What problems should be paid attention to during the installation and construction of POY spinning testing machine?

POY (pre-oriented yarn) spinning testing machine is a precision equipment used for developing and testing the spinning process of polyester, nylon and other chemical fiber materials, and its installation and construction quality directly affects the running stability of the equipment and the quality of spinning finished products. The following are the problems that should be paid attention to in the installation process, which are classified according to the construction stage:

First, the preparation stage before installation

1. Confirmation of environmental conditions

Workshop temperature and humidity:

The temperature should be controlled at 20~28℃ (air conditioning system is required) and the humidity should be kept at 50%~70%RH (to avoid moisture absorption or electrostatic accumulation of polymer raw materials).

Dehumidifier is needed in high humidity environment, and humidifier and electrostatic eliminator (such as ion fan) are needed in dry environment.

Cleanliness requirements:

The workshop should meet the 10,000-class cleanliness standard (dust can be reduced by dust-proof doors and windows and regular cleaning), especially to avoid metal chips and fiber wool from entering the spinning box or metering pump.

Spatial planning:

1.5 ~ 2m maintenance passage is reserved at the front, back, left and right of the equipment, and the installation position of crane or hoist is reserved above it (used for component hoisting).

Avoid being adjacent to high vibration equipment (such as air compressor) to prevent vibration from affecting spinning stability.

2. Foundation and floor treatment

Foundation strength:

The main equipment (such as spinning box and winder) should be installed on C30 concrete foundation, with a thickness of ≥300mm and a bearing strength of ≥15kN/㎡.

The embedded position of anchor bolts shall be accurately laid out according to the equipment drawings, with an error of ≤2mm.

Levelness calibration:

Use floor level to detect the foundation plane, and the flatness error shall be ≤ 3 mm/m. If necessary, use epoxy mortar for leveling.

For high-precision testing machines, damping pads or spring isolators (such as spinning pump area) can be added to reduce external vibration interference.

3. Acceptance of equipment and accessories

Unpacking inspection:

Check the packing list, and check whether the key components such as main engine, spinning assembly, metering pump and winding head are in good condition, and whether the surface is bumped or rusted.

The electrical control box needs to check whether the line is loose, and the models of PLC, frequency converter and other components are consistent with the technical agreement.

Fitting pretreatment:

Polymer melt pipes and spinning components need to be cleaned with alcohol or acetone to remove oil stains and metal chips, and then sealed and stored after drying.

The gear of metering pump should be coated with special lubricating oil (such as high-temperature lithium grease) to ensure flexible rotation.

Second, the mechanical installation stage

1. Installation of Rack and Core Components

Installation sequence:

Spinning box base → metering pump bracket → spinning assembly → cooling and blowing device → oiling mechanism → winder.

Installation accuracy:

Verticality of spinning box: detected by plumb line, with error ≤ 0.5 mm/m.

Coaxiality between the shaft of metering pump and the inlet of spinning assembly: error ≤0.1mm (calibrated by dial indicator).

Levelness of winding roller: error ≤0.2mm/m, and parallelism of adjacent rollers ≤0.3mm (affecting the tension uniformity of tow winding).

2. Transmission system debugging

Belt/gear drive:

The tension of the synchronous belt is moderate (it is advisable to press the sag with your fingers by 10~15mm), and the gear meshing gap is 0.1 ~ 0.3 mm.

Transmission parts need to be equipped with protective covers, and keep a safe distance of more than 50mm from the equipment shell.

Motor installation:

Coaxiality of winding motor and roller coupling is ≤0.05mm, and noise during trial operation is ≤75dB(A).

The motor in high temperature area (such as near the spinning box) should be selected with high temperature resistant model (insulation grade F or above).

Three, electrical and control system installation

1. Power supply and grounding

Power requirements:

Three-phase five-wire system (380 V 10%, 50Hz) is adopted, and a regulated power supply (capacity ≥ 1.5 times the total power of the equipment) is separately configured.

The control circuit (24V DC) is wired separately from the power circuit to avoid electromagnetic interference.

Grounding protection:

The metal shell, motor and control box of equipment shall be reliably grounded, and the grounding resistance shall be ≤4Ω.

Electrostatic discharge point (such as winding roller) shall be connected with independent grounding wire, and the resistance shall be ≤10Ω.

