WH - High Volume Picking

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8720 Red Oak Boulevard Suite 201 Perspectives on Material Handling PracticePerspectives on Material Handling Practice

Charlotte, North Carolina 28217-3992 Page 1 of 18

Perspectives on Material Handling PracticePerspectives on Material Handling Practice

P apers i n the P e r s p ec t i ves s e r i es have app ea red i n confe r ence p roceed i ngs o f P apers i n the P e r s pec t i ves s e r i es have appea red i n confe r ence p roceed i ngs o f

the Mater ia l Handl ing Ins t i tute between 1992 and the present . As such theythe Mater ia l Handl i ng Ins t i tute be tween 19 92 and the p resent . As such they

prov i de a po i n t o f r e fe rence as t o how the i ndus t ry i s chanpr ov id e a po int o f re f erence as to how the indus tr y i s changing as wel l as i ns ightging as wel l as ins ight

into accept ed p ract i ce d ur ing th i s per iod . I n many cases the authors c r ed i ted haveinto accept ed p ract i ce d ur ing th i s per iod . I n many cases the authors c re d i ted have

ei t her changed jo bs o r are no l onger i n the indus try . So me companies as wel l haveei t her changed j ob s or are no l o nger in the i ndus try . So me companies as wel l have

been thebeen the s ub j ec tsub ject o f merger s or r eor gani zat io n wi th a new cor po rateof merger s or re or gani zat ion wi th a new cor po rate id ent i t y .i d e n t i t y .

HIGH VOLUME CASE PICKING(A UNIQUE NEW APPLICATION FOR DEEP LANE STORAGE SYSTEMS)

SCOTT RICHARDSON,

MANAGERNORTH AMERICAN DISTRIBUTION

AND

SCOTT TELKMANAGER

NORTH AMERICAN DISTRIBUTION PLANNING

Black and Decker4041 Pleasant RoadFort Mill, SC 29715

ABSTRACT

When developing a vision and concept of operations for a new world class distribution center,

much effort and detail is focused on stipulating and estimating how the plant should and willperform. Design teams go to great lengths to ensure a process exists to meet not only every

business and customer requirement that can be identified, but also every imaginable exceptionand operating condition that will be encountered. Even with huge amounts of experience, talent,

vision, and lick most facilities are fortunate to have their arms around 75-80% of thesituations, conditions, and combinations of complications that will be encountered. However,due to the complex nature of integrating customers, factories, layers of software, people and

material handling equipment into one focal operation, various sets of circumstances can never beprojected or predicted, just simply encountered.


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The start-up of Black & Deckers new 80,000 sq. ft. distribution center in Fort Mill, SC was a

classic example of the above scenario. The highly automated facility, which features the latest indistributed software systems and material handling equipment presented a unique start-upchallenge. Due to the synchronous nature of the various processes, all pick types (pallet, case,

repack, non-conveyable) must arrive at the dock in a collapsed time frame, to enable outboundtruck docks to turn quickly, while simultaneously maximizing transportation dollars (see Figure

1). As new products and order types were added to the mix, and higher through-put levelsachieved, an array of obstacles and bottlenecks kept surfacing and moving from process to

process as the operation strived to maintain a synchronized balance with rapidly changing

workload complexions and order profiles. A variety of systems and material handling

enhancements were employed to offset a variety of constraints. However, replenishment of thefull case picking area was the most difficult to overcome. The major physical upgrade to this

process was the installation of a deep lane storage system.

Deep lane storage systems are typically used as a means to either increase space utilization

and/or to support high volume pallet picking operations. In this unique application, a deep lanestorage system with additional pushback rack was erected as pick faces for a pick to belt module.In effect, this allowed a huge buffer inventory of case pick to be presented to the pick face to

allow additional time for replenishment to arrive; protecting service levels, particularly when arun on a SKU within a wave was experienced. The Loadback has allowed for up to 40% of all

picks to come from a condensed area which required less replenishment travel time andphysically concentrated the workforce in the department for more effective supervision.


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INTRODUCTION

In the summer of 1992, while looking for ways to reduce costs within the distribution and

transportation areas, Black & Decker began examining the idea of consolidating its distributionnetwork.

