The core of the laminating process is to efficiently composite molten plastic with non-woven fabric, and its equipment performance directly determines product quality (such as film uniformity, adhesive strength, appearance flatness) and production stability. The requirements for equipment should revolve around the core logic of “melt plasticization uniform coating cooling shaping continuous production”, which can be specifically divided into three categories: core equipment, auxiliary equipment, and control systems, each with clear technical standards:
Core equipment requirements
Extruder: the “heart” of melt plasticization
The extruder is the key to converting plastic particles into a uniform melt, and its performance directly affects the quality of the melt. Requirements include:
Screw design
The aspect ratio (L/D) should be moderate (usually 25-30:1) to ensure that the plastic is fully plasticized (avoiding unmelted particles); The screw segmentation (feeding section, compression section, metering section) needs to match the characteristics of the raw materials (such as PE needs to focus on shear uniformity, PP needs to enhance melting efficiency).
The material should be heat-resistant and wear-resistant (such as 38CrMoAlA alloy steel, surface nitriding treatment, hardness ≥ HV900), to avoid melt contamination or screw wear.
Heating and temperature control system
Adopting zone heating (the material barrel is usually divided into 3-5 zones), the temperature control accuracy needs to reach ± 1 ℃ (such as PE melting temperature of 150-200 ℃, excessive deviation can cause fluctuations in melt viscosity and affect coating uniformity).
Equipped with cooling fans or water cooling devices to prevent local overheating (especially in the metering section to avoid plastic degradation).
Drive system
It is necessary to use a variable frequency speed regulating motor with a speed stability of ≤± 0.5% to ensure uniform output of the melt (speed fluctuations can cause film thickness deviation).
T-shaped die head: “precise valve” for melt distribution
The mold head is responsible for evenly distributing the melt to the full width of the non-woven fabric, and is the core component that determines the flatness of the film. The requirements include
Flow channel design
The flow channel should be in a “hanger style” or “fish tail style” to ensure uniform pressure of the melt in the width direction (deviation ≤ 5%) and avoid “eight shaped” defects with thick edges and thin middle.
The surface of the flow channel needs to be polished with ultra precision (roughness Ra ≤ 0.02 μ m) to reduce the flow resistance of the melt and prevent degradation caused by local retention.
Adjustment device
The lip width of the mold head needs to be adjustable (through bolts or fine-tuning motors) to adapt to different non-woven fabric widths (usually 1-5 meters); The accuracy of the lip gap should reach ± 0.01mm, and the deviation of the film thickness should be controlled (≤ 3%).
Equipped with edge baffles to prevent melt from overflowing from the edges, while also allowing for fine adjustment of edge thickness (solving the problem of thinning caused by “edge effects”).
Material and high temperature resistance
The mold body should be made of heat-resistant alloy (such as H13 mold steel), with a working temperature of ≥ 250 ℃ (suitable for PP, PE and other raw materials), and a thermal deformation of ≤ 0.05mm/m (to avoid the deformation of the mold head at high temperatures affecting the accuracy of the flow channel).
Cooling and shaping system: a “shaper” for film curing
The cooling system needs to quickly solidify the molten plastic while ensuring a tight bond with the non-woven fabric. The requirements include:
Cooling roller:
The surface needs to be mirror polished (roughness Ra ≤ 0.01 μ m) to ensure a smooth and defect free film surface; The material is chrome plated steel roller (with a chromium layer thickness of 50-100 μ m), with a hardness of ≥ HRC60, wear-resistant and easy to clean.
The diameter is designed according to the production line speed (usually 300-600mm), and a spiral cooling water channel needs to be installed inside to ensure uniform roller surface temperature (temperature difference ≤ 2 ℃) and avoid wrinkles in the film due to uneven local cooling.
The quantity is usually 1-3 pieces (multiple rollers can improve cooling efficiency), and the pressure can be adjusted (0.1~0.5MPa) to ensure that the plastic melt is tightly adhered to the non-woven fabric (insufficient pressure can easily generate bubbles, and excessive pressure can cause deformation of the non-woven fabric).
