PET preforming high-speed system: A core equipment for efficient and precise preform manufacturing

2025-09-30 15:37:01

The PET preforming high-speed system is an integrated equipment system specially designed for the large-scale production of PET preforms. Through the full-process coordination of injection molding - post-mold treatment - intelligent control, it realizes the high-speed mass production and high-precision control of preforms. Its core advantages are reflected in three dimensions: high production efficiency, accurate forming precision, and low energy consumption cost. As a key equipment at the front end of the packaging industry chain for beverages, condiments, daily chemicals, etc., it directly determines the quality of downstream bottle blowing and production economy. By 2025, the global PET preform market size had exceeded 42 billion US dollars, with China contributing over 35%. The high-speed preforming system is precisely the core technical equipment that supports this growth. The following is a comprehensive analysis from the aspects of system composition, core technologies, performance advantages, selection parameters, application cases and development trends:

I. Core Components of the System: A modular integrated manufacturing system

The PET preforming high-speed system is not a single device, but an integrated solution composed of four major modules: the main unit, the mold system, the auxiliary machine cluster, and the intelligent control system. Each module works together to achieve efficient conversion from raw materials to preforms. Typical configurations such as the Demag DP series system include key components like twin-screw Injection molding machines, 96-chamber precision molds, and three-station cooling manipulators.

Analysis of Core Module functions

(1) Mainframe unit: Forming power core

The main unit takes the high-speed injection molding machine as the core and undertakes the tasks of melting, plasticizing and high-pressure injection of PET raw materials. The key configurations include:

Twin-screw plasticizing system: Driven by imported servo motors, it enables the solubilization and injection processes to be carried out simultaneously. Compared with traditional single-screw molding, the molding cycle is shortened by more than 20%. The Demag DP series can compress the production cycle of 48-chamber preforms to within 12 seconds through synchronous solubilization technology.

High-efficiency accumulator group: Up to five sets of accumulators are configured, providing stable power for large injection volume scenarios, ensuring uniform filling of 96-cavity molds, and the injection repeatability accuracy can reach ±0.1%.

Direct pressure clamping mechanism: The template is specially designed for PET to ensure uniform force distribution in each cavity during high-speed opening and closing of the mold. The CSD-PET-DP series of Changshengda, through a double differential oil circuit design, increases the opening and closing speed by 30%, and the lead column does not come into contact with the moving template, avoiding the contamination of the preform by lubricating oil.

(2) Mold system: Key to precision control

The mold is the core that determines the consistency of the preform size. The mainstream configuration shows the characteristics of "multi-cavity + precision" :

Cavity quantity gradient: According to production capacity requirements, it is divided into specifications such as 16-cavity, 24-cavity, 48-cavity, 72-Cavity, and 96-cavity. The 16-cavity mold customized by Yizumi for Yaobang Plastic can achieve a daily production capacity of over 100,000 pieces per mold, and the weight deviation of the preform is controlled within 0.1g.

Intelligent temperature control of hot runner: It adopts temperature control modules of European brands, with an independent temperature control accuracy of ±0.5℃ for each cavity. By 2025, the mainstream systems will reduce energy consumption by 18% through hot runner optimization, and the power consumption per unit of production capacity will drop to 0.21 kilowatt-hours per thousand units.

Rapid cooling structure: The cavity adopts beryllium copper inserts and spiral cooling water channels, combined with a post-mold cooling manipulator, which reduces the preform demolding temperature from the traditional 80℃ to below 45℃, avoiding deformation.

(3) Auxiliary machine cluster: Process collaboration guarantee

It includes raw material processing and post-processing equipment for finished products, forming a closed-loop production:

High-efficiency drying system: It adopts a three-section dehumidification design to control the moisture content of PET raw materials below 0.005%, avoiding the formation of bubbles during molding.

Post-mold cooling manipulator: Three-station design is the mainstream. For instance, the manipulator of Demag system completes secondary cooling while picking up the part, allowing the preform to fully solidify and further shortening the production cycle by 5%.

Dew removal and detection unit: Equipped with online weight detection and appearance visual inspection modules, non-conforming products are automatically removed, and the detection speed matches the high-speed production of 1200 pieces per minute.

