wood furniture components implementation of flow-line technology.pdf

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Case studies of lean manufacturing in furniture and supplying industries Applications for increased international competitiveness

3Case StudyBy

W. Duane Motsenbocker Philip H. SteeleSteve L. Hunter Steven H. Bullard

Al Schuler

Research BulletinForest and Wildlife Research Center

#

Wood Furniture Components:Implementation of Flow-Line TechnologyBased on Lean Manufacturing Concepts


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Authors W. Duane Motsenbocker is interim director of Mississippi State University’s Industrial Outreach Ser- vice. His primary interest is production improvement in the furniture manufacturing industry. Philip H.Steele is a professor in the Department of Forest Products. His primary research interests is automated

wood processing systems. Steve L. Hunter is an associate professor in the Department of Forest Prod-ucts. His primary research interest is industrial engineering. Steven H. Bullard is Chair, Departmentof Forestry at the University of Kentucky. Al Schuler is a research economist with the USDA ForestService, Northeastern Research Station.

AcknowledgementsThe authors would like to express sincere thanks for financial support for this project which was providedby Research Work Unit NE-4803, Economics of Eastern Forest Use, Forestry Sciences Laboratory,USDA Forest Service, Princeton, WV, under cooperative Agreement 010-CA-1124234-021. Sincerethanks are also extended to study cooperators at Airline Manufacturing Company.

To Order CopiesCopies of this and other Forest and Wildlife Research Center publications are available from:

Publications Office Forest and Wildlife Research Center Box 9680 Mississippi State, MS 39762-9680

Please indicate author(s), title, and publication number if known.

Publications can also be found at our web site at www.cfr.msstate.edu

CitationMotsenbocker, W.D., P.H. Steele, S.L. Hunter, S.H. Bullard, A. Schuler. 2005. Wood furniturecomponents: Implementation of flow-line technology based on lean manufacturing concepts. Forest and

Wildlife Research Center, Bulletin FP333, Mississippi State University, 15p.

Research BulletinFP 333

Forest and Wildlife Research CenterMississippi State University

The Forest and Wildlife Research Center at Mississippi State University was established by theMississippi Legislature with the passage of the Renewable Natural Resources Research Act of1994. The mission of the Center is to conduct research and technical assistance programs relevantto the efficient management and utilization of the forest, wildlife, and fisheries of the state and region,and the protection and enhancement of the natural environment associated with these resources.FWRC scientists conduct this research in laboratories and forests administered by the University andcooperating agencies and industries throughout the country. Research results are made available topotential users through the University’s educational program and through Center publications such asthis, which are directed as appropriate to forest landowners and managers, manufacturers and users offorest products, leaders of government and industry, the scientific community and the general public.Dr. Bob L. Karr is interim director of the Forest and Wildlife Research Center.

FWRC


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Forest and Wildlife Research Center

Mississippi State University

By

W. Duane Motsenbocker

Philip H. Steele

Steve L. Hunter

Steven H. Bullard

Al Schuler

Wood Furniture Components: Implementation of Flow-Line

Technology Based on Lean Manufacturing Concepts

Case Study #3Case Studies of Lean Manufacturing in Furniture and Supplying

Industries: Applications for Increased International Competitiveness


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Introduction................................................................................................1

Overview of Lean Manufacturing...............................................................2

Airline Manufacturing Company................................................................ 3

Flow-line Production System......................................................................4

Before Lean...........................................................................................5

Implementation of Lean ........................................................................7

Benefits of Lean .........................................................................................8

Summary ..................................................................................................12

Glossary....................................................................................................14

References................................................................................................15

Table of Contents


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Introduction T his case study is #3 in a seriesof studies that relate specificallyto the development and application oflean manufacturing techniques for thefurniture and wood component sup-plying industries. Case study #3 isan example of how productivity can beincreased in a furniture manufacturingorganization by using flow-line technol-ogy.

This case study provides informa-tion about lean manufacturing and how

a lean manufacturing system can beimplemented, followed by a detailed

case study of a wood component manufacturing company’s adoption of a newflow-line technology based on leamanufacturing concepts.

