Creating Your MH System: Part 2 -- Retrofitting

May 1, 2001
In a 24/7 world, retrofitting offers material handling managers a way to deal with aging equipment and new productivity demands.

New Life for Old Equipment

In a 24/7 world, retrofitting offers material handling managers a way to deal with the challenges of aging equipment and new productivity demands.

by Leslie Langnau, senior technical editor

Age hits all material handling equipment. Wear and tear cut into productivity. Newer technologies outperform older features. And vendors stop stocking replacement parts, pushing equipment into retirement.

But age is not the only reason to upgrade equipment. As businesses embrace business model after business model, retrofitting can be a great way to upgrade equipment functions at low cost. Often, for a fraction of the cost of new, you can add flexibility and improve the performance of your systems, lengthen operating life, as well as reduce maintenance needs.

Despite the benefits of retrofitting, though, it’s not always a simple process. "Contractors are performing ‘open-heart surgery’ on someone’s functioning, productive, mission-critical system," said Mike Kotecki, senior vice president, material handling integration at HK Systems, "while they’re trying to get their job done. There’s no tolerance for failure."

To keep the disruption to a minimum and gain the most benefits, there are several steps managers and engineers can take.

Out with the old?

Whether you’ve decided to retrofit or even buy new, it’s important to consider your objectives. For example, how long is the system expected to last? Is the retrofit to help control specific costs, like maintenance?

"You also need to determine whether you will be handling the same types of items in five years," said Bill Craig, systems engineering manager for material handling solutions, Lockheed Martin. "Also, look at how well the current system meets the needs it was meant to satisfy. What’s changed in the functions now required? For example, if you expect the need for throughput to increase by 20 percent, you can probably accommodate this with a retrofit. If throughput needs are higher, then you may want to buy new or add a parallel system."

"Software should almost always be bought new," says Stafford Sterner, vice president of marketing at SJF Material Handling Equipment.

"There’s always upgrade potential with software," agreed Dan Labell, president of Westfalia. "The WMS algorithms can be improved, for example, grouping certain retrieval missions for better throughput. Plus, there’s a lot of smarts that you can add to software that older systems may not have. Some of this newer technology runs in the background and really isn’t noticeable. But, what you will see is greater flexibility in programming, such as using wireless communications to program PLCs. That’s functionality that didn’t exist before."

"In today’s world," added Sterner, "everything has a maximum life cycle of five years, including your business. The focus on how you run and do your business is in continual change. In five years, your present system isn’t going to be what you want; your business model will change; the product and how you handle it will change; the way you bar code it, track it and inventory it, are all going to change. Don’t get locked into trying to find a long-term, cure-all solution, because material handling is becoming an evolving process.

"And if you see things changing significantly," continued Sterner, "retrofit may not be the solution."

Another key factor is order profiles. "Profiles dictate the type of warehouse you should have and, thus, what can be retrofitted," said Paul O’Connell, president and CEO of Operations Concept. "Analyze your order profiles.

"It’s crucial to keep up with SKU profile maintenance," O’Connell continued. "For a warehouse management system to work well, it has to know cube information: weight, dimension, height, and so on. This is especially important when 60 percent to 70 percent of goods come in from overseas and U.S. companies let foreign vendors put product into just about any box they can find. Thus, the vendor may have changed the pack quantity. The biggest mistake made today is to accept these boxes without inspection. Maintenance is the most important function with WMS software and people don’t do it. In addition to SKU maintenance, you need to do location, equipment profile and people profile maintenance too."

Once you’ve determined system objectives, it can be quite a project to choose among all the available component options. It’s tempting to use new components just because they are new. "But those components may not be best for the application," said Kotecki.

Several companies can help you analyze whether you really need the latest components through a "modernization audit." They will compare the existing system with your objectives and either develop a design for retrofit and/or new, depending on available funds. The factors these audits can consider include internal rate of return or net present value, power consumption, labor issues, maintenance, insurance costs, OSHA issues, even tax consequences of accelerated depreciation. They can even give you an expected return on investment.

Some audits involve a simulation of the upgraded system, letting everyone see exactly what to expect from a retrofit. Others may be based on a program like Excel, which will provide speeds, throughputs, costs and other hard data.

Bit by bit

Whether you’re refurbishing AS/RS systems, carousels or conveyors, there are common components that can give you the most bang for your buck.

