Line balancing and its formulation

Line Balance of a manufacturing

plant (Assembly)

By Avijit Biswas

Course agendaCourse agenda• Introduction : What is line balancing?

• Where do we use line balancing?

• Example

• Line Balance – A simple example

• Pre-requisites for line balancing…

• The benefits of the pre-requisites

• Method

• Visual management

• Summary - flowchart

By Avijit Biswas

Introduction : What is line balancing?

Everyone is doing the same amount of work

Doing the same amount of work to customer requirement

No one overburdened

No one waiting

Everyone working together in a BALANCED fashion

Variation is ‘smoothed’

What is Line Balancing

By Avijit Biswas


By Avijit Biswas


Single Piece Flow

By Avijit Biswas

Example : Example : Line Balance ChartLine Balance Chart

This is a VISUAL production tool that enables the planning and organisation of individual, TIMED items of work to create the foundation for a balanced production line.

It is used as a tool to continuously drive out waste from operations and processes and it is also a valuable tool in implementing changes in customer demand,

By Avijit Biswas

Line Balance : Simple Example

1 2 3 4

25 mins5 mins 15 mins 10 mins

ConstraintOverburden

This operator must WAIT for

operator 2

Overproduction which causes the other 6

wastesWaiting

Over-processing

Inventory Rework

Transportation Motion

This operator must WAIT for

operator 3

5

10

15

20

25

1 2 3 4

mins

By Avijit Biswas

Line Balance : Simple Example

5

10

15

20

25Redistribute the work

1 2 3 4

15 mins15 mins 15 mins 10 mins

Promotes one-piece FLOW

Avoids overburden

Minimises the 7 wastes

Reduces Variation

By Avijit Biswas

Pre-requisites to line balancing…

StandardiseStandardise

Calculate TaktCalculate Takt

Achieve CONSISTENCY in operations

Enabling us to achieve our customers requirements by ‘managing our production effectively’

Variation in our operations demands more human intervention which, increases the risk of HUMAN ERROR

Understand the ‘drumbeat’ of the CUSTOMER

By Avijit Biswas

Takt Time

Takt is a German word

It is the principal that all activity within a business is

synchronised by a pulse, set by the customer

demand

It describes the metronome

Takt = total time available* total customer demand

By Avijit Biswas

Customer demand = 10 units / monthTotal time available = 20 days

Drumbeat = 1 part every 2 days

Each process needs to complete one unit every 2 days

Process 1 Process 2 Process 3 Customer

Every 2days

Process 4 Process 5

Takt time

Takt = total time available total customer demand

Every 2days

Every 2days

Every 2days

Every 2days

By Avijit Biswas

Standardise

Highlight key information

Operationsequence

From:

To:

Cell/ Area

Description: Part No.

Quality check Safety precaution Std in process stock Qty of SIPS Takt Time Cycle time

Standard work layout

Name / position Date Name / position Date Name / position Date

Scale:

stores

Work station 1

Work station 2

Tool cabinet

PPE MUST BE WORN AT ALL TIMES

6

Work station 3

Capture the layout

Indicate how the work flows

By Avijit Biswas

StandardiseNO REVISION DATE LOCATION: SHEET……..OF………

DEPT: DATE:

PREPARED BY:

AUTHORISATION:

WORK INSTRUCTION SHEETOPERATION NO. OPERATION DESCRIPTION

NO MAIN STEPS Q S E KEY POINTS EXPLANATION/ EXAMPLES/ DIAGRAMS

P.P.E. JIGS/ TOOLS REQUIRED CHECKS TRAINING COMMENTS

TIME

MEPUM

WP HRS

PEGS REF:

TL TL TL PUM ME

OPERATING DESCRIPTIONNO

As per PEGS requirement

By Avijit Biswas

The benefits of the pre-requisites

Takt time

Standard Operations

What do you think are the benefits?

By Avijit Biswas

Takt time maximises the productivity due to:

• Easily managed processes • Output of each process matches customer demand

Standard Operations provide:

• Capable and repeatable processes

• Process control at source

• Improves accuracy of planning

• Better adherence to plans

• A platform from which continuous improvement can be made

• Reduced costs

• Improved quality

• Basis for training

The benefits of the pre-requisites

By Avijit Biswas

Method - capture current state

Customer demand = 19 units a month

Time available = 20 days a month

TAKT = Available timeCustomer demand

TAKT = 25 hrs

TAKT = 20 days19 units

( x 24 hrs in a day)

TAKT

Total work content

Line Balance Ratio

Line Balance Efficiency

25hrs

Current State

Ops 3

Calculate TAKT

By Avijit Biswas


Why video?- Used to visually record activity- Accurate method of recording- Irrefutable and unambiguous- Modern approach to establishing method

