Precautions for use and maintenance of screw extruder

Screw extruders are commonly used in the plastics, rubber, and food industries for processing, melting, mixing, and extrusion. Proper operation and maintenance ensure production efficiency, product quality, and equipment life. The following are key usage precautions and maintenance guidelines.

Usage Precautions

Pre-Startup Inspection

Check the lubrication system: Ensure adequate lubrication (using the specified lubricant) in key components such as the gearbox, bearings, and screw.

Check the heating system: Confirm that the temperature controllers on each stage display normal and that the heating coils are not damaged.

Check the drive system: Check for loose belts or gears, and that the motor is rotating correctly.

Clean the hopper to prevent residual material from affecting the plasticization of the new material.

Operating Specifications

Temperature Control:

Preheat to the set temperature (usually 150-300°C, depending on the material) to avoid damage to the screw during a cold start.

Do not force feed if the temperature is below the set temperature!

Feed Control:

Feed evenly to avoid excessive feed that may cause blockage or motor overload. Wet materials must be pre-dried (to prevent bubbles and degradation).

Screw Speed:

Adjust according to material characteristics to avoid excessively high speeds that may cause shear overheating.

Abnormal Handling:

If unusual noise, vibration, or current flow is detected, immediately stop the machine for inspection.

Shutdown Operations

Empty Material: Stop feeding and extrude any remaining material until no residue remains at the die.

Cooling Procedure:

Turn off the heater and allow the screw to cool to <100°C at low speed before shutting down the machine.

Cleaning the Screw and Barrel:

Use cleaning compound (such as PP or a specialized cleaning agent) to prevent carbonization of the material.

Daily Maintenance and Care

Daily Maintenance

Clean the hopper and feed port to prevent impurities from entering the barrel.

Check fasteners: Bolts, couplings, etc. for looseness.

Record operating data: temperature, current, pressure, etc. for troubleshooting.

Regular Maintenance (Monthly/Quarterly)

Screw and Barrel Inspection:

Remove the screw and inspect for wear, corrosion, or scratches (severe wear requires repair or replacement).

Inspect the barrel interior with an endoscope and remove carbon deposits.Lubrication System Maintenance:

Replace the gearbox lubricant (recommended every 2,000 hours or six months).

Add high-temperature grease (such as molybdenum disulfide grease) to the bearings.

Electrical System Inspection:

Clean the electrical control cabinet from dust and inspect the heater coils and thermocouples for deterioration.

Long-Term Storage:

Thoroughly clean the screw and barrel and apply anti-rust oil.

Disconnect the power supply, cover with a dust cover, and store in a dry environment.

Safety Instructions

Protective Measures:

Wear high-temperature-resistant gloves during operation and avoid touching hot parts (barrel, die head).

The emergency stop button must remain operational.

Prohibited Actions:

Directly cleaning the running extruder with hands or tools!

Overheating or overloading.