2. Installation of sensors and instruments

Temperature sensor:

The thermocouple of spinning box, metering pump and melt pipeline should be inserted to a depth ≥ 2/3 of the pipe diameter, and sealed with high-temperature glue to prevent material leakage.

Temperature control accuracy requirement: 1℃, which needs to be calibrated with standard thermometer after installation.

Pressure sensor:

The installation position of melt pressure transmitter should be far away from elbows and valves to avoid turbulence affecting measurement accuracy.

The measuring range is 1.5~2 times of the working pressure, and the accuracy level is ≤0.5.

3. Control system wiring

Signal shielding:

Encoder and sensor signal lines need double-layer shielded cables, and the distance between them and the power line is ≥ 300 mm.

It is forbidden to use contactors to start and stop directly at the output end of frequency converter, and it is necessary to control relay switching through PLC.

Program debugging:

Before power-on, check the polarity of the line, and conduct no-load trial operation (simulate winding speed and temperature setting) to confirm the normal response of each module.

Write an emergency stop program to ensure that the heating system and motor stop within 5 seconds after pressing the emergency stop button.

Four, pipeline and fluid system installation

1. Melt conveying pipeline

Material and thermal insulation:

Adopt 316L stainless steel pipe (inner wall roughness Ra≤0.8μm), and argon arc welding shall be used as the backing for welding to avoid the blockage of flash.

The pipeline is wrapped with aluminum silicate thermal insulation cotton (thickness is 50~80mm), and the outer layer is fixed with aluminum skin or stainless steel belt to ensure that the surface temperature is ≤50℃.

Flow direction and slope:

The pipeline from the metering pump to the spinning assembly should be kept at an inclination of 1 ~ 3 (flowing to the lower part) to avoid the retention and solidification of the melt.

The highest point of the pipeline is equipped with an exhaust valve, and the lowest point is equipped with a drain valve (for cleaning up the residual materials).

2. Cooling and heating system

Cooling air network:

The distance between the blowing device and the spinning assembly needs to be adjusted according to the process requirements (usually 500~800mm), and the error of wind speed uniformity is ≤5%.

Install an air filter (accuracy ≤5μm) at the inlet of the air duct, and regularly clean the filter screen to prevent blockage.

Heating system:

The spinning box and metering pump are heated by electric heating rod or heat-conducting oil, and the temperature control module needs to be interlocked with the equipment (power off automatically when the temperature exceeds the temperature).

The heat transfer oil pipeline needs to be pressure tested (0.6MPa, no leakage after holding the pressure for 30 minutes).

3. Oil agent and pneumatic system

Oiling mechanism:

The flow accuracy of the oil pump should reach 1%, and the tubing joint should be connected with a ferrule to avoid dripping.

The oil tank shall be equipped with stirring device (to prevent sedimentation) and liquid level alarm function.

Pneumatic control:

Compressed air needs to be treated by three parts (filtration, decompression and oil mist), and the pressure is stable at 0.4~0.6MPa.

Pneumatic valve island should be installed in a dry and ventilated place, away from high temperature sources and water vapor gathering areas.

V. Safety and Environmental Protection Measures

1. High temperature protection

Heat shields (using aluminum silicate fiber board) should be installed at high temperature parts such as spinning boxes and melt pipes, and warning signs of "high temperature danger" should be affixed.

The operation area is equipped with anti-scalding gloves and goggles, and it is forbidden to touch hot parts with bare hands.

2. Electrical safety

The control box door should be equipped with a safety limit switch (automatically cut off the power supply when opening the door) to prevent the risk of electric shock.

Insulated floor mats shall be set around the equipment, and operators shall wear anti-static shoes.

3. Environmental protection requirements

Waste silk and waste oil agent need to be classified and collected into special containers, and regularly handed over to qualified treatment institutions for disposal.

The workshop needs to install ventilation system (ventilation times ≥12 times/hour) to reduce the concentration of polymer volatiles.

Six, debugging and trial operation

1. No-load test

Start all motors (winding, fan and oil pump), and observe whether the steering is correct and the vibration value is ≤2.5mm/s (detected by vibrometer).

Test the emergency stop function to ensure that all moving parts stop within 3 seconds.