As manufacturers progress in their digital transformation journeys, they are finding that hydraulic- and pneumatic-powered motion control solutions limit their ability to leverage the full capabilities of smart factory automation. Most of these companies are transitioning to electromechanical power primarily because electric actuators accommodate on-board electronics that support programming and communications. This enables smarter, more controllable applications that are easier to integrate, cleaner, quieter and less expensive to maintain. The first step in transitioning your digital automation strategy is to understand the many considerations for electromechanical technology within factory applications and the benefits it can deliver.
Control
A significant advantage of electromechanical actuators is the ability to program complex movements. Where a fluid-powered system might offer only on and off switching and limited speed controls, every actuator in an electromechanical system is under electrical control, opening significant possibilities for precision, monitoring and feedback. Controls that were previously external, such as switching, position feedback and system diagnostics, can now be managed directly within the actuator. (Figure 1)
Figure 1. The integration of onboard electronics has enabled enhanced control functions that were previously external, such as switching, position feedback and system diagnostics, directly into the actuator. Newer actuators incorporate microprocessor-based printed circuit boards with complementary software that allows communication between remote networks. (Image courtesy of Thomson Industries, Inc.)
If, for example, you are automating a high-precision, pick-and-place robotic operation, you can program the entire routine to start, run and stop without operator intervention. Or, you might control the timing and movement of a waterjet cutting tool on a Cartesian grid, optimizing control and consistency. Such precision would be all but impossible with a fluid-powered system. Even some bending-related applications, once totally dominated by fluid power, are increasingly controlled by electromechanical actuators.
Flexibility
Application flexibility is another reason that digital manufacturing requires electromechanical actuators. In a fluid power system, you first generate pressure, then transmit that power, and finally actuate the load. Every step introduces inefficiencies. Supporting that requires an infrastructure of hoses, reservoirs, tanks, valves and other components that must be built in.
Electromechanical actuators, in contrast, eliminate an entire step in the power transmission process. Electricity directly powers the motor, which then drives the load much more efficiently. This enables the use of smaller motors, matching load requirements with greater precision and using less space and energy. (Figure 2)
Figure 2. Instead of complex hoses, valves, pumps and other assemblies, electromechanical actuators embed all of their functionality in the actuator housing itself, which connects an electronic control unit with only a few wires.
Additionally, since electromechanical actuators can run on either battery, grid power or on-site generation, designers have more flexibility for location. Such flexibility makes these systems the ideal motion technology for automated guided vehicles (AGVs) where light weight, compactness, and elimination of fluid leaks and spills enable automation that contributes to a new level of warehouse productivity. (Figure 3)
Figure 3. Thriving on their minimalist design and lack of required maintenance, automated guided vehicles (AGVs) have been benefitting greatly from the compactness, sturdiness and control features of electromechanical actuators.
Integration
Integration can extend to other devices in your automation scheme as well. Across only a couple of wires, electromechanical actuators can interact and synchronize in real time with other intelligent devices on a CAN bus network. More control, monitoring and diagnostic feedback options eliminate the need for separate controls, and reduce installation costs for both simple and complex motion applications, including:
- Checking the position of doors and hatches and taking action depending on the situation
- Monitoring the temperature, overload condition or voltage variations, then taking action across the network as needed (i.e. start ventilation, reduce speed or stop an operation)
- Confirm when position or other criteria are met
- Synchronize the motion of several actuators
Staffing
Despite the gains in automating operations, advanced applications still need people to design, monitor and improve operations. A new generation of design engineers is emerging, and they are more familiar and comfortable with electromechanical systems than with fluid power. They are trained in using servo drives, linear actuators, and smart sensors, and how to design for them, and this shift is already changing the automation landscape.
Plus, this new cadre of system and machine designers are armed with advanced online motion design tools, such as Thomson’s Linear Motioneering tools. These provide guided, friendly interfaces to specify motion systems based on load, speed, environment and more. These tools reduce guesswork and empower design engineers to make well-informed decisions. It’s an example of how digital tools can help bridge the gap between product catalogs and real-world applications, and that translates into more accurate, high-quality applications.
The basics still apply
While electrifying your factory enables you to take your automation to a higher level of productivity and profitability, achieving the potential over the longest period of time still requires attention to the basics of installation and operating conditions. As much as 90 percent of component life depends on proper installation, and running an actuator at a duty cycle outside the manufacturer’s recommendations will most likely burn it out faster than expected.
Beyond automation
In addition to offering design engineers significant advantages in controllability, precision, safety and integration for digital applications, implementing electromechanical actuators comes with the following benefits:
- Cleaner operation, largely because hydraulic fluids tend to leak, causing potential slip and fall hazards. This is especially true in sanitary applications like food processing and medical device manufacturing.
- Quieter, more energy efficient operations. Hydraulic fluids must be replenished from time to time because of spills, drips or other losses during operation. And pneumatic systems feature parasitic losses as well. They must run 24/7 to maintain power, whether or not they are powering anything else. That hiss you hear emanating from plants using pneumatic power is valuable air being released.
- Low maintenance. Electromechanical actuators require little or no maintenance as long as they are installed properly and lubricated according to manufacturer guidelines, which can eventually translate to higher durability and lower total cost of ownership.
Conclusion
If you are thinking about upgrading or replacing hydraulic or pneumatic systems, an ROI comparison of the advantages of electromechanical actuators over fluid-based systems would be wise. The return could come in the form of tighter control over production quality with less costly downtime. It could come with greater flexibility and space efficiency. It could come through easier integration between motion control and the cloud. It could come as greater human/machine collaboration. It could come in the form of operator satisfaction. Or it could come from many other directions, nearly all of which would not be feasible with fluid-based controls.