As two major hollow blow-molding processes, extrusion blow molding (commonly referred to as “extrusion blow”) and injection blow molding (commonly referred to as “injection blow”) differ in several key aspects. What are their respective strengths and weaknesses, and in what application scenarios are they most suitable? What are the structural components of the machinery used in each of these two processes? What are the technical challenges involved in producing multi-layer blow-molded products? What is the current status of their domestic market applications, and what are the emerging trends in their technological development? To find answers to these questions, this journal has specially invited several domestic manufacturers of “extrusion blow” and “injection blow” equipment to provide us with a comprehensive explanation.

PT: What are the differences between the “extrusion blow molding” and “injection blow molding” processes? What types of materials are each suitable for, and what kinds of products can be produced by these methods? What are the respective advantages and disadvantages of each process?

Mr. Du Guoliang: “Extrusion blow molding” and “Injection blow molding,” as two types of hollow-molding processes, share a common basic molding principle: First, a hot parison is formed, and then compressed air is used to expand it into a finished product that has the same shape as the mold.

Nevertheless, these are two molding processes that are applied in different contexts. First, let’s look at “extrusion blow molding.” Its molding process consists of three steps: First, a tubular parison is formed using a parison head; second, the parison is inflated and shaped within a mold; third, flash material is removed, and leak tests are performed. As for “injection blow molding,” the first step involves injecting molten plastic, assisted by a core, to form a preform; the second step is the shaping of the preform at the blowing station; and the third step is demolding.

In theory, all thermoplastic materials are suitable for the “extrusion blow molding” process. However, due to factors such as draw viscosity, the plastics commonly used in practice include LDPE, HDPE, HMWPE, PP, PA, PVC, PC, PETG, and ABS/PC blends. As an early and widely adopted hollow-molding process, extrusion blow molding finds extensive applications in fields such as cosmetics, pharmaceuticals, food, agrochemical products, the automotive industry, petrochemicals, and large-volume packaging. For “injection blow molding,” the commonly used plastics generally include HDPE, LDPE, PP, PS, ABS, PVC, and PET; their products are primarily used in packaging for cosmetics, food, and pharmaceuticals.

The main advantages of “extrusion blow molding” include: relatively low molding pressure, minimal residual stress, and excellent overall performance; it is suitable for products with complex shapes and strong structural requirements. Through multilayer co-extrusion, sprue material can be fully recycled, making this process ideal for producing items such as pesticide bottles and automotive fuel tanks that demand high barrier properties. It is also well-suited for large-volume industrial packaging (IBCs). Additionally, product changes and updates are flexible, allowing for the production of a wide variety of products. The advantages of “injection blow molding,” on the other hand, include: high molding pressure and high dimensional accuracy; generally no waste generation, resulting in high energy efficiency; excellent surface quality and high smoothness; and relatively uniform wall thickness.

The shortcomings of “extrusion blow molding” include: the presence of flash, relatively low energy efficiency; longer changeover times when switching between different materials; and a relatively complex machine design. As for the shortcomings of “injection blow molding,” they are: it is not suitable for producing multilayer products with high barrier properties or large-volume products.

Mr. Li Hui: The extrusion blow molding process is primarily characterized by the continuous rotation of the screw, driven by the power provided by the transmission system, which enables the material to be continuously extruded in a tubular shape from the die. This is an open-type molding method. Extrusion blow molding has a wide range of applications and can virtually cover all fields of hollow products, especially those with complex external shapes, three-dimensional structures, multi-layer designs, and large sizes. However, for small- and medium-sized products—particularly small and medium containers with regular shapes, high sealing requirements, and stringent appearance quality standards—it exhibits obvious shortcomings when compared to injection blow molding. Moreover, during the extrusion blow molding process, flash often forms, necessitating secondary recovery. Additionally, since the molding process is open, the density of the resulting products tends to be lower than that of injection blow-molded products.