4. Identify which of the elements are Value-added and which are non-value added

1. Capture a representative sample of the process

2. Review the video with the operators present

3. Break down the ‘elements’ of work and record a time for each one

Calculate TAKT

Time the process

By Avijit Biswas

Method – capture current stateCalculate Takt time

Time the process

Break down the work elements

g

The operators cycle is broken down into elementsThese elements are put into three main categories, these being :

1. Working (man or machine)2. Walking3. Waiting

COMPANY DATE ORIGINATOR CHECKED

PART NAME SECTION

PART NUMBER VOLUME

PROCESS TAKT TIME SEC

WORKINGSEQUENCE MANUAL AUTO WAIT WALK

KEY:Manual Walk

ISSUER ̈ COORDINATOR ̈ MGR ̈ ISSUER Auto Waiting

TIME OPERATION TIMEOPERATION NAME

STANDARDISED WORK COMBINATION TABLE

TOTAL

10 3 41

10 4 2

152

0 0 0

1 Fit bracket A

Walk to bench

Inspect1

Machine 2 10 5

TAKT

18 of 43

By Avijit Biswas


Calculate total work content (stacked time) : 15 + 30 + 17 = 62 hrs Takt

Line Balance Ratio


25 hrs

62 hrs

Current State

Ops 3

Total work content

Constraint – customer demand not being met

30

25

20

15

10

1 2 3

5

Takt (25 hrs)

15

30

17

Draw current state Line Balance

Calculate Takt time

Time the process


By Avijit Biswas

Method - capture current stateOr alternatively …..

1. Identify the business area to be balanced

Machining Treatments Assembly

4. Agree estimated time for each job and number of operators involved

i. Estimate a time for each sub elementii. Add up all the elementsiii. Write on the main ‘post it’ the total time and total operators

Is it 1, 5 or 10 hours (use a rough guide)

Total estimated time

Number of operators

1

5 hrs

2

2

5hrs

1

3

1

5 hrs

2

2

5hrs

1

1

5 hrs

2

2

10hrs

1

1

5 hrs

2

21hr

1

3. Break down each process by task i. Use ‘post it’ notesii. Write on the process nameiii. Place on a board in sequence

Op1

Op 2

Sub elements of work

Main process steps

2. Form small group with team leaders/ operators

By Avijit Biswas


1

5 hrs

2

2

5hrs

1

3

1

5 hrs

2

2

5hrs

1

1

5 hrs

2

2

10hrs

1

1

5 hrs

2

21hr

1

• Lay all the ‘post its’ out in sequence so that all of the processes are visible

• Draw on the TAKT line (or use string)

TAKT

Calculate TAKT

Time the process



2

5hrs

1

By Avijit Biswas

Method - capture current stateTarget Manpower = Total Work Content

Takt time

= 2.48

= 3 operators

Takt time = 25 hrs

Total work content = 62 hrs

30

25

20

15

10

1 2 3

5

Takt (25 hrs)

15

30

17

Calculate Takt time

Time the process


Calculate target manpower


Takt

Line Balance Ratio


25 hrs

62 hrs

Current State

Ops 3

Total work content

By Avijit Biswas

Method – capture current stateLine balance ratio = Total work content

No. of stations x longest operation

Line balance Efficiency = Total work contentTarget manpower x Takt

Line Balance Ratio = 62 hrs (3 x 30)

X 100 = 69%

Line Balance Efficiency = 62 hrs (3 x 25)

X 100 = 83%

Takt

Stacked time

Line Balance Ratio


25 hrs

62 hrs

Current State

Target manpower 3

69%

83%

What could be achieved without reducing waste and still meeting TAKT – simply REBALANCING!!

30

25

20

15

10

1 2 3

5

Takt (25 hrs)

15

30

17

Calculate Takt time

Time the process


Calculate Line Balance Ratio &

Efficiency



By Avijit Biswas

Method – balance to TAKT

example

Target 83% Efficiency

30

25

20

15

10

1 2 3

5

Takt (25 hrs)

15

30

17

1 2 3

25 25

12

Takt (25 hrs)30

25

20

15

10

5

By Avijit Biswas


Update calculations

Balance to TAKT

Reduce Non Value Added and

eliminate waste

Re-allocate work & re-balance

Can this be improved?

