The domestic extrusion blow molding production lines have undergone nearly 50 years of development and progress, particularly in independent research and development and technological exchange since the reform and opening up. Its technological level has now approached that of similar equipment in developed countries, leading to the emergence of several manufacturers in China with independent R&D capabilities and substantial production scales.
Various specifications of domestically produced blow molding production lines have already made their way overseas and are being sold to multiple countries. With the rapid development and application of computer design, computer manufacturing, computer engineering technology, computer measurement technology, and rapid prototyping technology, the research and development capabilities of domestic extrusion blow molding production lines have significantly strengthened, achieving major technological breakthroughs and advancements in many critical components that constitute hollow blow molding production lines.
1. Currently, one of the key development directions for medium—and large-scale extrusion blow molding machines is to shorten the production cycle of blow-molded products and enhance production efficiency. To this end, the focus of development is primarily on improving the machines’ plasticizing capacity.
Efforts are being made to develop screw and barrel systems with high plasticizing performance and high conveying capacity, while vigorously promoting and applying the IKV structure, which features forced feeding and forced cooling for high-output plasticizing extrusion.
Increasing blowing pressure and utilizing low-temperature dried high-pressure air for blow molding are crucial for reducing cooling and forming time, as well as improving product quality.
2. In enhancing the performance of storage-type and continuous extrusion heads, it is possible to develop high-performance dual-layer and multi-layer heart-shaped enveloping flow channels, as well as various combinations of composite flow channels for both storage-type and continuous extrusion heads. Key features of high-performance storage-type heads include a first-in-first-out (FIFO) system, quick color and material change capabilities, and ease of cleaning. During the development of new blow molding machines, the application of advanced CAD/CAE/CAM technologies, along with the use of high-quality steel and precision processing equipment, is essential for creating new blow molding units and production lines.
3. In recent years, the development of pin-type and buckle-type rodless clamping mechanisms has progressed rapidly. These mechanisms offer advantages such as high clamping force, uniform distribution, ease of mold loading and unloading, large mold capacity, and energy efficiency. Therefore, their use should be promoted in large-scale extrusion blow molding machines. Additionally, the guiding motion components of the pin-type rodless clamping mechanism should utilize low-friction, smooth-moving, high-precision ball linear guides, with rapid mold movement achieved through a servo motor operating via a ball screw.
High-pressure clamping is achieved when a pin on one mold plate inserts into a locking sleeve on another mold plate, with two or more pairs of clamping cylinders distributed on either side of one mold plate pulling the other mold plate tight; conversely, this process is reversed for high-pressure mold opening. The hydraulic synchronous drive rodless clamping mechanism represents the latest advancement in clamping technology, employing two symmetrically arranged hydraulic drive systems to synchronously operate their respective mold plates. The force exerted by the hydraulic cylinders on the mold plate centers reduces the weight of the mold plates and minimizes clamping deformation, thereby facilitating easier mold loading and unloading, increasing mold capacity, and making it more suitable for robotic operation. This mechanism demonstrates superior performance compared to the pin-type rodless clamping mechanism and is worthy of further promotion and application.
The Coupling Sleeve Type External Two-Plate No-Rod Molding Machine System developed by the Yankang Plastic Machinery Engineering Technology Research Center boasts numerous advantages, including high clamping force, long service life, large mold capacity, significant template rigidity, minimal deformation, and stable operation.
4. We are accelerating the research and development, as well as the promotion of the Flexible Ring Radial Wall Thickness Control System (PWDS). When combined with the Axial Wall Thickness Control System (AWDS), it achieves optimal mold quality and a more desirable product wall thickness distribution. Currently, the servo motor-driven plastic mold control systems in use can achieve effective axial pulling forces of 30t, 120t, 200t, 250t, and 300t, enabling fully electric and servo-driven axial plastic mold control for medium to large blow molding machines. This effectively addresses the challenges associated with plastic mold control. Additionally, it completely resolves a series of long-standing issues faced by manufacturing enterprises, such as oil leakage, high maintenance costs, and stringent technical maintenance requirements associated with hydraulic servo control systems.
5. In recent years, fully electric hollow-forming machines have experienced rapid development. Given the high hygiene standards required for food packaging, fully electric hollow forming machines are increasingly favored over those with hydraulic systems, as they more easily meet stringent cleanliness requirements. Consequently, many blow molding companies are now investing in fully electric hollow-forming machines.
6. Multi-layer blow molding hollow forming machines represent a significant trend for future development. Multi-layer plastic products offer superior barrier properties and strength compared to single-layer counterparts. For instance, certain volatile liquid packaging necessitates the use of multi-layer plastic barrels to minimize evaporation. The strength of multi-layer hollow plastic products increases to varying degrees compared to single-layer products, depending on the number of layers.
7. The design and development of intelligent production lines for extrusion blow molding machines have progressed rapidly in recent years. Large-scale production of blow-molded products has already achieved a level of automation, and as the demand for larger blow-molded items increases alongside market expansion, intelligent blow molding production lines are currently under development. In the coming years, we can expect a greater number of blow-molded products to transition to fully automated intelligent production processes.