"For example, upgrades in motors, positioning systems and controls can boost throughput of automated storage and retrieval systems by 20 percent to 25 percent," said Craig. "Carousel upgrades usually consist of replacing some controls and mechanical elements, but the throughput won’t be as high as with other material handling equipment. That’s because people manage the picks in these systems. Control upgrades, however, will often make the system easier to maintain and will improve reliability."

"The software enhancements that have happened just in the past two years," said O’Connell, "have dramatically improved the efficiency of both miniload and standard AS/RS systems. With these enhancements you’ll get flexible picking, the ability to wave orders in many orientations, selective picking to order, bulk ordering, regional and state picking, and so on. Newer warehouse management programs work along with the equipment to give you the optimal or desired pick pattern."

Increasingly, continuously moving equipment is being replaced by systems that run only when needed. For example, upgrading belt or shaft-driven conveyors with roller conveyor systems that use photoelectric sensors to turn on roller sections only as needed. Not only does this change reduce noise levels, it’s also a good way to save on power, given the recent energy availability problems. (For more on noise reduction and conveyor maintenance, read the article, Keep ‘Em Running, page 45 in the February issue of MHM.)

Large automated storage and retrieval systems can be very expensive to retrofit. But there are some economical upgrades you can make. "For example, you can change the algorithms, location dimensions, and zoning or location matrix criteria," added O’Connell.


When retrofitting, attention must be paid to interfacing new or refurbished components with the old. Most problems in linking industrial components have been solved. The problems that occur now involve linking industrial systems with corporate business systems, such as the host financial systems. No one expected the need to tap into financial systems and take data from them. "However," said Kotecki, "the good thing about this link is that you rarely have to communicate in real time."

Special programs, usually known as software drivers, can be written by staff programmers or by system integrators, to facilitate the connection.

In other interface cases, solutions involve the use of a cell controller. Its function is to manage and isolate existing interfaces at the WMS or even AS/RS control level, reducing the disruption to these systems.

"Be aware, though," said Sterner, "that vendors tend to recommend their own line partly to avoid potential integration issues."

The latest development in retrofitting is to turn to "renewed" equipment. These pieces fit applications where you need devices for a new function but you don’t want to buy brand new. Not quite new, yet a step beyond reconditioned, this equipment has undergone disassembly, evaluation and comparison to original specifications, and finally re-engineering to fit the needs of new applications. In some cases, these devices can cost about 50 percent less than a new device.

Changes to material handling processes are increasing as new business models arrive. Upgrading equipment, in one format or another, is a good way to meet the demands brought about by these changes. MHM

Tapering noise, reducing maintenance

A common problem with roller conveyor systems is worn holes in the side frames. Eventually, the rollers bounce and rattle around in the holes, increasing noise and raising the price of maintenance. The solution for maintenance at Lillian Vernon Corporation’s National Distribution Center in Virginia Beach, Virginia, was to install tapered hex shafts on rollers.

The facility has more than a mile of powered and gravity conveyors, with about 20,000 rollers. The conventional fixes — installing tightening shims in the holes, welding shaft stabilizing plates on the side frame — worked, but were tedious and expensive tasks.

Wanting a permanent solution, the maintenance department turned to Taperhex precision conveyor rollers from Interroll Corp. These rollers have spring-loaded, tapered hex shafts at both ends. They wedge tightly in place, regardless of the condition of the mounting hole. As the hole size or shape changes, the rollers adjust to eliminate movement between the shaft and frame in all directions.

The rollers come with ABEC-1 precision ball bearings and are available with either 1.9- or 2.5-inch-diameter steel tubes.

How To Manage Retrofit Risks

You can avoid a lot of red ink by applying the right team to erase the risks of an installation project.

by Tom Andel, chief editor

Successful retrofits depend on your ability to control risks. There are uncontrollable and controllable risks. Examples of the former are weather delays of construction, tornadoes and strikes. These can’t be controlled or avoided, but you can minimize their impact through planning.

For example:

• Could you extend the use of your current operations if the opening of a new location were delayed?

• Could you shift work to other areas?

• Could you put some of the load of the facility you’re retrofitting on other locations?

• Can you spend more hours on the retrofit project to make sure it works the way it’s supposed to?

• Do you have sources of backup labor so you can do work-arounds?

Controllable risks can be reduced or eliminated. Some examples:

• Operator error;

• Communications failures;

• Equipment performance failures.

