1. What Are Jaw Plates?
Jaw plates are replaceable, wear-resistant steel plates that form the primary crushing surfaces of a jaw crusher. They are bolted or clamped onto the fixed jaw (stationary die) and the swinging jaw (movable die) of the crusher.
Physical Structure: Typically have teeth, waves, or smooth surfaces depending on the crushing application.
Wear Parts: Designed to be replaced after significant wear, protecting the crusher’s main frame.
Key Role in Crushing: Responsible for compressing, fracturing, and shearing raw materials (rocks, ores, concrete, etc.).
2. Functions & Working Mechanism
Primary Functions
Material Compression: The movable jaw plate exerts force on the material, crushing it against the stationary plate.
Particle Size Control: The tooth profile and gap setting determine the output size (coarse, medium, or fine crushing).
Wear Protection: Shields the crusher’s structural frame from direct abrasion, thus extending machine life.
How They Work in the Crushing Cycle
Feed Stage: Material enters the crushing chamber from the top.
Compression Stage: Movable jaw plate moves towards the fixed plate, compressing the material.
Discharge Stage: Crushed material exits the crusher from the bottom discharge opening.
Wear Patterns & Performance Impact
Uneven wear (e.g., faster wear at the bottom) can lead to poor crushing efficiency.
Deep grooves or cracks may cause premature failure or material buildup.
3. Jaw Plate Materials
A. High Manganese Steel (Mn13, Mn18, Mn22)
Benefits: Work-hardening property: Becomes harder under impact, increasing wear resistance.
Good toughness: Resists cracking under heavy loads.
Best For: High-impact crushing of granite, basalt, and other hard materials.
B. TIC (Tungsten Carbide) Insert Jaw Plates
Structure: Steel base with tungsten carbide inserts at high-wear points.
Advantages:2–3x longer lifespan than standard Mn steel in highly abrasive conditions.
Ideal for crushing abrasive materials like quartz, ferrosilicon, and recycled concrete.
C. Bimetal Composite Jaw Plates
Design: Combines a tough steel backing with a hard surface layer (e.g., chromium carbide).
Applications: Best for mixed materials, where both impact and abrasion resistance are needed.
D. Ceramic-Reinforced Plates
Use Case: Highly specialized for ultra-abrasive applications (e.g., silica-rich ores).
Limitations: More brittle than steel, requiring careful handling.
4. Jaw Plate Replacement
A. Excessive wear (>30% thickness loss, especially near the bottom).
Cracks or breakage affecting crushing performance.
Decreased product quality (unwanted fines or oversized particles).
Unusual vibrations/noises due to misaligned plates.
B. Required Tools & Safety Precautions
Lockout/Tagout (LOTO): Disconnect power before maintenance.
Tools Needed:
Hydraulic jack
Lifting slings & hoist
Torque wrench
Bushing puller (if applicable)
New jaw plates (ensure correct model number)
C. Step-by-Step Replacement Guide
Step 1: Shutdown & Lockout
Turn off the crusher and disconnect power.
Relieve hydraulic pressure if applicable.
Step 2: Remove Worn Jaw Plates
Loosen the tension rods or wedge bolts holding the plates.
Use a hydraulic jack to take pressure off the toggle plate (for movable jaw).
Lift out the worn plate using a hoist.
Step 3: Inspect Jaw Frame & Fasteners
Check for frame cracks, worn bushings, or misalignment.
Replace damaged bolts, nuts, and washers.
Step 4: Install New Jaw Plates
Apply anti-seize compound on bolt threads to ease future replacement.
Align the new plate precisely, ensuring no gaps to prevent premature wear.
Torque bolts evenly to manufacturer’s specifications (avoid uneven pressure).
Step 5: Test Run & Adjustments
Start the crusher without material (empty run).
Check for unusual vibrations or misalignment.
Adjust the discharge setting if necessary.
5. How to Maximize Jaw Plate Lifespan?
Correct Installation & Alignment
Even tightening prevents unnecessary stress concentration.
Check plate seating regularly to avoid loose fittings.
Rotate or Flip Plates Periodically
Move the plate top-to-bottom or left-to-right to distribute wear evenly.
Material Selection & Crushing Parameters
Match plate hardness to the material being crushed.
Avoid oversized feed (use pre-screening if necessary).
Regular Maintenance Checks
Inspect bolt tightness every 100 operational hours.
Monitor wear patterns to anticipate replacement needs.
Jaw plates are the heart of a jaw crusher, directly impacting efficiency, product quality, and operational costs. By selecting the right material, replacing plates at the right time, and ensuring proper installation, you can reduce downtime, lower costs, and improve crushing performance. Contact us to get the most cost-effective quote for jaw plates.