Other case studies in this serieare available as separate reports. (Foravailability see the publication linat the Institute of Furniture Manu-facturing and Management web site

www.ifmm.msstate.edu). Informatiohelpful in understanding lean manufacturing systems can also be found i

the resources listed in the next sectioof this report.

3Case Study#

Case studies of lean manufacturing in furniture and supplying industries Applications for increased international competitiveness

Wood Furniture ComponentsImplementation of Flow-Line TechnologyBased on Lean Manufacturing Concepts


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Case Study #3

Overview of LeanManufacturing

manufacturing processes offer greapotential for increasing productivityand product quality in this importantindustry. These processes represent a significant means of achieving and sustaining“higher order” competitive advantagesin a manufacturing environment facingstrong pressures from global competitors. Competitive pressures in the fur-niture industry today are particularlyrigorous from countries with relativellow wages and in some cases relativellow requirements for worker safetyenvironmental protection, and otherregulatory issues that directly impacproduction costs (Bullard and West,2002).

Lean techniques help manufactur-ers produce high quality products, on

time, with great flexibility and with high rate of productivity. Clearly thesemethods help producers capitalizeon “home court” advantages and are“higher order” competitive advantagesin that they are difficult to replicatequickly, particularly in countries thaare geographically distant from majoU.S. markets. Given the attractiveness of thebenefits of lean manufacturing, andtheir low cost, where might this type osystem be used in the furniture indus-try, and how might its adoption beimplemented? Answers to these ques-tions can be found by exploring somechanges within the Airline Manufac-turing Company.

• requires less labor and oor space;

• requires fewer design hours for

product development;

• requires less stock on hand;

• results in fewer defects;

• increases quality;

• enables faster delivery;• results in improved ergonomics; and

• results in maximum exibility in

product types and styles produced.

Compared to previous manufacturingsystems, lean manufacturing generally:

L ean manufacturing systems involvemanufacturing and assembly cells,“pull system” methodologies, and othertechniques to create the most effectiveand productive manufacturing systempossible for any given product. Leanmanufacturing differs greatly from theolder “batch” and “job shop” manu-facturing system designs offering previ-ously unattainable benefits.

Do the benefits of lean manufactur-ing outweigh the costs in your produc-tion facility? Although all facilities andproduction processes differ, the answerto this question is almost assuredly

yes. The benefits of lean manufactur-ing can be significant, while in mostcases the monetary costs are relativelylow. However, conversion to a leanmanufacturing system is not a simpletask and requires a strong, continuingcommitment from high-level manage-ment within the firm. Even though this system offers a

variety of benefits to manufacturerscommitted to its use, lean manufactur-ing has yet to be widely adopted in USfurniture production facilities. Theresults of this case study and the othersin this series demonstrate that lean

2


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Flow-line Production

3

Airline ManufacturingCompany

A irline Manufacturing Company isa wood component manufacturersupplying upholstered frame and casegood parts to the furniture industry.This family-owned business, locatedin Columbus, Mississippi, was found-ed in 1956. The company manufac-tures components from hardwoodand softwood lumber and compositeengineered panels. Some subassem-blies require assembly and finishing.In a typical week of production, thecompany manufactures hundreds ofdifferent wood parts. This case studyinvestigates the manufacture of onlyone of those parts: part number 146-3843.

Airline Manufacturing beganaggressive implementation of manufac-turing productivity improvements in

2001. Pressure from both internation-al and domestic competition alertedthe company that in some areas, theirmanufacturing costs were higher thanthose of their competitors. In response,the company installed more produc-tive manufacturing equipment such asautomated lumber cutup lines and high-speed computer numerically controlled(CNC) routers. In addition, thecompany began implementation of lean

manufacturing concepts throughout thefacility. This case study reports on theinstallation of one improvement, a flow-

line developed to replace a portion of afunctional job shop or batch processingsystem. (For more information aboutcell design and continuous flow see

Lean Manufacturing Systems and Cell Design by Black and Hunter, 2003.)

