Nintendo Enhances Conveyor Sortation Performance
Nintendo’s high-speed sorter utilizes industrialcontrol products from Rockwell Automation to increase speed and boostthroughput by more than 85 percent
In order to keep pace with market demand and maintain itsleadership position in the industry, Nintendo Co. sought to upgrade itsconveyor and sorting system at its North Bend, Washington, facility. The oldsystem had capacity limitations that prevented it from keeping pace with marketdemand. The system couldn’t handle smaller unit sizes, nor could it keeppace with the increased volumes associated with increased sales. As part of acomplete system retrofit, the company relied on Rockwell Automation controlcomponents to provide the speed, efficiency and flexibility needed for thiscritical system.
Nintendo Co. Ltd. of Kyoto, Japan, is the acknowledgedworldwide leader in the creation of interactive entertainment. Nintendo hassold more than one billion video games worldwide. It has created industry iconssuch as “Mario” and “Donkey Kong” and launchedfranchises like “The Legend of Zelda” and“Pokémon.” Nintendo manufactures and markets hardware andsoftware for its popular home video game systems, including the Nintendo 64 andGame Boy, the world’s best-selling hand-held video game system.
As a wholly owned subsidiary, Nintendo of America Inc.,based in Redmond, Washington, serves as headquarters for NintendoCompany’s operations in North America. The North Bend plant is the onlyNintendo-owned distribution facility in the U.S., so it is essential that thefacility operate at peak performance to meet the increasing market demand forNintendo products.
Nintendo’s existing conveyor system was not meetingthe distribution center’s throughput requirements. Because the system wasmore than nine years old, it relied on older controller and conveyor technologythat lacked the capabilities needed to enhance work flow and increasethroughput capacity. For example, the aging sortation system couldn’taccurately sort boxes under 12 inches in length, a critical issue given theindustry’s move to smaller unit boxes. In order to accommodate newerproducts, Nintendo needed to expand the capabilities of the distributionfacility to process newer products being shipped in boxes as small as sixinches in length. Nintendo knew an upgrade would enable the system to runfaster and more efficiently.
Overview of the distribution process
Nintendo video game systems are delivered to the North Benddistribution facility already assembled with several units packed in a carton.After arrival the units are put away into the warehouse storage system untilthe orders are picked. Units are shipped both to customer distribution centersand retail outlets in full- pallet, full-case, and mixed-case quantities.Direct-to-consumer shipments also are sent from the facility year-round, with agreater concentration of shipments occurring during the holiday season.
Full-pallet shipments bypass the conveyor and sortationsystem and are delivered directly to the appropriate shipping lane. Forfull-case and mixed-case orders, as well as direct-to-consumer shipments, theindividual boxes are placed on a conveyor and sorted by shipping service levelto the appropriate “takeaway” lane for loading and delivery.
Implementing a new conveyor system
To upgrade its aging sortation and conveyor system, Nintendoturned to material handling integrator R.H. Brown Co., Seattle, Washington, whothen teamed with Hytrol Conveyor Co., Jonesboro, Arkansas, and Serra Systems,Healdsburg, California, to engineer a retrofit of the sortation system thatwould meet the growing demands for Nintendo products.
The engineering team was determined to deliver an upgradedcontrol system capable of meeting their operating and efficiency goals. Sincethe Nintendo plant already had several Allen-Bradley products throughout thefacility, Jerry Danson, equipment manager, Nintendo of America, requested thenew system be controlled by an Allen-Bradley programmable logic controller.
“Over the years we’ve come to rely onAllen-Bradley control products to make sure we keep pace with consumerdemand,” said Danson. “As the market has changed and demand hasgrown for smaller units and greater volumes, we knew Allen-Bradley productswere the logical choice for our control system.”
The engineers considered an Allen-Bradley SLC Seriesprogrammable logic controller or an Allen-Bradley ControlLogix5550 controller.After evaluating the existing system and the controller options available, oneof the engineering team’s first and most important decisions was todesign a new system retrofitted with the ControlLogix5550 controller.
