Because they offer a straightforward, economical, and long-lasting method of implementing linear or other types of motion, pneumatic actuators are frequently utilized in a wide variety of equipment and machinery. They are frequently preferred to electric or hydraulic actuation, both of which can increase weight and complexity, because they are lightweight but powerful for the force they deliver.
However, given the large range of form factors, choices, and configurations, choosing might become challenging. The basic pneumatic cylinder configuration may be the most common, yet even this design includes a variety of variations. There are many different physical styles as well as numerous control and observational techniques.
How does a pneumatic actuator operate and what is it used for?
Compressed air technology is known as pneumatics. However, using the term "automation control" is more in vogue in some circles. A pressurized gas is used to actuate an end effector and perform work. This gas is typically air, which can be either dry or lubricated. Pneumatic actuators are among the most well-liked engineering equipment because they are sources of motion control that are extremely reliable, effective, and safe. Hundreds of different sectors are thought to require pneumatic actuators, particularly for usage in situations where valves need to be opened and closed.
The majority of the time, actuators are mechanical devices that accept energy and transform it into motion. Any motion, such as blocking, clamping, or ejecting, can be used to accomplish this. Pneumatic actuators are mechanical devices that move a load along a linear route by using compressed air acting on a piston inside a cylinder. The operating fluid in a pneumatic actuator is just air, unlike hydraulic alternatives, therefore leaks won't drip and contaminate nearby areas. Pneumatic actuators come in a variety of designs, including as through-rod, telescoping, diaphragm, and rodless cylinders. (Try the rodless cylinder configuration tool here.)
The pressurized air that is delivered to or discharged from one or both sides of a cylinder is controlled by pneumatic valves. These valves can be opened manually by a machine operator, electronically, or by using outside air sources. A wide range of materials and techniques can be used to create actuators. The actuator must be sized to guarantee it can generate the required motive force, and the equipment geometry must be taken into account while choosing the suitable mounting and connecting techniques.
Advantages of a Pneumatic Actuator
Pneumatic actuators have advantages over competing technologies. Most of the advantages of pneumatic actuators versus alternative actuators, including electric ones, come down to the devices' dependability and safety features. They are useful in industrial settings where there is a risk of fire or ignition. Where parking and combustion are prohibited, these gadgets are widely sought after because they don't need energy or ignition. This is so that compressed air can be safely stored and used again by a pneumatic actuator without the risk of a fire. Because pneumatic actuators are so tough, the costs associated with maintaining their functionality can be decreased. A longer product lifecycle and higher production result from less maintenance.
Choosing a Pneumatic Cylinder
It's crucial to choose the right air cylinder for the job, especially in terms of the force that will be needed. The actuator's theoretical force is equal to the piston surface area times the applied air pressure. For single action cylinders, spring force must be removed from this figure. Due to pressure losses in the system, the actual force applied to the load will be 3 to 20% less. The formula below can be used to determine the bore diameter (d) when the necessary piston surface area (A) is known.
The actuator's stroke length is set by the machine element's needed travel. The configuration that results from the mounting of the cylinder is the last selection criterion. Numerous manufacturers offer numerous pneumatic-actuator configurations. The more typical ones include the foot mount, rigid nose or tail mount, trunnion mount, and rear pivot mount. Other choices, end-of-stroke cushions or specialized seals, should be taken into consideration after the fundamental actuator size and arrangement are established. Position detecting switches are needed in various applications, and they are commonly implemented using a magnetic piston and switches.
Many designers use a hybrid approach to designing actuator controls in order to keep costs in check, especially when creating systems or subsystems that will be mass-produced. Engineers sometimes have a tendency to over-specify the instrumentation and place sensors in every conceivable area when a piece of equipment is first being developed.
This gives them complete access to use the automation platform for tracking cycle times and other operational metrics while the machine is in prototype mode. This aids in optimizing performance, adjusting timing, and troubleshooting issues.
However, once the device is operating as necessary, designers can hone their pencils and determine precisely which position switches are needed for use and maintenance. Unnecessary components can be eliminated during this value-engineering phase to reduce costs while still delivering the instrumentation required for safe and reliable operation.
The available air pressure and flow that are used to drive the actuator are affected by a number of variables, including system contaminants, corrosion, minor leaks, and wear. The actuator and fluid-power system should be sized by engineers to minimize energy waste and to allow for small fluctuations in pressure and flow.
Pneumatic actuators are the workhorses of numerous machine kinds. There are various reasons to monitor actuator position and incorporate this information into the control scheme, whether the actuator is manually controlled or operated as part of an automated system. The optimal match for every application can be selected by designers with the help of careful consideration of the necessary physical and electrical features.
There are thousands of variations of pneumatic actuators. Our team can help you choose the right ones for your application. Contact us today for a free consultation.
Sources: https://www.pneumatictips.com/pneumatic-actuator-control-options/; https://www.processindustryforum.com/article/what-is-a-pneumatic-actuator/; https://www.motioncontroltips.com/selecting-a-pneumatic-actuator/; https://www.processindustryforum.com/article/what-is-a-pneumatic-actuator