Operating Procedure for Single-Screw Sheet Extruders

1. Objective: To enable laboratory personnel to master the operating procedures and safety precautions for single-screw sheet extruders, and to provide effective support for timely inspection and quality control of finished products.

II. Operating Steps

1. Pre-Startup Inspections:

(1) Review the equipment usage and maintenance records to verify that the equipment was functioning properly during its last use.

(2) Identify impurities in the raw materials that may affect the equipment’s normal operation, and assess whether the materials’ basic properties (such as melt index and softening point) are suitable.

(3) Inspect all components of the equipment to ensure they are in good condition. Verify that the power supply, water source, and other relevant systems comply with the equipment’s operating requirements.

2. Power-on procedure:

(1) Preheat and raise the temperature: Turn on the equipment’s main power supply, and set the parameters of the temperature control instruments for each heating zone of the screw and die head according to process requirements. Once the set temperatures for each zone have been reached, maintain constant temperature for 30–60 minutes while further verifying that the temperature control instruments in each zone are functioning properly.

(2) After preheating is complete and the machine is started under normal conditions, first press the start button, then gradually adjust the speed switch while observing whether the motor operates normally. Once confirmed to be functioning properly, add the test material, and then slowly increase the speed until it reaches the operating condition specified by the process requirements.

(3) In the event of high-temperature conditions or prolonged equipment operation, the water-cooling system must be activated.

(4) During the extrusion process, the thickness of the extruded coating can be controlled by adjusting the upper and lower set screws at the die outlet (with the upper screw serving for fine-tuning).

(5) During the extrusion experiment, if any abnormal condition occurs, press the emergency stop switch; after resolving the issue, follow the operating procedure to restart the equipment and resume the test.

3. Shutdown Procedure:

(1) After the experiment is completed, gradually reduce the screw speed to thoroughly discharge any residual material remaining in the barrel. Once all material has been expelled, set the screw speed to zero and clean out any remaining material from the die head.

(2) Turn off the cooling water pump switch and valves, deactivate the start button, switch off the heating controls for each zone, and disconnect the main power supply at the equipment control cabinet. In cold winter conditions, after use, drain all cooling water from the equipment to prevent the water‑cooling system from freezing and cracking.

(3) After the experiment is completed, clean the equipment and the floor thoroughly and ensure proper sanitation.

4. Equipment Maintenance:

(1) Every 1,000 hours of operation, inspect the screw and barrel for wear, and check the wear condition of the screw‑end sealing ring; replace with spare parts as necessary.

(2) Replace the gearbox lubricant every 1,000 hours of operation, and inspect the gearbox’s gears, bearings, and oil seals once a year.

(3) In the event of prolonged shutdown, appropriate measures must be taken to prevent equipment from rusting and becoming contaminated.

5. Precautions:

(1) No foreign objects are allowed inside the material; metal, sand, gravel, and other foreign materials are strictly prohibited from entering the hopper.

(2) The screw may only be started at low speed, with no idle running time exceeding 1 minute. The screw speed may be gradually increased only after timely feeding has been initiated, and both the screw speed and current must remain within the specified technical parameters.

(3) When starting the cooling water, slowly open the valve and monitor whether the temperature remains within the controllable range; do not open it fully all at once.

(4) When inspecting the coating’s appearance, operators must wear heat‑resistant gloves to prevent burns from high temperatures.