An analysis of Airline’s previousbatch processing system was performed

in early 2001 by Duane Motsen-bocker, Interim Director, Industri-al Outreach Service, Mississippi

State University. The initial findingsconfirmed management’s concern thamovement and storage of work-inprocess comprised a high proportionof Airline’s total manufacturing costOther issues facing the company weredefective parts, long lead times, ordersmisplaced, and missed shipment dates.

Implementation of lean principles cansolve or reduce all of these problems.

Airline Manufacturing Company president Judy Dunaway (center) and Duane

Motsenbocker (r) watch an employee mark defects between interconnected CNCrip and crosscut saws.


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Case Study #3

4

Flow-Line ProductionSystem

L ean manufacturing principlesdemand the systematic elimina-tion of all steps that do not add valueto products. Storage and movement of

work in process are non-value-addingactivities that should be reduced asmuch as possible. The company wasassisted with the development andimplementation of a one-piece continu-ous flow-line concept to replace some ofthe batch system operations that werein place. Since completion of this work,the company has replaced many of itsbatch processes with flow lines.

Typically, manufacturing andassembly cells are designed and imple-mented first and they are the key to thebenefits of lean manufacturing systems.However, in this case study, manage-ment determined that a pull systemflow-line would be designed and imple-mented instead of the normally selectedlean manufacturing cell. Althoughnot as productive as a manufacturingcell, flow lines are a good choice forsome final assembly lines. (For moreinformation about continuous flow seeCreating Continuous Flow by Rother

Black, JT., and S.L. Hunter. 2003. Lean Manufacturing Systems and Cell

Design. Society of Manufacturing Engineers, Dearborn, MI, 336p.

MacInnes, R.L. 2002. The Lean Enterprise Memory Jogger. GOAL/QPC,Salem, NH, 166p.

Ohno, T. 1978. Toyota Production System. Productivity Press.Cambridge, MA, 143p.

Schonberger, R.J. 1982. Japanese Manufacturing Techniques. The FreePress, New York, NY, 260p.

Sekine, K. 1992. One-piece Flow. Productivity Press. Cambridge, MA,286p.

Womack, J.P., D.T. Jones, and D. Roos. 1991. The Machine That Changedthe World. First Harper Perennial Publishers, New York, NY, 336p.

Some further resources outside of this seriesregarding lean manufacturing processes:

and Harris, 2001.)The goals of developing and

implementing a new flow-linproduction system at Airline wereto produce high-quality parts whileminimizing non-value-added workreduce work in process, improve ontime shipment, reduce raw materialsand finished goods inventories, andreduce lead times. The companysought to achieve these goals withououtlay of new capital. This case studydocuments the company’s actions toachieve these goals in the production othe selected part.

One of the more salient issuesfacing the company in making theseimprovements was doubt regardingthe true benefits of lean-basedmanufacturing concepts supported

by a forty-year history of relativsuccess under previous managementThis doubt was shared at all levels,from senior management to machinetenders. However, the companypresident determined that changes werenecessary for the company to survivin a competitive global economy. Toovercome management and employedoubts, an intensive lean educationprogram was implemented, posters

were placed in the plant to informemployees that changes were cominand discussions were initiated with alemployees.


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5

A schematic representing a portionof Airline’s original batchproduction layout is shown in Figure 1.

Work in process parts were moved in theplant via buggies with an approximatethree- by five-foot load carrying area.Parts are normally stacked on thesebuggies to a height of about four feet,thereby providing a total volume of

about 60 cubic feet (about 1800pounds) per buggy. Table 1 detailsthe large number of buggy movementsand the distances traveled by workersto produce 2900 of the subject part.Based on actual measured distancesand the number of workers movingthese parts, the total distance traveledby workers to move the selected parts

Before Lean

between machine centers to producethe required 2900 parts was 34,158feet, or about 6.5 miles. Only eightof 25 workers or less than 1/3, wereadding value to the part as it movedthrough the original system.

