Flawless Injection-Moulding Technology
Since acquiring Netstal Maschinen AG, Krones has expanded its capabilities to offer a comprehensive solution for every step in the plastics cycle. This includes MetaPure recycling systems, equipment for preform production (enhanced by the Krones Prefero injection-moulding system), and MHT tools. The process continues with ErgoBloc for stretch blow-moulding, filling, and labelling PET bottles, completing the cycle with machines and systems for the dry end. Krones also provides extensive digitalization solutions and expertise in preform and bottle design, making it the only supplier capable of covering the entire PET value chain within its own portfolio.
The Prefero injection-moulding system is a standout feature, designed as a side-entry unit with fully electric clamping force and a five-point twin toggle. This machine is known for its smooth operation, low wear, and compact footprint. It achieves hourly outputs ranging from 300 to 1,600 kilograms of PET, thanks to its servo-electric drive with high-dynamic- response synchronous motors, which ensure exceptional dynamics and energy efficiency. The Prefero system guarantees homogenous melt qualities, superior color blending, and the ability to process 100% recycled PET (rPET).
One of the key advantages of the Prefero system is its ability to use more mould cavities per surface area and an adaptive injection-moulding process that allows for ultra-fast cycle times. This results in higher performance levels without increasing the machine size. The system features a total of 144 cavities on a 400-ton machine, making the newly developed PETX screw ideal for producing smaller and lighter preforms. Depending on the preforms’ wall thickness and weight, cycle times typically range between five and 14 seconds. An intelligent hydraulic unit with an adaptive drive prevents oil deterioration at low temperatures, and the dryer can operate at lower temperatures due to optimized shearing and heating stages.
The Prefero system integrates peripherals like dryers and coolers with Euromap 82, and offers post-cooling options, including preform inside cooling. The high-dynamic-response removal drive, standard-fitted with a double belt, features up to four post-cooling stations in the removal plate. The removal system can be freely positioned, as no fixed place is specified on the movable side. The PET production tools from MHT used by Prefero are industry-standard compatible, with titanium nitride (TiN) coating for the cores and diamond-like carbon (DLC) coating for the neck rings.
Krones’ philosophy of offering integrated systems is exemplified by the Prefero system, which completes the company’s line concept. This concept combines several perfectly harmonized individual machines into a holistic system, focusing on line efficiency and technical performance indicators. The direct link to the Contiform stretch blow-moulder creates additional synergies by reducing internal logistics. After injection-moulding, preforms are passed directly to the blow-moulder, eliminating the need for interim storage and reducing transportation costs and storage space. Producing preforms in-house also improves quality by minimizing surface scratches and eliminating the need for elaborate quality and hygiene checks upon receipt.
The Prefero injection-moulding system is suitable for both new and existing lines, enhancing production operations with security, reliability, continuous quality monitoring, low energy consumption, and minimized packaging weight. It uses approximately 20% less energy than comparable machines and offers real-time energy consumption transparency through its visual display. The application-specific HMI provides smart control options and simple start and stop functions, with a control panel featuring four soft buttons and a touchscreen. The optional Cycle Guard stabilizer reduces susceptibility to short power cuts, allowing for a restart within three minutes instead of the usual 50 minutes.
In packaging development, Krones’ team ensures optimal preform design, neck finish, and closure, enabling further reductions in packaging weight. The optimum stretch ratio enhances bottle characteristics such as top load, thermal stability, burst pressure, and CO2 impermeability. As Jochen Hirdinia, Head of Plastics Technology, explains, “One gram of material saved per bottle, calculated for 48,000 bottles and 6,000 hours per year, results in cost savings of more than 316,000 euros.” This calculation highlights Prefero’s cost- efficiency and sustainability.
