It used to be, when you considered ways to move material around your plant or warehouse, technology decisions were pretty easy:
• Electric lift trucks for general purpose movement of unit loads within and between storage and the dock;
• Internal combustion (IC) engine lift trucks for heavy-duty and outdoors applications;
• Conveyors for long-run, high-speed, high throughput transfers of packages between assembly or picking stations and on toward sortation; and
• Automated guided vehicles for fixed-path, predictable transfers of unit loads at huge manufacturing plants.
Technology advances have blurred the boundaries between these job descriptions. Manufacturers of electric lift trucks are adopting AC drive technology, boosting power and battery life in applications both outdoors and indoors. Conveyor systems are more modular and user configurable to provide a higher degree of flexibility in tighter spaces. And the paths of AGVs can be changed at a moment’s notice when there’s a change in business requirements. These new roles for established technologies were in evidence all over the ProMat show floor. In fact there was enough post-show grist for discussion with technology providers who didn’t even exhibit at ProMat. This article contains a wide variety of comments on state-of-the-art material movement. If you're looking to improve flow, you’re bound to find something to aid your fact-finding.
Electric lift trucks
The role of AC drive technology in pitting electric-powered trucks against IC models is the talk of the industrial truck industry. On top of technology advancements, there's legislative pressure to find ways to reduce emissions in the workplace. That’s making electric lift trucks a more powerful player.
Filippo Baldassari, sales and marketing manager, Carer (www.carer-italy.com)
"If you compare the purchase cost of an electric unit with that of an IC, the IC is cheaper, and the chassis itself is cheaper. But the purchase price of industrial equipment is only a portion of the total cost. With an electric truck you don't have a transmission, you don’t have filters to be replaced, and the electric motor itself is not subject to wear except for the bearings. Thanks to the great energy efficiency you achieve with 80-volt, 96-volt and 120-volt motors, the new generation electric units can work at least 8 hours, if not 10 or 12 hours before you recharge."
Donald Chance, president, Yale Materials Handling Corporation (www.yale.com)
"We're moving to AC because when we look at emissions and where California is going in 2004, there's legislation to move all powered lift trucks 8,000 pounds and under to electric. At the end of the year we'll introduce the first phase of our AC line. It'll be the heart of the line, 4,000 to 6,000 pounds. We'll also introduce higher voltages, up to 80 volts. We want to put enough energy into the truck so we can handle two shifts."
Jim Malvaso, president and CEO, Raymond Corporation (www.raymondcorp.com)
"As buyers look at electric lift trucks as alternatives to internal combustion trucks, electric truck manufacturers may be required to investigate technology that enables electric trucks to have operating characteristics similar to internal combustion trucks. This technology may include AC in some way. As for other trends in electric lift trucks, opportunity charging is becoming a more frequently requested feature. Also, The Raymond Corporation actively supports some major universities in their investigation of fuel cells so that it can stay in touch with the direction of fuel cell technology development."
Brett Wood, National Product Planning and Research Manager, Toyota Material Handling USA (www.toyotaforklift.com)
"Now, because you have fast charging, that makes electric lift trucks even more competitive. The more I'm hearing about fast charging the more I'm liking it. I've been tasking some of my guys to look into it so we can design lift trucks to be ready for it. You still need the power of engines for outdoor, heavy duty applications like lum-ber yards, or for use on ramps, but it's inevi-table that our industry will become AC."
Dirk Von Holt, president, Jungheinrich (www.jungheinrich.com)
"Our trucks with AC motors are as fast in acceleration and lifting speed as IC motors. We're moving with our trucks 12.5 mph with the lift speeds of an IC truck. There are no emissions and the trucks are very quiet. They work outdoors as well. The motors are totally enclosed. You can hose the motors down. The tires are solid elastic, which are like cushion tires but they are also like pneumatics, so it gives you the performance of a warehouse truck."
Timothy S. Quellhorst, vice president enineering, Crown Equipment Corporation
"In some cases, DC is still more appropriate than AC. Take lift systems found on three- or four-wheel counterbalanced lift trucks. For most customers, the most cost-effective solution is a series DC motor combined with a spool type hydraulic valve. No electronic controller is needed. While an AC system will provide some efficiency advantage over this simple DC system, it isn't because AC technology is inherently more efficient but, rather, because an AC system must have a motor controller. Compared to an on/off type of system, one with a motor controller can better match the amount of oil flow to the functional need. This is the real underlying reason for the efficiency improvement and can just as easily be achieved with a series DC motor controller. Having said that, it is likely that the marketplace will see more and more AC powered products in the future."
Kevin Reardon, chief executive of Clark Material Handling Company (www.clarkmhc.com)
"Our intent is, in the next 12 to 18 months, that all of our electric product will be AC drive. The big issue before was the motors were cheaper, but the controls were very expensive. In Europe, on the bigger trucks, they run 72 and 80 volt, and the controllers are not as costly. When you start getting down to 48, 36, and 24 volt, which are more predominant in the North American markets, the cost of the controllers have been higher. But now we're starting to see a settling of that, and the trade-off price-wise is about the same."
IC engine lift trucks
Even vendors who sell IC powered lift trucks are putting more resources into alternative technologies.
Larry Wuench, Executive Vice President, Mitsubishi Caterpillar Forklift Trucks America (www.mcfa.com)
"I don’t know that AC will have as much of an effect on the IC vs electric situation as the EPA situation in California and OSHA in general is having on IC engines, at least in the near future. In California there’s a proposition to prohibit the sale of all IC lift trucks below 8,000 lb capacity after 2007. I think the pendulum will swing toward electric trucks as they get more to the performance level of IC trucks. Another reason we’re looking more at electric trucks and the latest technology in electronics, particularly AC, is that those are the only places we can gain more control of our own vehicle power destiny."
