In today’s packaging industry, lightweighting has evolved from a marketing buzzword into a core engineering principle.

The demand for sustainable, high-performance containers is accelerating across industrial and automotive markets, which need millions of large-format bottles and canisters that are produced each year. Reducing material use while maintaining — or even improving — mechanical performance has become a decisive factor in competitiveness, cost control and environmental responsibility.

However, lightweighting a 20-liter industrial container is not simply a matter of reducing wall thickness. Structural integrity, stackability, drop resistance and functional usability all depend on careful distribution of material, precise process control and smart design.

Advanced design and process technologies can deliver substantial material savings while maintaining full product performance, as demonstrated in an fhw-moulds project. The project was developed for a global brand partner and resulted in a reduction of approximately 250 grams per canister, equivalent to a savings of more than 1,700 metric tons of HDPE in full-scale production.

The challenge: Achieving less weight without compromise

The starting point was a conventional 20-liter industrial canister with a total weight of 1,050 grams. The target was ambitious: Achieve a significant weight reduction — around 20–25 percent — without compromising any performance parameters.

That meant maintaining:

• Drop impact resistance at ambient and low temperatures,

• Stack load capacity under long-term warehouse storage conditions and

• Dimensional stability during blow molding and cooling.

At the same time, process consistency and cycle time were not to be negatively affected. The challenge was clear: Take material out where it’s not needed, and reinforce only the areas where stress and load require it.

Design as the key lever

Lightweighting starts with design — not with the machine or the resin. In extrusion blow molding, the geometry of a container dictates how the parison expands, how the wall forms, and how the stresses are distributed during cooling and use.

The team began by analyzing the mechanical load paths of the canister using finite element simulations and physical testing. The results showed that certain areas — such as the base corners, handle connection and shoulder transitions — carry the majority of the mechanical stress. Other regions, particularly the broad side walls, used excess material without adding performance value.

This analysis guided a complete redesign of the article, optimizing geometry for structural efficiency. Every radius, every corner, every transition was reconsidered to minimize local stress concentrations while maintaining a clean, manufacturable design.

Wall thickness optimization: PWDS and Push-Pull-Ring (PPR)

While design defines where the material should go, process control ensures that it gets there. Two advanced systems were essential to this success:

1. PWDS – Partial Wall Distribution System
   The PWDS is a partial wall thickness control system that enables dynamic, radial adjustment of the parison wall during extrusion. Unlike systems that merely compensate for sagging, PWDS allows the operator to precisely define wall thickness around the circumference of the parison. This radial control is crucial when transforming a round parison into a rectangular or complex container shape. The process can push more material toward the corners — where stretch and mechanical load are highest — while keeping the side walls thinner. The result is an optimized, geometry-specific material distribution that ensures structural integrity with less overall polymer use.
2. PPR – Push-Pull-Ring
   The Push-Pull-Ring is a statically deformable die system that works in combination with the PWDS. It allows mechanical fine-tuning of the die gap during extrusion, “pushing” or “pulling” material in specific areas of the parison. This enables an exceptionally precise material distribution within the article, ensuring that every gram of polymer contributes to functional performance.

The synergy between PWDS and the Push-Pull-Ring brings significant advantages inlightweighting — not by merely reducing material, but by redistributing it intelligently to points of structural relevance.

Together, these technologies enable precise material control — the canister isn’t made weaker; it’s made smarter.

Quantifying the gains

After multiple simulation loops and process trials, the final canister design reached an optimized weight of 800 grams — a 24 percent reduction compared to the original 1,050-gram design.

At a production scale of 7 million canisters per year (for markets in Europe, North Africa and Turkey), this translates into:

• Material savings of about 1,750 metric tons of HDPE annually

• Carbon dioxide reduction of approximately 4,000 metric tons per year, depending on polymer grade and source

• Cost efficiency, with significant long-term economic impact, compounded by reduced logistics weight and energy usage

Extensive testing validated that the lighter canister matched or exceeded the mechanical performance of its heavier predecessor:

• Drop tests showed equal or improved energy absorption.

• Stack tests confirmed long-term stability for 28 days.

• Top-load tests indicated lower deformation patterns.

The results demonstrated a clear message: Intelligent design can outperform brute force.

Cycle time reduction through Shell-Cooling Technology

Beyond material savings, cooling efficiency plays a decisive role in productivity. The project benefited from Shell-Cooling technology, a cooling concept used in fhw-moulds tooling systems.

