the sensor close to the point of force application is even the smallest tensile or compression strains are measured. It means that any condition that may result in the set mould safety force being exceeded is instantly addressed. Flowers explains: “The signal produced

Given that some high-end multi-cavity automotive and medical part moulds can exceed half a million pounds, mould tooling doesn’t come cheap. In fact, some cost more than the injection moulding machine itself. A trusted safety system to prevent causing irreparable damage to these sensitive tools is on every moulders' wish list


afety of the mould can be compromised if components do not

eject properly, if a foreign object enters the mould in production during the closing and opening sequence and when too much clamp force is applied. Very often, mould protection doesn’t

receive the attention warranted. In part, this can be due to the complexity of setting up the system, which requires a certain skill level, particularly with regard to understanding clamp forces. Additionally, few injection moulding suppliers offer active mould safety solutions that can sense and react instantaneously to an obstruction. Sumitomo (SHI) Demag provides

customers with a range of options, catering for the very latest hi-tech all- electric machines right through to hydraulic machines, and everything in between. Typically, machinery suppliers use

motor torque or tie bar loading measurements to gauge the mould status


on electric machines. Sumitomo (SHI) Demag remains the only known company to offer a mould safety system featuring high resolution sensors built into the toggle system itself, claims UK managing director Nigel Flowers. These sensors are positioned close to the point where force is applied and links to the NC5 machine control panel, detecting and transmitting changes in the force signature during the mould closing sequence. Forming part of the company’s active

range, the sensor safety system - known as activeProtect - is available as standard and can be retrofitted to machines featuring dynamic servo drives. This includes the company’s all-electric IntElect models and fast-cycling El-Exis SP range.

ON TOP OF SAFETY On these machines, the high-resolution sensor is located on the first link directly behind the moving clamping platen on the offside. The benefit of positioning

Thermal imaging is far cheaper than vision and can be used on all machine types, including hydraulics, to control the optimum point to eject parts from the mould

by activeProtect is so accurate it can detect even the slightest change in force patterns. Force values are converted in the transducer into a 0 to 10-volt signal, which is immediately transmitted to the machine’s NC5 operating control system. At this point, the real values of closing force, piston speed and stroke are compared with the master calculations, enabling the machine to react and stop before the mould faces touch. It’s like a chain reaction, with the entire mould safety decision and response taking place in less than 10 milliseconds.” For added mould protection,

activeProtect has now been extended to monitor the opening strokes. This helps to ensure mechanical mould elements, for example unscrewing devices, are protected from damage.

OTHER TECHNOLOGY AVAILABLE Additionally, users of the IntElect machines can be benefit from enhanced ejector control technology. Sumitomo (SHI) Demag’s latest advancement - Synchronized Ejector Operation - ensures that components are clear of the mould before it closes again. As well as preventing falling parts being crushed, it helps to mitigate damage to expensive mould tools. “In an ideal world the parts are ejected

with zero inertia and drop in a central line out of the mould space. It isn’t so much of a challenge for users of hydraulic machines, as plastic parts flow out of the mould in a cascade-like waterfall. In all-electric machines, this constant stream can be difficult to replicate. That’s because when the toggle clamp operates faster than the ejector mechanism, there’s less control over how and where the moulded components will fall,” explains Flowers. Through the application of this

technology, which enables synchronous operation of mould and ejector, the ejector speed is adapted to the master mould speed. If the mould speed is

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