An article we wrote two years ago "A Legacy of Performance," showed how various machine builders maintain installed machines for the long term. The control strategy for sustaining machines was different depending on the type of machine.
There are machines that make the same parts/assemblies continuously—fixed automation machines—and flexile machines that make multiple parts/assemblies. The former lend themselves more readily to the same type of control system, even as the machine advances through generational changes, as long as the supplier supports it.
One example of that 2005 control strategy was machine builder JVH Engineering, Grandville, Mich. JVH has installed A-B PLC5s on its injection-molding machines for more than 18 years. So, even though its machine design changes could justify more modern controllers at less cost, PL5s still are offered to customers whose maintenance capabilities still are at the PLC5 level.
Using 20-year-old controls would be a novel practice for many machine builders, but if it assists customers on long-term machine upkeep, it clearly is a valid strategy for sustaining fixed automation machines, regardless of design changes over the years. Having the same or similar controls lets factories move more quickly from a reactive to a preventive maintenance mode.
Moving forward, machine builders must be aware of how users sustain machine operation, regardless of personnel change influences. In many specifications for new, flexible machines, a predictive maintenance program is a requirement.
|FIGURE 1: LEAN INSIDE|
To meet lean standards, particularly in the installed base, machine builders respond with simpler, more easily maintainable equipment with embedded controllers. This gantry robot for end-of-the-line case packing and palletizing has an integrated control system, power supply, four servo-motors, and control computer in the machine itself.
A primary driver behind the movement to predictive maintenance processes is the growing implementation of lean manufacturing principles to optimize plant asset utilization—a move considered vital to compete globally. Interestingly, a recent study by Aberdeen Group shows more than 80% of those surveyed consider asset maintenance extremely important or very important to their facility’s success.
Are integrated controls and mechatronics a solution to long-term machine sustainability? Mechatronics supplier Precise Automation, Los Altos, Calif., thinks so. “We offer a series of robots that incorporate controls inside the robot,” says Brian Carlisle, Precise’s president. “The only wires coming out of the robot are an Ethernet cable and AC power. These robots feature lifetime lubrication and lifetime servo drives. All harnessing, including air lines, are contained inside the robot and designed for a minimum of 20 million flex cycles. With no external controller, the robots can be uncrated and running in minutes.”
Precise Automation also offers a series of multi-axis motion controllers with integrated drives small enough to be embedded inside a machine, eliminating the separate controller cabinet and associated cables. The reduction in wires greatly reduces the chances of bad connections, noise problems in extended cables, and damage to cables from environmental factors.
Remote diagnostics, support and upgrades through an integrated web server are included in these embedded controllers. Machine performance data can be logged, time-stamped, and uploaded to remote sites via an Ethernet link. Machine programs can be uploaded and downloaded over the web. This gives machine builders access to their equipment anywhere in the world, easing the burden of sustaining machines over an extended time.
An example of this forward-thinking design is found at machine builder CAMotion, Atlanta. CAMotion supplies gantry robots and control systems for high-speed industrial automation applications such as end-of-the-line solutions in case packing and palletizing.
CAMotion incorporated Precise Automation’s integrated controller solution for a custom depalletizing machine (Figure 1). The integrated, four-axis controller package fits nicely into the design, providing a smaller machine with simplified controls. “We selected the integrated controller because of cost, but more importantly, because it’s lightweight, small, and easy to replace,” says Steve Dickerson, CAMotion’s CTO. “For this depalletizing application, we embedded the entire control system, power supply, four servo-motors, and control computer into the machine. The control equipment moves with the gantry, so size and weight are very important. We even used wireless communications to eliminate any tether on the 100-ft-plus long machine.” For gantry maintenance considerations, Dickerson says the integrated controller is relatively easy to replace. “If something should fail, or get damaged, we would merely replace the entire unit, since it’s easily replaced and costs very little.”