Blow molding is more than just a production method – it’s a key technology for shaping the future of plastic components. At Kautex, we combine decades of experience with innovation to unlock the full potential of extrusion blow molding: economically efficient, design-flexible, and ready for the demands of sustainable production.
About Blow Molding
The extrusion blow molding process is a central component of modern plastics processing — but why exactly? The process offers a unique combination of cost-effectiveness, design freedom, and efficiency in the manufacture of hollow plastic bodies. From simple packaging bottles to highly complex technical components: blow molding enables the series production of lightweight, robust, and cost-efficient plastic parts in almost any shape and size.
Kautex Maschinenbau System GmbH is one of the world’s leading manufacturers of extrusion blow molding machines. In a global, dynamic competitive environment, we rely on innovative technologies, many years of experience, and customer-specific solutions. Our goal is to exploit the full potential of the blow molding process – both economically and ecologically.
In this section of our website, you can find out what blow molding was developed for, what advantages it offers in the plastics industry, and why it is now more than ever a key technology for sustainable production processes.
Extrusion Blow Molding and More
Modern plastics processing offers a wide range of processes that are used depending on product requirements, quantity, and material selection. The best known include extrusion blow molding, injection molding, rotational molding (rotomolding), and thermoforming. But how do these processes differ—and what are the specific advantages of blow molding?
Extrusion Blow Molding:
Ideal for Hollow Bodies
In extrusion blow molding, a plastic tube (parison) is extruded, placed in a blow mold, and shaped into the desired form using air pressure. This process is particularly well suited for the production of hollow bodies such as canisters, bottles, tanks, or technical parts with complex geometries. It scores with short cycle times, high cost-effectiveness, and great flexibility in component sizes.
Typical Segements:
- Packaging
- Automotive
- Specialties
Advantages: Great design freedom, cost-effective series production, short cycle times.
Rotomolding:
For Large-Volume Containers
Rotational molding or Rotomolding is a thermal process in which powdered plastic is melted in a rotating mold and distributed over the inner walls. It is ideal for large, single-piece hollow bodies with thick walls—but with long cycle times and higher unit costs.
Typical Applications:
- Playground Equipment
- Outdoor Products
- Water Tanks
Advantages: No weld seams, suitable for small series.
Injection Molding:
For Precise and Solid Plastic Parts
In injection molding, molten plastic is injected into a closed mold under high pressure. This process is particularly suitable for solid components with high dimensional accuracy. It is ideal for complex, filigree structures, but becomes inefficient or even unsuitable for hollow bodies.
Typical Segements:
- Housings
- Technical Components
- Consumer Goods
Advantages: High precision, can be automated, large selection of materials.
Thermoforming:
For Thin-Walled Plastic Packaging
In thermoforming, a plastic film is heated and pulled or pressed over a mold. It is particularly common in the packaging sector and is suitable for thin-walled components in large quantities.
Typical Applications:
- Food Packaging
- Blister Packaging
Advantages: Cost-effective for thin-walled parts, fast.
Benefits of Extrusion Blow molding
The Advantages of Extrusion Blow Molding – Efficiency and Flexibility in Perfection.
Unlike injection molding, which is primarily suited to solid or precise molded parts, extrusion blow molding enables the series production of hollow bodies in all sizes – from a few milliliters to several thousand liters in volume. Cycle times are short, tooling costs are moderate, and the process is particularly suitable for medium to high quantities.
loreWhere rotomolding reaches its limits, blow molding shows its strengths: multi-layer structures, integrated thread structures, grip or visibility strips, and asymmetrical contours can be implemented economically—even with technical requirements such as media or pressure resistance.m
The wall thickness can be precisely adjusted using state-of-the-art control engineering and tool technology. This means: material where it is needed – savings where possible. A clear advantage over rotomolding or thermoforming, where the wall thickness is often less controllable.
Modern extrusion blow molding systems—such as those developed by Kautex Maschinenbau System GmbH—support the processing of recycled materials, bio-based plastics, or multilayer systems with barrier layers. This makes the process future-proof and designed to meet the requirements of a sustainable circular economy.
