Acrylic Rod Extruder Usage and Maintenance Precautions

I. Usage Precautions (in stages: before startup → during startup → during operation → after shutdown)

(I) Pre-start Preparation: Avoiding Sources of Failure

Raw Material Pretreatment: Core Moisture-Proof Acrylic Resin is extremely hygroscopic (equilibrium water absorption rate is approximately 2%). Undried raw materials can cause bubbles, silver streaks, internal shrinkage cavities, and even affect the plasticizing effect in the extruded rods.

Drying parameters: Temperature 80~90℃, time 4~6 hours (adjust according to the moisture content of the raw material; a closed dryer is recommended); After drying, the raw material must be stored in a sealed container to prevent secondary moisture absorption (exposure to air should not exceed 30 minutes); Do not use damp, clumped, or impurity-laden raw materials (such as dust or metal shavings). Raw materials must be sieved beforehand (using a 40~60 mesh screen) to prevent clogging of the screw or die.

Equipment Inspection: Comprehensive Hazard Investigation

Mechanical Components: Are the screw, barrel, and die clean (free of residual old material or charred residue)? Is the clearance between the screw and barrel normal (too large a clearance leads to uneven plasticization, too small a clearance leads to wear)? Are the transmission systems (gears, chains, conveyor belts) of the traction machine, cooling water tank, and cutting machine flexible, and are the fastening bolts secure?

Electrical and Temperature Control: Are the heating coils and thermocouples (temperature sensors) functioning properly? Is the temperature controller display stable (error ≤ ±2℃)? Are the wiring connections of the motor, frequency converter, and control cabinet secure, and is the grounding reliable?

Auxiliary Systems: Are the cooling water tank level and temperature within the recommended range (15~25℃)? Is the linkage between the traction speed and extrusion speed calibrated? Is the lubricating oil (gearbox, motor bearings) level within the specified range?

(II) Start-up Operation: Smooth Start-up, Avoid Impact

After the no-load test run reaches the specified temperature, do not turn on the feeder. Start the screw motor and run it at low speed (5~10 r/min) for 3~5 minutes, observing:

Whether the screw rotates smoothly without jamming or abnormal noise;

Whether the temperature of each section remains stable without sudden rises or falls;

Whether the motor current is within the no-load rated range (generally ≤ 30% of the rated current).

Feeding and Speed ​​Increase: Gradual

After the no-load operation is normal, start the feeder (initial feed amount is 30% of the rated value), and simultaneously slowly increase the screw speed (increase by 5~10 r/min each time), observing the state of the melt extruded from the die:

Qualified Melt: Uniform color (transparent without yellowing), stable fluidity, no bubbles/burnt particles;

Abnormal Handling: If the melt is dark or has an odor (degradation), immediately lower the temperature by 5~10℃; if the melt clumps or has poor fluidity, appropriately increase the temperature and extend the holding time.

After the melt has stabilized during extrusion, gradually adjust the feed rate and screw speed to their rated values, while simultaneously starting the traction machine (traction speed slightly higher than the extrusion speed by 1-3% to ensure bar tension and prevent diameter reduction).

(III) In-operation Monitoring: Real-time Adjustment to Ensure Quality

Core Parameter Monitoring

Temperature: Record the temperature of each section every 15 minutes. It is strictly forbidden to exceed 240℃ (critical temperature for acrylic degradation). If the temperature is abnormal (e.g., a heating coil in a certain section does not heat up), stop the machine immediately for inspection to avoid localized charring of the raw material.

Pressure: The melt pressure (monitored by the die head pressure sensor) should be stable at 15~30MPa (pressure fluctuation ≤±2MPa). Excessive pressure may cause die blockage or equipment overload; insufficient pressure will result in insufficient plasticization.

Product Quality:

Appearance: The surface of the rod must be smooth, without scratches, bubbles, or silver streaks, and the color should be uniform (transparent rods should be free of haze).

Dimensions: Measure the diameter every 1 meter with calipers (tolerance requirement ±0.1~0.3mm). If the diameter is too large/small, adjust the traction speed (faster speed → smaller diameter, slower speed → larger diameter) or the die gap.