“The typical scan time for the SLC controller in thenew system would be about 20 to 30 milliseconds,” said Don Winkle,engineering manager, Serra Systems. “To meet the demands of the newsystem, the scan times had to be less than 10 milliseconds. With its fastprocessing speed, the ControlLogix controller averages a scan time of 5-6milliseconds in the new system.”
While the SLC programmable controller is designed for abroad range of industrial application customers who want a small controllerwith high value, performance, functionality, robustness and Allen-Bradleyreliability and support, it is best suited for discrete and factory floorprocess applications. The ControlLogix controller has the high-end capacityneeded to handle the speed and throughput requirements specified by Nintendo.The complexity of the application and the objectives determined by Nintendomade the system an ideal choice and well-suited for the robust capabilities ofControlLogix controller.
“With the ControlLogix platform, we gain theflexibility to program every parameter possible and still remain within the 10millisecond time window,” Winkle said. “For the SLC to meet thenecessary processing times, the programming would have to be cut, whichtranslates into fewer application features.”
Variable gap optimization process speeds throughput
To increase throughput speeds, several obstacles had to beovercome. Products are often pulled in waves to fill orders going to the sameretail store, and therefore are routed to the same takeaway lane. While themain conveyor system runs at 350 feet per minute, the takeaway lanes run atonly 100 feet per minute. Without making alterations to the system, boxes wouldeither build up in the takeaway lanes or need to be recirculated through theplant, slowing system throughput and impacting delivery times.
Given these challenges, the engineering team developed asolution that would eliminate backups in the takeaway lanes. They implemented avariable gap optimization (VGO) process designed to keep the system runningsmoothly. For example, the VGO process speeds or slows the conveyor in order tooptimally space adjacent boxes heading for the same takeaway lane. Thismaximizes sorter throughput and prevents backups from developing.
At the core of the system is the fast processing capabilityof the ControlLogix5550 controller. The VGO scanner reads the barcode of anentering box. The ControlLogix controller processes the information and assignsthe box to an appropriate takeaway lane. Simultaneously, the length of the boxis measured, added to the accumulated total length (linear feet) for that laneand stored in the ControlLogix controller memory. The actual gap between onebox and the next box also is measured. The larger the accumulated length in alane, the more space is created between one box and a subsequent box destinedfor the same lane. The process allows more time for the takeaway lane to empty,ensuring that the lane has the capacity to hold subsequent boxes. When the laneaccumulator completely empties, the space between boxes is set at the minimum,and the conveyor operates at full speed.
To accomplish this process, an Allen-BradleyControlLogix5500 controller is connected to an Allen-Bradley Ultra 200 DigitalServo Drive via an analog output module. The ControlLogix controller processesthe information to determine the optimal gap and commands the servo drive toeither speed or slow the conveyor. The fast processing time of the ControlLogixprocessor, combined with the rapid response time of the servo drive, allows thesystem to work efficiently and minimizes the amount of conveyor lengthnecessary to make these speed changes.
The VGO process also increases overall system throughput byminimizing the recirculation of boxes. Due to the previous sorter and controlsystem, the recirculation lane is long. If a box needs to be recirculated, itcan take a substantial amount of time to make its way back through the systemand down the appropriate lane. In a scenario where a truck is packed andwaiting for part of the shipment to recirculate, overall throughput can beaffected significantly. In addition, the VGO process prevents the sorter fromjamming and the takeaway lanes from overfilling.
Directing the boxes to the appropriate shipping lane
Once the boxes are placed on the conveyor in optimal spacingmeasurements, the boxes head to the next stage of the system — theshipping induction point where the boxes are sorted. Using an Allen-BradleyPanelView 550 interface, operators assign destinations (takeaway lanes) to thebar codes that are stored in the ControlLogix controller. Omnidirectionalscanners read the label on the box, and the ControlLogix controller processesthe information. Based on the information programmed via the PanelView,ControlLogix directs the box to the appropriate takeaway lane. The boxes arethen loaded onto trucks and shipped to the designated retailer.