No

Yes

Complete work instruction

(standardise) & implement

No

30

25

20

15

10

1 2 3

5

Takt (25 hrs)

15

30

17

1. Identify the elements of work that exceed TAKT

2. Refer to Standard Work Combination table

3. Identify where work can be re-allocated

COMPANY DATE ORIGINATORCHECKEDPART NAME SECTIONPART NUMBER VOLUMEPROCESS TAKT TIMESECWORKINGSEQUENCE MANUALAUTOWAITWALK

KEY:Manual WalkISSUER ̈ COORDINATOR ̈ MGR ̈ ISSUER Auto Waiting



TOTAL

10 3 4 1

10 4 2152

0 0 01 Fit bracket A

Walk to bench

Inspect1Machine

2 10 5

TAKT

By Avijit Biswas

Method – balance to TAKTOr alternatively……

1. Refer to the ‘post it’ notes on the wall

3. Using the experience of the team leaders/ operators, invite them to

rebalance the work to below TAKT

2. Use magnetic strips to signify the ‘post it’ notes (elements of time)

1

5 hrs

2

2

5hrs

1

3

1

5 hrs

2

2

5hrs

1

1

5 hrs

2

2

10hrs

1

1

5 hrs

2

21hr

1

Update calculations

Balance to TAKT


eliminate waste



No

Yes



No

By Avijit Biswas

Method – Identify value added and non-value added time

What is Value added and non-value added time?

Value Adding:Any process that changes the nature, shape or characteristicsof the product, in line with customer requirements e.g machining, assembly

Non-Value Adding,but unavoidable with current technology or methods. Any work carried out that does not increase product value e.g inspection, part movement,tool changing, maintenance

WasteAll other meaningless, non-essential activities that do not add value to the product you can eliminate immediately e.g. looking for tools, waiting time

And don’t forget !!

By Avijit Biswas

Method – Identify value added and non-value added time

Value Added Waste

Traditional Focus• Work Longer-Harder-Faster

• Add People or Equipment

Lean Manufacturing• Improve the Value

Stream to Eliminate Waste

LEAD TIME

By Avijit Biswas

Method – reduce non-value added time and eliminate waste

Update calculations

Balance to TAKT


eliminate waste



No

Yes



No

COMPANY DATE ORIGINATOR CHECKED

PART NAME SECTION

PART NUMBER VOLUME

PROCESS TAKT TIME SEC

WORKINGSEQUENCE MANUAL AUTO WAIT WALK

KEY:Manual Walk

ISSUER ̈ COORDINATOR ̈ MGR ̈ ISSUER Auto Waiting



TOTAL

10 3 41

10 4 2

152

0 0 0

1 Fit bracket A

Walk to bench

Inspect1

Machine 2 10 5

TAKT

So, identify the category of work on the standard work combination table

29 of 43

By Avijit Biswas


Detail each process step (on format above)Indicate whether the work is :

• Wait • Walk• Work

Now you can split the operations on the board into elements of Value added

and non value added work

Update calculations

Balance to TAKT


eliminate waste



No

Yes



No

Or alternatively…

By Avijit Biswas

Method – reduce non-value added time and eliminate waste

Update calculations

Balance to TAKT


eliminate waste



No

Yes



No

Highlight the Value added and the non-value added work elements on the line balance board

Non value added activity

Value added activity

Takt (25 hrs)

1 2 3

5

30

25

20

15

10

Use red strips to signify non-value added work

By Avijit Biswas

Method - reduce non-value added time and eliminate waste

Takt

Stacked time

Line Balance Ratio


27 hrs

57 hrs

Future State

Ops 2

Non value added activity

Value added activity

•Reduce the NVA activity by applying waste removal tools (changeover reduction, 5C, process mapping etc)

Attack the red,

redistribute the green !!

1 2 3

5

30

25

20

15

10

Takt (25 hrs)

Update calculations

Balance to TAKT


eliminate waste



No

Yes



No

By Avijit Biswas

Method – re-allocate & re-balance

1 2 3

5

30

25

20

15

10

Takt (25 hrs)

1 2 3

5

30

25

20

15

10

Takt (25 hrs)

Operator freed up for other process or

improvement team

Update calculations

Balance to TAKT


eliminate waste



No

Yes



No

By Avijit Biswas

Method - update the calculations

Update calculations

Balance to TAKT


eliminate waste



No

Yes



No

Line balance ratio = Total work contentNo. of stations x longest operation

Line balance Efficiency = Total work contentTarget manpower x Takt

Line Balance Ratio = 44 hrs (2 x 24)

X 100 = 92%

1 2

5

30

25

20

15

10

Takt (25 hrs)

Line Balance Efficiency = 44 hrs (2 x 25)

X 100 = 88%Previous balance ratio = 69%Improvement of 23%

Takt

Total work content

Line Balance Ratio


25 hrs

44 hrs

Future State

Ops 2

92%

88%

By Avijit Biswas

Method - Continuous Improvement

Update calculations

Balance to TAKT


eliminate waste



Yes



No Value Added Waste

LEAD TIME

Continuously use waste elimination

tools

P

DC

APlan

DoCheck

Act

By Avijit Biswas

Method - standardise

Highlight key information

Operationsequence

From:

To:

Cell/ Area

Description: Part No.

