INJECTION PRESSES: HYDRAULIC OR ELECTRIC TECHNOLOGY?
A bit of history…
It’s been a long time since Gino Bramieri recited on the carousel “… look, it’s made of Moplen”.
It was the end of the 60s, years of the development of injection molding and new plastics.
Since then this sector has undergone constant evolution, which continues to this day.
The constant market demand for new, increasingly technical plastic products has pushed injection press manufacturers to develop more sophisticated and precise machinery with the introduction of electronic controls and cutting-edge hydraulic systems.
A turning point in this sector occurred in 1983, the year in which the first press was presented where all the mechanical elements were managed by electric actuators.
The benefits of new technology
This new technology has introduced various benefits regarding:
- Precision and repeatability
- Production efficiency
- Energy saving
- Other related benefits
Precision and repeatability in the hydraulic system:
- The stabilization of the hydraulic pressure in the circuit, the variation of the oil temperature or its contamination cause inconsistency in the movements and in the volume injected during the start of production.
- The progressive aging of the oil and hydraulic sealing components causes a decrease in precision and repeatability.
Precision and repeatability with electrical completion:
- The digital control and electronic driver are not affected by changes due to physical effects or aging.
- The on-board CNC system allows absolute precision, self-adjusting each parameter to obtain the set profile.
Production efficiency in the hydraulic system:
- Less efficient superposition of motion achieved by using multiple pumps.
- High speed movements (injection, opening-closing) require an accumulator.
Production efficiency with electrical completion:
- Standard independent servo motors that activate each axis of the machine.
- Complete overlap of movement during the molding cycle.
- No latency due to the compression effect in motion transmission.
Energy saving in the hydraulic system:
- Pump constantly running throughout the cycle to ensure a pressurized oil flow to activate all movements as long as the machine is running.
- Lower intrinsic efficiency of hydraulic motors.
Energy savings with electric completion:
- Electrical energy consumed just to operate a movement, which means that much of the production cycle is spent idling, especially during the cooling phase.
Other related advantages in the hydraulic system:
- Water required to cool hydraulic system oil.
- Oil required for activation and lubrication of the movement.
- High noise due to the presence of pumps.
- Oil leaks not suitable for clean rooms.
- Relevant standard maintenance costs to keep the hydraulic system efficient.
Other advantages related to electric completion:
- It does not require water to cool the machine (for some sizes and models of motors, water is necessary to cool the inverters).
- No need for oil for lubrication, just grease cartridges (some versions have the toggle lock assembly lubricated with oil).
- Low noise level thanks to fully electric drivers.
- No oil means clean equipment (except for some auxiliaries, where external hydraulic power units are used).
- Electric drivers do not require significant standard maintenance.
With a view to continuous development and improvement, all manufacturers of components inserted into injection molding machines have invested many resources in order to reduce their respective gaps and improve the efficiency of their systems.
In the current panorama we find injection presses, with hydraulic or electric technology, with very high quality standards and excellent production performance with largely reduced management costs.
We also find hybrid solutions, where the combination of the two technologies gives rise to a product for “general purpose” moulding.
The final choice on the press model to purchase is currently linked to the product to be produced and the process characteristics connected to it.
KraussMaffei, historical leader in the production of injection molding presses, presents itself on the market with a portfolio that includes all the technologies we have talked about.
For further information you can consult our website www.kraussmaffei.com, or you can contact us at the following numbers:
KraussMaffei Group Italia s.r.l. Via Giannetto Mattei, 49 20044 Arese (MI) – Italy
Email : [email protected]
Phone: +39 0331 421201
Fax: +39 0331 422159
In our Consortium we can provide ad hoc courses regarding moulding for client companies in addition to those available on the calendar, visit our website. website on TRAINING AREA!
A special thank you goes to Massimo Fochesato, as a teacher in injection molding and commercial at KraussMaffei, who raises awareness on this issue so as to provide us with new content for these #laboratory pills!