Electric Axes vs Traditional Pneumatics: When to Switch and What Changes in the P&ID
Electric Axes vs Traditional Pneumatics: When to Switch and What Changes in the P&ID
Machine builders working in plastics, packaging and rubber processing have relied on pneumatic cylinders for decades, and for good reason: for point-to-point on-off movements, an ISO 15552 cylinder running at 6 bar is an economical, reliable and well-proven solution with a deep application track record.
The picture becomes more complex when the end customer's specification starts including requirements that traditional pneumatics cannot meet, or meets only with difficulty: multiple intermediate positioning, continuous speed control, programmable acceleration ramps, software-based format change with no mechanical intervention on limit switches. In these scenarios, staying with compressed air means introducing additional flow regulators, multiple limit switches, proportional valves — with a P&ID that grows in complexity without achieving the required precision.
This is the context in which AutomationWare cylinders and electric axes become a concrete technical alternative: not to systematically replace all installed pneumatics, but to solve the nodes of the circuit where air-driven actuators are no longer sufficient.
Architecture: From On-Off Signal to Continuous Digital Dialogue
With a pneumatic cylinder, the PLC sends a signal to the solenoid valve and the piston moves from A to B — the exchange of information ends there. With an electric axis — whether a screw or belt model from the AW range, or a compact electromechanical cylinder from the MECH LINE-FORCE-PLUS series — the relationship between PLC and actuator changes fundamentally: it becomes a continuous bidirectional dialogue.
The PLC sends complete motion "recipes" to the system: exact position targets, velocity profiles, acceleration and deceleration ramps. The integrated drive of the AW DRIVES series — with stepper or DC brushless motor — executes the movement in closed loop and returns real-time position, force and absorbed current.
At wiring level, the difference is substantial. There is no longer a need to run separate cables for every individual signal: the architecture uses fieldbus or industrial Ethernet networks, and the PLC cyclically queries the drives through a single network cable. Natively supported protocols include ModBus RTU, CanOpen CiA 402, EtherCAT CoE, PROFINET RT and IRT — ensuring compatibility with the main control platforms and simplifying integration on systems with heterogeneous automation environments.
Concrete Advantages for the OEM Machine Builder
Software-Based Format Change
When the end customer modifies the workpiece format, no mechanical adjustment of limit switches is required: the PLC transmits the new parameters in real time. For the machine builder, this translates into genuine 4.0 flexibility — and a solid technical argument in negotiations with end customers who require rapid adaptability between different production runs.
Predictive Maintenance
By continuously monitoring current draw, force and positioning errors, the system can identify potential anomalies or mechanical wear — for example on recirculating ball guides — before a fault occurs. In real-world applications, this approach can reduce machine downtime by up to 50%.
Energy Saving and Noise Reduction
A traditional pneumatic installation requires the compressor to keep lines pressurised continuously, with energy losses tied to physiological micro-leaks and pressure drops. The electric axis draws power exclusively during the movement phase or for active load holding. Eliminating or reducing compressed air usage also delivers a direct acoustic benefit: exhaust air noise and end-of-stroke impacts are removed from the working environment.
When the Pneumatic Cylinder Remains the Right Choice
If the required movement is a simple on-off cycle between two fixed positions, with no need for intermediate positioning or frequent format changes, the pneumatic cylinder remains the most economical and most straightforward solution to manage. The same applies to machines with high-frequency cycles that do not require continuous monitoring, and to end customers without stringent Industry 4.0 requirements.
The most effective approach is to evaluate axis by axis. In many machines the optimal solution is hybrid: pneumatics where performance allows, electric where application requirements demand it. Carrying out this evaluation at layout stage, before setting the final P&ID, allows both investment costs and operational simplicity to be optimised.
A Case Application: Pick & Place Gantry on an Extruder
A pick & place gantry serving an extruder is a representative scenario in the plastics and rubber injection sector, where the substitution delivers measurable benefits. By replacing traditional guides and air cylinders with multi-axis electric axes from the AWRoboline Series, the result is a more responsive machine with greater rigidity under dynamic loads. The end customer calls up a "recipe" from the operator panel for each format, eliminating manual adjustments. Energy consumption across the entire cell decreases measurably and the production environment becomes significantly quieter.
One aspect worth attention at design stage: AW DRIVES drives are certified for the STO (Safety Torque Off) function. When an operator needs to intervene for tool changeover, motor torque is cut safely and in a certified manner without needing to power down the entire control cabinet — a requirement that, in technical proposals to customers referencing Industry 5.0 standards, can make the difference against competitors.
A Progressive Integration Path
The transition towards electric actuation does not require a total replacement of existing architecture. In many cases, the most effective path is a gradual introduction, starting from axes with the most stringent precision or format-change frequency requirements and retaining established pneumatics where the machine cycle allows it without compromise.
For OEM machine builders active in industrial automation, packaging and plastics and rubber extrusion, the ability to offer machines with hybrid architecture — capable of responding to both simplicity-of-management requirements and advanced connectivity and flexibility specifications — represents a concrete competitive advantage in the market proposition and a valid argument during technical qualification with end customers