This document provides information on cellular manufacturing and designing cells. It discusses the three flows in manufacturing: information, material, and work flow. It defines cellular manufacturing and lists its benefits. The document outlines the problem with conventional layouts and provides guidelines for identifying product families and determining takt time. It presents the steps to plan cellular manufacturing, including process analysis and razing. Finally, it provides guidelines for cellular layout and questions to consider when designing cells to ensure optimized one-piece flow and continuous improvement.

1. 1
Cellular Manufacturing
Presented by
Ram Mohan
IN-O-Tech Engineers & Consultants

2. 2
Three Flows
1. Information Flow
Does everyone know the hourly production target?
How quickly are problems and abnormalities noticed?
What happens when there are problems and abnormalities?
2. Material Flow
Does the workpiece move from one value-adding processing
step right to the next value-adding step?
3. Work Flow
Is the operators’ work repeatable and consistent within each
cycle?
Can the operator efficiently go from performing one value-adding
work step (work element) to the next?

3. 3
What is Cell Manufacturing
• Combines human and machine operations most efficiently
to maximize value and minimize waste
• Ensure short lead time
• Ensure Processes one-piece at a time at each station
• Minimum material, work space, operator
• Ensure Consistency in production
• Ensure Multi-process handling
• Abnormalities become apparent immediately
• Simple, single purpose automation
• Number of operators as per customer pull

4. 4
Benefits of Cell Manufacturing
• Improves Quality
• Reduces Costs
• Shortens Lead Time
• Improves Customer Satisfaction

5. 5
Problem with Conventional Layout
• Excessive inventory information flow is inadequate
• Complex schedule and material handling
• Communication is inadequate
• Longer lead times
• Large sized lots
• Specialized workers
• No flexibility

6. 6
Is this a Cell?
• There is extra material, work
space, operators and lead time
• Processes are closer and
together in a “Cell” but there is
no continuous flow
• Work stations operate
independently as “isolated islands”
• Inventory is piling between the
processes
• Operators process in batches
material inventory inventory inventory inventory Finished
product

7. 7
Identification of Product Families
Similarity of process steps and equipment
Assess the Flexibility / Demand
Check the variation in total work content
Calculate the takt time
Check the customer and Demand Capacity
Determine customer location

8. 8
Making a Beginning Identification
of Product Families
What is takt time?
Do we have the correct end items?

9. 9
Takt Time
• Matches pace of production to pace of sales
• The rate for producing a product, and its components and
is based on sales rate
Takt time =
example: = 40 seconds
this means:
your available work time per shift
Customer demand per shift
27,600 seconds
690 pieces
The customer is buying this product at a rate of one
every 40 seconds.

10. 10
Takt Time (TT)
The customer demand rate
Planned Cycle Time (PC/t)
A production rate that is different from the
actual customer demand rate.
Operator Cycle Time (Oc/t)
Time an operator requires to go through
all of his or her work elements one time.
Lead Time (L/T)
The time it takes one piece to move all
the way through a process or a value
stream; from start to finish. (Envision
timing a marked part as it moves from
beginning to end.)
Op 1 2 3 4

11. 11
Steps to plan Cellular Manufacturing
Step 1 - Understand Customer Demand
Step2 - Carry out PQ analysis of your business
build a Product -Quantity analysis
( If the business is multi-product/ multi-
process then stratify into product families
with common thread )

12. 12
PQ analysis

13. 13
Steps to plan Cellular Manufacturing
Step 3 - Identify Runners ,Repeaters and Strangers
( Draw – 2-8 line /3-7line/4-6line )
- establish if the production flow follows wide
variety small –lot production
Step 4 - Carry out Product and Process route
analysis ( process flow analysis )

14. 14
Steps to plan Cellular Manufacturing
Assembly Steps & Equipment
1 2 3 4 5 6 7 8
A X X X X X
B X X X X X
C X X X X X
D X X X X X X
E X X X X X
F X X X X X
G X X X X X X

15. 15
Steps to plan Cellular Manufacturing
Step 5 - Regroup product and Process according to
the process flow
( Classify the products which have
similar process )

