Product lifecycle management (PLM) is typically considered as an enterprise tool for facilitating the integration and collaboration of a manufacturer's functional departments. With PLM's growing ability to digitally visualize the production environment, it is rapidly taking on additional roles. For example, the digital manufacturing tools of PLM are becoming the optimum means to simulate, plan and improve the use of factory assets, both machines and people.
The growing pressure to simulate, plan and optimize utilization of factory assets -- both equipment and people -- is due to increasing competitive demands for product flexibility. Growing production complexity can't succeed without efficient and affordable optimization.
The automotive industry is the classic success story for the 3-D simulation tools available with PLM solutions, says John Haning, information technology manager at automotive supplier HMS Co., Troy, Mich. In the past, automakers could compete without the advantages simulation software offers in process planning. Traditional auto plants produced only a couple models of a car or truck, relying on fixed tooling. But that's changed.
One of the biggest issues in today's production is the incorporation of multiple vehicles at the same plant in much higher densities than would ever have been considered in the past. "Proposed process changes must be quickly analyzed for safety and efficiency," says Haning. "It's a competitive imperative."
"In the old days, with dedicated [production] lines, asset and employee safety considerations were not often challenged by process reconfiguration," Haning notes. "With dedicated lines, we felt relatively confident that our lines would perform as intended once they were built on the plant floor. But today's flexible plants incorporate such a high level of automation, including robots, conveyors, fixtures and other equipment, that we need to verify that both the assets and employees can be reprogrammed or reconfigured to build vehicles with vastly different designs -- such as a four-door sedan versus a pickup truck."
Haning makes a compelling case for the 3-D simulation world. "The level of complexity in today's assembly lines could not be accomplished in a 2-D environment during processing," he says. For robot simulation, HMS relies on a simulation solution from DELMIA, a subsidiary of Dassault Systmes.
The software is DELMIA's IGRIP with the UltraSpot add-on for the design and simulation of complex spot welding tooling and fixturing.
Haning says HMS uses UltraSpot for robot positioning, tool and peripheral equipment placement, reachability, cycle time, validation of the process and off-line programming.
HMS typically receives a rough design of the assembly process from its customers consisting of such things as set robot speeds, predicted welds and cycle times. It then evaluates the supplied process, optimizes it and finalizes it after simulation, says Mark Kuzniarski, HMS simulation manager. "The whole point is that we find the issues during simulation, correct them, utilize the available time for the robots and make the line function to its best ability." (For employee simulation, HMS uses DELMIA's Human software.)
In addition to spotting equipment and employee safety issues, simulation tools make it easy to improve machine utilization, says Kuzniarski. One example involved a material-handling robot that was sitting idle for a period of time. "Simulation helped HMS to determine that the robot could be welding while it was waiting, so a weld gun was moved off one robot in the original design and mounted to the material handling robot which could now handle multiple functions. That eliminated the cost of an entire robot."
An on-line programming function enables the accurate programming of a robotic system without tying up physical resources on the customer floor, Haning explains. Benefits include reduced man-hours and process engineering lead-time, along with improved accuracy.
Another big benefit, adds Glen Porter, HMS general manager, is in simulation's ability to help avoid loss of production time where plants are already running production vehicles. "HMS is often retrofitting an existing single model plant to become multivehicle ready," Porter notes.
In one situation, HMS was able to retrofit 150 robots with 40 stations comprised of an average of 50 tools at each station across two plants within six months. Haning says the project involved a 6-year-old line reconfigured to accommodate both increased production of the existing model and a brand new style, all without losing any production time.
In addition, assembly lines are being planned and produced in half the time it used to take, says Porter. "Today, despite a two to three times heavier workload, we are reconfiguring faster because of simulation," adds Haning.