It should be noted that the 25 workers involved in the production othe part did not spend 100 percent of

Table 1. The part movement and labor requirements in Airline’s original batch processing system.

Travel Distance Using Flow LineMake 2900 each of part 146-3843

Description MovementMethodPieces per

LoadNumber of

LoadsNumber of

PeopleOne WayDistance

One vsTwo Way

Total PeopleDistance

Plywood warehouse to CNC Forklift 1104 3 1 272 1 1,632

CNC to Vertical Bore Buggy 380 8 2 288 2 9,216

Vertical Bore toHorizontal Bore Buggy 380 8 2 153 2 4,896

Horizontal Bore to T-nut Buggy 380 8 2 215 2 6,880T-nut to Clip Buggy 380 8 2 6 2 192

Clip to Dowel Buggy 380 8 2 139 2 4,448

Dowel to Band Buggy 380 8 2 20 2 640

Band to FinishWarehouse Forklift 380 8 1 173 1 3,664

Band to CNC Buggy 0 8 1 153 1 2,448

Total People Distance Traveled 34,158Feet

6.5 miles

11.8 FT/Pc


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Case Study #3

6

Batch Plant Layout

Figure 1. Airline’s original batch processing flow for part number 146-3843.Only a small portion of the plant is shown. Numbers represent actual distancetraveled in feet and are not to scale.

CNC Router

FinishedGoods

Warehouse

C l i p

D o w e

l

Plywood Warehouse

T - n u

t

B a n

d i n g

H o r i z o n

t a l b o r e

V e r t

i c a

l b o r e

B a n

d S a w s

T e n o n

M a c

h

445

288

153

139

215

20

173

153

6

their time producing only the one part.Two workers might push a loaded buggyfrom the vertical boring machine to thehorizontal boring machine and thenhelp with the boring or assist at anothermachine or move another buggy.Likewise, a machine operator mightonly spend an hour or two completinga process on a batch and then move toanother machine, or process anotherpart at the same machine. Frequently,the two workers involved in moving loaded buggy from point A to point B

walked back to point A or to a different work area. The result was a largenumber of workers walking around theplant after delivering buggies and/ormachine operators moving to anothermachine. After about three years ofimplementing lean production systems

the company reports that about 2,000buggies have been permanentlyremoved from the plant and head counthas been reduced by about 50 percent.


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7

T he first step taken by the companyto implement flow-line production was to prepare a product-grouping ma-trix. This initial step involves analysisof the “high-run” parts, the companyterm for parts produced in large quan-tities. High-run parts represent about20 percent of the total part numbersproduced, and represent nearly 80percent of the company’s total parts

volume. The matrix was created bylisting part numbers in the left column

with the production processes headingcolumns across the top. Across fromeach part an “X” was marked under

the processes required to manufacturethe part. Parts that required the samemanufacturing processes were com-bined to form product groups. In mostcases it was judged that these productgroups could be produced on a flowline created by arranging the machinecenters that followed the current batchmanufacturing sequence. Parts within aproduct group could then flow betweenmachines without the necessity of be-tween-machine buggy parts movement,and the resultant work-in-process. Anexample of the product-grouping ma-trix is given in Table 2.

It is not necessary for all parts within a product group to requireprocessing at every machine within thflow line. For example, a part might notrequire horizontal boring. To avoid theuse of a buggy to by-pass the horizontaboring machine, the company simplyused a 10-foot-long, wheeled gravityconveyor. The conveyor was placed infront of the horizontal boring machineand parts are placed on the conveyorafter the vertical boring is completedGravity then carries the part past thehorizontal boring machine to the T-nutmachine.

