RESTORATION OF ONE-PIECE FLOW

TO LINCOLN INDUSTRIESStephen Hassler

Jeffrey Troester

University of Nebraska – LincolnDepartment of Industrial & Management System Engineering

Presented on April 15, 2009

ContributorsAdventure Manufacturing, Inc. (OK)Franek Laser & Fab Systems (MN)

Duane Franek – Owner

Hotsy Equipment Co. (NE) Roy Gage – Sales Representative Dennis Klingemann – Sales Representative

Lincoln Industries (NE) Bill Hancock – Area Leader, Fabrication Eric Jacobs – Development Engineer

North American Cutting Systems (CA)

Images: www.adventureinmetals.com, www.franeklaser.com, www.hotsy.com

INTRODUCTION

Company Profile, Project Field, Problems, & Objective

Company ProfileIn 1952, Lincoln Industries was founded in

Lincoln, NE as a small job shop for custom electroplating.

The company has grown to become Lincoln’s largest water user and North America’s largest metal finisher.

In its 500,000 square feet of production and warehouse space, approximately 500 people are employed.

Annual revenues have grown rapidly over the past decade and now exceed $100 million.

Images: www.lincolnindustries.com

Project FieldLincoln Industries (LI) is

best known as North America’s largest metal finisher.  However, the company’s operations are diverse and our team took a look at their fabrication activities.  At a facility in Air Park (Lincoln, NE), LI fabricates exhaust stacks for semi-trailer trucks.

Images: www.lincolnchrome.com

Original ProblemUnfortunately, after the

production line was designed, installed, and operating, quality issues arose.  A set of operations occurring early in the production sequence was causing damage to the parts.

Original RemedyA quick solution was developed

by LI and another operation was added to the production process, though it occurred on a workstation off of the main production line.

Consequential ProblemBy locating the workstation off of

the main line, one-piece flow was disrupted.  As a result, material handling became excessive, processing time increased, and quality control declined.

Project ObjectiveIt is the goal of the investigating

team to develop a cost-effective proposal that remedies these undesirable byproducts and restores one-piece flow to the production line.

STUDY DETAILSAnalysis Method & Findings

Four Step Analysis MethodUnderstand Problem and

Magnitude Visual Aids, Quality Inspection, Time

Studies

Develop Alternatives Seek Expert Opinions, Creative

Brainstorming

Verify Feasibility of Alternatives Examine Attributes and Costs, Design

Experiments

Evaluate Alternatives Economic Analysis, Discuss Qualitative

Factors

Understand Problem and MagnitudeVisual Aids

The team developed a simple facility layout diagram to convey the problematic nature of the current arrangement.

Photographs and video were taken to document the process and highlight production issues.

Current Layout

SAW

DEBUR

CARTS

BEND

WASH

EMPTYAREA

(90 FT2)

≈ 100 FT

Lean IssuesFour of the Seven Wastes of the

Toyota Production System (TPS) were glaringly obvious as a result of the current layout.

Waste of Transportation Waste of Waiting Waste of Inventory Waste of Motion

Photographs

SAW

LOADING SAW

RAW MATERIAL

DEBURR MACHINEImages: www.lincolnchrome.com

PhotographsCHIPS

CHIPS

CARTCART

S

PhotographsWASH

WASH

BEND MACHINE

UNLOADING BENDER

Images: www.lincolnchrome.com

Understand Problem and MagnitudeQuality Inspection

Though inefficient, the current wash operation sufficiently removes chips from the tubes.

Chips are being introduced from various sources such as material handling carts, gloves, rags, and tools.

Understand Problem and MagnitudeTime Studies

Surprisingly, the inefficient wash operation is not typically the bottleneck of the production line.

However, when the wash operation becomes congested, it definitely has the ability to function as the bottleneck.

Saw and Deburr OperationTime Study Results

Mean/Median/Mode Unit Times = 49 s / 43 s / 44 s

Minimum/Maximum Unit Times = 34 s / 82 s

Key Observations Excessive Work-in-Process (WIP) Buildup

(25+ Tubes) Operator Sets Operation Pace Insignificant Operator Idle Time Not Typically the Bottleneck Operation

Wash OperationTime Study Results

Unit Times = 36 s (for 25) / 43 s (for 15)

TOTAL 900 s (See Below)

Move Cart to Wash Station 20 s

Idle - (Often > 100 s)