You can eliminate or reduce these risks with the right project team. There should be a program manager and project managers from each team. An executive steering committee should set the overall mandate for the project, i.e., increasing productivity or doubling the amount of orders shipped each day. Someone in the organization must have overall responsibility for each discipline. For example, project managers for WMS software, material handling and training.


Ask for resumes and profiles on each member of your team to make sure the team members share a similar culture to that of your company. Also make sure these people control the resources needed for the high-risk elements. If the people assigned to the team don’t mesh, you won’t succeed.

It also helps to set a broad timetable for implementation. Plan for implementation during a slow period, and break the project into multiple periods and sub-periods (such as weekends). Then set go/no-go points for each period.

Finally, to find out if the work you’ve done has been effective, schedule a go/no-go meeting before switching over to the new system. If you determine that the work you’ve done isn’t sufficient to support a Monday morning start-up, you must be able to restore the system to what it was on Friday.

Common risks include:

• Training;

• Non-automated systems;

• Changes in product mix;

• Performance metrics;

• Employee ownership of the software;

• Employee commitment.

"We identify risks such as the interface between the WMS and the legacy system," says Peter Counihan, president of Fortna, integrators of logistics and distribution systems. "Rank your risks and figure out what you have to do. In some cases you have to build work-arounds, temporary systems that let you work on the main systems so operations can still function. The risks range from training the people in your IT group, to downloading orders to the WMS, to timely, accurate shipping of orders."


You must be able to gauge progress every step of the way. Questions you must answer:

• What are the metrics?

• What are you going to measure?

• Whom will you tell about these measurements?

• Do you have master users who’ll know what to do when error messages come up and how to fix them?

• Are employees committed to the process?

These questions can go all the way back to the customer service and order entry departments. For example, you may want to reduce order cycle times so the order management system can feed a new WMS.

Other challenges

If you don’t have a process to marry non-conveyable or very slow movers with other items in a new high-speed material handling system, move these far away from the sorters and then consolidate orders, suggests Counihan. If you have non-conveyable orders in every wave, bring people in to pick those an hour or two ahead of time and have them staged.

"We’ve seen situations where new high-speed equipment was running 20 minutes every hour," Counihan adds. "You won’t get a payback running at that rate. It will be held back if there aren’t enough people in the non-conveyable area."

Make sure your system can handle changes in picking or shipping. Counihan explains, "Look at your original assumptions of how you justified your project. Boil them down to basic activities like line speed per hour, and measure them throughout the process. Tell people what they’re achieving. That helps drive productivity."

Finally, keep project managers on site at all times.


Take the necessary steps to implement risk management. The benefits will not only help ensure that your retrofit project is implemented successfully, but it will have a positive effect on your bottom line. MHM


Horsepower to Your AGVs

Got an aging fleet of troublesome automatic guided vehicles? You’re not alone. Now’s the time to retrofit those old workhorses into Clydesdales — with help from the newest technology.

by Christopher Trunk, managing editor

"When you look at all the automatic guided vehicle systems (AGVS) sold back in the 1980s, today there’s a tremendous market for retrofitting as owners are being forced into making a decision on retrofit or retirement," says Ken Ruehrdanz, manager, marketing communications for Rapistan Systems. He says many forces, in addition to the aging-fleet issue, are driving AGVS retrofit. These include consolidation of warehouse and manufacturing facilities, corporate acquisitions and a demand for increased distribution at each remaining facility.

"Back in the early ’80s, the AGV market took off too fast. A lot of new technology sprouted, and some systems worked and others were sold into the wrong site," says Mike Kotecki, senior vice president, material handling integration for HK Systems. He says there was enough failure to give AGVS a bad name. But with retrofitting, AGVs can evolve into robust, reliable, application-specific equipment. "We’re resurrecting old systems with new controls and new management software, and taking vehicles from one facility and reconfiguring them for a new site. We call that ‘remissioning’," adds Kotecki.

A whole new frontier

As life cycles for manufactured goods grow shorter and warehouses change their layouts and order profiles, the well-worn guide paths for AGVs need to be more flexible. In fact, embracing the flexibility provided by new AGV control technology can help you manage future product and throughput changes.

