Introduction

Vibrating screen is core classification equipment in stone crushing lines, gold washing plants and concentrators. Abnormal vibration, screen blockage, material deviation, bearing damage and side plate cracking frequently occur during continuous heavy-load operation. Unplanned shutdown caused by screen faults directly reduces aggregate output and delays mineral processing schedules.
This article systematically sorts out typical on-site failures, analyzes root causes and provides operable quick repair measures. All maintenance suggestions are summarized from mining and aggregate project operation experience, convenient for equipment supervisors and maintenance workers to use as reference standards.

1. Material Running Deviation & Uneven Feeding

Main Causes

• Feeding chute feeds material only on one side of screen surface
• Spring support height inconsistent; screen frame inclines left/right
• Exciter eccentric block angle asymmetric on both sides
• Screen mesh partially blocked, local material flow resistance changes

Quick Repair Methods

• Install material distributing baffle on feeding chute to realize uniform feeding
• Adjust spring height, ensure four-corner support level
• Stop machine to calibrate eccentric block phase angle of dual exciters
• Clean blocked screen holes thoroughly

2. Screen Mesh Blockage, Poor Separation Efficiency

Main Causes

• Raw material contains high moisture, clay and sticky mud
• Vibration amplitude too small, insufficient material jumping height
• Screen mesh aperture size mismatched with particle size
• Screen surface installation flat without reasonable inclination angle

Quick Repair Methods

• Install bouncing ball anti-blocking device under screen deck
• Adjust eccentric block to increase vibration amplitude appropriately
• Optimize screen inclination angle within standard range 15°~25°
• Control feeding moisture; avoid continuous feeding of ultra-wet sticky materials

3. Strange Noise, Over-Vibration and Shock

Main Causes

• Support spring fatigue fracture or serious deformation
• Bearing lack of lubrication, bearing wear and pitting corrosion
• Bolts of exciter, screen beam and side plates loose or fallen off
• Foreign hard objects stuck between screen frame and base
• Eccentric block falling off or weight inconsistent on two sides

Quick Repair Methods

• Replace damaged springs in full set; cannot mix old and new springs
• Supplement high-temperature lithium grease for bearings, replace damaged bearings
• Regularly tighten all high-strength bolts with torque wrench
• Clear stuck sundries; check and fasten eccentric locking blocks

4. Frequent Screen Mesh Tearing and Damage

Main Causes

• Material directly impacts screen surface without buffer plate
• Screen mesh tension insufficient, mesh surface vibrates loosely
• Pressing strip uneven, local stress concentrated
• Ore contains sharp hard rock, long-term abrasive wear

Quick Repair Methods

• Add wear-resistant buffer baffle at feeding inlet
• Re-tension screen mesh evenly to avoid sagging
• Replace aging rubber pressure strips; keep compression uniform
• Select polyurethane screen mesh for severe abrasion working conditions

5. Exciter High Temperature & Bearing Burnout

Main Causes

• Lubricating grease overdue, deteriorated or grease filling excess/insufficient
• Oil seal aging, dust enters bearing chamber
• Bearing clearance improper, installation deflection
• Long-time overload startup under full material load

Quick Repair Methods

• Drain old grease, clean bearing cavity and refill special high-temperature grease
• Replace aging oil seals to prevent dust intrusion
• Reinstall bearing, guarantee concentricity of exciter shaft
• Implement no-load startup specification; avoid starting with accumulated materials

6. Side Plate Crack & Cross Beam Breakage

Main Causes

• Long-term bolt looseness causes alternating vibration fatigue crack
• Spring support force uneven, local stress overload
• Welding quality defect, original welding seam stress concentration
• Long-term overloaded feeding exceeding designed capacity

Quick Repair Methods

• Grind crack tip, implement multi-layer symmetrical welding; install reinforcing plate
• Regular inspection and fastening all connecting bolts
• Adjust support spring to ensure balanced stress distribution
• Control feeding volume within rated processing capacity

7. Preventive Maintenance Checklist to Reduce Failures

• Check temperature and noise of exciter bearing every shift
• Inspect spring deformation, fracture condition daily
• Check all high-strength bolts for looseness every 3 days
• Supplement lubricating grease regularly according to working hours
• Clean screen mesh blockage timely to avoid overload operation
• Check screen mesh tension and pressure strip integrity weekly

Frequently Asked Questions

Q1: Can we only replace one broken support spring?
A: Not recommended. Springs must be replaced in complete set; inconsistent elasticity will cause screen frame inclination and accelerate other failures.

Q2: What temperature is dangerous for exciter bearings?
A: Normal operating temperature ≤75℃. If continuously higher than 85℃, stop immediately for inspection and maintenance.

Q3: Why screening efficiency drops after long running time?
A: Mainly screen hole blockage, amplitude attenuation caused by spring fatigue, or eccentric block slipping and weight shifting.

Q4: Is welding repair reliable for cracked cross beam?
A: Temporary emergency repair is available. Serious fatigue fracture needs new beam replacement to prevent sudden breakage during production.

Conclusion

Most vibrating screen failures are derived from insufficient daily maintenance, irregular feeding and improper adjustment. Timely troubleshooting can avoid catastrophic damage such as beam fracture and bearing burnout.
Enterprises should establish standardized shift inspection procedures. Once abnormal noise, temperature rise or material deviation appears, stop production for inspection as early as possible to reduce loss caused by long downtime. We provide matching spare parts including exciter units, polyurethane screen mesh, springs, bearings and fastening components for all types mining vibrating screens.