Implementation ofLean

Table 2. Part manufacturing operation matrix as the rst step in production analysis

Manufacturing Operations

AverageVolume

per week

Router Tenon VerticalBore Shaper Horizon-tal Bore T-nut Clip Band Dowel

Part Number

146-3843 15,000 X X X X X X X

146-2000 15,000 X X X

146-4000 20,000 X X X X

150-1000 45,000 X X X X X X

167-1200 39,000 X X X X X

189-3000 21,000 X X X

250-3800 16,000 X X X

260-2100 12,000 X X X X X


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Case Study #3

8

In addition to a significant reductionin non-value-added work, there areother benefits associated with usinga flow line. In batch manufacturing,a relatively large number of parts aremoved in batches between machinecenters. For part number 146-3843, abatch normally consisted of one buggycontaining 380 partially manufacturedparts. With this batch system, when amanufacturing error occurred at oneor more of the machines, frequentlythe entire batch of 380 defective partspassed through the remaining machinesbefore the error became evident at oneof the downstream machine centers.In the new flow line, parts are passedfrom machine to machine, typically afew at a time. This allows identifica-tion of manufacturing error at the

downstream machine centers almostimmediately after the production ofonly a few parts. One goal of theflow-line methodology is to continuallyreduce these small batches to a batch ofone part—one-piece-flow—thereby re-ducing the likelihood of having a largebatch of defective parts produced priorto discovery of a manufacturing prob-lem. This illustrates the superiority ofone-piece flow-lines. With one-piece

flow lines, defects are typically detectedimmediately at the work station which

created them or at the next downstreamprocess. Another interesting facet of flow-

line manufacturing is that qualityimproves not only by reducing manu-facturing errors, but also as a result ofthe flow-line workers functioning as ateam in which each member developsresponsibility for product quality. In abatch plant operating as a functional

job-shop manufacturing system, ma-

chine centers are normally grouped indepartments, where each department

operates similar processes in isolationfrom other departments. As a result, workers in these departments have lesconcern for quality as they have little ono contact with, or control over, workproduced in other departments. Thementality of “it’s not my job” frequentlcauses one department to have no inter-est in the quality of product producedelsewhere in the manufacturing system

Workers tend to push product volume

Bene ts of Lean

• promotes teamwork

• improves quality

• reduces space requirements

• increases productivity• reduces work in process

• improves order turn around time

• reduces waste and reject parts

Lean Bene ts


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through the system to achieve the re-quired production volume. Quality isoften viewed as the next department’sor the quality manager’s problem.

An additional benefit of flow-linemanufacturing is a more accurate countof finished parts. This benefit hasparticular significance when parts aremade of wood or other materials thatare not homogeneous and the mate-rial itself may contain hidden defects.Occasionally, those defects may notbecome evident until a late stage in theprocessing system. At Airline, defec-tive parts were most often discarded

without remanufacture. Productionruns were normally increased by somepredetermined percentage to accountfor those expected defective parts. Ifdefective parts were less than the es-

timated amount, “extras” were madeand subsequently discarded, sent to thecustomer at no charge, or placed in thefinished goods warehouse and carriedon inventory with the hope of a futureorder. Airline found that their new flowline was sufficiently closecoupled thata final count of completed parts couldexactly match the order quantity.

As in many batch-manufacturingplants, batches were often misplacedat Airline. Such misplacements ap-pear to have occurred when batches

were moved into a department and notimmediately processed. If a machineor worker was not available or work

the now-late part was rushed throughthe plant other batches were pushedout of the way and the cycle continued

With Airline’s new flow-line system theabove situation does not occur becauseupstream cells and flow lines do notproduce parts until they receive a signato produce from downstream work stations.

To clearly understand the benefitsof a flow line, the following describethe change from the original batch pro-cessing at the vertical and horizontalboring machines (Figure 2) to a two-machine flow line. In the example, a

9

backed up for a variety of reasons,the batch was moved out of the wayof other activity. As more batches ofthe same or other parts arrived in thedepartment, the batch may have beenmoved out of the way several times andeventually arrive in a corner or someless frequently traveled area to be ne-glected until its shipment date arrived.

When the batch was discovered to bemissing (usually on the ship date), it

was either found after hours of time ex-pended in searching, or another batch

was rushed through production—oftenrequiring overtime. In either case, as

11

Activity at Two Machines

12

34

5

7

10

Two machines, material moved 11 times.Two of 12 workers adding value.