16. 16
Steps to plan Cellular Manufacturing
Assembly Steps & Equipment
1 2 3 4 5 6 7 8
A X X X X X
D X X X X X X
G X X X X X X
B X X X X X
F X X X X X
C X X X X X
E X X X X X
A PRODUCT
FAMILY

17. 17
Steps to plan Cellular Manufacturing
Step 6 - Carry out process razing

18. 18
Study
current
conditions
of
processes
1. Did you go to the factory?
2. Did you observe the target process?
3. Did you record the facts?
4. Does the work-in-process flow in a straight line?
5. How many hours’ worth of dead inventory are there between the
target process and the previous or subsequent process?
6. Did you observe the conditions fully and carefully?
P-Q
analysis
chart
and
process
analysis
chart
Check-
points
Critique of
current
conditions
1. Do the current conditions enable synchronized one-piece
production?
2. Do the workers spend any time idly watching the equipment work?
3. Can the manpower requirements be reduced?
4. How much changeover loss is there (% of total operation time)?
5. Did you critique the current flow method and processing methods?
Flow
diagram
Check-
points
Define the
purpose of
the target
process
1. Did you think about the purpose of the process?
2. Is there any way to shorten the process?
3. Can multiple vertical operations be established?
4. Can some tools be universalized?
Proce-
ssing
route
analysis
chart
Check-
points
Determine
starting
point for
process
razing
1. Narrow the possible starting points to one.
2. Does the process suit the cycle time?
3. What is the line’s organizational efficiency rate and can manpower
be reduced without making improvements?
Line
organiz-
ation
efficiency
chart
Check-
points
1
2
3
4
Process
razing

19. 19
Develop
flow
concept
1. Which is best : straight line, L-shaped line, or U-shaped line?
2. Where should the line’s starting and ending points be?
3. Can the distances between processes be shortened?
4. Can inventory be stored on floor racks?
5. Can smaller containers be used with a more efficient placement
method?
Family
chart
Check-
points
Create
U-shaped
layout
to enable
manpower
reduction
Draft
new
layout
plan
1. Did you determine families based on the processing route analysis?
2. Did you determine the number of specialized and general-purpose
lines?
3. Are any subassembly parts assembled on the line?
4. Have you gathered enough technical information?
5. Have you determined which layout plan to try?
New
process
layout
diagram
Check-
points
Estima-
tion
developm
ent
1. Did you build a miniature model of the layout?
2. Can the line be shortened any more?
3. Do estimates show that the new layout substantially reduces
manpower requirements?
4. Does the new layout encircle the workers?
Estima-
ted
results
Check-
points
Trial
implem-
entation
1. Is there a central location where the line can be tried out right away?
2. Are people in the mood to give it a good try?
3. While trying out the new layout, implement corrections and labor-
saving ideas as you go.
4. Does the new layout encircle the workers?
Have the
improve-
ment plan
presented
by the
factory
Check-
points
5
6
7
8

20. 20
Steps to plan Cellular Manufacturing
Step 7 - Establish synchronized production
(of cycle time -coordinated ) using
one piece flow production

21. 21
Steps to plan Cellular Manufacturing
After Improvement

22. 22
Cell Designing
Is there one-piece flow?
Can the operator “make one, move one” without waiting?
Ask Yourself, how would the part build itself?
Do operators perform the work as specified in the operator
balance chart and standard work chart?
If not, why? Has a better method been found?
What is the right way to do it?
Do the team leader and supervisor understand their job
responsibilities?
Does the information flow?
Do the operators, team leader, and supervisor know:
• What is the takt time
• What to make?

23. 23
Cell Designing (Contd.)
• How many to make?
• How many are actually made?
• What problems are occurring?
• If changeovers are occurring at the correct time?
• If changeover are taking too much time?
Are parts and materials delivered in the proper quantities?
Is the size of flow racks and containers correct?
Are there too many parts? Are there part shortages?
Are material presentation devices correct or do the operators
reach too far?
How are the parts positioned when presented?
How do the operators pick them up?

