El-Exis SP impresses with high speed
Just a few months after the market launch of its new El-Exis SP (Speed Performance) series at the K 2010, Sumitomo (SHI) Demag Plastics Machinery GmbH, is conquering the high-speed applications of the packaging industry.
The enhanced hybrid machine is already demonstrating its advantages in terms of dynamics and efficiency. The El-Exis SP is impressive in the high-speed production of thin-walled food packaging, caps and closures for drinks, cartridges, flower pots and buckets.
"We're pleased that not only existing El-Exis S customers have switched over to the new El-Exis SP technology, but that we have also convinced new customers of the benefits of our machine," emphasises Christian Renners, General Manager of the Sales & After Sales Business Unit at Sumitomo (SHI) Demag. "Although the El-Exis S has already made its name as a racer in the packaging industry, its enhancement in the form of the El-Exis SP is another quantum leap with regard to cycle time," he continues. "With the new series we have tested the limits in the production of packaging while maintaining stable processes."
The series has been gradually expanded since its premiere at the K 2010 and with models in eight sizes already covers a clamping force range of 2,000 to 7,500 kN. In the fourth quarter of 2011 a 1,500 kN model will complete the series which is to encompass nine sizes. It must be particularly emphasised that the new models from 3,000 kN already offer an enlarged opening stroke for the toggle-type clamping unit as a standard feature. With the generous dimensions of the mould mounting space, Sumitomo (SHI) Demag offers manufacturers of larger containers like buckets and cartridges greater choice when selecting a model.
Robust high-speed models make full use of potential
With the development of its high-end, high-speed models Sumitomo (SHI) Demag is delivering exactly what packaging manufacturers need. Their main concerns are low unit costs, the maximisation of output and cost effectiveness. With the extremely short cycle times usual in the production of packaging, cycles that are just a few tenths of a second shorter represent a significant increase in productivity.
"When designing the new El-Exis SP series, the idea was to squeeze out the last tenths of a second, to make the injection moulding machine even more dynamic and faster and to produce parts with even thinner walls," says Bernd Tröger, Head of Product Management at Sumitomo (SHI) Demag, describing the task at hand. So the El-Exis SP opens up completely new areas of application for injection moulding which were once reserved for thermoforming. "Thermoforming was previously seen as the faster and more cost effective process. But with the El-Exis SP even thin-walled disposable containers can be produced economically using injection moulding processes," says Bernd Tröger with conviction.
This is also associated with a particular requirement regarding the robustness of the machines. "These machines have a cycle time of 2 to 3 seconds. During its lifetime, a high-speed machine passes through an immense number of cycles. A central point of the development was therefore to achieve a high degree of availability, despite the request for extreme performance data for producers of packaging," explains Bernd Tröger. With the El-Exis SP the manufacturer has adhered to the El-Exis drive philosophy that has proven its worth in more than 1,000 machines: The hybrid, high-performance machine has an electric drive for the rotate movement, an electro-hydraulic drive for the mould opening and a hydraulic accumulator for the injection movement. All secondary movements of the El-Exis SP are hydraulically controlled through a servo valve technique.
El-Exis SP for more dynamic mould movements
The main focus of the speed-performance model was the optimisation of the mould movement. In high-speed production the opening and closing of the mould can account for as much as 60 % of the total cycle time. Due to this dominant effect, simply increasing the speed of the mould movements can result in productivity increases of high single-digit percentages. The electro-hydraulic assembly driving the five-point double toggle of the El-Exis SP is a combination of a servo motor and a hydrostatic gear for the transmission of the motor rotation to the hydraulic linear movement. Improvements to the control behaviour of the motor and the optimised layout of the hydraulics and the valves mean that the El-Exis SP now has a more dynamic clamping unit with faster travel speeds and greater positioning accuracy.
Individual adjustment options result in a customised manufacturing cell
A highlight of the new machine is that users - in addition to general optimisation - can adapt the mould movement to suit their own particular packaging application. This is made possible by the new activeAdjust function. By means of a slide control, the operator can increase or - if necessary - decrease the dynamics of the mould movement in relation to the individual application - without external aid. The activeAdjust function is not limited to the mould movement, but can be used for every machine movement, such as the ejector movement and switching over from injection pressure to hold pressure. This allows the El-Exis SP, which leaves the factory designed for a broad range of applications, to be individually adjusted and easily adapted to the product and the process.
At the same time, the active mould protection system ensures a high degree of security. The tried and tested activeQ function, which stops the clamping motion of the mould in the case of unusually high movement force, has now been supplemented by the new active+ function for the controlled motion of the mould.
Users can also optimise the energy efficiency to suit their individual requirements. This is where the new activeEcon function comes into play. By taking detailed measurements of the energy consumption for the heating and drives, targeted improvements are possible throughout all parts of the cycle. The program automatically calculates how this affects the production costs.
Enhanced injection performance as well
The production of packaging makes enormous demands on the plastification (preparation of material) and injection performance of an injection moulding machine. In addition to an increase of around 30 % in the injection speed to a maximum of 1,000 mm/s, Sumitomo (SHI) Demag has also significantly improved the dynamics on the acceleration and deceleration of the injection process. In just 25 ms the screw of the El-Exis SP accelerates from 0 to 800 mm/s.
In addition, there has been a further enhancement of the plasticising and homogenising performance. "By significantly increasing the peripheral screw speeds, we are reacting to the continual rise in plasticising rates and already offer users reserves for future increases," emphasises Product Manager Bernd Tröger.
Packages for IML and the screw cap production
The El-Exis SP can be enhanced by the addition of special packages for in-mould labelling and screw cap production. The IML package includes the interfaces needed for the connection of the IML system and operation with open guard doors on the operator side.
The package for the efficient production of screw caps, for example, includes a barrier screw with an L:D ratio of 25:1 and a special non-return valve. Furthermore, a cavity control function and an interface for optical inspection systems supports the production quality. A powerful ejector safely and rapidly ejects even shrink-fitted caps.