Greiner Packaging, based in Kremsmünster in Austria, has been producing plastic packaging for over 60 years — with a passion for its field and a drive for continuous improvement. One key motivator for the company is sustainability. As packaging becomes lighter and fewer raw materials are required, production processes are meeting new challenges. Thanks to e-speed injection molding machines from ENGEL, Greiner Packaging is reducing the wall thickness of its food containers while enhancing efficiency.
“Our customer’s specification was to reduce weight as well as carbon emissions while maintaining container stability and improving recyclability,” said Greiner Packaging Application Engineer Andreas Ecker, looking back on the recently concluded project.
The client — Austrian dairy Ennstal Milch — already applied high standards of sustainability in its thin-wall monomaterial cups for Greek yogurt produced from polypropylene using the in-mold labelling (IML) process. Striving for even more, the manufacturer of dairy products turned to Greiner. Now the produced yogurt cups need 20% less material than before.
“We managed to reduce the container thickness by 0.1 millimeters to 0.3 millimeters on the sides and 0.35 millimeters on the base. In-mold labelling supports the lightweight trend,” said Ecker.
Greiner Packaging has developed a PP yogurt cup with a material saving of 20%.
Despite being just under 50 micrometers itself, the label provides extra stability. Thorough product testing revealed no drawbacks in filling or logistics; nor were consumers disadvantaged. Even when filled, the yogurt cups can be safely stacked; when consuming with a spoon, they sit in the hand with no noticeable difference. The cups are suitable for hot filling up to 85 degrees Celsius as well as cold filling. This is important for Greiner as the new light-weight IML cups are produced in different forms for many other products.
“Injection molding technology enables considerable variance of shape, with very low production tolerances,” said Kremsmünster Plant Manager Engelbert Pranzl.
“Energy efficiency of the machine was a key factor in our decision. We are committed to cutting energy consumption year by year,” said Engelbert Pranzl, plant manager at Greiner Packaging in Kremsmünster.
Sealing edge or base, round or square — every food producer has its own specific packaging design, and Greiner needs to adapt flexibly. The packaging specialist serves global markets from its base in Kremsmünster. The focus is on Europe, with other production sites serving local consumers in the USA and Asia.
Adjustments to the production process have made it possible to reduce wall thickness in food containers. With this in mind, Greiner invested in a new e-speed 380 injection molding machine from its long-term engineering partner ENGEL.
“We turn the hydraulic power of the hybrid machine to our advantage,” said Ecker. “We need extremely high dynamics in the injection stage, which pushed our electric injection units to the limit. For the yogurt cups, we have a wall thickness/flow path ratio of 1 to 240, and we inject at 1,700 bar.”
“Our customer’s specification was to reduce weight as well as carbon emissions while maintaining container stability and improving recyclability,” said Andreas Ecker, application engineer at Greiner Packaging.
With high mechanical stresses in mind, ENGEL designed its e-speed injection molding machines — which combine an electric clamping unit with a hybrid injection unit — specifically for high-speed thin-wall applications. To ensure the cleanliness demanded by the food industry, the toggle lever is encapsulated.
Expansion of the series over the past year has further enhanced the performance of all clamping force ranges. The hydraulic inline injection unit with electric plasticizing drive now delivers even greater injection performance. It is designed for injection speeds of up to 1,200 mm per second. The machine base and mold mounting platens have also been tailored more closely to the requirements of thin-wall packaging and the use of multi-cavity molds — both with and without IML. The main goal is to ensure precision of machine movements while achieving durability. In the case of in-mold labelling in particular, repeatability is critical.
As food packaging becomes lighter and fewer raw materials are required, production processes (with and without IML) have to meet new challenges.
The yogurt cups for Ennstal Milch are produced fully automatically in a six-cavity mold. For this purpose, the 3,800 kN machine is equipped with high-speed automation courtesy of Dutch IML specialist Brink. The robot takes the IML wrap arounds from the magazine and places them in the mold. After injection molding, it removes the decorated and ready-to-use cups, directs them to quality control and stacks them on a discharge belt. The stacked cups are then packed into boxes in another automated process. The quality check is visual and performed with a camera; among other things, the correct position of the label is checked to ensure the contents are properly protected and will not subsequently spill out. Greiner's clients insist on zero errors.
