Fully electric injection moulding machines have become increasingly popular in the last two decades, especially in industries where precision, energy efficiency, and clean production are essential. Below is a detailed comparison of their differences, advantages, and disadvantages compared to hydraulic machines.
Hydraulic machines: Power is transmitted through hydraulic oil pressure. The motor drives a hydraulic pump, which generates pressure to move pistons and actuators.
Fully electric machines: All axes (injection, clamping, screw rotation, ejection, etc.) are driven by independent servo motors and ball screws. No hydraulic oil circuit is used.
a) Energy Efficiency
Electric machines consume energy only when movement occurs; during idle times, consumption is almost zero.
They can save 50–70% more energy compared to hydraulic machines of the same tonnage.
The benefit is most visible in short-cycle, multi-cavity production.
b) Precision and Repeatability
Servo motors ensure micron-level position accuracy.
Injection speed, pressure, and shot volume are extremely consistent; part weight variation can be as low as ±0.1%.
Ideal for medical, optical, micro parts, and connector production where dimensional accuracy is critical.
c) Speed and Cycle Time
Each axis operates independently (for example, plasticizing during mold opening), shortening the overall cycle time.
Movements like injection, mold opening, and ejection can occur simultaneously, increasing productivity.
d) Clean and Quiet Operation
No hydraulic oil means no leakage risk or contamination.
Very low noise levels make them suitable for cleanroom production in medical, electronic, and optical industries.
e) Low Maintenance Requirements
No oil changes, filters, or seals to maintain.
Fewer wear parts result in lower operating costs over time.
a) Higher Initial Investment
The purchase cost is typically 25–40% higher than a comparable hydraulic model.
However, the difference is often recovered within 2–4 years through energy and maintenance savings.
b) Limited Availability in High Tonnages
Above 1000 tons, fully electric options are limited and much more expensive.
Therefore, large automotive, pallet, or crate production often relies on hydraulic or hybrid systems.
c) Mechanical Sensitivity
Ball screws and servo systems require precise lubrication and alignment; improper setup can lead to premature wear.
Mold misalignment may create mechanical stress on the drive system.
d) Shock Load Resistance
Hydraulic systems can better tolerate sudden high-pressure peaks (for example, mold jams).
Electric drives may enter protection mode under similar stress conditions.
Hybrid injection machines combine the servo-driven screw movement of an electric machine with the hydraulic clamping system.
They offer a good balance of energy efficiency and high clamping force, commonly used in packaging and technical part production.
| Criterion | Fully Electric | Hydraulic |
|---|---|---|
| Energy Efficiency | Very High | Low |
| Precision | Very High | Medium |
| Speed | High | Medium |
| Noise Level | Very Low | High |
| Maintenance | Low | High |
| Investment Cost | High | Low |
| Large Part Capability | Limited | Excellent |
| Cleanroom Suitability | Yes | No |
Fully electric injection machines are ideal for high-precision, small or medium-sized parts, and for production environments where energy efficiency, speed, and cleanliness are priorities.
Hydraulic machines remain the better option for large, heavy-duty applications and lower investment budgets.
In regions with high energy costs, the total cost of ownership (TCO) of electric machines is often more economical in the long run, despite their higher purchase price.