Thin walling delivers the whole package

Current market for thin-wall moulded products?

Global forecasts for the thin walled plastic packaging market is rising significantly. According to a report released in 2020 by Research & Markets, it will be worth an estimated USD 71 billion by 2027 expanding at a CAGR of 4.5% between 2019 to 2027. Food and beverage, and more widespread adoption of thin walled packaging in developing economies, will drive this growth. PE is projected to be the largest-growing segment during this forecast period. Light-weighting and consumer convenience are important factors in this expansion, with the combination of environmental pressures, improvements in recycle rates and high polymer prices placing increasing pressures on packaging manufacturers. Wider adoption of bio-based and recycled materials is also expected to boost market growth.

Growth applications

For several decades now light-weighting and consumer convenience have given packaging manufacturers the strong commercial incentive to do more with less. No strangers to responding to demographic and lifestyle changes and balancing a wide range of variables, including cost, increased strength, recycle rates and functional requirements, lightweight formats have become the industry norm. Especially in food and medical packaging. More recently, the market has been moving more towards novelty solutions that improve performance, functionality and shelf impact.

The Covid-19 pandemic has forced yet another re-think to our way of living and future reliance on packaging. While food and medical packaging saw rises in demand, other categories softened. As public health concerns gradually ease, we suspect demand for reusable and sustainable solutions will swiftly resume. The exact timings will be very much determined by consumers. Understanding how people interact with packaging and the channels they purchase through will be a clear driver, ensuring consumer safety, product security and future sustainability are evenly balanced.  

Main trends

Sustainability (including environmental, social and governance (ESG) performance) and personalisation are expected to be among the key trends. Sustainable packaging will form a critical part of brand storytelling and consumer unboxing experiences. 

As a material, plastic is inextricably linked with energy and resource savings. Its low weight makes it both cost effective and flexible to use, adding to the sustainability score when measuring ESG. If anything, the Covid-19 pandemic has presented retailers, brand owners and packaging manufacturers with the opportunity to review, realign and reinforce the value of their packaging.

Challenges and solutions

As packaging changes, so do packaging processes and equipment. Speed and lightweighting remain probably the most dominant trends. Efficiency and throughput are inextricably linked. 

From a machinery performance viewpoint, thinner wall sections bring changes in processing requirements. Among them, higher pressures and speeds, faster cooling times, and modifications to part-ejection and gating arrangements.  These process changes need to be factored into the mould, machinery, and packaging component design. 

Even when using less raw material, packaging forms the protective layer so still needs to be engineered to provide strength. Choosing the best machine for your packaging application is critical. Understanding the melt stability and how the plastic will perform as an end product should form the basis of all decisions. 

In caps and closures, the tethered market is a big focus area. As of May 2024, EU producers, retailers and manufacturers, as well as importers to EU countries will be obliged to implement tethered closures on all beverage containers up to three litres. Looking specifically at the moulding processing conditions, these in theory won’t change considerably. Providing the material isn’t altered, melt stability will be the same. The main investment outlay will be in mould tool design, which may require increasing the mould space of injection moulding machinery or opting for a larger tonnage packaging machine. 

Latest packaging technologies from Sumitomo (SHI) Demag

Economic viability is just as important a consideration for packaging moulders. Low unit costs, high output coupled with energy savings all need to be factored in. That’s why so many packaging manufacturers today are prepared to invest in new high-performance plant.

Our moulding machines will always be aligned to the market trends. Breaking these down, 2020 has seen increased demand for thin-wall applications due to rising in-house consumption of food and beverages throughout the COVID-19 pandemic. In 2021 we anticipate this continuing, and the additional trend of tethered caps being addressed with the EU Directive deadline due in 2024. Demand for tethered cap applications will continue to accelerate in 2022, and we anticipate high demand for stabilised packaging formats. By 2023, attitudes towards circular packaging will inevitably shift back and we envisage renewed focus on recyclable packaging materials once more.

Any packaging moulding machine selected will be dictated by mould design and the cavitation layout. With regard to auxiliary equipment, higher pressures and speeds, faster cooling times, and modifications to part-ejection and gating arrangements are all important factors that need to be considered when developing turnkey lines. 

Another way to achieve thinner yet stronger packaging containers is to apply injection compression techniques to stack moulds. With this, packaging moulders can increase output while reducing the wall thickness of containers and lids from 0.45mm to 0.35mm. This saves around 25% in raw polypropylene materials compared to the standard injection moulding process, while maintaining comparable mechanical properties. 

El-Exis SP developments

The latest generation of EL-Exis SP’s are specifically designed to withstand the higher stresses and injection pressures that are so critical in achieving repeatability, particularly in thin walled products. 

Capable of delivering a cycle time of less than two seconds, Sumitomo (SHI) Demag’s El-Exis SP remains the fastest injection moulding machine series for packaging manufacturers on the market today. The series also offers exceptional process consistency through acceleration, mould movement and deceleration. Having this additional control during the manufacturing process saves moulders and converters money by lowering operational costs and delivering energy savings of around 15%.

Being able to adjust the accumulator charging to the injection pressure required for the exact moulding process not only lowers energy usage, but also reduces wear and tear on parts. Additionally, to help factories make informed and conscious energy consumption decisions, the machine now includes an integrated energy monitor as standard.

Mould safety is another feature that can save money. Given that mould tools can be one of the costliest elements, protecting moulds from damage by foreign objects and any damage caused by general wear and tear without incurring cycle time penalties can significantly reduce the frequency for scheduled machine and mould maintenance.

The new generation of packaging El-Exis machines can all be equipped with an OPC Unified Architecture (OPC/UA) interface, offering broader scope for connectivity. 

Energy monitoring developments

Many of our customers are keen to opt for more energy efficient systems. But until recently, machinery suppliers have struggled to quantify and compare performance data in relation to energy consumption, investment and planned maintenance costs, mould wear, output quality etc.

To help with these, Sumitomo (SHI) Demag UK launched a new testing service. The company was already undertaking more than 300 performance measurements for customers annually. Due to its popularity, Sumitomo (SHI) Demag invested in three new Fluke energy monitoring devices to extend this service. Plugging the tool into existing machines, including legacy and competitor moulding systems, the company conducts the energy tests on-site using a real production scenario. Calculating the energy used in kilowatts for each kilogram of raw material converted, the team then provides the customer with a credible comparison if they were to purchase a newer Sumitomo (SHI) Demag machine.

In order to get a like-for-like comparison, our engineers run the same product before and after new kit is installed, with all ancillary equipment plugged in. As well as examining energy performance, the tests also examine other factors including the parallel movements and the impact of drive cycle times on output. The results are compiled into a comprehensive report that presents companies with robust data that can be included in annual CSR reports

McLaren Plastics used Sumitomo (SHI) Demag’s new test service to measure the energy savings realised after replacing two legacy hydraulic machines with two all-electric IntElect machines. One of the performance benchmarks was for a packaging black end cap. The investment resulted in the Midlothian business slashing 60% off their energy bill, saving them in excess of £7,000 a year.