What should be paid attention to during the installation and debugging of FDY multifunctional spinning testing machine?

FDY (Full Stretched Yarn) Multifunctional Spinning Testing Machine is the core equipment for R&D, process optimization and quality inspection in chemical fiber industry. Its installation and debugging should be combined with the spinning process characteristics (such as high-temperature melting, precise drafting, airflow control, etc.) and the mechanical accuracy requirements of the equipment. Any omission may lead to spinning breakage, unstable finished product quality and even equipment damage. The following four dimensions: preliminary preparation, core details of installation, key points of debugging, safety and maintenance plan, sort out the matters that need to be paid attention to:

First, preliminary preparation: lay the foundation of "precise installation"

Before installation, the environment, equipment and personnel shall be fully prepared to avoid subsequent problems caused by "insufficient innate conditions":

Installation environment suitability check

FDY spinning needs stable temperature and humidity, cleanliness and load-bearing conditions, and it is important to confirm:

Temperature and humidity control: the ambient temperature should be kept at 20-28℃ (temperature fluctuation ≤ 2℃), and the relative humidity should be 40%-60% (excessive humidity will easily lead to moisture absorption and broken ends; If the temperature is too low, it will easily generate static electricity, which will affect the yarn forming), so it is necessary to equip with a constant temperature and humidity system in advance (especially in the humid areas in the south, dehumidifiers should be installed, and the dry areas in the north should be humidified).

Cleanliness: The installation area should meet the 10,000-class cleanliness standard (to avoid dust adhering to the surface of spinning components and godet rollers, resulting in scratches or broken ends). It is suggested to set up an independent cleaning workshop, install an air shower room at the entrance, and lay an anti-static floor on the ground.

Bearing capacity and space: the bearing capacity of the equipment foundation should be ≥ 500 kg/m (the spinning machine contains heavy parts such as extrusion system, heating box and drafting roller, and the unstable foundation will cause the equipment to vibrate during operation); An operation space of ≥1.5m should be reserved around the equipment (convenient for debugging, maintenance and wire observation), and a space of ≥2m should be reserved at the top (for installing exhaust pipes and repairing heating boxes).

Power supply and air supply: 380V three-phase five-wire power supply (voltage fluctuation ≤ 5%, frequency 50 Hz 1 Hz) shall be provided, and a separate voltage stabilizer shall be provided (to avoid heating temperature fluctuation and abnormal motor speed caused by voltage instability); Compressed air should be dry and oil-free (pressure ≥0.6MPa, dew point ≤-40℃), and an air filter should be installed (to prevent impurities from blocking the spinneret hole of the spinning assembly).

Inventory inspection of equipment and accessories

Equipment main body: after unpacking, check whether the core components such as extruder, metering pump, spinning box, drafting roller and winder are damaged in transportation (such as deformation of heating tube, scratch of godet roller and damage of motor housing), and check that the model and specifications of the equipment are consistent with the order (such as the displacement of metering pump and the number/aperture of spinneret holes need to match the test requirements).

Key accessories: count spinning components (spinneret, filter sand, component shell), heating components (heating pipes, thermocouples), transmission components (synchronous belts, bearings), and electrical components (PLC, frequency converter, temperature controller) to ensure that there are no defects and no oxidation and corrosion (for example, spinneret needs to check the aperture uniformity, no burr and no blockage).

Auxiliary tools: Make sure that the special tools (such as assembly wrench, spinneret cleaning tool, tensiometer and thermometer) are complete and the accuracy reaches the standard (for example, the error of tensiometer should be ≤ 1% and the accuracy of thermometer should be ≤ 0.5℃).

Personnel and technical preparation

Operators should have the foundation of FDY spinning process and be familiar with the electrical schematic diagram and mechanical structure diagram of the equipment (they should attend the technical training of the equipment manufacturer in advance and master the logic of setting key parameters).

Communicate with the equipment manufacturer in advance, obtain the Installation and Debugging Manual and the Process Parameter Instruction, and specify the installation steps, debugging procedures and safety specifications (such as operation taboos of high-temperature components and electrical grounding requirements).

Second, the core details of installation: to ensure the accuracy of "machinery+technology"

The installation accuracy of FDY spinning testing machine directly affects the spinning stability (such as draft ratio deviation and temperature uniformity), and the following links should be controlled emphatically:

Leveling and Fixing of Equipment: Eliminating "Vibration Interference"

Foundation leveling: measure the levelness of the equipment base with a level (accuracy ≥0.02mm/m), and both the longitudinal (extruder-spinning box-winder direction) and transverse levelness errors shall be ≤0.1mm/m (if the levelness is not up to standard, it will lead to uneven feeding of metering pump, deviation of parallelism of drafting roller, and fluctuation of filament tension and breakage).

Fixation and reinforcement: fix the equipment base with the ground foundation through expansion bolts (the bolt specification should match the equipment bearing capacity, and the tightening torque should refer to the manufacturer's requirements), so as to avoid vibration when the equipment is running (especially when the winder is rotating at high speed) (vibration will lead to unstable spinning of the spinneret and the formation of bristles).