Compared to injection molding, tooling costs for extrusion blow molding are significantly lower, which is a decisive advantage, especially for small to medium-sized series. In addition, tools can be changed quickly—ideal for flexible production environments and changing product portfolios.
Boundaries with Extrusion Blow molding
As versatile as extrusion blow molding is, every manufacturing process has its limits. We know from experience that honest advice saves time and money and prevents misunderstandings. That is why we want to be transparent from the outset about where blow molding reaches its technical or economic limits and when other plastic processing methods may be more suitable.
No filigree structures or fine details
Blow molding is ideal for large-area, hollow geometries – however, fine contours, sharp edges, or extremely small tolerances can only be achieved to a limited extent with this process. Injection molding is much better suited for high-precision details and complex microstructures.
Limited wall thicknesses – no solid parts
Since extrusion blow molding involves forming a hollow body using air pressure, it is not technically possible to produce solid or full-material components. If the component requires a continuous solid volume or greatly varying wall thicknesses, the process reaches its limits.
Limited material variety
Although our modern blow molding systems can process many thermoplastics and recycled materials, the choice of materials is not unlimited. High-temperature plastics or fiber-reinforced compounds, such as those found in technical injection molded parts, cannot usually be used in the blow molding process, or only to a limited extent. Why not give it a try at our technical center?
No small quantities with high complexity
Blow molding shows its strengths in series production. For small quantities with high design complexity, the tooling costs are too high in relation to the quantity, and the changeover times are often not economically viable. In such cases, processes such as 3D printing or rotomolding offer more flexibility—especially in prototype construction or for niche products.
Our claim: The best solution – not just ours
At Kautex Maschinenbau System GmbH, we don’t just want to sell machines – we want to offer solutions that make technical and economic sense for your application. And that also means being open about when blow molding is not the right technology. We would be happy to advise you individually and show you whether and how your product can be manufactured using blow molding – or whether another technology is more suitable.
Blow Molding Glossar
Parison
A parison is a tubular plastic preform used in extrusion blow molding. It is extruded and then inflated within a mold to create the final shape. The uniformity of the parison directly affects the wall thickness distribution and product quality.
Extruder
The extruder is the heart of any blow molding machine. It melts and plastifies the plastic material and forms it into a parison. At Kautex, extruders are developed and built in-house with tailor-made screw geometry to match specific materials and applications.
Co-Extrusion
Co-extrusion refers to the simultaneous processing of multiple plastic layers, often used for barrier properties or recyclate integration. Especially in packaging, co-extrusion enables functional and sustainable multilayer products.
Wall Thickness Control
Precise wall thickness control ensures that material is used only where needed. It reduces material usage, improves quality, and makes the production process more efficient – especially with complex part geometries.
Recyclate
Recyclates are recovered plastics derived from waste materials. Modern blow molding machines, such as those developed by Kautex, can process recyclates reliably—supporting a sustainable circular economy.
FIFO System
FIFO means “First In – First Out”. In accumulator systems, it ensures that the material melted first is also the first to be processed—resulting in consistent melt quality and stable processing.
Downstream
Downstream refers to all processes following blow molding—such as cooling, deflashing, quality control, or packaging. Kautex offers integrated downstream automation for seamless production.FIFO means “First In – First Out”. In accumulator systems, it ensures that the material melted first is also the first to be processed—resulting in consistent melt quality and stable processing.
Blow-Molded Part
A blow-molded part is the finished product created through blow molding. Its properties—such as wall thickness, weight, or geometry—depend heavily on the quality of the parison, tooling, and process control.
Mold
The mold defines the shape of the final product. It consists of two or more halves that enclose the inflated plastic parison. Depending on the application, molds may include features like cooling channels, hot runners, or specialized surface textures.
Die Head
The die head, also called a blow head or parison head, shapes the molten plastic into a tube (parison). Kautex offers both accumulator and continuous heads for applications ranging from simple to highly complex. The die head plays a crucial role in wall thickness distribution and the processing of advanced materials like recyclates.
Clamping Unit
The clamping unit is the mechanical system that holds the mold tightly closed during the blow molding process. It must absorb high forces, operate precisely, and still enable fast cycle times. Kautex uses energy-efficient solutions such as its Blue Hydraulic technology to ensure reliability and speed.
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