How do you build a pneumatic power system? We turned to Festo, an industrial control and automation company that produces pneumatic and electrical control and drive technology for factory or process automation.
Pneumatic fluid power systems are used extensively in manufacturing across a wide range of industrial sectors. These systems are commonly powered by compressed air. An electrically powered compressor powers cylinders, air motors, pneumatic actuators, and other pneumatic devices. Pneumatic systems are valued for their ability to provide a lower cost, more flexible, or safer alternative to electric motors or hydraulic actuators.
Design News caught up with Frank Langro, director of product market management for pneumatic automation at Festo. He offered his view on the critical factors involved in building a better pneumatic system.
Design News: What type of fluid power systems does Festo support?
Frank Langro: Pneumatic systems. There are so many applications in fluid power. Every automated facility can have a pneumatic system. Automotive, semiconductor plants, food & beverage, packaging, and consumer goods. That’s just a sampling. With some of the applications in electronics, you have a lot of pick-and-place or putting parts on printed circuit boards. You have repetitive testing such as a cell phone where you’re testing the keypad or continuity testing contacting various points on an electronic device.
In semiconductors production, you have many pneumatic valves in wafter processing. They are typically used to pilot gas values. In packaging, a common application you see is pick-and-place putting products in a box or case. You also see a lot of stopping and holding along a conveyor line, as well as folding, holding, closing, and sealing. Any highly repetitive manufacturing activity offers a good use case for using pneumatics.
Here’s an example of an automation function that can be powered by pneumatics:
DN: What goes into the planning of a fluid power system?
Frank Langro: In a compressed air system in a plant, you have to understand how much compresed air you’re going to use. That determines the size of the compressor and how many compressors you need. It is a big capital expenditure. Oversizing is an additional cost and undersizing means you won’t have the capacity to run your machines to their fullest capacity.
On the lower machine level, the machine is designed to perform a task with a certain throughput – say 1000 parts per minute. To do this, you have to look at the task, whether you’re holding something or connecting something. You need to be able to provide the needed force, and that will determine what size cylinder bore and operating pressure you will need. That speed of the actuatorwill determine what flow rate your valve will need to provide. Once you get the basics of the demand, you can always have some additional optimization of the machine.
For example, if you look at a cylinder that moves a part into position. When it retracts, since you have no load to move you may not need to operate at the same high pressure. You can use a pressure regulator to reduce the pressure on the return stroke. The relieves the demand on the system and also relieves the wear on the cylinder.
DN: What engineering professionals are involved. What are the disciplines?
Frank Langro: With machine design, you’ll find the main engineering disciplines. Mechanical engineers being responsible for the construction, mechanical component selection, and defining the operating pressure and flow rates. You’ll have electrical engineers for the wiring and power distribution and Control engineers defining the control architecture, deciding on whether to use direct I/O or implement some serial bus interface.
The controls engineer will also work with the user interfaces, for example the HMI and the necessary programming to implement. An emerging discipline that we see now is a mechatronics engineer. Mechatronics merges electrical, mechanical, and control engineering. The mechatronics engineer is looking at the full approach machine and not just the individual discipline.
DN: What is the process from initial design through completion?
Frank Langro: You’ll definitely see simulation. One of the current trends is digitalization. What that does ideally for a machine builder is that they will digitally build the machine through the CAD models and component data. This will enable simulation of the design before you put one bolt in place. That creates optimization in the design, minimizing error and saving costs.
We recommend using sizing software so that a builder can get the best value and operational performance from the machine. If you put in a larger cylinder than you need, that means larger valves and more air consumption, the impact on the compressor is that it needs to work longer and harder. Right-sizing minimizes the amount of air you need and it optimizes the operation. Also, the smaller cylinders cost less money. There are old-school builders, and if they see a ¼ port, they use a ¼ valve. You should look at the operation based on the pressure and speed you need and size the components based on the application needs to avoid oversizing
DN: What are the testing and quality control processes?
Frank Langro: In terms of machines, a lot depends on the company. With the use of simulation and digital design tools, this will certainly help to streamline testing. Of course, nobody will accept a machine sight-unseen, there is always a customer sign-off where output, functionality, operation, and safety are all checked. The more that simulation is used the less likely changes will have to be made during the physical testing.
The testing and quality control are typically built into the design process. The design is checked and validated through simulation. Here you can identify throughput is not achieved. In the trouble shoting stages you need to determine if the poor performance is a result of a component defect or a misapplication. Quite often the component manufacturer will step in and help the OEM in the troubleshooting and help to come to a resolution.
Rob Spiegel has covered manufacturing for 19 years, 17 of them for Design News. Other topics he has covered include automation, supply chain technology, alternative energy, and cybersecurity. For 10 years, he was the owner and publisher of the food magazine Chile Pepper.