1. Layout and Flow

2. Chapter coverage Basic layout types Selecting a layout type
Detailed design of a layout

3. Layout:
The layout of an operation is concerned with the physical location of its transforming resources, that is deciding where to put the facilities, machines, equipment and staff in the operation.
Layout types:
Fixed position layout
Process layout
Cell layout
Product layout

4. Fixed position layout
In a fixed position layout, the transformed resource does not move between its transforming resources.
Equipment, machinery, plant and people who do the processing move as necessary because the product or customer is either:
Too large
Too delicate or
Objects being moved

5. Process layout
In a process layout, similar processes or processes with similar needs are located together because:
It is convenient to group them together or
The utilization of the transforming resource is improved
Different products of customer have different requirements therefore they may take different routes within the process.
The flow in a process layout can be very complex.

6. An example of a process layout in a library showing the path of just one customer
Entrance
Exit
On-line and CD-ROM access room
Loan books in subject order
Enquiries
Store room
Counter staff
Copying area
Company reports
To journal sack
Current journals
Reserve collection
Reference section
Study desks 9

7. Cell layout
In a cell layout, the transformed resources entering the operation move into a cell in which all the transforming resources it requires in located.
After being processed in the cell, the transformed resource may move to a different cell in the operation or it may be a finished product or service.
Each cell may be arranged in either a process or product layout.
The cell type layout attempts to bring order to the complex flow seen in a process layout.

8. Confectionery, newspaper, magazines and stationery
The ground floor plan of a department store showing the sports goods shop-within-a-shop retail ‘cell’
Sports shop
Menswear
Women’s clothes
Luggage and gifts
Confectionery, newspaper, magazines and stationery
Books and videos
Footwear
Perfume
& jewellery
Elevators
Entrance 9

9. Product layout
In a product layout, the transformed resource flow a long a line of processes that has been prearranged.
Flow is clear, predictable and easy to control.

10. An army induction centre with uses product layout
Waiting area
Waiting area
Lecture theatre
Blood
test
Doctor
Doctor
X-ray
Record personal history and medical details
Uniform issuing area
Blood
test
Doctor
Doctor
X-ray
Blood
test
Doctor
Doctor
Uniform store
X-ray 9

11. A restaurant complex with all four basic layout types
Fixed-position layout service restaurant
Cell layout buffet
Line layout cafeteria
Cool room
Freezer
Vegetable prep
Grill
Preparation
Oven
Process layout kitchen
Main course buffet
Starter buffet
Desert buffet
Service line 9

12. Volume-variety relationship
Fixed-position layout
Product layout
Cell layout
Process layout
Volume
Low
High
Variety
Flow is intermittent
Regular flow more important
Flow becomes continuous
Regular flow more feasible

13. Layout selection steps
Project process
Jobbing process
Batch process
Mass process
Continuous process
Professional services
Service shops
Mass services
Fixed position layout
Process layout
Cell layout
Product layout
The physical position of all transforming resources
The flow of the operation’s transformed resources
Process type
Basic layout type
Detailed design of layout
Volume and variety
Strategic performance objectives
Decision 1
Decision 2
Decision 3

14. Selecting a layout type

15. 1) The nature of the basic layout types
Manufacturing B
asic layout
Service
process types
types
process types
Project processes
Project processes
Fixed
Professional
position layout
services
Jobbing processes
Process layout
Service shops
Batch pro
cesses
Cell layout
Mass
processes
Mass services
Product layout
Continuous
processes

16. 2) Advantages and disadvantages
Fixed
Process
Cell
Product
- Very high mix and product flexibility
position
- High mix and product flexibility
- Good compromise between cost and flexibility
Lo- w unit costs for high volume
layout
layout
layout
layout
- Product/customer not moved or disturbed.
- Relatively robust if in the case of disruptions
- Fast throughput.
- Gives Opportunities for specialization of equipment
Advantages
- High variety of tasks for staff
- Easy supervision of equipment of plant
- Group work can result in good motivation
- Gives Opportunities for specialization of equipment
Low utilization of resources.
Can be costly to rearrange existing layout
Can have low mix and flexibility
- Very high unit cost.
Can have very high WIP
Disadvantages
Can need more plant and equipment
Not very robust to disruption
- Scheduling space and activities can be difficult.
Complex flow.
Work can be very
repetitive.

17. Use fixed-position or process Use process or cell or product
(a) The basic layout types have different fixed and variable cost characteristics which seem to determine which one to use. (b) In practice the uncertainty about the exact fixed and variable costs of each layout means the decision can rarely be made on cost alone
Use fixed-position
Use fixed-position or process
Use process
Use process or cell
Use process or cell or product
Use cell or product
Use product
Volume
Costs
Fixed-position
Process
Cell
Product
Use
cell
(a)
(b) ?
3) Consider total cost 9

18. Detailed design of a layout

19. Fixed position layout design:
The location of resources for each project is unique and it will be determined on the convenience of transforming resources themselves.
Although there are techniques which held to locate resources on fixed position layouts, they are not widely used because this layout can be very complex and planned schedules do change frequently.