At this point in time, in the North American consumer products arena, Black & Decker wascomposed of five unique divisions operating out of fourteen different distribution locations.

Most of these locations served one division only (Figure 2).

Single Division Distribution Locations

Pacoima, CA Price Pfister(Plumbing supplies)Anaheim, CA Kwikset (Locks and supplies)Bristow, OK Kwikset

Chicago, IL Price Pfister Morrow, GA Price Pfister Raleigh, NC (Millbrook) Household Products

Raleigh, NC (Triangle) Household ProductsRaleigh, NC (Longs) Household Products

Raleigh, NC (Carolace) Household ProductsColumbia, MD Power Tools

Multiple Division Distribution LocationsRancho Cucamonga, CA Power Tools, Accessories & Household ProductsHampstead, MD Power Tools, Accessories

Mexico City, Mexico Power Tools & Household Products

Brockville, Canada Power Tools, Accessories & Household Products

Black & Decker had successfully operated within this framework for years. Coupled with the


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desire to reduce costs, the launching of the De Walt product line in the early 1990s increased

throughput pressures on the network and strained it to the breaking point. To meet thesechallenges, a long term distribution strategy was developed:

large bi-coastal DCs consolidate all 5 business divisions selective automation highly systematized

In mid-1993, the decision was made to build a distribution center to increase capacity and at thesame time consolidate several smaller facilities to reduce the overall cost. Enhanced service interms of fill rates, order accuracy, and order turnaround time within the D.C. was also factored in

as project goals. Also, consolidated shipment of multi-dimensional orders to the same ship-todestination as one shipment was a major design target. Not only to reduce transportation cost,

but for ease of customer request of a Black & Decker shipment. This required all repacks, case

picks, pallet picks and non-conveyable picks to arrive at the shipping dock not only for an orderbut for a planned consolidated outbound truckload. Targets for fill rates and order accuracy were

99.5%, while D.C. order turnaround was to be reduced to within 24 hours.

After extensive cost modeling and a site search process, the Charlotte area was selected to buildthis east cost DC. Construction in Fort Mill began in November 1993. Thus, the North American

distribution network took the first step toward a bi-coastal multi-divisional strategy (see Figure3). The facility was designed to handle current volumes with anticipated growth:


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Building Design CriteriaFootprint 776,000 square feetHeight 32 feet clear Receiving 26 doorsShipping 34 doorsOffice Space 17,000 square feetOperating Design Criteria - Daily Requirements:Orders 10,000 - 12,000Loose conveyable cartons 100,000Full pallet picks 3,000Loose repack units 140,000Inbound trailers 70Outbound trailers 120SKUs 12,000Pickfaces 15,000Equipment Selection

Loose Carton Picking 3 tiered 3 pallets deep picking modules (Unarco)Conveyor 3 miles of accumulation (Rapistan) 2 shoe sorters (Rapistan)Full Pallet Picking VNA wire guidance (Raymond) Turret and reach trucks (Raymond) Single deep pallet rack (Ridg-U-Rak) Bulk floor storageLoose Unit Picking Carousels and carton flow rack (Raymond)Systems ArchitectureHighly IntegratedTransportation Planning System (TPS) - routing shipmentsWarehouse Management System (WMS) - planning work within the DCDistribution Control System (DCS) - carousel controlSortation Control System (SCS) - sorter and conveyor control

A detailed illustration of the system hardware and a total distribution system information flowchart are highlighted in Figure 4 and 5 respectively.Equipment began to be installed in July 1994. The building was completed by September. Allequipment was installed by mid-November. Integration testing lasted through January 1995.

Inventory was being moved into the building starting in November.On January 30, 1995, the Fort Mill DC received its first of orders and the real fun began.


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Technology Infrastructure (Figure 4)

Service Project Start NowPlatform 2 x Digital Axp

76201gb Memory

2 x Digital Axp8460

2gb MemoryStorage 24gb

Conventional

700m Solid state

62gbConventional

1.4gb Solid stateOperating

System

Open VMS 6.1

Open VMS 6.2

Database Oracle Version7.0.16

Oracle Version7.1.3.2

Terminals andPCs

100 VT420CRTs

10 PCs100 VT420

CRTs20 PCs

Radio FrequencySubsystem

75 Vehicle12 Handheld

81 Vehicle38 Handheld

Local AreaNetwork

Designed by Digital, FDDI Backbone,Cabletron Active Components

Wide AreaNetwork

T-1 Datalink with ISDN Dial Backup

Comments:

Two Platforms with Primary and Development that also Serve as FailoverTargets.