Quality check Safety precaution Std in process stock Qty of SIPS Takt Time Cycle time

Standard work layout

Name / position Date Name / position Date Name / position Date

Scale:

stores

Work station 1

Work station 2

Tool cabinet

PPE MUST BE WORN AT ALL TIMES

6

Capture the NEW layout

Indicate how the work flows

Scale:

storesTool cabinet

Work station 3

By Avijit Biswas

Method - standardiseNO REVISION DATE LOCATION: SHEET……..OF………

DEPT: DATE:

PREPARED BY:

AUTHORISATION:

WORK INSTRUCTION SHEETOPERATION NO. OPERATION DESCRIPTION

NO MAIN STEPS Q S E KEY POINTS EXPLANATION/ EXAMPLES/ DIAGRAMS

P.P.E. JIGS/ TOOLS REQUIRED CHECKS TRAINING COMMENTS

TIME

MEMgr

WP HRS

PEGS REF:

TL TL TL PUM ME

OPERATING DESCRIPTIONNO

By Avijit Biswas

Visual ManagementThe new line balance chart should be displayed on the cell

The impact of changes in resource or Takt on operator cycle times can be seen instantly

Opportunities for Kaizen activities can be easily identified

By Avijit Biswas

SummaryCapture the current state Balance to TAKT & eliminate waste

Update calculations

Balance to TAKT


eliminate waste



Yes



No

Balance to TAKT


eliminate waste


Update calculations




Takt

Total work content

Line Balance Ratio


25 hrs

44 hrs

Ops 2

92%

88%

Future State

Takt

Total work content


Line Balance Ratio

25 hrs

62 hrs

Current State

Operators 3

69%

83%

Calculate Takt time

Time the process



Efficiency



Calculate Takt time


Efficiency

Time the process




2

5hrs

1

By Avijit Biswas

Line Balancing Problem

A

B

C

4.1mins

D

1.7mins

E

2.7 mins

F

3.3 mins

G

2.6 mins

2.2 mins

3.4 mins

By Avijit Biswas

Questions?

• 1. What is the bottleneck?• 2. What is maximum production per

hour? 60/4.1=14.63 units• 3. What is efficiency and balance delay?• 4. How to minimize work stations?• 5. How should they be grouped?• 6. New efficiency?

4.1 minutes

By Avijit Biswas

Calculate efficiency• A. 73.2%• B. 56.7%• C. 69.7%• D. 79.6%• E. 81.2%

A

B

C

4.1mins

D

1.7mins

E

2.7 mins

F

3.3 mins

G

2.6 mins

2.2 mins

3.4 mins

By Avijit Biswas

(2.2+3.4+4.1+2.7+1.7+3.3+2.6)4.1x7

2028.7

69.7%

1-69.7%=30.3% Balance Delay

By Avijit Biswas

Number of Work Stations

time cycletimes taskTM

(bottleneck)204.1 = 4.88 work stations

By Avijit Biswas

Line Balancing Solution

A

B

C

4.1

D

1.7

E

2.7

F

3.3

G

2.6

Station 1

Station 2

Station 3

Station 4

2.2

3.4

All under 6 minutes?

(6.0)

(5.6)

(5.8)

4 Stations 20/24=83.3%

Max prod./hour60/6

10 units/hour

By Avijit Biswas

Line Balancing Problem

A

B

C

4.1mins

D

1.7mins

E

2.7 mins

F

3.3 mins

G

2.6 mins

2.2 mins

3.4 mins5.6

5.0

20/5.6x5 = 20/28 = 71.4%

5 Stations

Max Prod./hour60/5.6

10.7 units/hour

By Avijit Biswas

40 secs

59 secs

84 secs34 secs

56 secs 45 secs

What is the minimum # of work stations?Round down.

A. 3B. 2C. 4D. 5E. 6

By Avijit Biswas

timecycle

task timesTM

40+59+84+56+34+45 = 318

318/84 = 3.78 or 3 work stations

What is the efficiency with 6 operators?

100

timecyclestations ofnumber task times

%Efficency

318/6 x 84=318/504 =

63%

By Avijit Biswas

100

timecyclestations ofnumber task times

%Efficency

40 secs

59 secs

84 secs34 secs

56 secs 45 secs

99 secs

118 secs

3 Stations ?

318/3x118

318/354 = 89.8%101 secs

By Avijit Biswas

40 secs

59 secs

84 secs34 secs

56 secs 45 secs

4 Stations?99 secs

84 secs

56 secs

79 secs

318/4 x 99 =318/396 =

80.3%

Engineering

Line balancing and its formulation