Designing material handling systems for the future is a topic dear to Lawrence Dean Shemesh, vice president, Gross & Associates. "Material handling system design is based on forecasts, which typically take a five-year view because it’s difficult to establish ROI with less time. But looking more than five years out, it gets foggy. Given the time it takes to retrofit, that five-year forecast has to last six or seven years. But designs based on forecasts are by their nature inaccurate over the longer time frame," observes Shemesh. With fickle retail markets, it’s harder to know what your business will look like down the road. He advises that you retrofit your AGVs as flexibly as possible. "If you build your system precisely to your new plant design, the likelihood of that AGV being inappropriate down the road is greater."

Retrofitters agree that updating guidance controls is a great way to improve the efficiency and flexibility of your existing AGVS. Mark Fung, customer support manager for FMC Corporation, cites advances in laser-guidance technology. "To ratchet up the speed of your AGVS, you have to look at both vehicle speed and guidepath. The laser guidance we offer as a retrofit lets you update vehicle routing by installing a new database with a point-and-click of your mouse," he says.

Fung provides this example: Your warehouse currently has four pallet lanes, and you lay down five pallets per lane. But later, the pallet size changes, requiring a reduction to two lanes at eight pallets per lane. With a laser guidepath, it’s easy to adjust the AGV path.

Some vendors offer simulation software for designing AGV systems. "Simulation pays for itself, as it can let you quickly explore a host of design choices to enlarge a system or improve its throughput," says Kotecki. HK Systems used simulation in the expansion of Gillette’s South Boston, Massachusetts plant. The Mach III razor is made at this crowded downtown facility, and simulation let Gillette determine the right number of vehicles.

"At some point, productivity decreases with too many vehicles. That’s why it’s important to simulate first," adds Kotecki.

Why retrofitting makes sense

Vendors who retrofit automatic guided vehicles cite several reasons:

• "It’s cost effective to replace controls that get pounded while working three shifts a day. Control features and functions improve about every 10 years." — Ruehrdanz.

• "Retrofitting solves many problems, including excessive vehicle downtime, sky-rocketing maintenance costs and a scarcity of spare parts. It’s an opportunity to add laser bumpers and object detection optics that protect workers, equipment and inventory on the move." — Tim Wolf, manager, business development for Rapistan.

• "You can avoid production delays by refurbishing just a few vehicles at a time. As most retrofits are performed on live systems, careful planning and coordination are of utmost importance to project success. And don’t rule out expanding your current AGV fleet to meet throughput demands." — Bradley Moore, senior account manager for Swisslog North America.

• "With better control over your retrofitted or expanded AGV fleet, you’ll need less safety stock as deliveries can be scheduled just-in-time. Improved power sources require fewer amps so batteries last longer between chargings." — Moore.

• "Retrofitting AGVS can cost from 40 percent to 70 percent less than buying a new system; but success requires a sound vehicle frame and working closely with the vendor on your handling requirements." — Don Holdenrid, director of sales for AGV Products.

• "Retrofitting doesn’t alter your existing AGV interface points with other handling equipment like conveyors, AS/RS, palletizers, etc. There’s no need to re-engineer interfaces that aren’t broken." — Fung.

Buying decisions

Fung says that owners of AGV systems tend to retrofit or replace based on the size of their system. "The user of a small, two-vehicle system might not be able to afford having one vehicle taken out of service for retrofit. Whereas larger fleets of 50 or so vehicles may better handle missing five vehicles at a time in a well-planned,

sequential fleet retrofit," concludes Fung.

There’s a lot to consider when looking at an aging AGV system. Maybe those old mares can be made into champions again. MHM

For More Information

Contact these sources directly:

Fung, FMC: [email protected].

Holdenrid, AGV Products: [email protected]

Kotecki, HK Systems: [email protected].

Moore, Swisslog: [email protected].

Ruehrdanz, Rapistan: [email protected].

Shemesh, Gross & Associates: [email protected].

Wolf, Rapistan: [email protected].

Den Festerling, customer service engineer, Control Engineering: [email protected]

E-Commerce Retrofit: Manage Complexity with Simulation

Simpler isn’t necessarily better. Simulation software lets you lean back and consider the efficiency that complex material handling systems bring to a warehouse retrofitted for e-commerce.

by Christopher Trunk, managing editor

With e-commerce comes complexity. Bet on it. That’s what Jan Young, director of business development for Catalyst International Inc., says about retrofitting a warehouse. "Simulation software gives the user better visibility into all the variables of e-commerce fulfillment, making it simpler to understand."