However, there are vendors with a solid stake in the benefits that engine-powered vehicles can deliver.
Keith Allmandinger, director, marketing and product support, Nissan Forklift Corporation, North America
"Internal combustion lift truck manufacturers have been required to steadily increase the numbers of low emission forklifts sold into California since 2001. This proposed measure to eliminate IC trucks below 8,000 pounds certainly could have a detrimental effect on our sales. But worse yet is the detrimental effect this could have on our customers. Electric lift trucks do not have all the capabilities of engine powered models, so in many cases the customer would be forced to change their applications to fit the limited capabilities of the electric truck."
That proposed measure hasn't stopped foreign IC competitors from entering the U.S. market. Like their American counterparts, they're betting that IC's unique capabilities will maintain its strong user base.
Joe O'Brien, sales director, Aisle-Master (www.aisle-master.com)
"Our 44S articulated, narrow-aisle model offers "rack-to-truck" versatility, a 67 horsepower LP gas internal combustion engine, and hydrostatic drive. Users can perform yard-handling tasks over semi-rough terrain as easily as handling pallet loads in narrow-aisle storage."
Automated guided vehicles
The idea of removing the label "inflexible" from its products gives AGV companies plenty to talk about these days. Many are building user programmability and operational flexibility into their offerings. They want to build a bridge to users who previously couldn't justify an investment in automation. That's why many new AGV products incorporate man-aboard capability.
Yves Gazin, director of marketing and sales support, Egemin Automation (www.egeminusa.com)
"Our automated towing vehicle [ATV] handles up to 35,000 pounds and is ideal for facilities using or considering man-aboard tuggers. These ATVs operate in either manual or automatic mode. The user can input tasks, check maintenance and alarms through a touch screen graphical display. In automatic mode, we remove the need for a man aboard while material is transported, allowing an operator to perform other value-added functions at the work cell."
Mats Herrstomer, president, AGV Products, Inc. (www.agvp.com)
"We acquired advanced control technology from Nuovafima, an Italian manufacturer of laser guided AGVs used in the ceramic tile industry. You can change the system guidepath and destination in just a few seconds using a click and drag feature we’re integrating into our TRACE Windows-based control system. You can add hundreds of pick and drop locations in a matter of days without changing software, saving engineering cost and time."
Ryan Willis, director of marketing and business development, Transbotics (www.transbotics.com)
"Operators are a big cost and return on investment windows are shrinking. Companies used to say three years, now they require a year or less. Daimler Chrysler has a six months or less payback requirement. They operate 24 hours without breaks, and do automatic charging. A 24/7 operation is an ideal situation for justifying an AGV system."
Mark Longacre, marketing manager, FMC Technologies (www.fmcsgvs.com)
"In the past people have had to decide between a full blown AGV and a manual vehicle. There was no middle-of-the-road solution. We’ve worked with Hyster to develop the Hybot. The version we introduced at ProMat looks similar to a motorized pallet jack. You pick up and lower loads just as you would with a manual vehicle, but let go of the handle and on the display you get areas in your plant to which you can send the vehicle. Just push a button and it goes to that area without an operator. All that infrastructure you needed for an AGV system which costs about $150,000 is gone."
Scott Alexander, director of marketing, Hyster Company (www.hyster.com)
"There’s a subtrend to AGVs, which is fleet logistics services. People aren’t looking as much at replacing a truck, they're looking for a total solution to a material handling problem. Financial services are key from the standpoint that you get a lot of pressure to focus on operating cost per hour. If you’re talking about a monthly payment, that's a lot different from talking about a $40,000 piece of capital equipment."
Even conveyor systems are starting to be marketed as a more flexible solution to material movement problems. Modularity and programmability are the main reasons.
Larry Frey, senior vice president, HK Systems (www.hksystems.com)
"The HKiss servo slug merge operates in distribution and manufacturing environments. It can be operated with an 18-inch average carton at 227 cartons per minute. We've developed acceleration and deceleration algorithms to keep movement under control so there’s no twisting, turning or jamming. The flexible configurations adapt easily to building constraints while reducing the possibility of carton jamming. Today conventional systems using different types of merges are operating at up to 500 feet per minute. We can operate this equipment at 250 feet per minute and below, with much less wear and tear and less maintenance."
Dale Dratt, vice president development, Humphrey Products Co. (www.humphrey-products.com)
"We can play different tricks with our Gen2 control modules. They can talk to one another and do a little thinking for themselves. In the auto-slug mode, when the last two photoeyes become opened, that tells the conveyor system there's room downstream. You make a decision automatically inside the modules to create an instantaneous slug release on the conveyor line. This allows the conveyor to be more self sufficient. You increase efficiencies without needing continuous input from a PC to control it."
Leon C. Kirschner President, Ermanco Incorporated (www.ermanco.com)
"We're offering the latest variation on the narrow belt sortation concept. It includes right angle sortation with very close centers, for up to 120 sorts a minute. We have solved a lot of the problems from previous sorters such as when different belts stretch at different rates. We incorporate individual take-ups, therefore you keep constant belt tension. Pre-programmed PLCs make it easy for the installer to set up and program the system. It’s also very quiet. It has precision bearings throughout. The moving parts are primarily plastic and the belt is captured in rollers. There are no belt tracking problems. You get 800 pounds of belt pull out of it, so you can get a 300 foot long conveyor with a single drive. That’s the real savings. Any time we can eliminate a drive that’s several thousand dollars in controls."
For more information on any of the technologies mentioned in this article, visit the web sites listed. [email protected]