate.
2. Align the lower cheek plate with the bolt holes.
3. Insert bolts and washers and tighten the nuts so that a 12 mm (1/2”) gap exists between the cheek plate and the side plate.
4. Unlock and remove the lifting tool by turning the lever.
5. Tighten the cheek plate bolts to torque.

Changing or rotating the jaw dies

One piece jaw dies removal

To remove the jaw die, proceed as follows:

1. Stationary jaw die removal. Remove the hex nuts and the jaw die disc spring assembly; Remove the jaw die bolts, tightening wedge, and filling wedge; Exit the crushing cavity and remove the working platform; Remove the jaw die; Place the jaw die on wooden blocks.
2. Movable jaw die removal. Remove the hex nuts, jaw die disc spring assembly, and sleeve; Remove the jaw die bolts, tightening wedge, and filling wedge; Exit the crusher cavity and remove the working platform; Remove the jaw die; Place the jaw die on wooden blocks.

Jaw die installation

Before installing new or partially worn jaw dies, make sure that the jaw die and crusher cavity (front frame and pitman) seating surfaces are cleaned. The jaw dies must have metal-to-metal contact on all seating surfaces. Check the condition of the protection plate (if equipped). Replace if necessary.

1. Stationary jaw die installation. Clean all jaw die seating surfaces; Insert and lock the jaw die lifting tool to the jaw die according to appendix A; Install the jaw die into the crushing cavity, making sure that the jaw die seating surface makes full contact with the lower wedge; Insert the working platform into the crushing cavity; Install the filling wedge, tightening wedge and jaw die bolts; Install the disc spring assembly, Make sure that the disc spring stack up; Tighten the spring assembly and lock with double hex; Remove the jaw die lifting tool; Remove the working platform.
2. Movable jaw die installation. Clean all jaw die seating surfaces; Insert and lock the jaw die lifting tool to the jaw die according to appendix A; Install the jaw die into the crushing cavity. Make sure that the jaw die seating surface has full contact with the lower wedge; Install the filling wedge, tightening wedge and jaw die bolts; Install the disc spring assembly. Make sure that the disc spring stack up; Tighten the spring assembly and lock with double hex nuts; Remove the jaw die lifting tool; Remove the working platform.

Two-piece jaw die removal

To remove a two-piece jaw die, and proceed as follows:

1. The stationary jaw dies removal. Insert a working platform into the crushing cavity; Remove material build-up from the upper jaw die lifting holes; Remove material build-up between the stationary upper jaw die and cheek plates; Insert the jaw die lifting tool into the lifting holes of the upper jaw die and lock it in place; Make sure the lifting hoist is capable of lifting the weight of the two-piece jaw die; Remove the hex nuts and jaw die disc spring assembly; Remove the jaw die bolts, tightening wedge, and filling wedge; Exit the crushing cavity and remove the working platform; Remove the upper jaw die; Place the jaw die on wooden blocks; Insert the working platform into the crushing cavity; Remove material build up from the lower stationary jaw die lifting holes; Remove material build up between the stationary lower jaw die and cheek plates; Insert the jaw die lifting tool into the lifting holes of the lower jaw die and lock it in place; Remove the disc spring assembly from center jaw die bolts; Remove the jaw die bolts and center wedge; Exit the crushing cavity and remove the working platform; Remove the lower jaw die;Place the jaw die on wooden blocking.
2. Movable jaw dies removal. Insert a working platform into the crushing cavity; Remove material build-up from the upper movable jaw die lifting holes; Remove any loose material from between the upper movable jaw die and cheek plates; Insert the jaw die lifting tool into the lifting holes of the jaw die, and lock it in place; Remove the hex nuts and jaw die disc spring assembly; Remove the jaw die bolts, tightening wedge, and filling wedge; Exit the crushing cavity and remove the working platform; Remove the jaw die; Place the jaw die on wooden blocks; Insert the working platform into the crushing cavity; Remove material build up from the lower movable jaw die lifting holes; Remove any loose material from between the lower movable jaw die and cheek plates; Insert the jaw die lifting tool into the lifting holes of the jaw die, and lock it in place; Remove the disc spring assembly from the center movable jaw die bolts; Remove the jaw die bolts and center wedge; Exit the crushing cavity and remove the work platform; Remove the lower jaw die; Place the jaw die on wooden blocks.