Installation of High Temperature System: Controlling "Temperature Uniformity"

Heating cylinder of extruder: during installation, ensure that the deviation of coaxiality between heating cylinder and screw is ≤0.05mm (poor coaxiality will lead to uneven shearing of materials and local overheating degradation); The heating pipes should be evenly distributed on the outer wall of the heating cylinder and closely attached to the cylinder wall (gap ≤0.5mm) to avoid insufficient melting of materials due to low local temperature.

Spinning box (spinning tunnel): during installation, ensure that the box is vertical (verticality error ≤0.5mm/m) and the internal insulation layer is not damaged (to prevent the temperature gradient in the box from being > 2℃ due to heat loss); Thermocouple (temperature sensor) should be inserted into the box to a specified depth (usually at the center of the heating zone), and the distance from the material channel should be ≥5mm (to avoid inaccurate temperature measurement caused by direct contact with the material).

Heat medium/hot oil system: If the spinning box is heated by heat medium, it is necessary to check the connection tightness (no leakage) of the heat medium pipeline, the insulation layer of the pipeline is complete (to reduce heat loss), and the heat medium pump rotates correctly (to ensure smooth heat medium circulation).

Transmission system installation: ensure "synchronous stability"

Drafting roller group: the axes of multiple drafting rollers should be parallel (parallelism error ≤0.1mm/m), and the roll surface runout should be ≤0.03mm (excessive runout will lead to tension fluctuation of filament); The center distance between the drafting rollers should be set strictly according to the process requirements (deviation ≤0.5mm) to avoid insufficient or excessive stretching of filaments caused by deviation of drafting ratio.

Winding machine: the center distance between the winding head and the last group of draft rollers should be accurate (deviation ≤1mm), and the winding shaft should be parallel to the axis of the draft roller (parallelism error ≤0.1mm/m) to avoid irregular arrangement of filaments during winding (such as "overlapping filaments" and "fuzzy filaments"); Wiring of frequency converter and servo motor of winding machine shall be firm, and grounding resistance shall be ≤4Ω (to prevent speed fluctuation caused by electrical interference).

Installation of Fluid System: Avoid "Blockage and Leakage"

Material conveying pipeline (melt pipeline): the inner wall of the pipeline should be smooth (roughness Ra≤0.8μm) and free of scratches and impurities (to avoid material retention and degradation); Flange seal shall be used for pipeline connection, and the sealing gasket shall be made of high-temperature resistant material (such as PTFE, which can withstand temperature ≥250℃), and the bolts shall be tightened in diagonal order (uniform torque to avoid leakage).

Compressed air pipeline: the pipeline should be degreased (to avoid oil pollution), and the end should be equipped with a precision filter (filtering accuracy ≤5μm). The installation position of pressure gauge and flowmeter is easy to observe, and the range should match the process requirements (for example, the air pressure for airflow stretching is usually 0.2-0.5MPa, and the range of flowmeter should cover this range).

Electrical system installation: ensuring "safety and accuracy"

The main circuit and the control circuit are wired separately (the distance is more than or equal to ≥100mm) to avoid strong electricity interfering with weak current signals (such as thermocouple and tension sensor signals); The control line is shielded wire, and the shielding layer is grounded at one end (grounding resistance ≤4Ω) to prevent the parameters from getting out of control due to electromagnetic interference.

Grounding system: The equipment general grounding, motor grounding and electrical cabinet grounding shall be independently connected to the grounding electrode (grounding resistance ≤4Ω) to avoid electric shock or equipment failure caused by poor grounding due to common grounding; The emergency stop button, overload protection and leakage protection devices should be installed in conspicuous positions, and the function test is normal (if the emergency stop button is pressed, the equipment needs to be powered off immediately).

Third, the key points of debugging: to achieve "process parameters up to standard"

After the installation is completed, it needs to be debugged in stages, and gradually verified from "no-load → no-load temperature → load spinning", focusing on the following details:

No-load debugging: troubleshooting "mechanical and electrical faults"

Electrical system debugging: turn on the power supply (control power first, then main power), and check that the electrical components such as PLC, touch screen and frequency converter are electrified normally, and there is no error code; Test whether the steering of each motor (extruder motor, drafting roller motor and winder motor) is correct (consistent with the equipment identification) and the speed adjustment is smooth (from low speed to high speed, without jamming and abnormal sound).

Mechanical action debugging: manually rotate the extruder screw (without jamming) and test the feeding accuracy of the metering pump (the deviation between the rotating speed of the metering pump and the set value is less than or equal to 0.5% under no load); Debug the clutch mechanism of the drafting roller and the doffing mechanism of the winder, so that the action is flexible and free from jamming (for example, after winding is completed, the doffing device needs to accurately send the bobbin to the designated position).

Safety device test: when the emergency stop button is triggered, the equipment needs to be stopped immediately and all motors are powered off; Test the over-temperature protection of the heating system (for example, set the upper temperature limit of the heating tube, when the actual temperature exceeds the limit, the heating tube needs to be automatically powered off and give an alarm).