The injection blow molding process involves the injection system using an injection stroke to feed raw material from the hot runner into the mold cavity, forming a parison. Next, the melt is heated, the screw retracts, and the system waits for the next injection cycle. Finally, the mold closes, and the blow-molding system completes the bottle blowing operation. Since this process is a closed-mold forming method, the resulting products exhibit excellent density and high sealing performance at the bottle neck. Moreover, the entire production process generates no flash or waste materials, making it particularly well-suited for manufacturing packaging bottles for pharmaceuticals and cosmetics. It’s worth noting that Jingye Machinery Co., Ltd. (hereinafter referred to as “Jingye Machinery”) has developed a patented product—the fully automatic injection blow molding machine—which, thanks to its vertical molding technology and integrated cavity design, combined with another patented technology—the composite core technology—enables the production of highly transparent special materials such as PC, PETG, and Tritan. These highly transparent bottles are primarily used for baby bottles, sports water bottles (space cups), and reagent bottles. The main drawback of the injection blow molding process is its relatively narrow application scope; it is suitable only for producing small-capacity containers with regular shapes. Even with the injection blow molding machines provided by Jingye Machinery, the largest conventional models currently available can produce bottles with a maximum capacity of only 2000 ml.

Mr. Gao Xuefei: “Extrusion blow molding” refers to the hollow-molding process involving extrusion and blow forming. First, plastic in a viscous-flow state is extruded through an extruder, and a parison with uniform wall thickness or one whose wall thickness is distributed regularly according to the shape of the product is obtained via the die head. Next, the extrusion-blow mold is clamped shut, the parison is cut, and then high-pressure blow molding is carried out. After cooling, the mold is opened, flash is removed, and the hollow product is ready.

Stretch-blow hollow molding is well-suited for producing large-capacity, multi-layer products with complex shapes. However, it also has certain drawbacks, such as uneven bottle mouths and poor sealing performance. The raw material typically used is LDPE, which has significantly lower barrier properties compared to HDPE and PP, resulting in a shorter shelf life and storage duration for the packaged contents.

“Injection Blow Molding,” or “Injection Blow Molding Hollow Molding,” can be categorized into two-step and one-step processes. The two-step injection blow molding involves two separate machines for the injection and blow-molding stages. In the first step, a conventional injection molding machine is used to inject and form the parison—the preform that will eventually become the bottle. At this stage, the bottle’s neck (including the bottle mouth and thread) is fully formed. In the second step, the parison is placed on a honeycomb heater or an automatically circulating heated conveyor belt for temperature adjustment. It is then transferred to a blow-molding machine, where compressed air is used to inflate and shape the parison into the final bottle. The advantages of the two-step process include: simpler equipment, lower investment; a smoother bottle mouth with excellent sealing performance; faster product development and lower mold costs. However, the disadvantages are: since the injection of the parison and the blow-molding process are carried out in separate steps, the parison is more prone to contamination, making it difficult to ensure microbiological safety; product consistency is poor, making this method less suitable for large-scale production.

The “one-step injection blow molding” process involves both injection and blow molding being carried out on the same machine. The equipment typically comprises three stations arranged in an equilateral triangle at 120° angles. The first station is the injection-molding station, the second station is the blow-molding station, and the third station is the bottle-ejection station. This one-step injection blow molding machine is particularly well-suited for producing pharmaceutical bottles. Since all three stations operate simultaneously, the production efficiency is high and the cycle time is short. Moreover, the machine can be connected to a conveyor belt for automatic counting and packaging, truly achieving “contactless” handling throughout the entire production process of pharmaceutical plastic bottles—thus ensuring that the products remain hygienic and clean.

Mr. Liang Kuanqiang: The “injection blow molding” process (including “injection stretch blow molding”) requires two sets of molds—one for injection and one for blow molding. First, the plastic is melted and injected into an injection mold using an injection molding machine, producing a preform. After the preform’s temperature is adjusted, it is then blown into shape in a blow molding mold using high-pressure air. In contrast, the “extrusion blow molding” process requires only one set of blow molding mold. An extruder melts and plasticizes the plastic and feeds it to the die head. The molten plastic is extruded through the die orifice to form a tubular parison, which is then blown into shape in the blow molding mold using high-pressure air.

The injection blow molding process is currently used exclusively for the production of small-sized articles and involves relatively higher mold costs. However, it also offers several distinct advantages: it can produce parts with no scrap material; it ensures more uniform wall thicknesses in the molded articles; it allows for precise control over the dimensions of the bottle neck; and it enables very high production volumes—such as when using the injection-stretch-blow molding process to manufacture PET bottles. The extrusion blow molding process is well-suited for producing hollow articles of various sizes, especially large-scale hollow products, and it features lower mold costs. On the downside, this process generates scrap material, and it is more challenging to achieve precise control over wall thickness. Virtually all plastics suitable for extrusion blow molding can also be used in injection blow molding; however, for easily meltable plastics such as PET, PAN, and PS, only the injection blow molding process is appropriate, and they cannot be processed using the extrusion blow molding method.