20. Process layout design:
When cost of traveling is important:
Collecting information such as:
number of loads per day
cost per distance traveled
When process relationship is important
Relationship chart

21. Collecting information in process layout
LOADS/DAY
(a)
(b)
LOADS/DAY
If direction is not important, collapses to 9

22. Collecting information in process layout
LOADS/DAY
(d)
LOADS/DAY A B C D E 30 - 40 80 60 20
Or alternatively 9

23. Collecting information in process layout
LOADS/DAY
UNIT COST/DISTANCE TRAVELLED
(f)
If cost of flow differs between work centers, combine with 9

24. Collecting information in process layout DAILY COST/DISTANCE TRAVELLED
To give 9

25. Collecting information in process layout
(h)
DAILY COST/DISTANCE TRAVELLED
(i)
DAILY COST/DISTANCE TRAVELLED
If direction is not important, collapses to 9

26. A relationship chart DEPARTMENT Metrology E Electronic testing A I
Analysis
Ultrasonic testing
Fatigue testing E I A U O X
DEPARTMENT
Impact testing 9

27. Cell layout design
Cells in an operation can be created based on two interrelated decisions:
What is the extent and nature of the cell i.e. the amount of direct and indirect resources the cell has as shown in Fig 7.28
Which resources to allocate to which cell using:
Cluster analysis – which process group naturally together
Parts and family coding – based on similar characteristics of parts of products OR
Production Flow Analysis (PFA)
Examines both product requirement and process grouping
(See Fig. 7.31)

28. Types of cell High e.g. Specialist process Plant-within-a-plant
Low
Complete
component
manufacturing cell
Lunch and snack
produce area in
supermarket
Small multi-machine
Joint reference and
copying room in a
library
Plant-within-a-plant
manufacturing
operation
Maternity unit
in a hospital
Specialist process
Internal audit group
in a bank
Amount of indirect resources included in the cell
Proportion of the resources needed to complete the transformation included in the cell
e.g. 9

29. (a) and (b) Using production flow analysis to allocate machines to cells
Cell A
Machines
Machines
Cell B
Cell C 9

30. Product layout design
Product type layout is designed based on a technique called line balancing. The technique consist of the following steps:
Calculating the required cycle time.
Calculating the number of stages.
Producing a precedence diagram.
Finally allocating activities to the stages.

31. Cycle time:
It is the time between completed products emerging from the process.
Example:
Suppose the regional back-office operation of a large bank is designing an operation which will process its mortgage applications. The number of applications to be processed is 160 per week and the time available to process the applications is 40 hours per week.
Cycle time = = 1/4 hours = 15 minutes
160
1 product every 15 minutes

32. Number of stages Required no. of stages = total work content
required cycle time
Where the total work content is the total quantity of work involved in producing the product given in time.
Example:
Suppose that the bank in the previous example calculated that the average total work content of processing a mortgage application is 60 minutes. The number of stages needed to produce a processed application every 15 minutes can be calculated
Required no. of stages = 60 minutes = 4 stages
15 minutes
If you get a fraction round it up to the higher whole number.

33. Precedence diagram
This is a diagram representing the ordering of the elements which comprise the total work content of the product or service.
Two rules when constructing the diagram:
The circles which represent the elements are drawn as far to the left as possible.
None of the arrows which shows the precedence of the elements should be vertical. a b c d e f g h i
0.12 mins
0.30 mins
0.36 mins
0.25 mins
0.05 mins
0.17 mins
0.10 mins
0.08 mins

34. Allocating activities to the stages
The general approach is to allocate elements from the precedence diagram to the first stage, starting from the left, until the work allocated to the stage is as close to, but less than, the cycle time.
When the stage is full of work without exceeding the cycle time, move to the next stage.
Two rules help to decide which activities to allocate to a stage:
Choose the largest that will fit into the time remaining at the stage
Choose the element with the most ‘followers’.

35. Balancing loss
The effectiveness of the line balancing activity is measured by the balancing loss.
This is the time wasted through the unequal allocation of work as a percentage of the total time invested in processing the product or service.
Balancing loss = Total idle time
No. of stages x Cycle time

36. Balancing loss is that proportion of the time invested in processing the product or service which is not used productively
Load
Stage
Cycle time = 2.5 mins
Cycle time = 3.0 mins
2.3
2.5
2.2
3.0
An ideal ‘balance’ where work is allocated equally between the stages
But if work is not equally allocated the cycle time will increase and ‘balancing losses’ will occur
Work allocated to stage
Idle time
Calculating balancing loss:
Idle time every cycle =( ) +
( ) +
( ) = 2.0 mins
Balancing loss = 2
4 x 3.0 =
= 16.67% 9

37. Worked Example
Consider Karlstad Kakes, a manufacturer of specialty cakes, which has recently obtained contract to supply a major supermarket chain with a specialty cake in the shape of a space rocket. It has been decided that the volumes required by the supermarket warrant a special production line to perform the finishing, decorating and packing of the cake. This line would have to carry out the elements shown in the next slide, which also shows the precedence diagram for the total job. The initial order from the supermarket is for 5000 cakes a week and the number of hours worked by the factory is 40 per week. From this:
The required cycle time = 40 hrs x 60 mins = 0.48 mins
5000
The required number of stages = 1.68 mins (total work content)
0.48 mins (required cycle time)
= 3.5 stages

38. Element listing and precedence diagram for Karlstad Kates
Element De-tin and trim mins a
Element Reshape with off-cuts mins b
Element Clad in almond fondant mins c
Element Clad in white fondant mins d
Element Decorate, red icing mins e
Element Decorate, green icing mins f
Element Decorate, blue icing mins g
Element Affix transfers mins h
Element Transfer to base and pack mins i
Total work content = 1.68 mins
0.12 mins
0.30 mins
0.36 mins
0.25 mins
0.05 mins
0.17 mins
0.10 mins
0.08 mins 9

39. Allocation of elements to stages and balancing loss for Karlstad Katesh i
0.12 mins
0.30 mins
0.36 mins
0.25 mins
0.05 mins
0.17 mins
0.10 mins
0.08 mins
Stage 1
Stage 2
Stage 3
Stage 4
Cycle time = 0.48 mins
Idle time every cycle = ( ) + ( ) + ( ) = 0.24 mins
Proportion of idle time per cycle = = 12.5%
4 x 0.48 9