Pneumatic motion control has been on the automation scene for decades and doesn’t appear to be heading for the exit ramp any time soon despite advances in technologies such as electric actuation.
Driven by the rise of automation across industry as well as the infusion of smart technologies like sensors, pneumatic industrial equipment is enjoying sustained growth. One report projects a CAGR of 7.3% for the pneumatics systems segment between 2023 to 2028. Another anticipates the smart pneumatics industry to generate revenue of $6.3 billion by the end of 2032.
Automation World spoke with Frank Langro, director of product market management, pneumatic automation, North America at Festo, and Pat Phillips, product manager at AutomationDirect, to understand the basics of pneumatics systems and why they remain a preferred option for many.
Automation World: What are the primary advantages of using a pneumatic system for manufacturing and automation processes compared to other types of motion control?
Frank Langro, Festo: The most common motion control technologies are hydraulic, pneumatic and electric motion. Each offers some distinct advantages, and all will continue to have a place in manufacturing. Hydraulic is mostly found where high forces are required because of the nature of it being non-compressible. Typically, you’d see this in heavy industries like construction with excavators or in the high-pressure presses used in mining.
Pneumatics is a fit when you don’t need the high forces of hydraulics. It is also a cleaner technology and has an advantage in hazardous environments.
Pat Phillips, AutomationDirect: A typical advantage of a pneumatic system is to lower costs, especially upfront expenditures. Assuming you have the infrastructure for compressed air, which is nearly always present in a manufacturing and automation environment, pneumatics is a very proven and durable technology. Another advantage is for creating systems that are totally non-electric, which is useful in certain hazardous environments. While there are new things being developed, a lot of pneumatics products still in use today were developed in the 1940s and 1950s, but they are still viable options.
Automation World: What are the most common applications of pneumatics in manufacturing?
Frank Langro, Festo: Pneumatics are widely used in a variety of manufacturing applications across many industries. The most common use cases are for lifting, clamping, pressing or pick and place. You’ll often find pneumatics in assembly equipment where you may be holding a part while something is being pressed, riveted or soldered. Pneumatics are great on machine tools for opening or closing doors and gates and in packaging equipment to form boxes or for picking and placing items into packages. Pneumatics is everywhere in those types of use cases because it is a simple, low-cost motion technology. You don’t see pneumatics in high-precision applications or when you need a variable position—for example, when there’s variety in part size. That’s where you’d typically see more electromechanical positioning solutions.
Pat Phillips, AutomationDirect: Pneumatics should come into play if you need basic linear motion. If you just need to move something from point A to point B in a certain amount of time, pneumatics does a really good job at a really affordable cost. There is a huge number of pneumatic components used in packaging machines and material handling systems as well robotic systems that use pneumatic grippers for picking up and moving parts. If you need very high precision motion control, you need to be looking at either hydraulics or electric.
Automation World: What are the key components of a pneumatic system and how do they work together?
Frank Langro, Festo: The key components of a pneumatic system are the compressor, the air preparation unit, the control valve and a cylinder. The air prep usually consists of an on-off valve, a filtration unit to clean the air and a regulator to deliver the air at the right pressure. Under-sizing a compressor can lead to tremendous problems in your facility because you won’t have enough air to effectively run your equipment, but oversizing isn’t necessarily a good thing either, because it’s going to cost you.
Pat Phillips, AutomationDirect: Consider the pressure and flow requirements throughout the system and make sure everything is sized to work together properly because oversizing components means spending unnecessary money on operations. Yet, if you under-size components, they can’t do the job they’re supposed to do. For example, a valve that is far too small to drive a really large actuator. Nevertheless, there is a little more gray area with pneumatics compared to other systems. It’s a rather forgiving technology.
Automation World: How should manufacturers ensure the safety and reliability of pneumatic systems in their facilities?
Frank Langro, Festo: From a reliability standpoint, make sure the air is clean. That’s why using proper filtration is key. Dirty air leads to valves getting stuck and seals getting damaged, which means a loss in system pressure to the actuator and a machine that doesn’t operate properly. Regarding safety, it’s really important to follow the manufacturers’ operating conditions like staying within operating pressure and following voltage requirements, including ensuring proper grounding of any electrical equipment. It’s also important that every machine go through a risk analysis—this is something that the OEM should do with the customer at the beginning of the design phase.
Pat Phillips, AutomationDirect: One of the things that helps more than anything is educating and training the workers. If people don’t really understand how a pneumatic system works and what it does, it’s quite easy to adjust something to the point where it doesn’t work anymore. Sensors and monitoring also help. There are new devices and things like the IO-Link [an open communications protocol] that are a great way to get a lot of information that would have been difficult [to get] a decade ago.
Automation World: How do you calculate the air consumption of pneumatic equipment, and what factors affect it?
Pat Phillips, AutomationDirect: Specifying pneumatics systems can be pretty forgiving. Look at all the actuators on your machine in a particular system because they’re going to have a certain displacement every time they cycle. If you consider displacement and the rate that they cycle, that gives you a volume of air that’s needed per minute or per hour. Always be sure you have a little bit of extra capacity to allow for some leakage.
Frank Langro, Festo: It’s back to the basics. To solve for CFM (cubic feet per minute), you would multiply the volume of compressed air per cycle by the compression ratio and the number of cycles per minute.
CFM = V x Pr x N
V = (A rear x Stroke)* + (A front x Stroke)* / 1728**
Remember the area that the compressed air acts upon on the rear side of the cylinder is larger than the area on the front side. This is due to the piston rod on the front side of the piston.
* square inches; ** converts to cubic feet
Pr (compression ratio) = (Operating pressure (PSIG) + 14.7)/14.7
N = cycles per minute
