Adjustment of The Tightness of The Transparent Film Three-dimensional Packaging Machine

The tightness of the transparent film three-dimensional packaging machine directly affects the moisture resistance, impact resistance and transportation stability of the product. It needs to be achieved through the coordinated efforts of multiple dimensions such as film material tension control, molding process optimization, heat sealing parameter matching and equipment adjustment. The following analysis is conducted from four aspects: the influencing factors of compactness, adjustment methods, solutions to common problems, and long-term stability maintenance.

First, the key factors affecting the tightness of packaging

Membrane material characteristics

Elasticity and rigidity: If the elasticity of the film material is too high (such as some PVC films), it is prone to relaxation after packaging. If the rigidity is insufficient (such as thin BOPP films), it will be difficult to fit the product contour.

Thickness and strength: Insufficient thickness of the film material (such as less than 25μm) or low tensile strength will lead to a decrease in tightness after packaging.

Heat shrinkage: Heat shrinkable films (such as PETG) have an excessively high shrinkage rate after heating, which may cause the packaging to be too tight or undergo local deformation.

Equipment structure and operation

Forming mold: If the mold size does not match the product (such as excessive gap), it will cause the film material to not wrap tightly. If the surface roughness of the mold is too high, it will increase the frictional resistance.

Tension control system: Tension fluctuations exceeding ±5% will cause uneven stretching of the membrane material, resulting in local relaxation or excessive tightness.

Heat sealing and cutting: Insufficient pressure of the heat sealing knife or wear of the cutting knife can cause the edges of the film material to become loose, affecting the overall compactness.

Process parameter matching

Speed and temperature: If the speed is too fast (such as >120 pieces per minute), the membrane material may be cut before fully adhering to the product. If the temperature is too high (such as >180℃), the membrane material may soften and deform.

Cooling efficiency: Insufficient cooling will cause the membrane material to continue to shrink during subsequent processing, damaging its compactness.

Second, the method for adjusting the tightness of packaging

Membrane material selection and adaptation

Balance between elasticity and rigidity: Prioritize the selection of membrane materials with moderate elasticity and high rigidity (such as BOPP/CPP composite films), and the thickness is recommended to be ≥30μm.

Tensile strengthening: For products prone to deformation, select membrane materials with tensile strength ≥30MPa, or increase the transverse tensile pretreatment of the membrane materials.

Heat shrink control: If heat shrink film is used, the optimal shrinkage temperature (such as 140-150℃) and shrinkage time (such as 1.5-2 seconds) should be determined through experiments to avoid excessive shrinkage.

Equipment adjustment and improvement

Optimization of forming molds

Adjust the mold gap according to the product size. It is recommended that the gap be 0.5 to 1mm smaller than the maximum size of the product to ensure a tight adhesion of the film material.

Regularly grind the surface of the mold, keeping the roughness at Ra≤0.8μm to reduce frictional resistance.

Tension control system upgrade

Closed-loop tension control is adopted, and the tension is adjusted in real time through tension sensors and magnetic powder brakes/clutches, with fluctuations controlled within ±3%.

Add floating rollers along the membrane material conveying path to buffer tension fluctuations and prevent local tightness or looseness.

Improvement of heat sealing and cutting processes

Increase the pressure of the heat sealing knife (such as 0.3-0.5MPa) to ensure that the edges of the film material are completely sealed and reduce loosening.

Replace the cutting knife regularly to ensure the blade is sharp and avoid burrs or tears on the edge of the membrane material.

Refinement of process parameters

Speed and temperature matching:

Reduce the packaging speed by 10-15% (such as adjusting to 80-100 pieces per minute) to ensure that the film material has sufficient time to adhere to the products.

Adjust the heat sealing temperature according to the type of film material. For example, the sealing temperature for BOPP/CPP film is 160-165℃, and for PETG film, it is 140-150℃.

Improved cooling efficiency

Add a cooling air knife or water cooling device to ensure that the film material cools to room temperature within 1 second after sealing, reducing subsequent shrinkage.

Optimize the design of the cooling air duct to ensure uniform air velocity (such as ≥5m/s) and avoid insufficient local cooling.

