Simulation expands its role

Long used to model materials handling systems, simulation software is now solving other problems too.

By Bob Trebilcock, Editor at Large -- Modern Materials Handling, 4/1/2005

Simulation software has long been used by systems integrators as a cost-effective way to model new materials handling processes before spending money on new equipment. And that is still the primary application for simulation.

"Materials handling solutions are more complex than ever, which makes it harder to envision how they're going to work," says Rick Herlacher, planning manager for supply chain solutions, Siemens Logistics and Assembly Systems (877-725-7500). "When a customer is spending upwards of $50 million for a solution, they want to be sure that it's going to work."

But fans of simulation software are finding new uses for this tool.

"Five years ago, simulation was used to visualize the bottlenecks in a new materials handling solution," says Jay Stacey, business development manager, Brooks Automation (978-262-2600). Today's it's a planning and decision support tool. Simulation is being used to re-optimize a production schedule after a piece of equipment goes down and to determine the number of pickers needed after signing a new customer."

Four pillars of simulation

In fact, simulation delivers value in four important ways, says Vivek Bapat, director of simulation marketing, Rockwell Automation (724-873-5476).

The first is cost-avoidance. "Users not only visualize and model materials handling systems, but they also ask whether they actually need new equipment or additional labor," says Bapat.

Simulation also allows a user to optimize the performance of an existing operation without adding new labor or equipment. "There's a lot of interest in using simulation around retrofits," says Herlacher. "A user can take full advantage of assets they've already paid for."

A third is that simulation can uncover value in a system that a company may not have realized was there in the first place. "Simulation can not only help you identify the bottlenecks, but it can also identify ways the system is underutilized," says Bapat.

Finally, simulation can be used to define new manufacturing or distribution processes to meet increased customer service requirements.

A deeper look

One reason simulation is so successful is that companies must define and measure the processes to be simulated, something they may not have done in the past.

"Simulation forces you to take a step back and look at your process flow in a way you may not have done before," says Jared LeBaron, principal engineer, simulations, HK Systems (800-457-9783). "A lot of the benefit we see comes from asking them questions to define assumptions they haven't really thought out."

LeBaron, for instance, worked on a project for a company planning to add a mini-load automated storage and retrieval system to buffer raw materials on the plant floor.

"On paper, this looked like the way to go," says LeBaron. "But when we collected data to use for the simulation, we turned up more replenishment activities than we expected. Those activities created congestion that hampered operations. Without simulation, we could have thrown a million bucks at a system that would have been a counterproductive move."

As a result, the user addressed operational issues around the scheduling, buffering and releasing of materials in a more productive way rather than adding new equipment.

New uses

Those are the kinds of benefits that simulation has traditionally turned up. But as the software has become more accepted, operators have started to apply it to solve new problems.

In part, that's because the tools are easier to use. "Simulation has caught up with the pace of business," says Kevin Hume, director of consulting services, ESYNC (419-842-2210). "Simulations that used to take a month can now be turned around in minutes on a laptop."

That's because the information needed to get good results from simulation is easier to access. "Today, you can download a year's worth of data at a discrete level of detail onto a zip drive," Hume explains. That allows you to become more creative and focused on how you can apply the technology."

"Today's systems will allow you to repeat different scenarios very quickly," adds Siemens' Herlacher. "You can take an existing system designed to do one thing, and then throw something at it that it wasn't designed to do, like run two shifts instead of one, and ask 'what if?'"

While Hume recently used simulation to validate a new materials handling system, he also used the software when he was interviewing for a new operations manager to run the facility. "We were able to play with the data and run 'what-if' scenarios, then ask the candidates how they'd handle those situations," says Hume. "It was a tool that allowed us to see very quickly whether a manager picked up on things."

The next step for simulation is to tie operational processes to information technology solutions. "One of the things we're looking at now is how to merge facility design expertise with our information systems integration," notes Hume. "That will allow us to answer questions like whether it's more cost-effective to change my operations to work with a baseline warehouse management package. Or, does it make more sense to pay for modifications and customize the software around current processes?"