 

PT: What are the main components of blow molding machines that employ both “extrusion blow molding” and “injection blow molding” processes? What auxiliary equipment is required?

Mr. Du Guoliang: The “extrusion blow molding” machine primarily consists of a mold-closing mechanism, an extruder, a parison head, a control system, a mold, a frame, and a power unit. The composition of “injection blow molding” and “extrusion blow molding” machines is basically the same; the key difference lies in that “injection blow molding” uses a hot runner system during分流 (parting/division). The auxiliary equipment for “extrusion blow molding” mainly includes: a feeding and mixing system, a chiller, an air compressor, a leak-testing machine, a mold-drying system, a conveyor belt, a crusher, and a labeling machine, among others. The commonly used auxiliary equipment for “injection blow molding” includes: a raw-material dehumidifying dryer, a dew-point removal unit, a chiller, an air compressor, and a conveyor belt, among others.

Mr. Li Hui: The equipment for the extrusion blow molding process mainly consists of the following components: the extruder main unit, die head, air-blowing system, mold-moving system, blow-molding clamping system, mold assembly, and part-handling and conveying system. The equipment for the injection blow molding process, on the other hand, primarily comprises the injection system, injection-clamping system, blow-molding clamping system, mold assembly, and demolding and part-removal system. Among these, the mold assembly is considerably more complex than the mold component used in extrusion blow molding; it includes hot runners, parison molds, core molds, and blow-molding molds, among others.

The auxiliary equipment required for both processes includes air compressors, chillers, dry hoppers, and automatic feeding systems, which can be selected according to specific requirements. A mold temperature controller is an essential auxiliary device for the injection blow molding process. In most cases, injection blow molding equipment manufactured by Jingye Machinery only needs one mold temperature controller; only when producing containers made from special materials is it necessary to equip two controllers. Compared with other injection blow molding equipment, this reduces the number of mold temperature controllers needed by one to two units.

Mr. Gao Xuefei: Here, we’ll use the Vida MSZ series 3-station injection blow molding machine to illustrate the structural composition of a one-step injection blow molding equipment. This equipment features one standard horizontal injection unit (driven by a hydraulic motor, with a screw L/D ratio greater than 20 and equipped with 3+1-zone electric heating). The injection station consists of an injection mold (preform mold) and an ultra-high-pressure hydraulic clamping system. The blow-molding station comprises a blow-molding mold (final-forming mold) and a high-pressure hydraulic clamping system for blow molding. The bottle-ejection station mainly includes bottle-gripping mechanisms, as well as internal and external cooling devices for the core rod. The three stations are evenly arranged at 120° intervals, and the central tower along with the connected core rod can rotate counterclockwise by 120°.

The injection blow molding molds配套 with the MSZ series injection blow molding machines consist of an injection mold, a blow mold, a core rod, a hot runner system, sub-nozzles, a bottle-ejection pallet, and a core rod holder. The auxiliary equipment required for this machine includes a mold temperature controller, a chiller, an air compressor, a feeding machine, and a conveyor belt, among others.

Mr. Liang Kuanqiang: Extrusion blow-molding equipment generally comprises an extruder, a die head, a clamping mechanism, a blow-up mechanism, a robotic arm for removing the finished product, a frame, an electrical control system, and hydraulic and pneumatic systems, among other components.

The injection-blow molding process can be categorized into a one-step method and a two-step method. The two-step method involves two separate, independent processes: injection molding of the preform and blow molding of the bottle. Specifically, the preform is first produced on an injection-molding machine, and then it is blown into a finished bottle using a blow-molding machine. The blow-molding machines used in this process mainly consist of a preform-transfer mechanism, a preform-heating and temperature-control unit, a blow-molding clamping mechanism, and a product-removal mechanism. In the one-step method, injection molding and blow molding are combined into a single process. Although the underlying principle remains the same, the equipment for this method comes in two types—three-station and four-station models—and the specific structural designs of these machines vary among different manufacturers.