Process monitoring and feedback

Real-time tightness detection

Install pressure sensors or laser rangefinders to monitor in real time the adhesion between the packaged product and the film material. An automatic alarm will be triggered when the deviation exceeds 0.3mm.

Finished product spot check

Randomly inspect the packaged finished products and assess the tightness by hand feel or pressure tester. It is required that the products have no obvious shaking or loose film material after packaging.

Use a visual inspection system to check the adhesion of the membrane material and remove products with poor adhesion or wrinkles.

Third, common problems and solutions

The packaging is loose or the film material does not adhere to the product

Reasons: Insufficient tension, excessive mold gap, and excessively high elasticity of the membrane material.

Solution: Increase the tension by 5-10%, reduce the mold gap by 0.2-0.5mm, and replace it with a more rigid membrane material.

The packaging is too tight or the film material is broken

Reasons: Excessive tension, too small mold gap, insufficient tensile strength of the membrane material.

Solution: Reduce the tension by 5-10%, increase the mold gap by 0.2-0.5mm, and replace it with a film material with higher tensile strength.

The edges of the membrane material are loose or the seal is not tight

Reasons: Insufficient pressure of the heat sealing knife, wear of the cutting knife, and uneven thickness of the film material.

Solution: Increase the pressure of the heat sealing knife by 10-15%, replace the cutting knife, and use film material with uniform thickness.

The film material shrinks or deforms after packaging

Reason: The shrinkage rate of the heat shrink film is too high and the cooling is insufficient.

Solution: Reduce the shrinkage temperature of the heat shrink film by 5-10℃ and extend the cooling time to more than 2 seconds.

Fourth, equipment maintenance and long-term stability

Daily maintenance

Cleaning: Clean the heat sealing knife, cutting knife and guide roller daily to prevent the accumulation of glue residue or film debris.

Lubrication: Lubricate the transmission components (such as chains and gears) weekly using high-temperature resistant grease.

Inspection: Check the membrane material conveying path daily to ensure there is no jamming or wear.

Regular calibration

Mold calibration: Use a micrometer to check the mold clearance every month. Make adjustments when the deviation exceeds 0.1mm.

Sensor calibration: Calibrate the tension sensor, pressure sensor and visual inspection system every quarter to ensure measurement accuracy.

Calibration of heat sealing knives: Check the parallelism and pressure uniformity of the heat sealing knives every six months. Repair should be carried out when the deviation exceeds 0.05mm.

Spare parts Management

Key spare parts reserve: Stock up on commonly used spare parts (such as cutting knives, heat sealing knives, tension sensors) to ensure timely replacement in case of failure.

Spare parts quality: Select spare parts that match the original equipment to avoid affecting the compactness due to spare parts quality issues.

Fifth, suggestions for adjusting and optimizing the compactness

Technological upgrade

Automation control: Introduce PLC and touch screen to achieve automatic adjustment of parameters such as tension, temperature and speed, as well as self-diagnosis of faults.

Online inspection system: Equipped with high-precision visual inspection and pressure sensors, it can monitor the compactness in real time and automatically remove non-conforming products.

Process optimization

Segmented heat sealing and cooling: The heat sealing process is divided into three stages: preheating, main sealing, and cooling to reduce local overheating and insufficient cooling.

Negative pressure adsorption forming: Add a negative pressure adsorption device in the forming area to ensure that the membrane material closely adheres to the mold and the product.

Personnel training

Operation training: Regularly train operators to master the skills of equipment adjustment, parameter setting and troubleshooting.

Quality awareness: Strengthen the quality awareness of operators to ensure that operations are carried out in accordance with standards.

Summary

The adjustment of the packaging tightness of the transparent film three-dimensional packaging machine needs to be comprehensively optimized from multiple aspects such as film material, equipment, process, monitoring and maintenance. By choosing high-rigidity film materials, optimizing tension and forming processes, upgrading equipment control systems, strengthening daily maintenance and real-time detection, the tightness of packaging can be significantly improved. Operators must strictly abide by operating procedures, promptly identify and address issues, and continuously improve packaging quality in combination with technological upgrades.