But that doesn’t mean your material handling systems will be simple. In warehousing, simplicity for its own sake is counterproductive. Young provides this example: Warehousers make a common mistake when allowing all those small-sized, but plentiful orders to be shipped by just one carrier, like UPS. But this may not be the most efficient means, as certain commodities shipped to different locations might be handled cheaper and with more customer service by Fed Ex." This requires a more complex sortation system, and simulation makes these systems easier to understand — with as much repetition as you need and according to your schedule.

Increased complexity holds true when retrofitting a warehouse for e-commerce. You can easily organize storage by ascending part numbers or by which vendor owns the inventory, allowing any worker without an RF terminal to pick items. But this can be grossly inefficient because it ignores that one item is picked faster than a slow-mover, not to mention wasted cube use. Simulation allows you to tweak a storage and picking layout to reduce both time and travel with various kinds of material handling equipment and systems.

Breaking dishes JIT

As business moves from the old economy into the hectic e-commerce marketplace, order management and time management are more critical. Split-case picking of eaches replaces full-case picking, and with it the material handling equipment used to present cases to workers, take away and sort those picks and eventually package them for shipping. Training is also an issue as product damage can skyrocket. Face it, not every worker accustomed to hauling cases is suited to individually picking pretty porcelain platters. That’s why its important to present items to workers in a well-considered design.

"We can examine different kinds of rack configurations, material handling vehicle choices or travel paths when retrofitting an existing warehouse for e-commerce," says Dan Trew, vice president, product strategy for Catalyst.

But many e-commerce sites live or die on the time it takes to fill that Web order. "Turnaround time for customers is key, and simulating a model can gather statistics on critical time factors," points out Debbie Kotlarek, director of simulation services for HK Systems. "If turnaround time isn’t sufficient with the model, then you can electronically change material handling equipment or controls to improve order accuracy, product protection and fulfillment time."

Simulation spares you having to go live without these kinds of tests. Then you can phase in new hardware, software or controls during shutdowns or third shifts to minimize downtime.

Retrofitting decisions

"With e-commerce warehouses, you have a completely different order profile," says Jim Higdon, sales engineer and supervisor of simulation for Ann Arbor Computer. "Smaller order size, more packages and fewer palletloads to handle, may mean changing equipment and developing new strategies for orderpicking." And instead of shipping to other distribution centers, you’re more likely to ship direct to customers. An in-line manifesting system may be required where once there was none.

With an e-commerce retrofit, Higdon says you might be replacing a pallet conveyor with a light-duty belt conveyor or adding a tote and tub handling system to your existing pallet handling system. Of course, there are pick-to-light, pick-to-belt, carousels, vertical lifts and A-frame dispenser options to consider.

In these tougher economic times, simulation software offers yet another benefit. "Simulation is a low-cost way of experimenting with different designs and equipment to test their effect on throughput and to see just how flexible systems are as orders increase," says Robert Kudis, vice president, consulting for HK Systems. The software also provides a nice format to present an e-commerce proposal to upper management and investors. It gives not only the financial justification but also a look at the finished e-commerce retrofit."

Results reflect experience

To make the most of the off-the-shelf simulation software available today, Higdon says you need a designer who both uses the software frequently and who is a little bit mechanical engineer, a little bit controls engineer and someone who knows about conventional and e-commerce orderpicking and warehouse equipment. To aid the simulation engineer, you’ll need a team of people to advise the warehouse designer on all the exceptions that crop up, and all the customer order nuances.

Warehouse managers can’t just hope for simulation software to do everything for them. Simulation is a tool, another engineering discipline that complements CAD drawings and spreadsheet analysis. Simulation forces definition of a project.

"It’s easy to obtain equipment parameters and to simulate lift truck drivers or picking performance," finds Kotlarek. But she says what’s really needed are estimates from the buyer on: types of orders, number of SKUs, order characteristics and number of line items. These factors influence how you stock items, where you stock them and what kind of equipment is needed to process the anticipated order volume.

It’s clear that complexity goes hand-in-hand with e-commerce warehousing. And simulation may be your best bet to leverage an e-commerce retrofit. MHM


Here’s how to contact those mentioned in this article:

Higdon: [email protected]

Kotlarek: [email protected]

Kudis: [email protected]

Trew: [email protected]

Young: [email protected]