Performance and Usage Driven Upgrade from 190mhz CPUs to (6) 300mhzCPUs

(500% Increase in Power). All Production Disks are Host Mirrored with Some Controller Based StripeSets.

Open VMS Chosen for Clustering and Stability. WAN Oversized to Support Timing Requirements and for Responsive X-Windows

Traffic Between Towson and Fort Mill.


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FACILITY START UPDuring the two year time period from conceptual design to the first order being shipped, adetailed start up plan was developed. This plan outlined and tracked every detail about the

facility plan, implementation and start up for the building, equipment, system and people.Black & Deckers business volume varied throughout the occurred in quarterly cycles with peakshipping occurring in March, June, September and December. Due to the large retail sales in themonths preceding the holiday season, heavy volume occurs September through December. That

transfer of inventory and orders was planned to occur in stages. Only a portion of the total

business would be transferred into Fort Mill at a time. After that piece was digested, anotherwould be moved into the new building. Because of this spiking in the latter part of the year, it

was decided to make the first transfer in late January or early February - the lowest volume of theyear.The Household Products Group was selected to be transferred first due to its simpler processingand handling requirements. The fewer SKUs were involved and all processing was done ineither full carton or full pallet increments with the volume split roughly between the two. Only

Household would be handled in February to allow any bugs to be worked out of the system. Asmall Portion (about 25%) of the Power Tool and Accessory business would be moved in March

due to the quarter end occurring that month. During the low month of April, the bulk of theremaining Power Tool and Accessory business would be moved. The last 25% would wait untilMay for transition. This would allow the summer for all problems to be worked through in

anticipation for the holiday shipping months. (See Figure 6 for SKU breakdown by division).

Design Assumptions: Active SKUs (Figure 6)

Business Unit SKUsHousehold Products 300

Power Tools 2500

Accessories 5600

TOTAL 8300

85,00 Storage Locations (33,000 Double High)Repack : 8,000 SKUs

Pick to Belt: 4,000 SKUsNon-Convey: 300 SKUs

The phased approach was designed to allow a steady stream of people to be hired and trainedrather than a large amount all the one time. Systems, equipment or other problems could also be

worked out at lower volume levels with lesser impact on customers.And then January 30th arrived


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As anyone who has ever been through a start up can tell you, at the very least it was a veryinteresting day. For years, Black & Decker was used to shipping tens of thousands of cartons perday. On this day, it took 50 people 15 hours to ship 30 cartons. Not a stellar beginning.

Although it wasnt a day to write home about, it was all up hill from there.Through the next 12 months, volume increased steadily as problem after problem was overcome.Capacity barriers at 2,000 - 5,000 - 10,000 - 20,000 and 30,000 cartons per day were

experienced. Each of these barriers were overcome using a combination of system

modifications, training and process improvement. Training was not just for the hourlyassociates. It was also for the management team as we learned to manage the building and the

flow of work.Patterned loosely after previous facilities, the new building was designed to work synchronously.

In other words, all parts of the building had to flow and work together otherwise, work from thefaster areas had to slow down for the slower area to catch up. The system was designed this wayto enable the customer to receive one pallet/one shipment even if they ordered a drill bit (not

conveyable, needs repacking), a drill (conveyable) and a workmate (not conveyable). The goalwas to have all of the items for the order arrive at the shipping dock at the same time. On a daily

and hourly basis, the work load and people in each area had to be examined and balanced toinsure that product kept flowing through the building. This was an educated step for manymembers of the management team.

ICEBERG EFFECTDebugging, start-up and testing is a orderly progressive affair normally performed by the vendorwith little or no input from the owner. The purpose of this work is t satisfy the vendor that thesystem will satisfactorily perform for acceptance tests conducted for the owner. Each sub-

system will must be independently processed and any deficiencies corrected prior to continuing.After sub-system requirements are satisfied, each one must be integrated with others to proveinterface compatibility. Finally, all sub-systems are tied together to form the total system.

