Pneumatics vs Electromechanical Motion Control. It can sometimes be one of the more clear-cut decisions you have to make. For instance, if your application requires rigid accuracy, then your hand might be forced toward traditional electromechanical motion control. However, if your application doesn’t have extreme accuracy requirements, then you might be pleasantly surprised by how effective a pneumatic solution is.
A Simpler, Money-Saving Example
An OEM customer in Virginia contacted me concerning a motion control application he was working on. I went to visit him and we discussed multiple solutions, both electrical and pneumatic. To his delight, we settled on a pneumatic solution. When applied appropriately, pneumatics are less complex and easier to troubleshoot than electromechanical motion control, as well as being cheaper to implement. Here’s how we made this decision.
The application in question was to be a palletizing solution. During a visit with my customer, he described a neat idea about how to pick up flat boxes of various sizes, which were coming down a conveyor, and place them on a pallet. Pretty standard, right? However, there were several key factors to consider for a potential solution, chief among them was overall cost.
The idea he came up with was very simple yet ingenious design. As the flat boxes were coming down the conveyor, they would stop at a known location. A robot would get into position, extend a slide to that predetermined location, pick up the stack of boxes, then place them on a pallet. The initial idea was to use typical electromechanical motion control: an electric slide with a stepper motor and controller. However, upon discussion, it was clear that this solution did not require the level of accuracy, repeatability, and speed of typical electromechanical motion control.
Numatics SentronicD Proportional Valve
This freed us up to look into pneumatics, which would save him a lot of money upfront and some potential headaches in the future. I recommended the Numatics SentronicD unit, which I showed him in a previous meeting. The Numatics SentronicD is a direct-operated 3-way proportional valve with digital control. This would allow him to couple the unit with an LVDT and make an infinitely adjustable pneumatic solution.
If you have every tried to stop a cylinder using a reed switch, or some other type of mechanical switch, then you understand how incredibly difficult-to-impossible that can be. This situation is where the SentronicD proportional valve really thrives. The feedback on position is sent to the SentronicD, which meters pressure to the cylinder accordingly. We used two SentronicD proportional valves along with an LVDT and a Numatics rodless gantry slide to solve this application and palletize his boxes.
The End Result
Going this route saved him one-quarter of what he would have spent doing the same task with an electric slide and controls. The reason we were able to use the pneumatic solution over the electromechanical solution, and save money, was because his solution did not require extreme accuracy or speed. If the robot’s gripper fingers extended 1/16th of an inch further or shorter, it didn’t matter to the application. The speed of the system wasn’t so fast it had to be regulated carefully as the boxes didn’t need to be palletized at a tremendous velocity and the gripper didn’t need to close quickly.
Our customer was shown how to program the SentronicD unit once, and he handled it from there since the software is easy to use and very intuitive. When the application allows for it, there are major advantages to using this a pneumatic system over traditional electromechanical motion control. Pneumatics are easy to install to troubleshoot, are less complex to program, and are less expensive.