(4) Intelligent control system: Full-process scheduling hub

Developed based on the industrial PC platform, represented by the Demag HCI system and adopting the BECKHOFF control solution from Germany, it possesses three core capabilities:

High-speed response capability: The PLC execution cycle is ≤1ms, and millisecond-level communication among injection molding machines, manipulators, and inspection equipment is achieved through the EtherCAT bus.

Adaptive adjustment function: It can automatically adjust the injection pressure and speed according to the changes in raw material viscosity and environmental temperature. The newly added self-calibration algorithm in 2025 has improved the molding stability by 25%.

Visual operation and maintenance interface: A 15-inch touch screen integrates production data monitoring, fault alarm, and process parameter storage functions. It supports the management of over 100 groups of formulas and is suitable for rapid switching of multi-specification preforms.

Ii. Core Technology Breakthroughs: Key Innovations Supporting high-speed and Precision Production

The performance advantages of the system stem from the coordinated application of four core technologies, which solve the pain points of traditional injection molding such as "low efficiency, poor precision and high energy consumption"

1. Synchronous molding technology

Breaking through the limitations of the "sol-injection" serial process, the plasticizing and injection actions are carried out simultaneously through the independent drive of the twin-screw and the coordination of the accumulator. Take the production of 48-chamber preforms as an example. The traditional system's molding cycle takes 18 seconds, while the CSD-PET-DP48 model from Changshengda compresses the cycle to 12 seconds through synchronous technology, increasing the daily production capacity of a single unit by 50%.

2. Servo closed-loop control technology

The "servo motor + servo valve" dual closed-loop control scheme is adopted: during the injection stage, the flow and pressure are precisely controlled by the servo valve, and the error of the repeated injection volume is ≤0.1%. During the clamping stage, the position and pressure are closed-loop regulated through servo motors. The clamping force deviation of each cavity in the 96-cavity mold is controlled within ±2%, effectively avoiding uneven wall thickness of the preform.

3. Efficient thermal management technology

Build a three-dimensional thermal control system of "mold - product - environment" : The mold adopts zoned temperature control (independent temperature control for nozzles, cavities and cores), and is combined with a three-station cooling manipulator after the mold, reducing the cooling time of the preform from 8 seconds to 3 seconds. The main screw adopts electromagnetic induction heating, with a thermal efficiency of up to 95%, which saves more than 30% energy compared with resistance heating.

4. In-mold integration technology

By 2025, the penetration rate of in-mold labeling technology has reached 48%. Some high-end systems have achieved the integration of "injection - labeling - inspection" : label implantation is completed simultaneously during the injection molding process, and the label adhesion is directly inspected after the preform is demolded, eliminating the subsequent labeling process. The processing cost of a single preform has been reduced by 0.02 yuan.

Iii. Core Performance Advantages: Dimensional upgrades compared to traditional equipment

Compared with ordinary injection molding machines, the PET preforming high-speed system, through modular integration and technological innovation, has formed a significant advantage of "three highs and one low", especially suitable for the demands of large-scale production

1. Ultra-high production efficiency

The combination of multi-chamber design and synchronous technology has achieved a significant breakthrough in production capacity: the single-mold cycle of the 96-chamber system can be as low as 10 seconds, and the hourly production capacity of a single machine can reach 34,560 pieces, equivalent to the total output of 4 ordinary 16-chamber injection molding machines. The two production lines customized by Yizumi for Yaobang Plastic have achieved a daily preform production capacity of 400,000, requiring only two operators and reducing labor costs by 75%.

2. Ultra-high forming accuracy

Through precision molds and servo control, the key dimensional accuracy control of the preform has reached the top level in the industry: the tolerance of the bottle mouth thread diameter is ≤±0.02mm, the uniformity error of the wall thickness is ≤3%, and the weight repeatability accuracy is ≤±0.1g. This precision has raised the downstream blow molding qualification rate from the traditional 92% to over 99%, significantly reducing the loss of defective products.