6

89

Figure 2. The original batch-processing layout at the vertical and horizontal bor-ing machines. Smiling faces indicate workers who add value while frowning faceindicate workers who are not engaging in a value-added activity.


15/21


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ties to improve the total effectiveness ofthe system so that we produce exactly

what the customer wants—exact count,perfect quality, and on-time delivery.

Experts consider it important toinclude a variety of employees in theflow-line layout and location discussion

when such changes are implemented(See Leading Change by J. K. Kotter,1996). Weekly flow-line developmentmeetings were held at the plant todiscuss manufacturing of the productgroup, processes required and theirlocation, operator workstations, toolsrequired, etc. Many hours were spentdetermining the location of the flow line

within the plant, its relation to futureplant changes, and ancillary needs,and in balancing the work distributionamong the machine operators. Work

balancing is important to maintainingsmooth flow through the flow line.In this respect, flow lines differ fromfully implemented lean manufacturingsystems, which by their nature do notrequire line balancing.

To assist in developing the finalflow line, the team first prepared alayout drawing of the plant and equip-ment. Flow-line development meetingsincluded the manufacturing director,operations director, plant engineer,plant foreman, and maintenance direc-

11

tor. The mechanism for coordinatinginput from participants was to projectthe plant drawings onto a screen andmove equipment on the drawing untila consensus was reached about the bestlocation and arrangement. The diffi-culty of making the basic changes beingconsidered was evident in the intensityof discussion within the group as allinvolved moved beyond their past batchprocessing experience.

The final-flow line concept thatemerged from the group meetings is

T - N

u t

H o r i z o n

t a l B o r e

Figure 4. Airline’s new flow-line includes all the operations required to completethe product-group parts.

Activity in Flow Line

Clip Band Dowel

34

Vertical Bore

5

11

10

9

8

CNC Router

Six of 8 workers adding value (was 8 of 25).Material moved 12 times (was 27)-- NO BUGGIES.Batch plant had 4 more workers.Batch production: 480 parts per dayFlow production: 2900 parts per day

12

1

6

2

T - N u

t

H o r i z o n

t a l B o r e

7

shown in Figure 4. Raw material,in this case plywood, is moved to theCNC router by a forklift directly fromthe raw material warehouse. Com-pleted parts are banded in packagesof 10 on the flow line and placed on apallet to be carried by forklift either tothe finished goods warehouse or, moreideally, directly to a truck for shipment.

All of the workers on the flow-line areperforming value-added work. Onlythe forklift operators are performingnon-value-added work.


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Case Study #3

T he flow line summarized in thisreport is comprised of a CNCrouter, vertical and horizontal boringmachines, and a T-nut machine,followed by clipping, banding, andautomated doweling machines. Rawmaterial is delivered to a CNC routerthat provides shaped parts directlyto the vertical boring machine. Aqueue area is required following theCNC router due to the batches ofabout 40 parts produced from each4-by-8-foot sheet of plywood. Eachof the subsequent machine operatorsreceives parts as they are completedby the upstream operator and placedon a small table within reach of thedownstream operator.

In the flow line, small accumulationsof parts occur between operators as

variations in individual work and theskill and speed of workers prevents theline from ever being perfectly balanced.Part accumulations between operationsare not allowed above five to ten parts.

And, parts are never allowed to bestacked on the floor. If accumulationsbegin to occur, the upstream operatorsteps over to the CNC router for a fewminutes and assists with picking partsoff the table, vacuuming sawdust orsome other needed work.

Another less obvious benefit of aflow line is constant demand for workat each machine as parts are pulledaway from the upstream operator. Theproduction pace of the slowest machinebecomes the production constraint.In this flow line, the CNC router isthe constraint. There are always littlethings the other operators can do tohelp the CNC operator when they havea few minutes available. The result hasgreatly increased production fromthe router. Prior to the router being

moved into the flow-line, two operator were required for its operation. Aftermoving the router, the number ofsheets processed by the machine perday increased approximately threetimes with only a single operator beingassisted occasionally for a few minuteby other workers.