The auxiliary equipment used in extrusion blow molding and injection blow molding processes is basically the same; the only differences lie in the specifications selected according to specific needs or in the presence of certain specialized functions. These auxiliary devices mainly include: crushers or recycling systems, mixers, feeding machines or feeding systems, weighing and metering systems, mold temperature controllers, and chillers, among others.

PT: Can both “extrusion blow molding” and “injection blow molding” processes be used to produce multi-layer products? What do you consider to be the technical challenges in blow-molding multi-layer products? And what solutions can your company provide to address these challenges?

Mr. Du Guoliang: In fact, multilayer structures are already quite common in the “extrusion blow molding” field. However, multilayer applications in “injection blow molding” remain largely unexplored in China at present—though this is precisely a growing trend, as multilayer injection blow molding has already emerged internationally. The main challenges in producing multilayer structures lie in the plastic melt’s plasticizing efficiency and its stability, as well as ensuring uniformity across the multiple layers. To guarantee high-quality extrusion, we have adopted extruders and parison heads designed by Germany, whose technology is well-established. All critical components—including heating systems, power supply units, and electrical control elements—are imported, which greatly ensures the superior quality of the equipment we provide.

Mr. Li Hui: Currently, the “injection blow molding” process still finds it difficult to produce multi-layer container products, whereas the extrusion blow molding process can effectively achieve this goal. Multi-layer extrusion blow-molded products are primarily used in packaging applications such as chemicals and pesticides.

Mr. Gao Xuefei: Generally speaking, it is relatively difficult to produce multilayer structures using the “injection blow molding” process. However, by adopting the multilayer co-extrusion blow molding process, it is possible to manufacture high-performance multilayer hollow products. The primary technical challenge in blow-molding multilayer products lies in whether the co-extrusion die head can effectively fuse different layer materials together, thereby forming a multilayer molten parison.

Mr. Liang Kuanqiang: Both the “extrusion blow molding” and “injection blow molding” processes can be used to produce multilayer structural products, representing cutting-edge technologies in their respective fields. Multilayer co-extrusion technology leverages the unique properties of different materials, complementing their strengths and significantly enhancing various product performance characteristics, such as barrier properties, sealing performance, corrosion resistance, high-temperature resistance, low-temperature resistance, antibacterial properties, non-toxicity, and freshness preservation. In “injection blow molding,” multilayer preforms are produced using co-injection equipment, ultimately yielding multilayer hollow products. In “extrusion blow molding,” multilayer tubular preforms are extruded through a co-extrusion die head and then subjected to blow molding to obtain multilayer hollow products. The technical challenge lies in producing high-quality multilayer preforms or multilayer tubular preforms—this requires not only uniform layer thickness distribution across each plastic layer but also continuous and stable operation. Consequently, the control systems employed must meet higher standards than those for conventional equipment.

Our company primarily provides extrusion blow-molding equipment. In the field of multilayer extrusion blow molding, in 2001 we took the lead in China by developing the SCJC500×6 multilayer hollow-body machine—a six-layer plastic fuel tank production line—specifically for the domestic high-end automotive fuel tank market. This machine filled a significant domestic gap; the largest fuel tanks produced by it can hold up to 500 liters and have now become standard components for multiple models of brands such as Haima and Chery. In 2006, our company successfully developed the SCJC230×2 double-layer plastic hollow-body machine, designed for producing containers with a dual-layer structure. Such containers are widely used for packaging both hazardous and non-hazardous liquid and solid chemicals, food products, and daily chemical goods. Since the inner and outer layers of these containers can be made from different formulations, they can meet specific functional requirements. Additionally, in response to market demand for small multilayer hollow-body containers, we have also developed the SCJC30×3 three-layer, dual-station hollow-body machine, which is used to produce small hollow-body containers with capacities below 30 liters.

Multilayer blow molding is a high-end technology in hollow blow molding. With the advancement of automotive manufacturing technologies and the ever-increasing environmental and safety requirements worldwide, countries are placing ever-higher demands on the performance of plastic fuel tanks and packaging containers for automobiles. Therefore, multilayer hollow-molding machines represent one of the key development directions for our company’s future hollow-molding equipment.

PT: In the “extrusion blow molding” and “injection blow molding” processes, which stage(s) are critical to the forming process? What advanced technologies has your company adopted in these stages for its blow-molding equipment?

Mr. Du Guoliang: In “extrusion blow molding” applications, plastic extrusion, die forming, motion control, and molding process control are all critical to the extrusion blow molding process. In these areas, our company has adopted optimized designs from Germany’s Kautex.