The injection molding machine, automation and quality control are designed for flexibility, so as to ensure the shape of the container and the form of the label can be changed in a short conversion time. Another consistent priority across the spectrum of products and molds was maximum energy efficiency.
To utilize energy as efficiently as possible even in high-speed operations, the e-speed 380 is fitted with an energy recovery system. This system absorbs braking energy from the moving mold mounting platen and returns the stored energy to the motor to accelerate the platen again.
“For us, the energy efficiency of the machine was a key factor in our decision,” emphasized Pranzl. “Even though we are continually enhancing the performance of our production systems, we are committed to cutting energy consumption year by year.”
Greiner Packaging appointed a dedicated energy efficiency manager to closely monitor all energy efficiency projects on the spot, paying particular attention to production processes. Within the factory, ageing hydraulic injection molding machines are gradually being replaced with hybrid and all-electric machines.
ENGEL first delivered an all-electric injection molding machine to Greiner almost 20 years ago. Since then, Greiner has been closely involved with ENGEL’s development of electric drive technology, the two companies acting as development partners on numerous projects.
“From our viewpoint as a user, we have a wealth of knowledge and experience to contribute,” said Pranzl. “Another thing we appreciate about ENGEL is the fact that as a user, we are listened to — our suggestions really are taken into consideration as the machines develop. For example, our ideas were applied to the support for mold mounting platens on the e-speed machine.”
Engelbert Pranzl (left) and Andreas Ecker from Greiner Packaging are using ENGEL e-speed injection molding machines to reduce the wall thickness of food containers and increase efficiency at the same time.
Another example would be the speed version of the ENGEL viper linear robots — originally conceived as a special development for Greiner Packaging. In many applications without in-mold labelling, viper robots remove products from the injection mold for Greiner.
“Thanks to the speed version, the viper robots keep these interventions as short as possible. This means we can cut overall cycle times yet further,” said Pranzl.
“Our partnership is one of mutual respect, even if it is highly demanding,” stressed ENGEL’s Regional Sales Manager (Central Austria) Klaus Mittmannsgruber.
Both partners see their proximity as an advantage: Kremsmünster is only a 45-minute drive from the ENGEL headquarters in Schwertberg. Both look forward to the resumption of face-to-face meetings in the wake of the pandemic, even if ENGEL’s virtual trade fair and symposium were warmly received by the Greiner team.
“Innovations were presented in an efficient way, plus we were able to ask certain questions and discuss specific requirements in smaller groups,” Pranzl said. “If we should be unable to meet in person for any reason, the virtual format makes a very good alternative.”
When it comes to enhancing sustainability and establishing a circular economy, packaging manufacturers, mechanical engineering companies and the food industry are on the same page. Greiner Packaging and ENGEL are both founding members of “Packaging with a Future,” an initiative that harnesses the expertise, experience and commitment of companies across the packaging value chain with the aim of facilitating the resource-efficient utilization of packaging.
One high priority for Greiner Packaging will be to conserve even more material in future while cutting carbon emissions further; all packaging will be 100% reusable, recyclable or compostable, with greater use of recycled material. rPET was the first recycling material to be positively rated by the European Food Safety Authority and approved for the manufacture of food packaging. Pranzl has no doubt that rPP will follow suit.
Work continues on the temperature resistance of PET with a view to making rPET an option for the packaging of dairy products in the near future. Greiner Packaging is already processing bioplastics, the proportion is also set to increase.
“Our goal is to be a climate-neutral company by 2030,” revealed Pranzl — and engineering partner ENGEL will help Greiner achieve that target.
Are you interested in injection molding, looking for the right equipment or just want to learn more about ENGEL?
Don’t hesitate to reach out to us by filling out the form, giving us a call at +1 (717) 714-3235 or by contacting us by email. For more information, visit engelglobal.com.
Please enter a valid email address.
Please enter your email address.
Please select at least one newsletter to subscribe.
Staying current is easy with Plastics News delivered straight to your inbox, free of charge.
Plastics News covers the business of the global plastics industry. We report news, gather data and deliver timely information that provides our readers with a competitive advantage.
1155 Gratiot Avenue Detroit MI 48207-2997