5-Lecture 5 Slides

8/8/2019 5-Lecture 5 Slides

1/30

WORK CELL DESIGNWORK CELL DESIGN

Principles for Implementing Lean Manufacturing


2/30

Cellular Flow

Definition

Cellular Flow Manufacturing is a method of

organizing manual and machine operations in the

most efficient combination to maximize value-added

content and minimize waste.


3/30

Cellular Flow

Lean Building Blocks

Quick

Changeover

StandardizedWork

BatchReduction

Teams

Quality at

Source

5S System Visual Plant Layout

POU

S

Cellular/FlowPull/Kanban TPM

ValueStreamMapping

Continuous Improvement


4/30

Cellular Flow

Cellular Manufacturing Benefits

Simplified scheduling and communication Minimal inventory needed between processes

Increased visibility

provide quick feedback and problem resolution

Development of increased product knowledgeDevelopment of increased product knowledge

workers are trained to understand the totalworkers are trained to understand the total

processprocess

Shorter lead timesShorter lead times

Small lots and one piece flowSmall lots and one piece flow

to match customer demandto match customer demand


5/30

Work CellWork Cell Realization of a Lean ProcessRealization of a Lean Process

A work cells effectiveness is not separable from relatedA work cells effectiveness is not separable from relatedelements:elements:

-- The product(s)The product(s)

-- Workers must be able to manufacture and assemble theWorkers must be able to manufacture and assemble the

product to meet customer demandproduct to meet customer demand [DFA, DFM][DFA, DFM]

--A breadth of products often must be accommodated by aA breadth of products often must be accommodated by asingle manufacturersingle manufacturer [Product families][Product families]

-- The people(s)The people(s)

-- Work cells must produce varying products and varying ratesWork cells must produce varying products and varying ratesto meet customer demandto meet customer demand [Product families, Takt time][Product families, Takt time]

-- Work cells must be designed such that workers can safelyWork cells must be designed such that workers can safelyand repeatedly perform necessary steps to meet customerand repeatedly perform necessary steps to meet customerdemand.demand. [Human factors][Human factors]

Principles for Implementing Lean Manufacturing


6/30

Cellular Flow

The Five Step Cell DesignProcess

Group Products

Establish Takt Time

Review the Work Sequence

Balance the Process

Design the Cell Layout


7/30


8/30

Cellular Flow

Product Grouping Tool:The Product/Process Matrix


9/30

Product PortfolioProduct Portfolio

The set of different product offerings that aThe set of different product offerings that a

company provides. Products can be unique, sharecompany provides. Products can be unique, sharecommon systems, and/or production methods.common systems, and/or production methods.

Product portfolio architectureProduct portfolio architecture system strategysystem strategyfor layout out components and systems onfor layout out components and systems onmultiple productsmultiple products

3 Portfolio Architectures3 Portfolio Architectures

1.1.Fixed unsharingFixed unsharing each product is unique, no sharingeach product is unique, no sharingof components, typically very high volumeof components, typically very high volume

2.2.Modular platformModular platform -- share modules, components, orshare modules, components, or

systems to meet the needed varietysystems to meet the needed variety -- commoncommonelements are called the platform and each supportedelements are called the platform and each supported

product is called a variantproduct is called a variant

3.3.Massively customizableMassively customizable varies to meet customervaries to meet customerneedneed either by customer (e.g. car seat) oreither by customer (e.g. car seat) or

manufacturermanufacturer

- Otto and Wood, 2000


10/30


11/30

Cellular Flow


Group Products

Establish Takt Time


Balance the Process



12/30

More on Takt TimeMore on Takt Time

Takt time can change!!Takt time can change!!

What can you change to match takt time?What can you change to match takt time?-- Number of peopleNumber of people

-- Number of cells (requires investment in machinery)Number of cells (requires investment in machinery)

Takt Time Rounding Rules:Takt Time Rounding Rules:

Crew sizeCrew size calculation for an assembly line doing one piececalculation for an assembly line doing one pieceflow paced to Takt Time is:flow paced to Takt Time is:

-- Crew size = Sum of ManualCycle Time / Takt TimeCrew size = Sum of ManualCycle Time / Takt Time

If Manual Cycle Time = 1,293 seconds and a Takt time =If Manual Cycle Time = 1,293 seconds and a Takt time =345 sec345 sec

Crew size = 1,293 personCrew size = 1,293 person--seconds / 345 secondsseconds / 345 seconds Crew size = 3.74 peopleCrew size = 3.74 people

In this case the crew size will be 4 people since 3 peopleIn this case the crew size will be 4 people since 3 peoplewould not be able to meet customer demand.would not be able to meet customer demand.