With simulation, a user can take real data from a year's worth of very different order profiles and have confidence that the system they choose is the best solution from the available options.

Click on the icon to read more about simulation software. (Virtual reality -May 2003)

Pepsi avoids costs with simulation

A simulation project (Arena Software, 412-741-3727) saved PepsiAmericas nearly $150,000 by improving an automated control system. This saved the company from having to purchase an additional stretchwrapper, which the bottler thought was essential to keep up with production.

One of the largest canning and bottling groups within the Pepsi organization, PepsiAmericas was experiencing growing pains at its Austin, Ind., bottling plant. A full-pallet conveyor system was having trouble keeping up with increased production on the bottling lines.

In the original system, bottles or cans were palletized at one of five palletizers at the end of the production line. From there, full pallets were diverted by conveyor to one of two stretchwrappers. After they were wrapped, two pallets at a time were removed by lift trucks and delivered to the warehouse. As business increased, a bottleneck formed between the palletizers and the stretchwrappers.

PepsiAmericas' engineers initially thought the solution was to add a third stretchwrapper to handle the increase in pallet loads. But before ordering the new equipment, the engineers decided to simulate the solution.

It was the first time PepsiAmericas had used simulation before a new implementation.

The learning curve was short. It took two engineers just two training days to learn to use the software. Then, they modeled the full-pallet conveyor system, using animation that allowed them to visualize the new system. The simulation model also provided a way to share the results with the plant manager and plant-level personnel.

The results were a surprise. Once the engineers and plant personnel could see the system in action, they discovered that a third stretchwrapper wasn't required. Instead, PepsiAmericas changed the logic in the programmable logic controls governing the flow of pallets from the five palletizers to the two stretchwrappers. That allowed the system to more intelligently feed the stretchwrappers and keep up with production.

The savings was approximately $150,000. What's more, PepsiAmericas is now simulating other systems before purchasing new equipment.

Dell simulates outside the four walls

Like many companies, Dell began using simulation software (Brooks Automation, 978-262-2600) to develop and test traditional materials handling concepts inside the four walls of its facilities.

Given the computer maker's reputation for operational innovation, it's not surprising that Dell began looking for ways to apply simulation to improve operations outside the four walls of a facility, beginning with the yard and dock activities at a 214,000 square foot distribution center in Nashville.

"The volume of business in Nashville has been growing quarter after quarter," explains Ameet Ravetkar, a Dell manufacturing engineer. "We realized that at some point we would have to improve our processes to extend the life of the facility, move some volume to another facility or build a new facility altogether."

The starting point for that analysis was the yard and docks. The reason was simple: before product can be moved through the facility, it has to be unloaded. What's more, yard and dock activities are more dynamic than they might appear at first glance.

"You have an ever increasing volume of inbound and outbound trailers," Ravetkar says. "Plus there are constraints, like a limited number of spaces to accommodate the trailers plus the limitations of the yard dog that's used to move the trailers to a parking space or to the docks. And there are a finite number of dock doors. Those are a lot of processes with complex interactions."

Dell took a multi-step approach to simulating those interactions. The first step was to model the yard to determine the current capacity. With that information, Dell next simulated yard and distribution center activities to pinpoint bottlenecks in the yard and their impact on capacity.

"One of the things we learned is that we weren't able to keep up at the dock doors with the number of trailers we were receiving with high-volume products," Ravetkar says. "That led us to look at how the materials team was ordering inbound products to see if we could generate fewer trailers."

Once the current bottlenecks and capacity were identified, Dell began modeling different solutions based on projected volumes. The solutions that resulted from those scenarios were broken down into a six-phase action plan, spread out over time.

"We organized the phases around when the facility hit certain volumes," says Ravetkar. "We told the different teams involved in improving operations what they needed to fix. But more importantly, we told them when they needed to fix it. That way, we were not making investments before they were needed, which will improve the return on each phase."

As a result of the simulation project, Dell will have more than doubled the yard capacity by the time all phases have been implemented. "That's going to allow us to stay in this facility longer than we would have stayed," says Ravetkar.

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