Unveiling the working secrets of laminating machines and BOPP film laminating machines in the plastic weaving industry

In the plastic weaving packaging industry, laminating technology is a key link in improving product performance. Whether it is a common waterproof ton bag or a delicate BOPP film composite packaging, the precise operation of the laminating machine is indispensable. Today, we will deeply analyze the working principles of laminating machines and BOPP film laminating machines in the plastic weaving industry, and at the same time see how the Gachn Group-90-FMS800 dual-host plastic laminating machine, this "industry expert", stands out with its hard-core technology.

1. Raw material preparation and melt plasticization: the transformation from granules to melts

（1） Raw material input

Conventional plastic weaving laminating is mainly PE granules, and functional masterbatches such as antioxidants and masterbatches can be added according to needs, and enter the extruder through the hopper. When laminating BOPP film, in addition to base materials such as PE, raw materials with better compatibility with BOPP film are often selected to ensure a more stable composite effect. The GC90-FMS800 laminating unit is equipped with an automatic feeder, making the input of raw materials more convenient and efficient.

（2） Heating and melting

The heating device outside the extruder barrel (such as a resistance heating ring) cooperates with the internal rotating screw to "double-treat" the raw materials: heating the raw materials to a molten state (PE melting point 105-135℃, PP 160-170℃), and the screw shearing makes the melt mixed more evenly. The Gachn Group-90-FMS800 dual-host plastic laminating machine uses a Toudao refined screw with a diameter of 90mm. It is also equipped with a fast column screen changing machine, which can stabilize the extrusion volume. The maximum extrusion volume of a single machine can reach 200kg/h. The barrel screw material is 38CrMoAlA, which is sturdy and durable, ensuring the stable melting and plasticization of the raw materials. For BOPP film laminating, due to the high melting point of BOPP (165-175℃), the ceramic heaters (30kw each) and Omron automatic temperature control instruments (eight) of the unit can accurately control the temperature, ensuring that the raw materials are fully melted and avoiding high temperature damage to the BOPP film.

2. Melt extrusion film forming: the birth of uniform film

(1)Melt filtration and voltage stabilization

The melted melt is first filtered through the filter to remove impurities, and then enters the voltage stabilizing device. This step is particularly critical for BOPP film laminating - the surface of the BOPP film is flat. If the melt pressure is unstable, it is very easy to cause defects such as bubbles and uneven thickness after compounding. The relevant devices of the Gachn Group-90-FMS800 dual-host plastic laminating machine can effectively ensure the stability of the melt pressure and lay a good foundation for subsequent film forming.

(2)T-die extrusion

The melt is finally extruded through the "T-die". The die flow channel is designed in a gradual change, which can evenly distribute the melt to the entire width to form a molten film that matches the width of the substrate. BOPP film laminating requires higher die precision to ensure that the film can perfectly cover the surface of the BOPP film. Gachn Group-90-FMS800 dual-host plastic laminating machine adopts a T-type die with a width of 1050mm. The die block is adjustable from 200 to 1050mm, which is achieved by adjusting the plug-in plate with a hand wheel. The die material is 5 chromium nickel molybdenum, equipped with ten Omron automatic temperature control instruments and ten Taiwan-made thermocouples to ensure stable discharge, allowing the plastic melt to flow evenly in the die, avoiding dead corners and speed fluctuations.

3. Substrate pretreatment: Make the bond stronger

In order to enhance the adhesion between the laminating layer and the substrate, the pretreatment link is essential, and BOPP film is particularly dependent on this:

·Corona treatment: Oxidize the surface molecules of the BOPP film through high-voltage discharge, increase the surface tension, solve its "non-stick" problem, and effectively prevent delamination.

·Preheating: The preheating temperature of BOPP film needs to be strictly controlled at 40-60℃, which can not only reduce the temperature difference with the melt, but also avoid deformation caused by high temperature; the preheating temperature of conventional woven fabrics is slightly higher (50-80℃). The laminating machine of the GC90-FMS800 unit is equipped with a preheating roller with a diameter of 350MM, which can accurately control the preheating temperature and improve the bonding effect between the substrate and the melt.

