Gum 300

High efficiency for elastomers

Productivity, flexible operation and high energy savings are the key features of IMG’s Gum injection moulding machines

In the world of industrial manufacturing energy efficiency and process optimisation have become key concepts that each and every firm must know how to cope with them in order to get the best results and stay ahead of its competitors. For this reason machinery and systems manufacturers have been forced to focus on performance and, above all on those aspects connected to the kind of energy saving and efficiency levels their products can offer the end user. An Italian manufacturer, IMG (Industrie Meccaniche Generali) had this trend in mind when it came up with its Gum series of injection moulding machines for elastomers.

From energy savings to efficient production

«The energy saving aspects and the efficiency of production offered by these presses says Fabrizio Piovanelli, head of the IMG technical department – can be achieved by using a cutting edge servo-assisted system with the pump servomotor driven by an inverter that speeds up cycle times».

Compared to a more conventional system (asynchronous motor driven by an inverter, and therefore with open loop function), the use of a closed loop system like that of the Gum series delivers measurable energy savings (depending on the external conditions) of between 30 and 35%. «We can achieve this results because the servo pump optimises flowrates and pressure depending on the actual operational requirements – Fabrizio Piovanelli adds –. Therefore oil consumption and or discharge never rises above the levels required. Additional benefits include reduced heating of the system and smaller tank size and last but not least fewer waste disposal problems».

Close up of a piston plus screw injection system which can be used with horizontal Gum 300 machines

Other advantages are the precision and simplicity of the machine, represented for example by the use of mono-directional valves that allow the user to make individual sequential movements instead of a proportional hydraulic valve system. The decision to simplify the component parts, without compromising performance also offers real advantages from a maintenance point of view.

Clamping unit and injection system

One of the most distinctive features of the Gum series, including the 300 model, is the Hydroblock clamping system. This solutions stands out due to an absence of greasing nozzles in each area of the machine, which operates exclusively using self-lubricating bearings. «Another noteworthy detail – Fabrizio Piovanelli goes on to say – is the application of free tiebars. This means the weight of the load on the platen rests on a linear ballscrew guides, thus eliminating friction on tiebars that are already exposed to scratching and protecting them from wear».

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Precision and flexibility are Gum’s strong points

Fabrizio Piovanelli

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The injection units that can be fitted on the machine are the FIFO type (first in first out), with screw and piston or with reciprocating screw. With the 300 model, in the first case there is a 500cc capacity with a completely retractable system that allows the user to achieve fantastically low pressure loss thus guaranteeing a constant injection pressure of over 2,400 bars while at the same time offer a more compact machine. «In this case – Fabrizio Piovanelli points out – if the machine is less than4.3 metresin length it can be preset for a reciprocating-screw injection system as well as a piston plus screw system. This possibility offers a variety of operational benefits, not least of which is enormous flexibility and adaptability to different operational conditions». As well as the possibility of using a FIFO injection system – which apart from the advantages described above ensures rapid and efficient material changes – the user can count on the (more common) reciprocating screw system or even a piston plus screw system.

«The main feature of a piston plus screw system – Fabrizio Piovanelli stresses – is the ability to mould pieces from 500cc to 2,000cc shot capacity by changing the piston and the injection system chamber. On the other hand a traditional reciprocating screw system has the advantage of being able to process most of the mixture; not only that, but it can be predisposed for use with a hopper for silicone paste or for moulding liquid silicone. Which is not possible for FIFO injection systems of piston plus screw system».

A Gum machine can be fitted with B&R touch screen and Moog PLC control units

Control unit

As for the control system, these machines are available in a standard version with both PLC B&R touch screen and PLC supplied by Moog. Therefore its flexibility can also be seen from the management point of view, where simple, rapid operations are once again key. «All the settings and operational options the machine offers – Fabrizio Piovanelli goes on – can be applied from the PC in real time, and successive sequences will also be monitored according to logic that aims to offer an initial pre-diagnostic stage. Should it become necessary to implement additional cycles, the operator is completely free to do so using a USB drive which can be installed easily and quickly. If however the machine is linked to a network, the same thing can be achieved remotely from our technical department».

The control unit also offers an interface between the machine and any data concentration management system. This option makes monitoring the process even more immediate and efficient.

Gum 300 Hydroblock: technical features 
CLAMPING UNIT
Mould clamping pressure3,000 kN
Floating platen stroke500 mm
Maximum mould opening850 mm
Mould thickness0-350 mm
Tiebar distance625 x625 mm
Tiebar diameter105 mm
Extractor stroke100 mm
Extraction force80 kN
Heating platen dimensions730 x730 mm
INJECTION UNIT
Theoretical injection capacity500 cm3
Specific injection pressure2,500 bar
CONTROL UNIT
Moog or B&R

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