Lift Cart with Crane and Dunk in Bath

120 s

Cart Air Dry and Release from Crane

100 s

Hand Wipe (25) Tubes 640 s

Idle - (Often > 100 s)

Move Cart to Bend Operation 20 s

Wash OperationKey Observations

Excessive Idle Time Frequently Congested Workstation Operator Sets Operation Pace Potentially the Bottleneck Operation

Bend OperationTime Study Results

Mean/Median/Mode Unit Times = 88 s / 82 s / 68 s

Minimum/Maximum Unit Times = 66 s / 133 s

Key Observations Machine Sets Operation Pace Minimal Operator Idle Time Potentially the Bottleneck Operation

Develop AlternativesSeek Expert Opinions

The first technique for developing alternatives was to conduct interviews with LI management and assemble the ideas that had already been considered.

LI management had considered two types of solutions. Those that washed parts and those that did not generate chips in the first place.

Two wash systems included power washing cabinets and power washing conveyor systems.

To eliminate chips altogether, laser cutting, abrasive water jet cutting, and precision saws were considered.

Develop AlternativesCreative Brainstorming

The second technique for developing alternatives was to do some “thinking outside of the box”. The team considered several unorthodox chip removal procedures.

The team considered only solutions that washed parts.

Use of vacuums and magnets were considered. Both in handheld and fixed configurations. Also, a simple water bath with drying fans was considered.

Develop AlternativesSeek Expert Opinion – Idea List

Power Washing Cabinet Power Washing Conveyor System Laser Cutting (No Chips) Abrasive Water Jet Cutting (No Chips) Precision Saw (No Chips)

Creative Brainstorming – Idea List Vacuum (Handheld or Fixed) Magnets (Handheld or Fixed) Water Bath with Drying Fans

Verify Feasibility of AlternativesExamine Attributes and Costs

The team first considered whether or not each alternative would accomplish the intended purpose.

Cost data was then used to eliminate some alternatives. Due to current economic conditions (including recent layoffs at LI), most high cost alternatives were deemed infeasible.

Design Experiments The team was forced to design

experiments in some cases to verify alternative feasibility.

Power Washing CabinetAttributes

Sufficiently Cleans Parts (Prior Testing at LI) Fits in Space between Saw and Bend

Operation No Labor to Dry Parts, Flash-Dry (60 s) Smaller Batches

Drawbacks Purchase Price = $10,650 Still Batching Parts Operating Costs, Consumables,

Maintenance

Power Washing Conveyor System

Attributes Fits in Space between Saw and Bend

Operation Transports Parts from Saw to Bend

Operation Pure One-Piece Flow

Drawbacks Purchase Price = $20,000 to $30,000 Unlikely to Effectively Clean Tube Interior Operating Costs, Consumables,

Maintenance Labor to Dry Parts Slip Hazards

Photographs

Images: www.adventureinmetals.com, www.globalspec.com

POWER WASHING CABINET

POWER WASHING CONVEYOR SYSTEM

Laser CuttingAttributes

No Metal Chips Eliminates Need for Deburr Operation Eliminates Need for Wash Operation Precision Cuts Cuts Harder Materials (Stainless Steel)

Drawbacks Purchase Price = $300,000 to $400,000 Operating Costs, Consumables,

Maintenance Hazardous Fumes

Abrasive Water Jet CuttingAttributes

No Metal Chips Eliminates Need for Deburr Operation Eliminates Need for Wash Operation

Drawbacks Purchase Price = $200,000 to $300,000 Operating Costs, Consumables, Maintenance Slower than Laser Cutting Requires Abrasive Particles in Water to Cut Abrasive Particles Necessitate Machine

Cleaning

Photographs

Images: www.advancedwaterjet.com, www.alspi.com

ABRASIVE WATER JET CUTTING

LASER CUTTING

Precision SawAttributes

No Metal Chips Eliminates Need for Deburr Operation Eliminates Need for Wash Operation Cuts Harder Materials (Stainless Steel)

Drawbacks Purchase Price = $400,000+ Operating Costs, Consumables,

Maintenance

Verify Feasibility of AlternativesList of Experiments Designed

Vacuum (Handheld or Fixed) Magnets (Handheld or Fixed) Water Bath with Drying Fans