4. Composite lamination: "Intimate bonding" of substrate and film

(1)Synchronous lamination

The pretreated substrate (woven fabric or BOPP film) is transported to the bottom of the die head by the guide roller and accurately aligned with the extruded molten film. BOPP film is thin and has good stiffness. It has extremely high requirements for the synchronization of the travel speed and the melt extrusion speed. It needs to be guaranteed by a precise control system to avoid wrinkles or uneven stretching. The control system of the Gachn Group-90-FMS800 dual-host plastic laminating machine adopts PLC and touch screen, which can complete the synchronous operation of the whole machine. Its laminating line speed can reach 250m/min, and the unwinding is equipped with EPC automatic deviation correction, with a stroke of ±100mm, ensuring the precise lamination of the substrate and the film.

(2)Roller lamination

The substrate and the melt enter the roller group (steel roller + rubber roller) and fit tightly under pressure: the laminating pressure of BOPP film is about 0.2-0.6MPa, and that of conventional woven fabric is about 0.3-0.8MPa. The steel roller passes cold water to quickly cool the melt and solidify it into shape; the rubber roller plays a buffering role to ensure uniform lamination. The hardness of the rubber roller for BOPP film needs to be more carefully selected. The Gachn Group-90-FMS800 dual-host plastic laminating machine has two sets of laminating machines, including a 700MM diameter matte large cold roller (manufactured by a professional roller factory, spiral cooling) and a 250mm diameter silicone roller, as well as two QGB 125×80 pressing cylinders, which can provide stable pressure to make the lamination tighter.

5. Cooling, shaping and winding: the final "shaping" of the finished product

(1)Cooling and curing

The composite product is further cooled by multiple sets of cooling rollers (circulating cooling water) to completely cure the laminating layer. The thermal stability of BOPP film is poor, and rapid cooling can reduce the heating time and ensure dimensional stability. The laminating thickness is usually 0.01-0.1mm, which can be adjusted by the die opening, extrusion speed, etc. The BOPP film laminating has stricter control over thickness uniformity. The total water supply of the GACHN GROUP-90-FMS800 dual-host plastic laminating machine is 0.5m³/min, which can provide sufficient water for the cooling system. The laminating thickness can be adjusted between 0.008-0.03mm to meet different needs.

(2) Traction and winding

The cooled finished product is transported to the winder by the traction roller (the speed is slightly higher than the pressure roller, forming a slight tension to ensure flatness). When winding the BOPP film, the tension must be precisely controlled to avoid stretching and deformation, and finally rolled into a neat coil to complete the entire laminating process. The winder of the GACHN GROUP-90-FMS800 dual-host plastic laminating machine is a double-station large roller friction winding frame, which can realize automatic roll change without stopping the machine. The maximum diameter of the winding is 1500mm, and the winding shaft is 8 inches. It is also equipped with an automatic tension roller device and a 5.5kw variable frequency dedicated motor and Huichuan inverter, which can accurately control the winding tension to ensure that the coils are neat and tight after winding.

Six. Unique advantages of GACHN GROUP-90-FMS800 dual-host plastic laminating machine machine.

In addition to the above-mentioned outstanding performance in each link, the unit has many highlights: the use of wall panels and aluminum alloy guide rollers is durable and ensures smooth operation; equipped with automatic trimming devices, including two sets of Aibo trimming related equipment, edge material blowing fan and edge material automatic recovery system, which can improve the utilization rate of raw materials; total power reaches 100kw, air flow rate 0.6m³/min, power and air source are sufficient; the overall dimensions are (14.5 length × 7.5 width × 3.5 height) m, and the structural layout is reasonable.

I hope that through this analysis, you will have a clearer understanding of the working principle of the laminating machine and the advantages of the GACHN GROUP-90-FMS800 dual-host plastic laminating machine. If you want to know more equipment details or process skills, please leave a message in the comment area!