In terms of extruders, our equipment features optimized screws equipped with mixing and shearing sections, enabling a broader range of plastics to be processed. Moreover, we can also design specialized screws tailored specifically for certain types of plastics used in particular applications. Our extruders boast high efficiency—take, for example, our E120 extruder, which can achieve an extrusion capacity of over 460 kg/h. As our next step, we will introduce the latest Q-series extruders designed by our German parent company. This represents a highly anticipated technological advancement.

In terms of parison heads, we can provide models ranging from single-cavity to 12-cavity and from single-layer to six-layer designs. These heads feature either a core-type complementary flow channel design or a central-feed splitter-type design, making them suitable for processing a wide variety of plastics while ensuring uniform wall thickness distribution. By employing a dual-layer complementary parison head, we guarantee independent operational performance—such as accommodating the differing viscosities and flow characteristics of various plastics. This also means that the parison head exhibits characteristics that are independent of temperature, pressure, and extrusion settings.

In terms of hydraulics and transmission, to ensure smooth and high-speed operation, all hydraulic valves are equipped with imported components. The system features oil temperature preheating and cooling functions, as well as monitoring capabilities for oil temperature and oil contamination. It adopts an energy-efficient dual-oil-circuit design (high- and low-pressure), and is fitted with an accumulator and a low-noise internal gear pump.

In terms of process control, our company ensures perfect “extrusion blow molding” by adopting the Blow command 4 molding control system, which incorporates Kautex’s more than 60 years of accumulated expertise in extrusion blow molding technology.

Mr. Li Hui: In the extrusion blow molding process, there are three critical stages: First, the uniformity and stability of screw plasticization; second, the extrusion die head—a core component with a high technical content. Differences in its performance will directly affect the final quality of the product. A good extrusion result ensures uniform and continuous material flow from the die, with no deformation and consistent wall thickness. Third, the mold-moving mechanism, which must feature rapid and stable operation as well as precise positioning.

The two most critical stages in the injection blow molding process are: First, the station-handling system, which must ensure both high speed and precise positioning during the transition between the parison and bottle-blowing stations. The station-handling system used in the WIB Cyclone series of injection blow molding machines developed by Jingye Machinery is a servo-driven system that completes the transition within about 1 second while maintaining exceptional positioning accuracy. Additionally, this system boasts advantages such as low noise levels and no oil contamination. Second, the mold section—particularly when using multi-cavity molds for production. In such cases, the hot runner system must ensure consistent injection volumes across all cavities, as well as uniform filling speeds and nearly identical temperatures in each cavity. The WIB Cyclone series injection blow molding machines from Jingye Machinery allow molds to adopt a double-row configuration. This design maximizes the utilization of the equipment’s effective space while increasing the number of mold cavities, thereby reducing the overall machine footprint. The hot runner system employs a uniformly distributed gating arrangement, ensuring that the distance from each cavity’s gate to the main runner is roughly the same, thus effectively guaranteeing consistent filling behavior across all cavities. Currently, in China, Jingye Machinery’s WIB Cyclone series injection blow molding machines are among the few that can be equipped with molds featuring this particular structural design.

Mr. Gao Xuefei: In the one-step injection blow molding process, several critical factors are essential for ensuring high efficiency and quality—namely, a high-speed, highly efficient injection system, a stable and rapid mold-opening/closing system, a three-station rotary lifting system, precise dimensional accuracy and flow-channel control in the injection-blow molds, and stringent quality control of the finished products. Our MSZ series machines excel precisely in these areas, which is why they have gained widespread acclaim among processing customers in the medical and healthcare sectors. Specifically, these machines feature a professional injection system and a sophisticated control system that guarantee stable plasticization of raw materials. The adoption of a three-cylinder mold-clamping system not only ensures rapid mold opening and closing but also meets the requirements for high clamping force and uniform distribution of clamping force across all mold positions. The three-station rotary lifting system can rotate by 120°, enabling the injection, blow molding, and demolding stations to operate continuously and smoothly. Moreover, thanks to the use of a hydraulically driven linkage mechanism, this system offers more precise positioning, lower maintenance costs, and faster, more stable operation. Relying on today’s advanced machining centers and patented mold designs, our injection-blow molds have reached an internationally advanced level. At the demolding station, a conveyor belt facilitates automatic demolding, automatic counting, and automatic packaging. Throughout the entire process, human contact is completely eliminated, ensuring that the products manufactured by this machine meet the stringent requirements of the medical and healthcare industries.