24. 24
Cell Designing (Contd.)
Does the cell use the minimum amount of equipment and
inventory?
Are the correct levels of standard work-in-process inventory being maintained?
Is inventory accumulating between machines? (Exception: Where two operators
have a hand-off there should be one unit of standard work-in-process stock to
account for minor fluctuation in operator cycles.)
Is any excess material sitting on the floor?
Are you using the minimum amount of equipment required to make the product?
Is the travel distance of moving machine parts minimized?
If a table in the cell is used for just one end item in the product family why walk
past it all the other times?
If the actual work surface of a machine is only 12 inches wide, why is the
machine 3 feet wide?
Can the cell change over between different end items in less than takt
time?
Does the cell reduce lead time? Compare before and after results.

25. 25
Guidelines for Cell Layout
Place machines and workstations as close as possible to
minimize walking distance
Remove obstacles from the efficient operator walking path
Try to keep inside width of a cell to approximately 5 feet to
allow flexibility in reallocating work elements among team
members
Eliminate spaces and surfaces where work-in-process
inventory can build up
Maintain consistent heights for work surfaces and point of use
Locate the start and final processes near one another
Avoid up-and-down and front-to-back transfers of the
workpiece

26. 26
Guidelines for Cell Layout (Contd.)
Use gravity to assist operators in placing parts and moving
materials whenever possible
Install flexible utility drops from the ceiling to make layout
adjustment easier
Keep hand tools as close as possible to point of use and place
them in the direction that they are used by operators
Use dedicated hand tools instead of tools that require bit
changes, and combine two or more tools wherever possible
Ensure absolute safety and good ergonomics
Keep manual, operator-based work steps close together to
allow flexible work element distribution and value-added
operator work
Segregate Level 5 automation and continuous-cycle operations
(like ovens) from manual operators or operator-based work flow

27. 27
Guidelines for Machines
Use small equipment dedicated to a single task rather than
large, multi-task equipment
Introduce auto-eject (Level 3 automation) whenever operators
must use both hands to handle part
Install one-touch automation where possible
Avoid batching
Incorporate sensors to signal abnormal conditions and even
automatically stop machines if necessary, so operators don’t
need to watch machines during their cycle.
Design in maintainability
At the pacemaker process, strive to devise machine
changeovers between different end items that take less than
one takt time cycle

28. 28
Guidelines for Materials Management
Keep parts as close as possible to the point of use, but not in
the walking path of the operators
Keep parts so that operators can use both hands
simultaneously
Try to keep all part variations at the operators’ fingertips at all
times to eliminate changeover time
Do not have operators get or restock their own parts
Keep no more than two hours of materials at point of use
Do not put additional parts storage in or near the process
because this makes the operation of the cell or line harder to
understand and encourages operators to get their own parts

29. 29
Guidelines for Materials Management (Contd.)
Utilize kanban to regulate parts replenishment
Size parts containers for the convenience of the operators or as
a multiple of finished goods packout quantity, not for the
convenience of the material handler or the supplying process
Do not interrupt operator work cycles to replenish parts

30. 30
What is Goal?
takt time
Op Op Op Op
A B
takt time
Op Op Op Op

31. 31
Machines, Material & Layout for Flow
Is the Equipment capable of Meeting Takt Time
Can we go for Automation
Design and layout the process

32. 32
Is the Equipment Capable of
Meeting the Takt Time
Machine cycle + load and unload + machine changeover must
be within takt time
20% margin
Status of new machinery (capability, quality…)

33. 33
Levels of Automation
Loading Operator Cycle Unloading Transfer
0 Op Op Op Op
1 Op M/c Op Op
2 Op M/c M/c Op
3 M/c M/c M/c M/c
4 M/c M/c M/c M/c
The dividing line
LEVEL

34. 34
Multifunction Machines – Limitations
takt time
50 sec.
40s. 40s.
M1
M2
Flexibility to take
increased demand and
more products
Machines cycle time
40 seconds
OperatorOperator