3. Ultra-high operational stability

The core components are equipped with industrial-grade high-end configurations: the mean time between failures (MTBF) of the servo motor exceeds 20,000 hours, and the mold cavity is made of P20 pre-hardened steel, with a service life of over 5 million mold cycles. The continuous operation failure rate of Demag DP series systems is less than 0.5%, which is far superior to the 3% failure rate of ordinary injection molding machines.

4. Low energy consumption and low maintenance costs

The servo double closed-loop system significantly reduces energy consumption per unit of production capacity: The unit power consumption of the 48-chamber system is only 0.21 kilowatt-hours per thousand units, saving 40% of energy compared to traditional equipment. At the same time, through modular design, the replacement time of key components has been shortened to within 2 hours, and the annual maintenance cost has been reduced by 30%.

Iv. Key Selection Parameters: Core indicators that match production capacity and quality requirements

Selection should focus on three core elements: production scale, preform specifications, and quality requirements. Special attention should be paid to the following six parameters to avoid "overcapacity" or "insufficient precision" :

1. Cavity quantity (C

Select based on daily production capacity requirements: For a daily production capacity of less than 100,000 units, choose 16-24 chambers; for 100,000 to 300,000 units, select 32-48 chambers; and for over 300,000 units, choose 72-96 chambers.

2. Molding Cycle (T

The shorter the cycle, the higher the efficiency. A comprehensive judgment should be made based on the number of cavities and the weight of the preform: For 12g lightweight preforms (30/25 specification), the cycle of a 48-cavity system should be ≤12 seconds, and that of a 72-cavity system should be ≤15 seconds. The Changshengda CSD-PET-DP48 model can stably achieve a 12-second cycle under this specification.

3. Injection Accuracy (P

In terms of weight repeatability accuracy, food-grade preforms should be ≤±0.1g, and medical-grade ones should be ≤±0.05g. The weight deviation of the edible oil bottle preforms produced by Yizumi 16-cavity molds is controlled within 0.1g, meeting the requirements of high-end customers such as COFCO.

4. Temperature control accuracy (ΔT)

The temperature control accuracy of each area of the mold should be ≤±0.5℃; otherwise, it is easy to cause uneven crystallization of the preform. Both Demak and Changshengda systems adopt temperature control modules of European brands, which can stably meet this precision requirement.

5. Energy Consumption Index (E

Give priority to systems with a unit production capacity power consumption of no more than 0.25 kilowatt-hours per thousand units. Based on an annual production capacity of 10 million units, electricity costs can be saved by over 100,000 yuan annually (calculated at 1 yuan per kilowatt-hour).

6. Compatibility (M

It needs to be adapted to different preform specifications and raw material types: The bottle mouth specifications are compatible with mainstream standards such as 28mm and 30mm, and the raw materials can be adapted to new PET and recycled PET (the blending ratio of recycled materials is ≤30%), meeting the requirements of the new European environmental protection regulations.

V. Typical Application Scenarios: From food packaging to large-scale production in the daily chemical field

The PET preforming high-speed system, with its high efficiency and precision, has become a core equipment in the downstream packaging industry. Its typical applications are mainly concentrated in three major fields:

1. Beverage packaging: Mass production of lightweight preforms

Bottled water/carbonated beverages: A 72-96 chamber system is adopted to produce 12-15g lightweight preforms. For instance, a well-known bottled water enterprise has selected the Demag DP3500 system, achieving a daily production capacity of 800,000 bottles per unit. The preform weight has been reduced from 18g to 14.5g, and the raw material cost per bottle has been lowered by 0.04 yuan.

Juice/Tea beverages: A 48-chamber system with in-mold labeling function is selected to produce 20-25g preforms. The label adhesion accuracy is ≤±0.1mm, eliminating the subsequent labeling process and increasing the production line efficiency by 20%.

2. Condiment packaging: Non-standard customized production

Sauce preform: In response to the demand for irregular-shaped bottle bodies, the system achieves flexible production of over 10 types of preforms through rapid mold changing technology (mold changing time ≤30 minutes), which is suitable for small-batch and multi-variety orders.