Mr. Liang Kuanqiang: In the extrusion blow-molding process, the plastic’s plasticization and extrusion, the flow and distribution of the molten plastic within the die head, the servo-controlled wall-thickness regulation of the extruded parison, as well as the precision and stability of the control system—all these factors are crucial to the successful forming of hollow products. In these areas, our company has independently developed advanced technologies—including a highly efficient extruder with fully independent intellectual property rights, a servo-control system for axial and radial wall thickness of the parison, and a specialized control system tailored specifically for hollow-molding machines—thus ensuring that our hollow-molding machinery consistently maintains a leading position in China.

PT: Whether it’s “extrusion blow molding” or “injection blow molding,” improving production efficiency and reducing production costs are common goals pursued by processors. Could you please share how your company’s blow-molding equipment meets these needs of processors?

Mr. Du Guoliang: As competition intensifies, processors are increasingly inclined to purchase and use blow-molding equipment that can enhance production efficiency and reduce manufacturing costs. By adopting standardized designs, utilizing components with high energy-efficiency ratios, optimizing extrusion units, and ensuring long-term, trouble-free operation, we have not only lowered our own procurement costs but also helped our customers save on material and energy expenses. Additionally, by offering multi-layer, multi-head (6 to 12 heads) and fully automated production machines, we are able to meet our customers’ objectives of improving production efficiency and reducing manufacturing costs.

Mr. Li Hui: The WIB Cyclone series injection blow molding machines developed by Jingye Machinery meet manufacturers’ needs to enhance production efficiency and reduce costs. This series of injection blow molding machines features a dual-station design, with the injection molding and blow-molding stations arranged in a 180° symmetrical configuration. Moreover, it continues to incorporate Jingye Machinery’s proprietary patented technology—the vertical injection molding process. Compared to Jingye Machinery’s earlier models, this new series boasts a 70% increase in production capacity, with a maximum output reaching up to 120,000 units per day. Thanks to the adoption of variable-pump technology, energy consumption has been reduced by approximately 30%, significantly lowering manufacturers’ energy costs. Additionally, since the molds can adopt a double-row structure, the equipment’s effective space is utilized to the fullest extent, thereby minimizing the machine’s overall footprint. The rotary mechanism employs a servo system, ensuring both rapid operation and low noise levels with zero pollution. In summary, thanks to these unique advantages, the WIB Cyclone series injection blow molding machines can greatly enhance manufacturers’ competitiveness.

Mr. Gao Xuefei: Enhancing production efficiency and reducing production costs means manufacturing more products with lower energy consumption. To this end, our company is actively developing new products and improving existing equipment to make them more energy-efficient and highly productive. Take our MSZ series three-station injection blow molding machine as an example—the machine boasts several key advantages: First, it uses a variable-displacement piston pump, which significantly saves electricity; second, it features a single crossbeam and our company’s proprietary dual-side-panel structure, thereby providing greater mold-cavity space; third, it incorporates a synchronized mechanism for tower lifting and mold opening/closing, an efficient and stable lifting-and-rotating mechanism, and a high-speed injection molding machine, all of which greatly shorten the overall cycle time.

Mr. Liang Kuanqiang: Providing users with efficient and energy-saving hollow blow-molding equipment has always been the guiding principle of our company.

In recent years, our company has conducted extensive R&D and testing in this area. Currently, advanced technologies such as energy-saving hydraulic control systems, the PWDS radial wall-thickness servo control system, patented extruders, and optimally designed material-storage and continuous extrusion heads have been successfully applied to our hollow blow-molding equipment. Additionally, to enhance equipment productivity, we have developed a series of dual-station blow-molding machines, including models such as SCJ30×2, SCJ50B×2, and SCJ120C×2. Compared to single-station equipment, these dual-station machines can double production efficiency while reducing the energy cost allocated to each individual product. Moving forward, we will continue our research in this field, striving to provide customers with equipment that boasts even more advanced performance and greater energy efficiency.

PT: How would you assess the current market demand for plastic hollow products in China’s automotive, medical, and other industries? What blow-molding solutions can your company offer for these sectors?