The total system must then be stress tested for short durations and the results documented and

deficiencies corrected. The total system must then be stress tested for a longer duration. Whenthe system appears to be functioning as specified, the system is accepted.Taking over a major automated Distribution Center when the vendors leave is very much liketaking over as Captain of a ship, hopefully not the Titanic. Everything is new and looks neat andclean. However, below the surface, obstacles that will cause great pain and suffering are

lurking. These obstacles take on different forms in every new project but they are always there. Ramp-Up and Obstacles - Each sub-system performed as planned and the total integrated

system gave every impression of working. New businesses were brought in and dailycapacity increased. Problems were encountered in mechanical equipment, controls and

software. Most of these problems were corrected without major difficulty, they did howevercause orders not to be completed within the allotted time and the backlog started to grow.


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The first reaction is to blame the vendor. The vendor comes in and checks the system and

sometimes finds a deficiency in the design or maybe the vendor finds the system functioningproperly and says the problem must be with other equipment or systems that are interfacedwith him. Very often the vendor says that the system was not designed to handle, process or

function in the manner you are requesting. OOPS, a failure to involve operations personnelin the design and functionality of the system. This Is probably the most devastating thing

that can happen in a project. It is generally the hardest to change. It almost always involvesaddition hardware and software and worst of all you have no one to blame but yourself.

Capacity Wall - The corrective actions were put in place and facility capacity starts to grow

and just as we reach our peak months, we find we have hit a capacity wall. Again, blame the

vendor, why cant we get more than 25% of the design volume through the system. There isone thing that many people fail to comprehend and that is that no matter how much bruteforce you throw at an automated system, you are only going to get so much through-put out

the door. It was at this point that we realized we needed help in determining the extent andsolutions to our problems. We contracted Allen Zeiler Technical Consulting (AZTEC) toinspect the material handling equipment and Garr Consulting to probe the Warehouse

Management System (WMS). We looked deeper into how we were using the system,starting at the shipping dock and working back all the way to wave planning. We stoppedand analyzed each bottleneck along the way and made adjustments as follows:

With the queue lanes available we found that we could not release cartons fast enough

from the Primary sorter. The Primary sorter has 50 lanes and each lane can hold up to

three pallets worth of cartons. The problem was that the waves were too large and laneswere not being filled, at the same time future waves were being released and they had noplace to go. It was decide to reduce and restrict a wave to utilize half of the Primary sortlanes (25 lanes). The other 25 lanes could then start queuing up the next wave when it

was released. This we termed flip flopping as we would flush half the lanes while wefilled the other half. This one adjustment literally increased our through-put by 100%and allowed us to meet projections for the end of the first quarter of 1996.

Repacked cartons posed its own set of problems. Part of the original justification for the

project was to reduce freight by consolidating orders. Hence, repacks are palletized withfull cases. Repacks are stored in 20 horizontal carousels with one associate operating 2

carousels in what we call a pod. A conveyor circles the carousels with diverts intoeach pod. The problem is that piece picking is slower than picking full cases and thesystem did not allow us sufficient visibility into the orders to properly plan the wave.

We do have five holding lanes so repacks should theoretically stay five waves ahead.Unfortunately, some waves will have a small number of repacks and the holding lanessoon become full, then a large repack wave occurs and the next thing you know, repacks

are behind and full carton picking has to be shut down in order for repacks to catch up.We somehow got through the first quarter without making significant changes in this

area. However, this area was only producing about 75% of what would be required inthe forth quarter and solutions would have to be found.

Carton Pick to Belt (PTB) was having problems getting replenishments to the pickface ina timely manner. Rack was cleared out in the proximity of the PTB area to hold fast


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moving stock keeping units (SKUs). This helped gain through-put but created a lot of

double handling.The Replenishment Manager (Software) had been written to call for replenishment at the time a

wave was planned. This flooded the area with product before there was a place to house it.Consequently the Replenishment Manager was turned off and replenishments were called for on

an emergency basis. This had its own set of problems in that some waves would call for moreproduct than a pallet flow lane could hold and then the associate would be waiting for product tocomplete the wave. By creating the holding rack (described earlier), we accomplished the task of

getting through the first quarter.