ControlLogix Multi-Vendor Interface module makes deviceconnection simple
To connect the scanners to the ControlLogix controller, thenew system uses a ControlLogix Multi-Vendor Interface (MVI) module. Thealternative to the MVI module is an SLC BASIC module. The MVI module representsa key upgrade from the BASIC module, as the MVI module has three ports and theBASIC module has only one port. The six scanners (three at the VGO process andthree at the shipping induction point) are connected to two ports. With thecapacity to store a small amount of code written in C programming language, theMVI cards can complete minor processing functions before presenting theinformation to the ControlLogix controller to process and evaluate.
The third port is used as a host interface, directlyconnecting ControlLogix5550 to the AS/400 Warehouse Management System (WMS).This enables a checks-and-balances system: ControlLogix sends divert verification messages to the WMSto notify the WMS that the cartons have been switched to “divertedstatus.” All connections are made via RS232 protocol links.
Because of the programming capability of the MVI card, thesystem achieves substantial speed enhancements. Other benefits also areachieved as a result of using the MVI module over the BASIC module, including asignificantly minimized footprint. With the BASIC module, Nintendo would havehad to install two additional cards to the rack. Doing so would requireextending the rack, taking up valuable electrical enclosure space. Using theBASIC module also would require more power, software and maintenance, as therewould be three modules instead of one to achieve the same results as thosegenerated by using the MVI module.
Diagnostics and troubleshooting made easy
The ControlLogix controller is programmed using theRSLogix5000 programming software. The RSLogix family incorporates superiordiagnostics, reliable communications, an intuitive user interface and enhancedreporting options to help maximize performance and reduce development time.
“It’s one of the best development environmentsout there,” Winkle said. “It’s easy to install, stable andintuitive.”
RSLogix5000 also uses a Microsoft ActiveX control, TrendX.TrendX allows users to integrate the programming software with an HMI softwarepackage such as Rockwell Software RSView32 to monitor real-time data andprovide historical trending from HMI data.
“It [RSTrendX] is one of the best features ofRSLogix,” Winkle said. “You can run a histogram to see the internalworkings of the ControlLogix controller. RSTrendX allows you to comparehistorical data to current data, and the troubleshooting capabilities of thatfeature are enormous.”
Direct remote access simplifies updates and speeds troubleshooting
Serra Systems now has direct remote access to the system atthe Nintendo facility. This allows the engineers at Serra Systems to accomplishchanges or enhancements over the phone line, greatly simplifying system updatesand troubleshooting.
“Direct remote access is a valuable timesaver when itcomes to troubleshooting,” Winkle said. “If they have a problemwith the system, technicians may have to troubleshoot for a couple hours tofind the problem. We know the system so thoroughly that we can often pinpoint aproblem very quickly. For example, something as simple as someone unknowinglychanging the parameters on the HMI could cause minor problems. Internally, theymay not notice the change, but we would notice it because we know what theparameters should be.”
Increasing system throughput
The Nintendo distribution facility met its goals with theupgrade of the conveyor and sorting system. On average, the new conveyor systemruns just slightly faster than the previous system. However, with the highdelivery accuracy and low rate of product recirculation attributable to the VGOprocess, the throughput has increased from about 80 cases per minute to about150 cases per minute. While the old system couldn’t handle boxes lessthan 12 inches in length, the new system can accurately sort and move boxes assmall as six inches in length, routinely handling boxes in the six- tonine-inch range. With throughputs also significantly increased, Nintendo ispleased with the new system.
“The new conveyor and sorting system has allowedNintendo to accurately and effectively expand their sortingcapabilities,” Winkle said. “It also has enabled them to nearlydouble their throughput to meet the increasing market demand for Nintendoproducts.” MHM