Mr. Du Guoliang: In recent years, the rapid development of China’s automotive and medical sectors has significantly boosted the growth of the market for plastic hollow products. China has become the world’s largest producer and consumer of automobiles, and automobiles today widely employ various blow-molded components—such as plastic fuel tanks for gasoline and diesel—making automotive blow-molded products one of the most promising segments within China’s plastic hollow product industry. In the medical sector, with the advancement of China’s healthcare insurance reforms and substantial government investment, blow-molded pharmaceutical bottles and other blow-molded medical products are poised to experience unprecedented growth opportunities. Currently, we can offer the following innovative “extrusion-blow molding” production systems tailored specifically for the automotive and medical industries:

1. Automotive radiator production system. Automotive radiators are characterized by numerous inserts, complex mold movements, intricate cavity designs, challenging post-processing procedures, and sophisticated manufacturing processes. By seamlessly integrating machinery with molds, we can provide customers with a comprehensive, turnkey solution.

2. Plastic gasoline/diesel tank production system. Plastic gasoline/diesel tanks are characterized by wall thicknesses exceeding 5 mm and numerous inserts, resulting in long molding cycles and complex machine operations. Through extensive experimentation and leveraging our specialized technical strengths, we have successfully developed a plastic gasoline/diesel tank production system.

3. Top-and-bottom blow molding system for medical bottles. This is a production system that can double the capacity of medical bottles without making major modifications to the machinery. We achieved this technology by employing both top-blowing needles and bottom-blowing needles for simultaneous shaping.

Mr. Li Hui: Currently, the injection blow molding equipment manufactured by Jingye Machinery is primarily used in the pharmaceutical and cosmetics packaging sectors. With the continuous improvement of people’s living standards, these two sectors in China are currently experiencing robust growth, and their future market potential is enormous. Notably, when combined with Jingye Machinery’s patented technology—the Re-Verification Core Technology—this equipment enables the use of a wider range of raw materials, particularly transparent resins such as PC, PETG, and Tritan. On the injection blow molding equipment provided by Jingye Machinery, products like baby bottles, sports water bottles (space cups), and reagent bottles made from these materials exhibit exceptional clarity, no flow marks or blemishes, high strength, and superior safety and hygiene—all qualities that are fully comparable to those produced by imported equipment, earning widespread acclaim in the market.

As for the automotive parts industry, our company rarely engages in it due to limitations inherent in the injection blow molding process.

Mr. Gao Xuefei: As people’s living standards continue to improve, China’s demand for high-quality packaging containers in the medical and cosmetics sectors will maintain steady growth over the long term. Our company’s MSZ series three-station injection blow molding machine is capable of producing medium- and small-sized packaging containers for both the medical and cosmetics industries. These containers boast advantages such as safety, sealing performance, high strength, glossy surfaces, flexible design options, and material efficiency—fully meeting the stringent requirements for pharmaceutical and cosmetic packaging.

Mr. Liang Kuanqiang: In recent years, the domestic market demand for plastic hollow products—such as packaging for automobiles, medical devices, and chemical products—has been steadily growing. To meet these market demands, our company has provided customers with comprehensive and targeted product solutions. For example, the SCJC500×6 hollow molding machine is used to produce 6-layer automotive fuel tanks; smaller-scale hollow molding machines like the SCJ50T are employed for manufacturing automotive air ducts, oil storage tanks, and water storage tanks; the SCJ230, SCJ120, and SCJ50 series of hollow molding machines are used to produce various types of packaging drums for chemical products; the SCJ1000 hollow molding machine is used for manufacturing IBC drums and pallets; and the SCJ300 hollow molding machine is utilized for producing hollow medical bed boards, guardrail table tops, and similar items.

PT: Please predict the development trends of “extrusion blow molding” and “injection blow molding” technologies, as well as their blow molding machines.

Mr. Du Guoliang: Factors such as pressure from cost competition, the expanding scope of product applications, and improvements in product performance have placed increasingly stringent and higher demands on “extrusion blow molding” and “injection blow molding” technologies and equipment. Although these technologies have matured over several decades, they still have considerable room for further development. For extrusion blow molding technologies and equipment, energy conservation, environmental friendliness, high productivity, and the application of multi-layer technology represent the key directions for future development.