3. Daily chemical packaging: High-end quality control

Washing products preform: Preforms with handle structure are produced by using a 32-chamber system. The injection speed is precisely controlled by a servo valve to avoid shrinkage marks at the handle, and the surface finish reaches Ra 0.8μm.

Cosmetic preforms: A 24-chamber precision system is selected to produce 10-15g small capacity preforms, with a wall thickness uniformity error of no more than 2%, ensuring that the transparency of the bottle body after blowing meets the packaging requirements of high-end cosmetics.

Vi. Key Points for Use and Maintenance: Crucial Measures to Ensure Efficient and Stable Operation

The long-term stable operation of the system relies on standardized operation and maintenance. Especially in high-speed mass production scenarios, the following aspects need to be given special attention:

1. Prepare the norms before starting up

Raw material pretreatment: PET raw materials need to be dried at 165℃ for 4 to 6 hours to reduce the moisture content to below 0.005%. Damp raw materials can cause bubbles to form in the preform, and real-time monitoring is required through an online moisture meter.

Mold preheating: Gradually increase the mold temperature to 120-140℃, with the temperature difference in each area controlled within ±2℃. The preheating time should be no less than 30 minutes to avoid dimensional deviations caused by cold mold injection molding.

Parameter calibration: Calibrate the injection volume and clamping force through standard test mold parts to ensure repeatability accuracy ≤±0.1% and servo valve response time ≤10ms.

2. Key points for monitoring during operation

Real-time parameter monitoring: The injection pressure (fluctuation range ≤±5bar), mold temperature (deviation ≤±0.5℃), and the speed of the mechanical hand picking up parts are monitored through the HCI system. The system will automatically alarm when any abnormality occurs.

Periodic random inspection: 10 preforms are randomly inspected every hour to check the weight, wall thickness and bottle mouth accuracy. If the data exceeds the tolerance of ±0.03mm, the machine will be stopped immediately for adjustment.

Raw material cleanliness control: Install a 120-mesh filter screen at the feed inlet and replace it every 8 hours to prevent impurities from entering the cavity and causing mold wear.

3. Maintenance and Troubleshooting

(1) Daily maintenance (daily/weekly

Daily: Clean the residual material chips in the mold cavity, check whether the cooling water passage is unobstructed (inlet water pressure ≥0.3MPa), and lubricate the clamping guide rail (using food-grade lubricating oil);

Weekly: Check the accumulator pressure (maintained at 12-15 mpa), calibrate the temperature control module, and clean the dust on the servo motor cooling fan.

(2) Common Fault resolution

Uneven wall thickness of the preform: Check whether the clamping force is uniform (adjust the parallelism of the template), and whether the temperature of the hot runner is deviated (recalibrate the temperature control).

Injection speed fluctuation: Check the wear of the servo valve (replace the seal), and whether the accumulator pressure is insufficient (replenish nitrogen).

The mechanical hand failed to pick up the piece: Adjust the position of picking up the piece (accuracy ±0.1mm), check the sealing of the vacuum suction cup (replace the aged suction cup).

Summary: Technological development trends

With the upgrading of the packaging industry towards "high efficiency, greenness and intelligence", the high-speed PET preforming system is presenting three major development directions:

Parallel development of ultra-high cavity and miniaturization: On the one hand, breakthroughs are made in ultra-high cavity configurations of over 128 cavities, with a single unit production capacity exceeding 40,000 units per hour. On the other hand, a dedicated system for 5-10g micro-preforms was developed to meet the packaging requirements of small capacities under 500ml (orders for this type in the North American market increased by 23%).

Recycled material compatibility and low-carbon design: Optimize the screw plasticizing structure to increase the blending ratio of recycled PET to 50%, adopt all-electric drive technology to further reduce energy consumption by 20%, and use water-soluble mold release agents to reduce VOC emissions.

Digital Twin and Intelligent Operation and Maintenance: By integrating sensors to collect real-time data such as mold temperature and screw wear, a digital twin model is constructed to achieve process prediction. We have developed a remote operation and maintenance system, reducing the fault response time to within one hour and adapting to the "preform + filling" integrated service model (with a coverage rate of 27%).