With the exception of the CNCrouter operator position, all machineoperators are cross-trained to performother jobs within the flow-line. Thebenefit of this cross-training is twofold

Summary

12

Table 3. The transportation and manpower requirements in Airline’s new owline

Travel Distance in Lean PlantMake 2900 each of part 146-3843

DescriptionMovement

MethodTotal People

Distance TraveledPlywood warehouse to CNC Forklift 1632

CNC to V Bore

Vertical Bore to HorizontalBore

Horizontal Bore to T-nut

T-nut to Clip

Clip to Dowel

Dowel to Band

Band to Finish Warehouse Forklift 3664

Band to CNC

Total People Distance Traveled: 5,296 Feet1.0 Miles


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(1) when a worker misses a day or stepsaway to the rest room, others in the flowline can take over the missing person’s

job; and (2) the volume of productoutput can be adjusted by changing thenumber of workers on the flow line.

The reduction in travel distanceresulting from this flow-line installationis summarized in Table 3. Forkliftdelivery of panels to the CNC routerand subsequent removal of componentsby forklift are the only materialsmovement required above that providedbetween work stations by operatorsmoving individual work pieces. Table3 summarizes the comparable flow lineproductivity and travel distance valuesin the same terms as Table 1 for theprevious batch system. Table 3 showsthat the new flow line reduced total

distance traveled to 5,296 feet from theprevious 34,158 feet, a reduction ofmore than 84 percent. Total non-value-adding workers have been reducedto 2 from the 25 required for thebatch system, a 92 percent reduction.Product is moved 12 times comparedto the previous 27 times. In addition toreduction in handling and travel time,the production of component partsincreased from 480 to 2900 parts perday, a 600-percent increase.

The result of the installation andimplementation of the new flow line

was a dramatic quality improvement,increased on-time delivery, sharplyreduced work in process and finishedinventory, and a large area of floorspace made available for other uses.The success of this flow line hasencouraged Airline to proceed withthe installation of additional flow lines,cells, and other improvements basedon lean manufacturing principles.These improvements have allowed

Airline to permanently remove 2,000buggies from the plant freeing over30,000 square feet of floor space

and eliminating as much as 12,000cubic feet of work in process (abou$800,000).

According to Judy Dunaway,President of Airline, when speakingof the company’s lean manufacturingconversion, “We would have closed ourdoors by now without implementationof lean manufacturing concepts inour manufacturing processes. We arenow totally committed to adhering tothe key lean principle that our leanmanufacturing journey has begun but

will never end.”

• Over 40,000 square feet of oor space cleared for

new uses

• Shortened order lead time from average of 5 weeks

to one week (many items only 2-3 days)

• 83 percent reduction in nished goods inventory• 78 percent reduction in raw material goods inventory

• $800,000 reduction in work-in-process

• $3 million in annual labor savings

• 42 percent productivity improvement

Lean ImplementationPlant Wide Realized Bene ts to Date

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Glossary

Batch and queue operations - a manufacturing process used by the functional job shop manufacturing systemsthat manufactures and moves large numbers of identical units at once. Each lot of units, called a batch, movesthrough a queue of operations during the process of production.

Cellular manufacturing system - a manufacturing system using a one-piece flow through a variety of work-stations in a cellular way to achieve a final product. Each cell specializes in manufacturing a family of partscompletely in one aspect of the production process. Machines used in cells are not “super machines” instead, theyaccomplish only one task in parallel. Workers check product quality, machine function, and performance with eachstep of production.

Cycle time - the time it takes to complete the tasks required for a work process to be completed successfully.

Economy of scope - a characteristic of lean production where a factory is capable of productivity and making aprofit on a wide variety of products.

Kanban - a physical production-control system that uses cards or other visual signals to trigger the flow of materi-als from one part of the production process to the next.