Unlike conventional cooling — which relies mainly on channel-based water flow inside the mold body — Shell-Cooling directly targets the surface layer of the mold cavity. This allows faster and more uniform heat transfer from the blown article.

The result is remarkable. On a double-station machine, the cycle time of 28 seconds amounts to the production of one container every 14 seconds. The demolding temperature is consistently below 140 degrees Fahrenheit. By contrast, conventional 20-liter canisters of similar geometry, typically weighing 1,000–1,050 grams, often require cycle times around 38 seconds or longer.

Shell-Cooling thus adds a second lever to the efficiency equation: shorter cycles with less material — a rare combination that directly increases output and improves energy efficiency across the entire production line.

Functional innovation: Design beyond weight

While material efficiency was the main goal, the project also integrated severalfunctional enhancements — each adding value for the user, the filler and the brand owner.

Anti-Glug Device (AGD)

A small but impactful internal design feature, the AGD modifies airflow inside the canister during pouring. The result: the liquid can be emptied up to 50 percent fasterwithout splashing or “glugging.” This not only improves user experience but also supports precise dosing in industrial environments.

Light Safe – Tamper-evidence for industrial containers

Product integrity is a growing concern in the chemical and lubricant industries. The Light Safe feature provides a built-in originality protection system that clearly indicates whether a container has been opened or refilled. A small tab is integrated into the canister itself, which locks underneath the teeth of the cap. When the canister is opened for the first time, this tab is removed; even if a new cap is put on, the missing tab on the canister will indicate that it has been opened. This makes manipulation much more difficult and helps protect the authenticity and integrity of the original filled product. It’s a simple, robust way to combat counterfeiting and unauthorized reuse.

Ergonomic handle design

The handle and grip area were redesigned to enhance ergonomics, especially for high-density products, with specific gravity above 1.0. The new contour allows safe handling even with gloves and reduces user fatigue during manual transport or palletizing.

Optimized footprint and palletization

The canister base was re-engineered to align efficiently with multiple regional pallet standards. The result: better cubic utilization and fewer transport movements per unit — another indirect but important sustainability gain.

Holistic design thinking

The 20-liter canister project illustrates the importance of a holistic approach to blow molded packaging:

• Design engineers shape the geometry to manage stresses.

• Toolmakers ensure process stability and precise parison control.

• Material suppliers provide rheological data for process simulation.

Lightweighting success doesn’t happen in isolation — it is the result of collaboration across disciplines. Every decision, from parison programming to handle contouring, contributes to a system-level optimization.

Equally important is the cultural mindset shift. In blow molding, “heavier” has long been equated with “better.” Projects like this demonstrate that lighter can be stronger when driven by design and data rather than tradition.

Digital tools and experience

The use of simulation software was a key enabler. By predicting parison inflation, cooling shrinkage and wall-thickness distribution, the team minimized the number of trial iterations. This digital validation shortened development time and ensured that tooling modifications were based on data, not guesswork.

Yet, simulation alone is not enough. Decades of hands-on experience in extrusion blow molding — understanding machine behavior, die-head geometry and polymer response — remains invaluable. The combination of digital precision and practical expertise is what makes such projects both efficient and successful.

Sustainability perspective

The environmental benefits of lightweighting extend far beyond material savings:

• Lower transport emissions. Less weight per filled container means fewer trucks and reduced fuel consumption.

• Reduced energy use, because there’s less polymer to melt and cool during processing.

• Improved recyclability. Thinner walls can shorten regrind cycles and reduce contamination risk.

Sustainability is not only about biopolymers or recycling systems — it starts with using less material intelligently.

Outlook: The future of design-driven blow molding

Looking forward, the principles of this project point toward a broader transformation in the industry:

• Artificial intelligence (AI)-supported design optimization could soon predict ideal parison programs automatically.

• Digital twins will link article simulation directly to machine control systems.

• Circular design will focus not only on production efficiency but also on second-life usability and recycling compatibility.

In all these areas, one truth remains: The foundation for innovation in blow molding lies in design— rethinking form, function and material flow together.

Conclusion

The lightweight 20-liter canister demonstrates what is possible when advanced design, precise process control and decades of blow molding experience come together. By reducing weight by nearly one quarter while enhancing performance, productivity and usability, the project sets a benchmark for sustainable industrial packaging.

It proves that lightweighting is not a compromise — it’s a strategic advantage.

This article appears in the summer 2026 issue of The Journal of Blow Molding. 

© 2026, Society of Plastics Engineers Blow Molding Division