Two Piece jaw die installation

Before installing new or partially worn jaw dies, make sure that the jaw die and crusher cavity (front frame and pitman) seating surfaces are clean. The jaw dies must have metal-to-metal contact on all seating surfaces. Check the condition of the protection plate (if equipped). Replace if necessary:

• Two Piece Stationary jaw die installation. Clean all jaw die seating surfaces; Insert and lock the jaw die lifting tool to the jaw die; Install the jaw die into the crushing cavity, making sure that the jaw die seating surface makes full contact with the lower wedge; Install the center wedge and jaw die bolts; Install the spring assembly making sure that the disc spring stack up; Tighten the center jaw die bolt nuts until most of the clearance between all the wedge retention components is removed. The center wedge should be positioned farthest away from the front casting on top of the lower jaw die; Clean all jaw die seating surfaces of the stationary upper jaw die; Insert and lock the jaw die lifting tool to the jaw die; Install the jaw die into the crushing cavity, making sure that the jaw die seating surface makes full contact with the center wedge; Insert the working platform into the crushing cavity; Install the filling wedge, tightening wedge and jaw die bolts; With center jaw die bolt hex nuts, adjust the gap between the lower and upper jaw die. A gap of 5 – 8 mm (.20” – .30”) must exist between the two jaw dies; Tighten the disc spring assembly and lock with a double hex nut;  Remove the jaw die lifting tool; Remove the working platform.
• Movable Two Piece jaw die installation. Clean all jaw die seating surfaces; Clean all jaw die seating surfaces; Install the lower movable jaw die into the crushing cavity, making sure that the jaw die seating surface makes full contact with the lower wedge; Insert the working platform into the crushing cavity; Install the center wedge and jaw die bolts; Install the spring assembly making sure that the disc spring stack up; Tighten the center jaw die bolt nuts until most of the clearance between all the wedge retention components is removed. The center wedge should be positioned farthest away from the pitman on top of the lower jaw die; Clean all jaw die seating surfaces of the movable upper jaw die; Insert and lock the jaw die lifting tool to the jaw die; Install the jaw die into the crushing cavity, making sure that the jaw die seating surface makes full contact with the center wedge; Insert the working platform into the crushing cavity; Install the filling wedge, tightening wedge and jaw die bolts; With center jaw die bolt hex nuts, adjust the gap between the lower and upper jaw die. A gap of 5 – 8 mm (.20” – .31”) must exist between the two jaw dies; Clean all jaw die seating surfaces of the stationary upper jaw die; Insert and lock the jaw die lifting tool to the jaw die; Install the lower movable jaw die into the crushing cavity, making sure that the jaw die seating surface makes full contact with the lower wedge; Insert the working platform into the crushing cavity; Install the filling wedge, tightening wedge and jaw die bolts; With center jaw die bolt hex nuts, adjust the gap between the lower and upper jaw die. A gap of 5 – 8 mm (.20” – .31”) must exist between the two jaw dies; Install the disc spring assembly making sure that the disc spring stack up; Tighten the filling wedge spring and lock with double hex nut; Remove the jaw die lifting tool; Remove the working platform.

PITMAN EYE PROTECTION PLATE  REPLACEMENT

Pitman eye protection plate is designed to protect the pitman from wear. The wear to the protection plate is contributed by feed material impact if the feed material enters the crushing cavity too fast. In addition, the protection plate will show premature wear, if it is allowed for the feed material to be crushed to high in the cavity. To prevent the protection plate from wearing through, periodic replacement is necessary.

FEED HOPPER LINER REPLACEMENT

The jaw crusher feed hopper is lined with an abrasion-resistant plate. This liner should be replaced, and not allowed to be worn through. Abrasion of the material being crushed will dictate the frequency of replacement.

TOGGLE PLATE SEAT REPLACEMENT

The toggle plate seats are hardened in the toggle plate contact area. The hardness depth is approximately 3 mm (.12”). If the seats are worn more than 3 mm (.12”), they should be replaced.