Lean manufacturing - a manufacturing process that productively adds value to materials by capturing produc-tion processes in manufacturing cells supplied by sole-source vendors. Lean manufacturing addresses material,administration, and labor costs - including the costs of storing and handling materials within the factory.

Lean production - a manufacturing system consisting of manufacturing and assembly cells and other vitalsubsystems dedicated to elimination of waste. Products created using a lean production system are produced on anas-needed basis using one-piece-flow methodology.

Manufacturing cell - an area, usually “U” shaped, on the production floor responsible for manufacturing parts,subassemblies, and the end product. These cells are flexibly designed to decrease cycle time and normally consistof different machining processes arranged to produce a family of parts.

Manufacturing system - a system focused on converting raw materials into usable goods.

Multifunctional worker - a worker responsible for more than one aspect of the manufacturing process. Workersoften carry out all of the processes required in a production cell in a lean manufacturing system.

One-piece flow - the movement of products through the cell one unit at a time rather than in batches of multipleunits.

Pull system - a production system in which nothing is produced until it is needed by either the internal orexternal customer. Goods are manufactured only when they are requested by a downstream process or a customerorder.

Push system - a production system in which goods are produced then stored as inventory until needed. Stock-on-hand inventory - when labor, new materials, and process capacity is available regardless of systemneeds. Material within a cell is called stock-on-hand. Material between cells is referred to as work-in-process.

Takt time - the total available work time per day or shift divided by customer-demand requirements per day orshift. Takt time sets the pace of a production system to match the rate of customer demand.

Work-in-process inventory - material, usually in small batches, between cells is called work-in-process. Material within cells is referred to as stock-on-hand.

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Black, JT, and S.L. Hunter. 2003. Lean Manufacturing Systems and Cell Design. Society ofManufacturing Engineers. 336 p.

Black, JT. 1999. Black’s blueprint for lean manufacturing. Unpublished manuscript, Industrial and SystemsEngineering Dept., Auburn University, AL.

Bullard, S.H., and C.D. West. 2002. Furniture manufacturing and marketing: Eight strategic issues for the21st century. Forest and Wildlife Research Center, Bulletin FP 227, Mississippi State, MS 24p.

Chazin, M. 2003. The top 50 largest upholstery manufacturers. Upholstery Design and Management16(5):16-29.

Kotter, J.P. 1996. Leading Change. Harvard Business School Press, Boston, MA.

Hunter, S.L., S.H. Bullard, P.H. Steele, W.D. Motsenbocker. 2004. The Double-D cell for assemblinghardware in upholstered furniture production. Forest and Wildlife Research Center, Bulletin FP300,Mississippi State University. 13p.

Hunter, S.L., S.H. Bullard, P.H. Steele, W.D. Motsenbocker, A. Schuler. 2004. Parallel pull flow: Anew lean production varient. Forest and Wildlife Research Center, Bulletin FP312, Mississippi StateUniversity. 12p.

Hunter, S.L. 1992. The design and implementation of a manned remanufacturing cell: A case study.Proceedings of APICS Aerospace &Defense Symposium, p.177.

Mital, A. 1995. The role of ergo in designing for manufacturability and humans in general in advancedmanufacturing technology: Preparing the american workforce for global competition beyond the year 2000.International Journal of Industrial Ergonomics 15(2):129-135.

Monden, Y. 1983. Toyota Production System. Industrial Engineering and Management Press, IIE,Norcross, GA.

Rother, M, and R. Harris. 2001. Creating continuous flow. Lean Enterprises Institute, Bookling, MA.p. 15

Schonberger, R.J. 1982. Japanese Manufacturing Techniques: Nine Hidden Lessons in Simplicity.The Free Press, New York.

Schonberger, R.J. 1986. World Class Manufacturing: The Lessons of Simplicity Applied. The Free Press, New York.

Womack, J.P., D.T. Jones, and D. Roos. 1991. The Machine that Changed the World: The Story ofLean Production. First Harper Perennial Publishers, NY.

References

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