Updated on July 8th, 2019
Many of the machines used for industrial applications require linear movement as part of the operating sequence. One of the most straightforward ways to achieve linear motion is by using pneumatic cylinders. A pneumatic actuator pertains to a device which can translate static power into motion. Another use of pneumatics aside from movement is to apply force. Machines that use a pneumatic actuator typically produce actions such as clamping, ejecting, or blocking.
A pneumatic cylinder uses compressed air as a source of power. It is generally a mechanical device which has an advantage over hydraulics because it does not contain fluid that drips and contaminates other parts of the assembly.
1. Configuration And Application Of Pneumatic Cylinders
There are various configurations of pneumatic actuators used today. Examples include rodless actuators, telescopic actuators, diaphragm actuators, and through-rod actuators. But perhaps the most commonly used type of pneumatic actuator is one that consists of a rod and piston inside a closed cylinder. This actuator configuration is further categorized as either single acting or double acting.
- Single-acting pneumatic cylinder. This cylinder configuration uses a single air port where compressed air enters the cylinder and moves the piston. Similarly, the assembly also has one internal spring which returns the piston to its original position.
- Double-acting pneumatic cylinder. Instead of a single airport, this type of actuator consists of an airport on each end moving the piston back and forth.
The parts of a pneumatic actuator are usually assembled and may come from various suppliers. OEM manufacturers like SMC have an extensive inventory of pneumatic cylinder parts suitable for different industrial applications.
A typical pneumatic cylinder assembly connects the body to a frame, and the end of the cylinder rod is connected to the part of the machine that requires movement. There is a valve used to turn on the actuator which releases compressed air into the actuator. In these assemblies, the cylinder is only one portion of the system. Apart from the pneumatic actuator, a fluid system consists of pressure regulators, compressors, lubricators, and valves.
It is essential to consider the requirements of the pneumatic cylinder in choosing other components that make up the system. If these components are the wrong size, the pneumatic cylinder will also perform poorly, or worse, not move at all.
2. Selecting A Pneumatic Cylinder
The basic rule of thumb in choosing a pneumatic cylinder is to match the required force of the application with the cylinder. In addition to this, the mounting arrangement, as well as the desired configuration, also need to be taken into account in selecting a pneumatic cylinder.
Configuration can vary from one manufacturer to another. Standard settings include foot mount, rear pivot mount, and trunnion mount. In some applications, it may be necessary to consider adding special seals or cushions for the end-of-stroke.
Factors such as corrosion, contamination, wear and tear, and leaks all impact the performance of a pneumatic cylinder. Hence, it is also critical to account for how these factors will affect the performance of the chosen pneumatic cylinder over time.