Temperature control device:
Equipped with a chiller unit, the water temperature control accuracy is ± 1 ℃ (conventional 20~40 ℃), and the flow rate is stable (to avoid inconsistent film shrinkage caused by water temperature fluctuations).
Requirements for auxiliary equipment
Non woven fabric unwinding equipment
It is necessary to ensure smooth transportation of non-woven fabric, avoid wrinkles or stretching deformation, and require
Tension control system: using magnetic powder brakes or servo motors, with a tension control accuracy of ± 5% (adjusted according to the weight of the non-woven fabric, such as 30-50g/㎡ of lightweight non-woven fabric requiring low tension to avoid stretching; High tension is required for 100g/㎡ and above to ensure flatness.
Correction device: equipped with photoelectric or ultrasonic correction system, with a correction accuracy of ≤± 1mm, ensuring that the non-woven fabric is aligned with the center of the mold head (excessive deviation can cause the film to become thicker on one side).
Preprocessing components: Optional preheating rollers (temperature ≤ 60 ℃, to prevent non-woven fabric from overheating and shrinking) and static eliminators (ion air rods, static elimination rate ≥ 90%) can be selected to enhance the adhesion between plastic melt and non-woven fabric.
Post processing equipment
Edge cutting machine: using a round knife or laser cutting, with an edge cutting accuracy of ± 0.5mm, ensuring a neat width; Blade hardness ≥ HRC55, avoid burrs (burrs can easily cause uneven layering during winding).
Winder.
Adopting central winding or surface winding, the tension can be automatically adjusted with the increase of winding diameter (to avoid the inner layer being too tight and causing the film to stretch, and the outer layer being too loose and causing looseness).
The winding diameter can reach 1-2 meters, and it is equipped with a winding diameter detection device to ensure that the winding speed is synchronized with the production line (speed deviation ≤ 1m/min).
Online detection system: equipped with CCD visual inspection instrument (resolution ≥ 20 million pixels), it can identify defects such as film bubbles, leakage, and uneven thickness in real time (detection accuracy ≥ 0.1mm ²), and automatically mark non-conforming products with a linkage removal device.
Control system requirements
The entire production line needs to be linked through a central control system, with the core requirements being
Synchronization: The synchronization accuracy of extruder speed, non-woven fabric speed, cooling roller speed, and winding speed is ≤± 0.5% (speed mismatch can cause film stretching or wrinkling).
Parameter adjustability: Real time setting and storage of extrusion temperature, die gap, cooling water temperature, tension and other parameters (supporting 100+formula storage, adaptable to different raw materials and product specifications).
Stability: Adopting PLC control system (such as Siemens S7-1200 series), response time ≤ 10ms, to avoid production fluctuations caused by signal delay.
Summary: Core demands of equipment
The core requirements of film coating equipment can be summarized as “three highs and two stabilizations”
High precision: Temperature control, die gap, and cutting accuracy need to reach micrometer level; High compatibility: can adapt to various plastics such as PE/PP, non-woven fabrics of different weights (10-200g/㎡) and types (spunbond, needle punched); High efficiency: supports a production speed of up to 300 meters per minute (requires matching with high flow extruders and efficient cooling systems); Stable operation: The downtime due to faults within 8 hours of continuous production is ≤ 10 minutes; Parameter stability: The fluctuation range of key parameters (such as film thickness) is ≤± 3%.
Only by meeting these requirements can we ensure the consistency, qualification rate, and production efficiency of the coated products, and adapt to the needs of large-scale industrial production.
Dongguan Liansheng Non woven Technology Co., Ltd. was established in May 2020. It is a large-scale non-woven fabric production enterprise integrating research and development, production, and sales. It can produce various colors of PP spunbond non-woven fabrics with a width of less than 3.2 meters from 9 grams to 300 grams.
Post time: Jul-16-2025