When choosing the best type of actuator for your design, there are several questions to ask, like what do you need to move, how do you need it to move, and under what conditions?
Your three choices are electric, hydraulic, or pneumatic. The difference between these cylinders gives each one distinct advantages and disadvantages when used for certain applications.
By definition, actuators move or control devices or system components. A linear actuator moves a load in a straight line and can be powered in several ways. The power source is the main difference between each type of cylinder, but the question still remains–which should you choose?
Resource: A Complete Guide to Air Cylinders
Electrical Cylinders
Since the cylinder portion is so compact, electric actuators offer excellent design flexibility when it comes to control options. The actuation process is somewhat more complex than pneumatic or hydraulic operations, where pressure moves a piston that moves the load. Electric cylinders use an electric motor as their power source; the motor actuates gears that turn a screw or drive a belt (rather than a piston) to move the load. That means the motor has to be physically part of the actuator, which takes up more space.
However, thanks to the controllability of electricity, these cylinders can exert highly precise, infinitely scalable movement control. They can also be electronically programmed. These factors make electric actuators perfect for a variety of applications, including material handling, robotics, cutting equipment, positioning solar panels, and opening and closing valves where precision is necessary. They are also completely sealed, which makes them great choices for operations that require sanitary environments, such as medical device manufacturing, food and beverage processing, and more.
- Electric Belt Actuators: these use a timing belt and are efficient, easy to operate, and long-lasting.
- Electric Screwdriver Actuators: these use a screwdriver and are useful for high-thrust applications where accuracy and repeatability are important.
Electrical cylinders cost more upfront but can be very affordable to operate. They also pose no environmental threats because there are no fluids to leak. In general, though, they are best suited for projects that require only a few cylinders.
Resource: 9 Real-World Applications for Electric Linear Actuators
Hydraulic Cylinders
Bottom line, hydraulics can give you the greatest power and torque, which is ideal when brute force is required. These cylinders can deliver 25x more force and horsepower per weight than pneumatic cylinders of the same size. One of their main advantages is their ability to hold torque and force without the continuous application of fluid pressure from the power source because fluids are not compressible.
Additionally, hydraulic cylinders can stand up to shock loads and can withstand harsh environments. These powerhouse cylinders are great options for elevators, car carriers, and heavy-duty and construction equipment like forklifts. Ultimately, for big jobs that require sheer power and reliability above all else, hydraulic cylinders are often just the ticket.
However, there are more moving parts to any hydraulic system, so more maintenance opportunities and costs. And they do leak, which would be a deal-killer in applications where sanitation is crucial. It also takes an assortment of other equipment to operate hydraulics—motors, pumps, fluid reservoirs, etc. And hydraulics are very noisy, even when outfitted with noise-reduction equipment. All this makes this type of actuator too unwieldy for many environments.
Pneumatic Cylinders
Pneumatic cylinders are powered by compressed air. Because air compressors are common in many industrial settings, supplying air to actuate cylinders is comparatively easier than oil. However, air can sometimes be less efficient as a power source because it can be compressed. It is also possible for the air to become contaminated by equipment lubricants, which increases the risk of damage.
Despite that, these are the most versatile workhorses among actuators, making them a good choice for a wide variety of movements where high torque and precise linear movements are required, even at high speeds. Pneumatic actuators are known for their quick response and defined stroke. To achieve maximum efficiency, it is important to size pneumatic actuators accurately for the job at hand.
Resource: Choose the right actuator for your job with our Cylinder Force Calculator
Pneumatic cylinders are also tough enough to withstand harsh environments, where water or extreme temperatures could present problems for other types of cylinders. Between their performance in less-than-ideal environments and not needing to worry about contamination from leaking hydraulic fluid, pneumatic cylinders are excellent choices for packaging and material handling equipment, food processing, and even car washes.
Many pneumatic actuator brands, such as Branham’s partner Artec, come in a multitude of sizes, styles, and configurations without the use of a motor or hazardous materials. Artec offers a variety of cylinders including short-stroke and compact ISO-certified cylinders, which feature high-quality seals to prevent leakage and safeguard internal components. Branham carries a wide variety of Artec cylinders to meet your specific performance and precision requirements.
How Do You Decide?
Force, speed, and precision are important to consider when choosing which type of linear actuator is best for your application. For example, both hydraulic and pneumatic designs can deliver more speed and force per unit than electric actuators, but pneumatic actuators are far more precise than hydraulic actuators. Other important functional factors include:
- Acceleration and deceleration
- Load weight and pressure
- Stroke length
- Positioning
- Required mid and end-of-stroke load support
- Potential external force or bending movement
Consider the up-front and operating costs, too. For instance, electrical actuators can cost more upfront but may cost less to operate, which can be beneficial if the application only requires a few actuators.
Pneumatic cylinders are much less expensive, but you may experience longer downtime when changeovers are needed. Ultimately, cost-efficiency comes down to your operating cost per cylinder. For example, using a high-capacity compressor to power a few small pneumatic cylinders wastes money, whereas it would be a cost-efficient choice to power many pneumatic devices.
Whether you choose pneumatic cylinders or another type, you must make the right decision during the design process. it will be expensive to change your mind. So, are you ready for that consultation phone call? We’re here to help.