Moreover, we’ve also observed a trend: in many industries, “extrusion blow molding” is gradually encroaching on the injection-molding market. For instance, plastic pallets, toys, plastic flower pots, and anatomical models are now being produced using extrusion blow molding rather than injection molding. By adopting the extrusion blow-molding process to manufacture these products, we can bypass the previously complex procedure of first injecting parts using multiple sets of molds and then welding them together. We believe that as the extrusion blow-molding process continues to improve, its applications will expand into even more fields.

Mr. Li Hui: Whether it’s the “extrusion-blowing” or “injection-blowing” process, the future development direction will be energy-saving, environmentally friendly, highly efficient, featuring high product yield, and greater automation. Moreover, equipment manufacturers will engage in specialized development tailored to specific products, thereby guiding new trends in packaging development.

Mr. Gao Xuefei: The development trends in extrusion blow molding and injection blow molding equipment are reflected in the following aspects: developing co-extrusion die heads to meet the requirements of multi-layer co-extrusion blow molding machines for different materials, varying numbers of layers, and diverse product diameters; developing large-scale extrusion blow molding machines for hollow plastic products to significantly shorten production cycles and enhance production efficiency; accelerating the production speed of injection blow molding machines by reducing mold-change downtime, increasing blow-molding speeds, and optimizing heat-transfer systems; and developing electrically driven extrusion blow molding and injection blow molding machines to achieve precise positioning, high speeds, vibration-free operation, and superior self-cleaning capabilities.

Mr. Liang Kuanqiang: For the “extrusion blow molding” technology, efficiency, energy conservation, and environmental friendliness have always been unchanging development trends. At the same time, extrusion blow molding technologies for large-scale products as well as products with specific specialized functions will also see rapid development. Moreover, with the introduction of various new raw materials suitable for blow molding processes, there is a continuous need to develop new extrusion blow molding technologies and equipment that can seamlessly match these materials.

PT: To further meet the demands of the domestic market, what are your company’s future plans and initiatives?

Mr. Du Guoliang: Compared with other plastic machinery, blow molding machines have disadvantages such as long delivery times, high costs, and a relatively high failure rate. To enhance the competitiveness of our machines and ensure our leading position in the domestic market, we have consistently been committed to:

1. Standardization. It helps shorten the machine’s delivery time. Additionally, by keeping a certain quantity of standard parts in stock, we can ensure that parts can be replaced immediately whenever issues arise.

2. Low energy consumption. Since most of the energy consumed by blow molding machines is concentrated on heating the plastic, we have maximized the reduction of machine energy consumption by continuously improving screw design and introducing innovative technologies such as AC drives, motor water cooling, and forced feeding systems.

3. 24-hour customer service. To ensure that customers can receive technical support at the earliest possible moment, we have established a 24-hour service hotline. No matter what time it is, customers can simply make a phone call to get our technical support.

In short, whether in the past, present, or future, technological innovation and continuous improvement of service quality will always remain our unwavering pursuit. We have only one goal: to provide customers with world-class machinery and services that not only meet but even exceed their expectations.

Mr. Li Hui: To meet the growing market demand for pharmaceutical, cosmetic packaging, and other injection-molded products in China, our company will continue to innovate on the basis of our existing models and technologies, with the goal of “creating greater value for our customers.” We will develop equipment that is more energy-efficient, environmentally friendly, and highly productive, and tailor customized solutions to meet our customers’ specific needs.

Mr. Gao Xuefei: To meet market demand, we are continuously striving to produce and develop blow-molding equipment that is more energy-efficient, faster, more efficient, and more stable. At the same time, we will also launch a full range of models—covering various tonnages—to cater to customers’ diverse requirements for different products.

Mr. Liang Kuanqiang: Our company has been specializing in the development and production of plastic machinery, with a particular focus on plastic hollow-molding machines, for nearly 30 years. We are now one of the largest manufacturers of large-scale plastic hollow-molding machines in China. After years of steady growth, our business has expanded to include plastic hollow-molding machines, wood-plastic molding equipment, specialized high-efficiency extruders, as well as trading in new materials and raw materials. In the field of plastic hollow-molding machines, to better meet the demands of the domestic market, we will continue to broaden our product range and enhance machine performance—especially by stepping up our efforts to develop multi-layer hollow-molding machines of various specifications—and, as always, provide customers with customized hollow-molding equipment.

Source: PT “Modern Plastics,” February 2010 issue

Time: 2010-02-19