Rodless cylinders are considered to be excellent for operation within automatic applications. In this article, we take a look at the options available for pneumatic actuators, their use in automatic applications, and exactly how a rodless cylinder does work.
First, let’s get a quick refresh on Pneumatic actuators and how they are the unsung heroes of automatic applications. In recent times, electric actuators have taken the starring role due to their precision control and acceleration/deceleration rates, and hydraulic actuators still steal the show where loads are weighty.
However, where an application needs clean operation, minimal financial investment and high force to speed ratios, pneumatic actuators remain the most effective equipment for the job. That is the reason you will find them throughout processing and manufacturing plants in a broad range of operations.
How do pneumatic actuators work?
An actuator converts energy – usually electrical, hydraulic or pneumatic – into mechanical force to enable controlled movement. In the world of automation, actuators are used in robotic arms, in shifting loads between processes, for adjusting the height of equipment such as saw blades, or for jobs within the packaging process. Any process that requires movement is likely to involve an actuator of some kind.
A pneumatic actuator uses pressurised air or gas to convert potential energy into rotary or linear motion. For the majority of pneumatic actuators in automatic applications, they have linear stroke setups with two or more piston stops. It is common to use air cushions or damping seals to minimise the stop times.
Why use a pneumatic actuator?
As well as being cost-effective and offering an excellent force-speed ratio, pneumatic actuators perform well in situations where sparking from an electric actuator could cause a potential fire hazard, such as with flammable materials or chemicals. They are also especially appropriate for the rapid operation of valves.
Pneumatic cylinders are often the preferred option in industrial settings because compressed air is readily available. They can function between 15 and 110 psi and come in both single- and double-acting variants.
Single-acting actuators will only move loads in one direction; they are of a straightforward design, which is an advantage where ruggedness and reliability are required.
Double-acting actuators are more common within automated applications; they move loads both back and forward or up and down, providing an excellent level of control overload movements.
What are the benefits of a rodless actuator?
Rodless actuators are extremely common in processing and manufacturing environments. Since the housing contains the entire actuator assembly, the overall footprint of the product for any given movement is smaller than a conventional linear actuator. This gives them greater structural strength and load-bearing characteristics.
Rod-type cylinders carry restrictions in terms of the ability to offer long strokes; because the cylinder rod is unsupported, it tends to flex in the extended position, which can lead to premature wear and the need for more regular maintenance. Rodless cylinders, however, are held within a self-contained unit, which means fewer components and a longer lifecycle as well as more controlled, precise movement.
Rodless pneumatic cylinders can be configured in endless ways to suit any number of production processes, and it is this versatility that makes them such a popular choice.
How does a rodless cylinder work?
With rodless cylinders, an internal piston moves within the cylinder barrel where compressed air drives it. Depending on the air pressure on each port, the piston moves in either direction along the length of the cylinder. The piston is attached to a carrier that is attached to a load and moves with the piston. There are usually buffers at both ends of the barrel to prevent hard stops after full travel. This design gives the advantages of having a stroke length that is comparable to the assembly’s size, no rod buckling to worry about with high loads or long strokes, and it delivers the same force in both directions.
Clients often ask us questions such as how does a rodless cylinder work and what are the benefits of pneumatic rodless actuators in an automation environment? We hope to have offered some explanation in answer to those questions.
We have a complete range of rodless actuators in stock and the expertise to offer guidance on which one would be best suited to any given application. Contact Best Pneumatics on 01254 390555 or [email protected].