Internal Quality: Randomly cut samples and observe whether the cross-section is dense, without shrinkage cavities or delamination. Safety Operating Procedures:
**Operators must wear high-temperature resistant gloves and safety glasses to avoid direct contact with the heating coil, die head, or molten material (temperature > 200℃, risk of burns);**
**Do not disassemble the die head, screw, or adjust the heating coil while the equipment is running. If any abnormality needs to be addressed (e.g., die blockage), the machine must be stopped, cooled, and depressurized first;**
**Maintain good ventilation in the workshop (acrylic degradation produces a small amount of methyl methacrylate monomer, which has an irritating odor). Activate exhaust gas treatment equipment if necessary.**

(IV) Post-Shutdown Procedures: Cleaning and Maintenance to Prepare for Next Startup

Normal Shutdown: Empty Residual Material to Prevent Solidification

First, shut down the feeder, then continue running the screw (at low speed 5~10 r/min) until the residual material in the barrel is mostly emptied (no melt extruded from the die);

Gradually reduce the temperature of each section (first reduce the die → die head → metering section → feeding section), and once the temperature drops below 120℃, shut down the screw motor and heating system;

While the die is still hot, clean it (use a copper scraper, do not use an iron scraper to avoid scratching the die wall) to remove residual melt; if there is any charred material, soak it in alcohol or a special cleaning agent and then wipe it.

Emergency Shutdown: Handling Special Situations In case of emergency such as motor overload, sudden increase in melt pressure, or fire, immediately press the emergency stop button, turn off the main power and heat source, and troubleshoot after the equipment has cooled down (e.g., clean the clogged die, check the cause of screw jamming). II. Maintenance Precautions (By Cycle: Daily Maintenance → Periodic Maintenance → Replacement of Wear Parts)

(I) Daily Maintenance (Before Start-up / After Shutdown)

Cleaning
Equipment Surface: Clean dust and raw material debris to prevent accumulation on heating coils or electrical components (which can cause short circuits);
Cooling System: Clean impurities (such as raw material dust and scale) from the cooling water tank, check for blockages in water pipes, and ensure smooth water flow;
Feeding System: Clean the feeder hopper to prevent residual raw materials from becoming damp and clumping.

Basic Inspection
Lubrication: Check the lubrication levels of the gearbox and motor bearings. Replenish as needed (use the manufacturer-recommended lubricating oil, such as 220# industrial gear oil for the gearbox);
Tightening: Check the bolts on the screw connection flange, traction machine roller, and cutter blades to prevent loosening that could cause vibration;
Electrical: Check the heating coil terminals for looseness and oxidation, and verify the accuracy of the temperature controller display (calibrate regularly with a thermometer).

Maintenance Precautions:

**Do not use hard metal tools (such as iron scrapers or wire brushes) to clean the screw, barrel, or die, as this may scratch the surface (leading to raw material sticking to the walls and uneven plasticization);
**Do not mix different types of lubricating oil (such as gear oil and hydraulic oil), or add excessive lubricating oil (this can easily lead to leaks and high-temperature carbon buildup);
**Do not disassemble high-temperature components (such as the die head or heating coils) before the equipment has cooled down, to avoid burns or component deformation;
**Do not arbitrarily adjust electrical parameters (such as inverter frequency or temperature controller settings); this must be done by qualified personnel.** (iv) Special Maintenance: Maintenance after Long-Term Shutdown

If the equipment is shut down for more than one month, the following precautions must be taken:

Thoroughly clean any residual material from the screw, barrel, and die (rinse with PE material and then apply anti-rust oil);

Drain the lubricating oil from the gearbox and motor bearings (or replace with new oil) to prevent the old oil from deteriorating and corroding parts;

Turn off the main power and water supply, cover the equipment with a dust cover, and keep the workshop dry (to prevent electrical components from getting damp and metal parts from rusting);

Before restarting, a comprehensive inspection must be carried out according to the "Pre-Startup Preparation" procedure, especially the electrical and lubrication systems.