Innovative technology and application prospect

In the field of modern plastic processing, the combination of blow molding and IML technology is opening up new application possibilities. This fusion process not only retains the advantages of traditional blow molding in the production of large capacity hollow products, but also brings excellent decorative effect and functionality to the product surface through IML technology. This paper will comprehensively analyze the technical principle, process characteristics, application fields and future development trend of blow molding IML machine, and provide valuable reference for technicians and decision makers in related industries.

Overview of blow molding IML Technology

Blow molding IML technology represents the innovative combination of blow molding and in mold labeling, which has brought revolutionary changes to the plastic container manufacturing industry. This technology combines the advantages of the two processes, which not only retains the high efficiency of blow molding in the production of hollow products, but also realizes the high-quality decorative effect of the product surface through IML technology.

Blow molding is a plastic processing method by placing a thermoplastic parison in a mold, then blowing compressed air into the inside of the parison to make it expand and fit the inner wall of the mold, and finally cooling it to the desired shape. According to different processes, blow molding is mainly divided into three types: extrusion blow molding, injection blow molding and stretch blow molding. This process is especially suitable for the production of hollow plastic products, such as bottles, barrels, cans, etc., and is widely used in the fields of food packaging, daily chemical products, medical containers, etc.

In mold labeling (IML) is a decorative technology that puts a pre printed label or decorative film into the mold and combines it with the plastic melt in the process of injection molding or blow molding. Compared with the traditional labeling method, IML technology makes the label an integral part of the product, with significant advantages such as not easy to fall off, wear resistance, moisture resistance and antifouling. IML technology was initially mainly used in the field of injection molding, such as mobile phone shell, home appliance panel, etc., but with the progress of technology, it has been successfully extended to the field of blow molding.

Blow molding IML machine is a professional equipment that organically combines these two processes. In this equipment, labels or decorative diaphragms are first accurately placed in the open mold, and then positioned and fixed by manipulator or automation system. Then, the plastic parison is introduced into the mold and blown into shape. In this process, the melted plastic is closely combined with the back of the label. After cooling, the final product integrating decoration and container is formed.
This technology integration brings many process advantages:

Improvement of decoration quality: IML labels can achieve high-resolution images and complex patterns, rich and stable colors, and are not easy to fade

Improve production efficiency: combine decoration and molding processes into one, reduce subsequent processing steps and shorten production cycle

Enhanced product durability: the label is embedded in the plastic, which is scratch resistant, chemical resistant and extends the service life of the product

Improvement of environmental protection performance: no adhesive is needed to reduce the emission of volatile organic compounds (VOCs), meeting the environmental protection requirements

Expanded design freedom: 3D surface decoration can be realized, breaking through the limitations of traditional plane labeling

With the continuous improvement of consumers' requirements for product appearance and quality, and the pursuit of automation and intelligent production in the manufacturing industry, blow molding IML technology is gradually becoming an important development direction of the plastic packaging industry, especially showing strong market competitiveness in the fields of high-end daily chemical packaging, food and beverage containers and so on.

Working principle and key technology of blow molding IML equipment

The blow molding IML equipment is a complex mechatronics system that integrates the traditional blow molding system and advanced in mold labeling technology. Its working principle and key technologies determine the quality and production efficiency of the final product. An in-depth understanding of these core elements is essential for equipment selection, process optimization and troubleshooting.

Basic structure and workflow of equipment

A complete set of blow molding IML system is usually composed of the following key subsystems: parison forming system, mold system, IML label processing system, blow molding system, control system and auxiliary equipment. These subsystems work together to achieve fully automated production from raw materials to finished decorative products.

The standard workflow can be divided into the following stages:

Label preparation and feeding: the pre printed label coil enters the equipment through the automatic feeding system, is cut into a single label and is accurately grabbed by the manipulator or vacuum suction cup. Label materials are usually PP, pet and other films with good printing performance and thermal stability.

Mold preparation and label positioning: when the mold is opened, the label is accurately placed at the predetermined position on the inner surface of the mold, which is usually fixed by electrostatic adsorption or vacuum adsorption to ensure that it will not shift during mold closing and blow molding.

Parison formation and introduction: plastic particles are melted and plasticized in an extruder to form a parison. The parison length and wall thickness are controlled by program. For the injection blow molding process, the green body is first injected.

Mold closing and blow molding: the mold is closed and the parison is clamped. High pressure gas (usually 20-40bar) is injected into the parison through the blowing needle to make it expand and fit the inner surface of the mold. In this process, the molten plastic is closely combined with the back of the label.

Cooling and demoulding: the formed product is cooled and shaped in the mold, and then the mold is opened, and the finished product is ejected or taken out by the manipulator to complete a production cycle.
Analysis of core key technologies

High precision label positioning system is one of the key technologies of blow molding IML equipment. The label must be accurately placed in the designated position in the mold, and the error is usually required to be within ± 0.1mm. To achieve this goal, the equipment adopts high-precision servo drive, machine vision positioning and advanced control algorithm. The vision system first collects the image and identifies the position of the label and mold, and then adjusts the position and posture of the manipulator through the motion control system to ensure that the label is accurately in place.

Mold design and temperature control technology directly affect product quality and production efficiency. IML blow molding mold needs to consider label fixation, exhaust channel design and cooling system layout. The mold surface is usually designed with micro vacuum adsorption holes or electrostatic generation devices to fix the label 7. Temperature control is also crucial. Too high mold temperature may lead to deformation or scorching of the label, and too low temperature will affect the bonding strength between the plastic and the label. Modern equipment adopts segmented temperature control system to realize accurate temperature management of different areas of the mold.

Gas pressure control technology has a decisive impact on product molding quality. Different from traditional blow molding, IML blow molding needs to consider the influence of label on gas flow and plastic distribution. The equipment needs to be equipped with a precise air pressure control system, which can adjust the blowing pressure and curve according to the shape and size of the product. For complex shape products, multi-stage pressure control technology may also be used. Raymond technology and other equipment manufacturers have developed an ultra-high pressure gas forming machine with a pressure of up to 150bar, which is especially suitable for difficult to form materials such as PC.

Material compatibility and pretreatment technology are the basis to ensure the success of the process. Plastic materials (such as PP, PE, ABS, etc.) and label materials (such as PP, PET film) must have good compatibility and bonding performance. In some application scenarios, the label also needs to be pretreated, such as corona treatment to improve the surface energy, or coated with a special hot-melt adhesive layer to enhance the adhesion. The drying treatment of materials can not be ignored, especially for materials with strong moisture absorption, such as pet, moisture will lead to defects such as bubbles.

Automation and intelligent control system is the symbol of modern blow molding IML equipment. The advanced PLC control system integrates motion control, temperature control, pressure control and other functions to achieve fully automated production. Some high-end equipment is also equipped with artificial intelligence algorithms, which can monitor process parameters in real time and adjust them automatically to ensure production stability and product consistency. Through the industrial Internet of things (iiot) technology, the equipment can be connected to the plant MES system to realize remote monitoring and data analysis, and provide support for predictive maintenance and quality traceability.