Sumitomo Demag Servo Drive
Keeping costs down is an issue that faces all business, but factor in rising energy tariffs and green targets and many manufacturers face an uphill struggle.
Enter the hybrid hydraulic activeDrive from injection moulding specialist Sumitomo (SHI) Demag, which promises to slash energy costs more effectively than switching to an all-electric system.
An increasing number of injection moulding businesses are turning to hydraulic machines equipped with a servo drive in a bid to keep their overheads as close to the centre of gravity as possible. Sumitomo reports that more than half of the hydraulic machines they have delivered to customers over the past 12 months now feature activeDrive technology, which reduced energy consumption by as much as 60 per cent.
Managing Director Nigel Flowers said: "The market for hydraulic machines remains buoyant, especially in the UK and across Europe. While it’s true that there’s a shift towards all-electric machines for precision work, hydraulic machines still remain a popular choice for general purpose moulding. Thanks to applications like activeDrive, hydraulic machines deployed in all sectors, including precision and automotive, can benefit from variable-speed drives, bringing energy-savings in closer alignment to that of all-electric injection moulding systems."
For injection moulders with plenty of life left in their hydraulic machines, activeDrive can be easily retrofitted to Sumitomo equipment, even those from two-decades back.
"We can quickly assess the feasibility on a case-by-case basis," Flowers added. "The actual process itself is straightforward and the cost minimal compared to the immediate energy savings. We fit a frequency converter to the machine pump and modify the controller. This has no impact on output or quality.
"With sustainability high on everyone’s agenda, it’s important that every customer has access to a viable energy-efficient option that matches their operational requirements."
Sumitomo’s Systec Servo plugs an important gap and offers an alternative to all-electric. The system, which was launched in 2013, proved extremely popular with Sumitomo’s loyal customer base; one out of every two hydraulic machines dispatched and installed by the team is now equipped with this energy-saving servo drive.
"To have achieved a 50 per cent switch in such a short timeframe demonstrates that customers are eager for a quick solution to cut their energy bills,” Flowers remarked.
Sumitomo’s Systec hydraulic injection moulder is built to suit customers' needs and combines the advantages of servo technology with hydraulic pump control. This is especially attractive for partial load operations typical of general purpose moulding applications, where activeDrive guarantees optimum performance for every phase of the machine cycle. Whereas standard hydraulic pumps will run at a fixed speed continuously, the frequency-controlled servo motor automatically matches the amount of oil volume required for the output task being undertaken. If no additional flow is required, the pump simply stops operating. As a result, hydraulic machines equipped with activeDrive can be up to 60 per cent more energy efficient, depending on the application.
Managing partners Norbert and Sven Borscheid and Carlo Wenig of the German-based plastics manufacturer Borscheid + Wenig GmbH has adopted this technology and is extremely satisfied by the hybrid's performance. So much so, they are about to take delivery of a new Systec 50-310 machine featuring activeDrive, which the partners advocate further supports their company environmental policy.
Toggle joints also play a vital role in energy savings and machine durability. The Systec features a toggle clamping unit, offering a force ranging from 1,600 to 20,000 kN. In real terms, a larger hydraulic machine will have larger pipes and pumps and will use considerably more oil when opening and closing a mould, Flowers said.
"Converting to a mechanical system significantly reduces the time it takes to lock the mould. For larger machines this can equate to 50 per cent in energy savings and 30 per cent for smaller systems," he noted.
Furthermore, an activeDrive equipped machine is almost as quiet as an all-electric, making for a much more pleasant working environment. Hydraulic injection moulding machines used to emit noise levels of over 70dB, which is why operators wear ear-defenders. With activeDrive, this plunges to down to 60dB, which is equivalent to a normal conversation or a household air conditioning unit.
While the argument for all-electric machines is a compelling one, hydraulic machines are far from redundant. Zero energy waste is the real target and thanks to technologies like activeDrive, fully hydraulic machines are closing the energy-efficiency gap, boosting business profits, without compromising on product quality or cycle times.