PhotographsWATER BATH

VACUUMMAGNETS

Verify Feasibility of AlternativesResults of Experiments

Vacuum – Time Consuming, Only Fair Cleaning

Magnets – Time Consuming, Poor Cleaning

Water Bath and Drying Fans – Poor Cleaning, Slow Drying

Verify Feasibility of Alternatives

ALTERNATIVE FEASIBILITY DETERMINATION

Power Washing Cabinet Feasible

Power Washing Conveyor System

Infeasible – Poor Cleaning

Laser Cutting Infeasible – Cost

Abrasive Water Jet Cutting Infeasible – Cost

Precision Saw Infeasible – Cost

Vacuum (Handheld or Fixed) Infeasible – Poor Cleaning

Magnets (Handheld or Fixed) Infeasible – Poor Cleaning

Water Bath with Drying Fans Infeasible – Poor Cleaning

Evaluate AlternativesEconomic Analysis

Cost savings are likely to result from reduced labor (drying tubes), reduced overall processing time (from elimination of idle time), reduced WIP, potentially improved quality, and a cleaner, more orderly work space.

Will the savings from the installation of a power washing cabinet justify its expense?

PROPOSAL DETAILSDescription & Benefits

ProposalPurchase the Power Washing

CabinetInstall it in the Empty Space

between the Saw and Bend Operation

Wash the Tubes in Batches of 5Wash the Tubes for 120 sLet the Tubes Dry for 60 sSpend Minimally on Consumable,

Only Enough to Inhibit Washer Rusting

PhotographsPOWER WASHING

CABINETHOTSY MODEL 7663

Images: www.hotsy.com

Current Layout

SAW

DEBUR

CARTS

BEND

WASH

EMPTYAREA

(90 FT2)

≈ 100 FT

Proposed Layout

SAW

DEBUR

CARTS

BEND

WASH

WASH

≈ 10 FT

RationaleMoving water seems to remove

chips from the tubes better than other methods. For a relatively low cost, the team believes that LI can achieve significant savings with the installation of a power washing cabinet. However, the efficiency of the machine is dependent upon some batching. Therefore, pure one-piece flow will not be achieved.

Proposal Quote from HotsyPurchase Cost

$10, 650

Tube Fixtures (5) $1,250

Consumables $1,200 / Year

TOTAL – YEAR 1 $13,100

Proposed ProcessPower Washing Cabinet

Batch Size: 5 Tubes Wash Phase: 120 s Dry Phase: 60 s Unload Phase: 50 s

Key Assumptions Saw Operation Unit Time Increases (5 s)

for Added Material Handling Bend Operation Unit Time Increases (10

s) for Added Material Handling

Processing Time Comparison

Current Process 25 Tubes 72 min + Wash Station Idle Time 15 Tubes 45 min + Wash Station Idle

Time

Proposed Process 25 Tubes 74 min 15 Tubes 45 min

Key Observations Excessive Idle Time at Wash is Controlled No Significant Changes to Ideal Processing

Times

Labor SavingsKey Assumptions

Labor Expense (Hourly) = $15

Source of Labor Savings Labor Reduction at Wash Operation (1 Operator) Idle Time Avoidance at Wash Operation (3

Operators)

Projected Labor Savings Labor Reduction per Wash = 13 min = $3.35 Idle Time per Wash = 6 min * 3 = 18 min = $4.50 Total per Wash = $7.85 Total per Day = $7.85 * 5 = $39.25 Payback Period = 334 Workdays = 16 Months Salvage Value Not Considered, Likely Substantial

Labor Savings RobustnessCalculated Savings

are Intentionally Conservative

Using 6 Washes per Day or Idle Time Avoidance of 10 min Significantly Improves Expected Payback Period

Payback Period02468

1012141618

Conservative 6 Washes

Idle 10 min

Other BenefitsAdded Washing CapacityLiberated Wash Station OperatorOne Year Warranty on WasherWasher Salvage ValueLess Consumables (Gloves, Rags)Less Material Handling

Equipment (Carts)Cleaner, More Orderly Facility

Potential DrawbacksFailure to utilize liberated

operators.If proposal assumptions do not

hold in practice, the projected labor savings are likely to change significantly.

If maintenance issues happen more frequently than expected (typically twice per year), the projected labor savings will not be realized.

RecommendationsIn the opinion of the investigating

team, the following steps should be pursued as soon as convenient:

Initiate Contact with Hotsy Request Delivery of Washer to Air Park for

Trials Verify the Cleaning Ability of the Washer Install the Washer if Cleaning Ability is

Satisfactory Run Trials through the Installed Washer Verify the Practicality of Proposal Assumptions Purchase the Washer if Practicality is Verified

DISCUSSIONQuestions & Comments