Pneumatic actuators are simple, proven, and relatively inexpensive. That can make the upfront comparison with an electric actuator look pretty straightforward.
And in many applications, pneumatics remain a good fit. They can generate significant force and work well when the motion requirement is relatively simple. There are also environments where electric actuation may not be appropriate without proper safety configuration or protection standards addressed. These typically include certain hazardous or explosive applications.
(Manufacturers who supply compliant actuators for hazardous applications should be consulted before any electric actuator is put in place.)
But purchase price is only one part of the comparison. Actuator life, maintenance, energy consumption, and operating costs can change the total cost over time. Moreover, electric actuators provide greater control over position, speed, acceleration, and deceleration, as well as providing feedback to force exerted and other positional data.
When does an existing pneumatic application become a good candidate for conversion to electric? If you're evaluating a pneumatic-to-electric conversion, start with what the application needs to do, how the existing system is performing, and what it's costing you to operate.
A traditional pneumatic cylinder is primarily an end-to-end device. It extends through its stroke and retracts again. An electric actuator can provide more control over where it stops along the way. If an application needs to move a part to five different positions, for example, a single electric actuator can be programmed to move to multiple spots along its stroke, rather than primarily operating between fully extended and fully retracted positions.
Electric actuation also provides greater control over how that movement happens. Speed, acceleration, and deceleration can be adjusted for the application. That allows the actuator to ramp up and slow down rather than moving rapidly toward a hard stop.
That additional control can be useful when a product needs to be handled carefully, a load needs to move at different speeds during different portions of the stroke, or repeated impact is putting unnecessary stress on the product and supporting equipment.
Electric actuators also offer greater flexibility. When products running on the same line require different settings, positions, or speeds, electric actuators can accommodate those changes through programmable controls. Pneumatic systems can also adapt, but often require additional components or adjustments to achieve the same level of flexibility.
An actuator that occasionally cycles presents a different business case than one that extends and retracts thousands of times during a production shift.
Pneumatic cylinders repeatedly move to the ends of their stroke, and over time, that repeated movement and impact can wear on seals and other components. In a high-cycle application, the result can be more frequent maintenance or replacement.
Electric actuators control acceleration and deceleration as they move; that reduces the hard stopping action that can contribute to wear.
If you're regularly repairing or replacing the same pneumatic actuators, look at the number of cycles they're performing and what those interventions are costing you. The purchase price of the replacement cylinder may be relatively low, but the maintenance involved needs to be part of the comparison, too.
Initial cost is often one of the biggest arguments in favor of pneumatics. A pneumatic cylinder may cost less than an electric actuator. But the component purchase price doesn't tell you what that actuator will cost to operate over its life. A lifecycle comparison should account for several factors:
Energy consumption: Pneumatic systems lose substantial energy through compressed-air generation and distribution, including heat generation, pressure drops, and air leaks. Electric actuators eliminate the need for compressed air, significantly reducing energy consumption. According to IAI, replacing pneumatic cylinders with electric actuators can reduce energy consumption by 60% to 90%, depending on operating conditions.
IAI electric actuators also consume less power when stationary because they don’t require a compressor to maintain system pressure. Features like Energy Saving Stop reduce standstill power consumption by about 45%, and automatic servo-off/current-down modes lower holding current.
The difference is substantial. In one study based on a three-shift operation (6,000 hours annually), a pneumatic cylinder can consume more than 4,200 kWh per year, compared with about 270 kWh for an IAI RoboCylinder. That’s roughly 15 times as much energy for the pneumatic application. Lower energy consumption also reduces CO₂ emissions in applications with frequent cycling or multiple actuators.
The table below shows the energy consumption and CO₂ emissions of an IAI actuator (EleCylinder) compared with a pneumatic cylinder at a duty of 30%.
Maintenance requirements: Pneumatic systems require ongoing attention to air lines, seals, valves, dryers, and other components. Electric actuators eliminate much of that supporting infrastructure, although they still require appropriate maintenance.
Operating life and replacement costs: IAI electric actuators last up to 5 times longer than pneumatic cylinders because they replace harsh end-of-stroke impacts with controlled ball-screw mechanisms and built-in feedback. Fewer replacements also means less maintenance labor and production downtime.
Pneumatic actuators have a lower upfront purchase price and easier initial installation if a compressed air plant is already present. But cumulative savings on electricity, zero air-leak waste, and reduced maintenance labor can yield a faster long-term return on investment for electric actuators.
In either case, compare what it takes to perform the required motion over the expected life of the equipment.
The next step is to determine whether an electric actuator can meet your application requirements.
These requirements affect the type of actuator, how it is supported, how it is controlled, and whether electric actuation is appropriate at all.
Pneumatics may continue to make sense in certain applications. But where greater control, lower operating costs, or reduced maintenance could improve the process, it may be worth evaluating what electric actuation could change.
Motion & Control Enterprises can help evaluate pneumatic applications, determine where electric actuation is a good fit, and select a solution based on the motion and operating requirements of the application. Reach out today for a consultation.