35. 35
Simple Machines – Advantages
M1
M2
M3
M4
M5
M6
20s. 20s. 20s. 20s. 20s.
takt time
50 sec.
Greater flexibility to take increased demand
and more products
Machine cycle time
20 seconds
Op 1 Op 2 Op 3 Op 4 Op 5 Op 6

36. 36
Separating Operator and Machine Work
Waiting for machine cycle vs. multi-process handling
Standard WIP
(one piece) Unload &
Load
Machine
Cycle
Unload &
Load
Machine
Cycle
Standard WIP
(one piece)

37. 37
Operator Line Balancing

38. 38
Three Types of Work Motion
motion
Eamples:
Weld flange onto part
Bolt part to product
Value
Adding
Waste
Eamples:
Pull down tool
Unclamp & clamp fixture
Eamples:
Walking to get parts
Waiting times
Incidental
Work
Work

39. 39
• Need for balancing
• Basic elements of operations
• What is standard work ?
• Standard work - Basic elements
• How to implement balancing
• Examples
• Process of Analysis
• Findings
• Improvement Idea(s)
• Summary
Contents

40. 40
Need for Balancing
• To eliminate Muda, Mura and Muri
• To balance the allocation and utilisation of
resources both human and machine
• Prerequisite for implementing the Lean Philosophy
• To improve efficiency of operations
• To work as per takt time.

41. 41
Basic Elements of Operation(s)
All factory operations comprise of following three elements
• Cycle Time
• Quality Operations of Each Work Station
• Line Balance
In fact, operating a factory may be compared to playing music
in an orchestra containing rhythm, tone and harmony as basic
elements.

42. 42
Standard Work
Is the method of carrying out all the tasks, especially
those involving people in a perfect sequence where
all the muda is eliminated in order to produce as per
the takt time and achieve highest level of efficiency.

43. 43
Standard Work – Basic Elements
The standard work comprises of following three basic
elements :
• Cycle Time
Time between the completion of the last product and
the completion of next product
• Work Sequence
Workers sequence of operations and not the material
flow
• Standard Inventory
Minimum amount of WIP inventory necessary to
conduct smooth operations

44. 44
How to Implement Balancing
• Establish a visual control tool
• Effectively combine materials, workers and machines to
produce efficiently
• Establish a basis for continual improvement
• Involve worker and the supervisor in the development
process
…… for doing all of this, use a standard work sheet

45. 45
Standard Work Sheet
Manual Auto Walk

46. 46
Standard Work Sheet - Example

47. 47
Standard Work Sheet - Example

48. 48
The Operator Balance Chart
• Represents one continuous
flow
• line = Takt time
• Each bar show the per-
cycle work elements for one
operator
• Bars go from bottom to top
• Your line/cell layout,
equipment requirements,
and parts delivery build
right off this operator
balance chart
takt time
time
(in seconds)
Op 1 Op 2 Op 3 Op 4

49. 49
Process of Analysis
• Observe the processes
• Complete standard work sheet for all processes
• Determine the cycle time
• Analyse the work sheets
• Compute manual, auto and walk time elements
• Establish finding(s)
• Rebalance the line. Fully utilise operators time.

50. 50
Findings
Total handling time = 318 sec. (34%)
Total net working time = 611 sec (66%)
Total operating time = 929 sec. (100%)
Total operating time
Utilization of operator’s time =
Cycle time X Number of
operators
929
= = 74%
126 x 10

51. 51
Improvement Ideas
• Move operators appropriately to fully utilise operators time
• Develop/improve fixtures
• Use gravity fed racks
• Develop relay zone arrangements
• Improve material handling methods
• Improve work place organisation

52. 52
Summary
• Develop Standardised work practices
• Re-orient the organisation towards improvement rather
than establishing rigid standards
• Involve the operator is improvement of standards
• Reduce/eliminate operator time continuously

53. 53
Conducting Kaizen
• Do not consider any walking as a work element
• Do not consider out-of-cycle work for operators as work
elements
• Do not consider operators waiting for machines to cycle
as a worker element
• Do not consider time for removing finished parts from
machine wherever you believe automatic eject could
reasonably be introduced