Cellular Flow

Example from

http://www.gemba.com/uploadedFiles/Know%20Your%20Takt%20Time.pd

f


13/30

Cellular Flow


Group Products

Establish Takt Time


Balance the Process



14/30

Cellular Flow

Steps in the Process

Observe and document the tasks each worker performs

- Observe, dont just ask

- The steps are defined (explicitly or implicitly) by the

designer

Break operations into observable segments

Study machine capacity, cycle times, and changeover

times Look for value-added and non-value-added elements


15/30

Cellular Flow


Group Products

Establish Takt Time


Balance the Process



16/30

Cellular Flow

Combine Work to Balance the Process

0

0

0

0

0

0

60

Second

s

1 2 3 4 5

Operation Work Content

Before

0

10

20

30

40

50

60

Seconds

1 2 3 4

Operation Work Content

After


17/30

Cellular Flow

Standard Work Combination Sheet Example

Date: 8/20/00

Manual Auto Walk

1

4 2 2

24 11 2

36 2 2

14 4 6

Part Name: Circulation Pump Takt Time: 27 seconds

Step #Work Content Time

Description

Work Content Graph (1.5 sec/div)

Manual

Machine

Walking

Work Sequence: 7 of: 15 Quota: 1,000 per shift

Total = 24

Pick up shaft and rotor;

load, assemble, unload

Unload, load, start

Pick up 2 nuts & bracket;

load, assemble, unload

273 6 9 12 15 18 21 24


18/30

Cellular Flow

Alternative Work Combinations

Market demand = 220,000 units per yearTakt time = 27 seconds

Lathe Mill Mill InspectDrill

Drill

TestDrillPack

1 2 3 4 5

10 9 8 7

6

27

seconds 27

seconds

Inspect

27

second

s


19/30

Cellular Flow

Staffing For Increased Demand

Market demand = 312,000units per yearTakt time = 19 seconds

Lathe Mill Mill InspectDrill

Drill

TestDrillPack

1 2 3 4 5

10 9 8 7

6

Inspect

19

seconds

19 seconds

19

seconds

19

seconds


20/30

Cellular Flow


Group Products

Establish Takt Time


Balance the Process



21/30

Cellular Flow

Design Goals for All WorkAreas

Flexible output

Lot size of1

Point of Use Storage (POUS)

Mixed models

Visual management

Source inspection

Zero NVA activities


22/30

Cellular Flow

Water Pump Case StudyWater Pump Case Study

Circulation Pump Assembly Cell

Bearing

Assy

MotorAssy

Solder

Make

Box

PackTestFinal

Assy

WindBobbin

Weld

ContactAssy

Rivet

BracketAssy

RotorAssy

Lathe

BobbinAssy Terminal

Assy

StatorAssy

)


23/30

Cellular Flow

Water Pump Case Study

Testing

Packaging

Bobbin

Winding

New U-Shaped Cell


24/30

Cellular Flow


Workplace Organization

Material flow chutes

Tools within reach


25/30

Cellular Flow


Machining andAssembly

Material Flow Chute


26/30

Cellular Flow

Ergonomic Factors in Work Station (andProduct) Design

Design the work to:

Minimize motionAvoid natural postures

and movements

Avoid sharp turns in motion Make moves easy to perform

without much concentration

Use hands and forearms insteadof upper arms and shoulders

for light work Minimize lifting Follow a rhythm


27/30

Cellular Flow

Tool and Material Design andLayout Guidelines

Place tools and materials close to and in front of the

operator

Keep tools and materials in a designated place

Design fixtures for specific purposes, not general purposes

Combined usage tools are recommended when more than

one tool is required


28/30

Cellular Flow

Ergonomic Resources

Ergonomic resources

are understandable,

practical, andaffordable.

Fitting the Task to the Man: An

Ergonomic Approach - Grandjean

The Measure of Man and Woman:

Human Factors in Design Tilley

and Dreyfuss

Your FE Resource Guide


29/30

Cellular Flow


30/30

Cellular Flow

Documents

5-Lecture 5 Slides