Common Issues with Double-Shaft Shredders – A Quick Guide

Double-shaft shredders are essential in recycling lines, but, like any heavy machinery, they can encounter operational issues over time. Below is a concise summary of common problems, their causes, and practical solutions.

1. Blade Wear & Breakage

Symptoms: Reduced shredding efficiency, oversized output particles, visible edge damage.

Causes:

• Processing high-hardness or contaminated materials

• Blade material not suited to application

Solutions:

• Replace worn blades promptly

• Use high-grade alloy steel (e.g., SKD-11, D2) for better wear resistance

• Sort feed material to remove hard contaminants

2. Bearing Overheating & Failure

Symptoms: Unusual noise, temperature rise above 25–30°C over ambient.

Causes:

• Insufficient or degraded lubrication

• Overloading

• Bearing fatigue or quality defects

Solutions:

• Implement regular lubrication schedule

• Monitor bearing temperature daily

• Replace with high-quality bearings

3. Shaft Jamming / Stalling

Symptoms: Rotor stops during operation, motor overload alarm.

Causes:

• Metal or hard foreign objects entering the cutting chamber

• Flexible materials (film, woven bags) wrapping around the shaft

Solutions:

• Install metal detection / magnetic separator upstream

• Use anti-wrapping scrapers for soft materials

• Clear jams promptly and safely

4. Motor Overheating / Shutdown
Symptoms: Thermal overload protection trips, motor housing hot.

Causes:

Overloading beyond rated capacity

Poor ventilation / clogged cooling fins

Voltage fluctuation (±10% or more)

Solutions:

Reduce feed rate to match rated capacity

Clean the motor cooling system regularly

Ensure a stable power supply

5. Material Blockage
Symptoms: Reduced output, material accumulation in cutting chamber.

Causes:

Overfeeding or uneven feed rate

Material moisture too high

Improper rotor speed setting

Solutions:

Control feed rate – steady and even

Pre-dry material if moisture exceeds 15–20%

Adjust rotor speed to match material type

6. Excessive Vibration
Symptoms: Machine shakes during operation, structural stress.

Causes:

Motor shaft and rotor shaft misalignment

Uneven knife weight distribution

Loose foundation bolts

Solutions:

Align shafts precisely during installation

Balance knife groups symmetrically

Tighten all foundation bolts; add vibration dampers if needed

7. Abnormal Noise
Symptoms: Grinding, knocking, or screeching sounds.

Causes:

Worn bearings

Loose or incorrectly seated blades

Loose machine mounting

Solutions:

Inspect and replace damaged bearings

Re-tighten and re-align blades

Secure equipment base

8. Hydraulic System Leakage
Symptoms: Low pusher pressure, visible oil seepage.

Causes:

Worn or aging seals

Hydraulic oil contamination

Solutions:

Replace seals regularly

Maintain oil cleanliness (filtration and scheduled changes)

9. Control System Malfunction
Symptoms: PLC alarms, unresponsive controls, failure to start.

Causes:

Loose wiring connections

Sensor failure

Software / programming errors

Solutions:

Inspect and secure all electrical connections

Replace faulty sensors

Contact technical support for program diagnostics

10. Gearbox / Transmission Failure
Symptoms: Reduced power transmission, grinding noise, gear slippage.

Causes:

Gear wear due to fatigue

Insufficient lubrication

Shock loading from foreign objects

Solutions:

Use shock-protection (torque limiter)

Maintain the proper oil level in the gearbox

Replace worn gears promptly

Final Recommendation

Preventive maintenance is always more cost-effective than emergency repairs. A well-trained operator, regular inspections, and prompt attention to early warning signs can reduce unplanned downtime by over 80%. For any persistent or complex issue, consult your equipment supplier for professional technical support.

Huatao provides comprehensive after-sales support, including spare parts supply, remote diagnostics, and on-site technical assistance for all our shredding equipment.

Any more interest in the shredder, crusher, and the spare parts for the recycling line, kindly contact us for more details.

Contact us: Team5@huataogroup.com
 Tel:+86 13383116640 (Wechat/whatsapp)
http://wa.me/13383116640
Website:www.huataoshredder.com