With the quick fixes that we implemented in the first quarter, total through-put had more than

doubled. Fortunately, the end of the second quarter was to be about the same as the first quarter.The problem was that the third quarter was going to require greater through-put and we haddiscovered another wall. The Team had been observing the changes incorporated in the first

quarter to determine what had to be done in the next five months to push the wall back oncemore. The following Items were approved as projects: Replenishment is the Culprit - Rewriting the software for the Replenishment Manager was

going to be a fairly large undertaking with limited resources and other software projects that

higher priorities. The best available solution appeared to be changing a portion of the currentthree deep pallet flow pickfaces to a deeper controlled flow pickface. It was determined that

addition racking could be added to the existing flow rack and gain an additional five palletpositions for a total of eight pallets deep.

Additional Queuing Conveyor - Bu putting the fast movers in the deep lane picking system,

it was determined that there would need to be additional conveyor between the PTB module

and the sortation system. It was determined that about 180 feet of additional accumulationconveyor would have to be installed to handle the volume.

No-Reads and Mis-Picks - Cartons being conveyed out of the pick modules were not being

rejected until they were on the loading dock. This caused last minute problems on the dockand required runners to get the right product to the right Queue lanes in short order. This wasnot working and it was decided that no-read and mis-picks would be rejected earlier in order

to re-label or re-pick and accelerate the cartons return to the sortation system. No-Reads at the Secondary Sort (Palletizing lanes) - It was determined that if all the real

problems were being taken care of at the Primary reject. The reject for the secondary shouldconvey to a point just upstream from the scanner where an associate could take corrective

action and re-induct the carton. The Repack Area - This area needed to become more ergonomically friendly and designs

were submitted to rearrange the area reusing most of the existing conveyor. Hard copypacking lists would be replaced by scanners to verify orders. Totes would be purchased

allowing consistency in the size of footprints being conveyed to reduce jams. (See Figures 7and 8).


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NEW CAPACITY WALL DISCOVEREDDuring the second quarter the above enhancements were ordered and installed. Work-around

plans had to e established and cut over mythologies employed.

The system had stabilized at 45,000 to 50,000 cartons per day. It was anticipated that with the

new equipment, the system would achieve rates of 65-70,00 cartons per day. However, duringthe second quarter pallet picking and receiving activity has been low, and has masked the depthof the replenishment problem, allowing the system to muscle replenishments, making these

product moves to the pickface the best task for virtually all rolling equipment.

Also, at the higher sustained volumes, we began to see continued floor cuts on certain SKUs

throughout the day.Upon analysis, we found that some location would historically turn once a week until the

upsurge in demand, and then they would turn as high as 10 times per day. This resulted in a lotof stock outs. This fact was aggravated by the Transportation Planning System (TPS) and WMS.The systems would group orders together to minimize shipping costs and maximize productivity.

The system would group all the picks for one SKU within one wave. Instead of spreading the3,000 picks across 8 hours, all the picks would be grouped into the same 30 minute wave. It was

physically impossible for replenishments to keep up. Another unfortunate side effect happenedwhen these high demand days occurred and replenishments could not keep up for the locations.As resources were focused on these high demand locations, the resources were frequently pulled

from other tasks causing stock outs to occur in normal locations.Once production planning was smoothed out to spread the work across the day, another rock

emerged from the lower lake. Replenishments were not being released and worked in a logicallysequential fashion.When the replenishment module was written for WMS, it envisioned and designed so that thereplenishment would arrive at the pickface the exact moment that it was needed. A lofty goal.To accomplish this feat, the replenishment had to be worked on before the product was picked.

There are four major control points on the life of a wave: at planning, at release for picking, at

picking and at closing. The replenishments had to be released for work at one of these points tokeep it in synch with the wave. At closing and picking were too late for the replenishment toarrive when needed. It was decided that at releasing and at picking were too close together to

allow time for the replenishment to be accomplished. At planning was the replenishment releasepoint.Unfortunately, this became a serious problem. Although the time period between wave releaseand wave picking was short, the time between wave planning and picking sometimes becamelengthy. Yet the replenishments would be released when the wave was planned and associates

would begin working them. This caused a lot of product to arrive at the pickface too early.Priorities also became meaningless. When a location was projected to go bellow empty, thereplenishment would be bumped to top priority. A top priority that was needed for a wave being

picked could be superseded by a phantom top priority from a future wave.