No-load temperature debugging: verifying "temperature control accuracy"

Step-by-step heating: gradually increase the temperature of extruder and spinning box according to the heating curve required by the equipment manual (for example, raise the temperature from room temperature to 100℃ and keep the temperature for 30min；; Raise the temperature to 200℃ and keep the temperature for 60min), so as to avoid the deformation of heating cylinder and spinning box (especially stainless steel parts) caused by too fast temperature rise.

Temperature stability test: when the temperature of each heating zone reaches the set value (for example, the PET spinning temperature is usually 270-290℃), keep the temperature for 2-4 hours, and record the temperature fluctuation value of each thermocouple (the fluctuation is required to be ≤ 1℃); If the temperature fluctuation in a certain area is too large, it is necessary to check whether the heating pipe is damaged, whether the thermocouple is loose, and whether the parameters of the thermostat need to be optimized.

Load Spinning Debugging: Optimizing "Process and Finished Product Quality"

Material preparation: raw materials matching the test requirements are selected (for example, PET chips need to be dried until the water content is less than or equal to ≤50ppm, so as to avoid the breakage caused by bubbles during spinning), and the raw materials need to be uniformly added into the extruder hopper (a filter screen is installed in the hopper to prevent impurities from entering the screw).

Initial parameter setting: refer to the process parameters provided by the manufacturer (such as extruder speed, metering pump speed, drafting ratio, winding speed, cooling air temperature/wind speed), and set the initial value (such as the initial drafting ratio of PET FDY is usually 3.0-4.0, and the winding speed is 3000-4000m/min).

Commissioning of filament forming:

Spinning out of spinneret: start the extruder and metering pump, and observe whether the spinning out of each hole of spinneret is uniform (no broken wire, no fine and thick wire). In case of broken wire, it is necessary to check whether the spinneret hole is blocked, the heating temperature is too low, and the material is fully melted.

Cooling setting: Adjust the temperature (usually 20-25℃), wind speed (0.5-1.0m/s) and wind direction (perpendicular to the direction of filament) of cooling air to ensure uniform cooling of filament (uneven cooling will lead to deviation of crystallinity of filament and affect strength).

Drafting and winding: gradually adjust the drafting ratio (adjust 0.1-0.2 each time), and monitor the tension of the filament with a tensiometer (the tension fluctuation should be ≤ 5%) to avoid the breakage of the filament due to excessive tension and the relaxation of the filament due to low tension; Adjust the winding speed to match the drafting speed to ensure that the winding bobbin has no "hard edge" and "edge collapse" and the wires are arranged neatly.

Quality inspection of finished products: after debugging is stable, sample and inspect the key indexes of the yarn (such as linear density deviation, breaking strength, elongation at break and evenness). If the indexes are not up to standard, it is necessary to optimize the parameters (such as adjusting the rotating speed of the metering pump if the linear density deviation is large; Low breaking strength, adjust the drafting ratio or heating temperature).

IV. Safety and Maintenance Plan: Avoiding "Risks and Losses"

FDY spinning testing machine involves high temperature, high pressure and high speed moving parts. During debugging, it is necessary to strengthen safety control and establish initial maintenance awareness:

Safety operation specification

High-temperature protection: When operating the heating zone (extruder and spinning box), wear high-temperature gloves (temperature ≥300℃) and a protective mask to avoid direct contact with high-temperature parts and burns; It is forbidden to place flammable materials (such as alcohol and rags) near the heating area to prevent fire.

Protection of high-speed components: When the drafting roller and winder are running, it is necessary to close the protective cover (the protective cover should have interlocking function, and the equipment will automatically stop when it is opened). It is forbidden to touch the rotating components with hands or tools to avoid being involved in injuries.

Electrical safety: it is forbidden to operate the electric cabinet and touch screen with wet hands; If live wiring is required during debugging, two people shall operate it (one for wiring and one for monitoring) and insulating tools shall be used.

Temporary maintenance and recording

During debugging, check the status of all components regularly (for example, check whether the heating pipe is heated normally, whether the pipeline leaks and whether the motor is abnormal), and stop the machine immediately if problems are found (if the melt leaks, it needs to be cooled to room temperature before dismantling and cleaning).

Record the debugging data in detail (such as the temperature of each heating zone, motor speed, wire tension and finished product quality index), and establish the corresponding relationship of "parameter-quality" to provide basis for subsequent process optimization; After the commissioning is completed, sort out the Installation and Commissioning Report, which shall be signed by the equipment manufacturer and the operator for confirmation.

summary

The core of the installation and debugging of FDY multifunctional spinning testing machine is "precision control+process matching+safety guarantee": the mechanical coaxiality, temperature uniformity and transmission synchronization should be focused in the installation stage, and the debugging stage should be gradually verified from no-load to load, so as to finally realize "stable filament forming and up-to-standard finished product quality". At the same time, it is necessary to strictly abide by the safety regulations, establish debugging records and maintenance plans, and lay the foundation for long-term stable operation in the future.