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During slower volume days and periods, the facility could muscle through these problems. Asthroughput increased and demand requirements doubled, the problem with replenishment timingand volatility of SKU became a new capacity wall.

THE ULTIMATE SOLUTION

An aggregating factor to the inability to predict a new facilitys operating behavior prior to

reaching steady state is that new issues and obstacles continue to surface along the start-up

ramp. As problems are resolved and bottlenecks eliminated, higher throughput rates, and closerto optimal performance levels continuously lower the water, only to expose new rocks which

hinder the flow to the next level.After months of fire fighting, and as consistent operating levels were approached, it was

discovered that replenishment to the case picking area was the remaining limiting factorpreventing the operation from obtaining its full operating throughput capacity. This was causedby the overly complicated designed algorithm which used a future, time phased replenishment

strategy, coupled with lumpy SKU velocity by pick wave, this created by the TransportationPlanning System.With the replenishment problem obviously being created through a culmination of multiplecontributing factors, no one fix would completely correct the situation. Finally, a three-

pronged approach was agreed upon to solve the problem. This included: Producing Planning - Enhancements were made to the pick wave planning process which

would balance the demand for a SKU within parameters to prevent slugging of pickfaces.(Lumpy demand using an average days worth of stock in one 20 minute wave).

Warehouse Management System - Logic changes were made to the replenishment

algorithm itself. Specifically changing the strategy from replenishment task creation at timeof wave planning to wave release --- and a change from a pickface stock allocation conceptto a simple min/max concept with priority bumping.

Deep Lane Storage System - A Loadbank deep lane system was erected as pickfaces at a

pick to belt module. This created a buffer inventory case pick stock to be presented to thepickface which protected against stock outs as heavy replenishment quantities were allowed

more time to arrive. (For Loadbank specs and elevation see Figure 9).Loadbank Deep Lane Pickface System (Figure 9)

Structural Dimensions

Height: 8 Pallets Deep, 33 Feet LongWidth: 4 Feet, 1.5 inches per PickfaceSystem Height: 28 feet w/ 5 Pallet Levels 3 Picking Levels


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2 Storage Levels

System CapacityPicking Lanes:51 Locations / Level 153 Total possible SKUs 1224 total Pallet CapacityPallet Return: 7 Locations / Level 21 Total LanesPushback Lanes: 58 Locations / Level = 116 Total possible SKUs 116 Total Possible SKUs 348 Total Pallet Capacity

Working Requirements:

Operation at 50 - 120 degrees Fahrenheit Unit Load Weight Maximum = 3000 lbs. Nominal Load Size = 48 in. long x 40 in. wide x 52 in. high Safety Decking within Lanes will Accommodate Minimum Load =

300 lbs.

Minimum Air Supply = 80 psi with 2 air drops

Controls

Controlled by Cattron System RI Interface 3 Decoders of 15 Outputs each User control Methods: Hand Held Transmitters w/ 4 Digit ActivationCode for control from Change. 15 Push Buttons for Control fromdischarge end.

Adjustable Timing Circuit:

Parameter Min(Sec) Max(Sec) ON 0.1 3.8 OFF 4.2 25.5

Duration 10 300

CONCLUSIONEven with huge amounts of experience, talent, vision, and luck most facilities are fortunate to

have their arms around 75 - 80 % of the situations, conditions and combinations ofcomplications that will be encountered. Due to the complex nature of integrating customers,factories, layers of software, people and material handling equipment into one focal operation,

various sets of circumstances can never be projected or predicted, just simply encountered.


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By taking a well proven and seemingly low tech technology and applying it in a new way, wewere able to solve a specific and complicated problem in a very high tech environment.

The software enhancements coupled with the deep lane installation resulted in a 20% increase in

productivity in the pick to belt operation, as in an example of how unique and new applicationsand configurations of existing, and proven equipment can offer affordable solutions, with

productivity gains, and minimal capital investment.

Documents

WH - High Volume Picking