Facility layout process selection

1. Process Selection
and Facility Layout

2. • Process selection
– Deciding on the way production of goods or
services will be organized
• Major implications
– Capacity planning
– Layout of facilities
– Equipment
– Design of work systems
Introduction

3. Forecasting
Product and
Service Design
Technological
Change
Capacity
Planning
Process
Selection
Facilities and
Equipment
Layout
Work
Design
Process Selection and System Design
Inputs Outputs

4. Key aspects of process strategy
– Capital intensive – equipment/labor
– Process flexibility
– Adjust to changes
– Design
– Volume
– Technology
Process Strategy

5. • Variety
– How much
• Flexibility
– What degree
• Volume
– Expected output Job Shop
Batch
Repetitive
Continuous
Process Selection

6. Process types

7. • Job shop
– Small scale, wide variety of goods
• Batch
– Moderate volume, flexible
• Repetitive or assembly line
– High volumes of standardized goods or services
• Continuous
– Very high volumes of non-discrete goods
• Projects
– Non-routine work, unique set ob objectives, limited
timeframe and resources
Process types and volume

8. Product – Process Matrix
The diagonal of the matrix
represents the ideal choice
of processing system for a
given set of circumstances.

9. Functions/activities affected by process
choice
Job variety, process flexibility, unit cost
Volume
Limited
(not ongoing)

10. Some examples
(find the process type of each)
Movie production
Bakery
Restaurant
(non fast food)
University
Car repairing
(car mechanic shop)
Oil mining
Producing office tools
Veterinarian
Project
Batch
Batch
Batch
Job shop
Continuous
Repetitive
Job shop

11. Product and service life cycles
• Alongside the life cycle the sales and with it
the production volume can change.
• Thus managers must be aware of the change
in the optimal processing system.
(the necessity of change is highly dependent
on the particular good or service)

12. Example
• Computer building shop in a garage (working for
order only, one computer at a time for given
purposes)
• The shop hires some workers and producing
some dozens of computers for one customer at
a time
• Computer factory is established, creating large
number of computer series
• The R&D function of the firm invents a new
computer prototype
Job shop
Batch
Repetitive
Project

13. Product/Service Profiling
• Linking key product or service requirements to
process capabilities.
• Design the process with taking into
consideration the following:
– Range of products/services
– Expected order size
– Pricing
– Expected frequency of changes in schedules etc.
– Order-winning requirements
– …

14. Sustainable production
• Non-polluting
• Conserving natural resources & energy
• Economically efficient
• Safe and healthful for workers, communities
and consumers
• Socially and creaqtively rewarding for workers

15. • Automation: Machinery that has sensing and
control devices that enables it to operate
– Fixed automation
– Programmable automation
Automation of production and services

16. Advantages of automation
• Low variability in performance and quality
• Machines do not
– get bored or distracted
– go out on strike or ask for higher wages
– lower variable costs

17. Disadvantages
• Higher initial (investment) cost and
• Higher fixed costs
• Lower felxibility
• Higher skills needed
• Lower morale of human workforce
• Need for standardisation
– Products
– Processes
– Equipment and materials etc.

18. • Computer-aided design and manufacturing
systems (CAD/CAM)
• Numerically controlled (NC) machines
• Computerized numerical control (CNC)
• Direct numerical control (DNC)
• Robot: mechanical arm + power supply + controller
• Manufacturing cell
• Flexible manufacturing systems (FMS)
• Computer-integrated manufacturing (CIM)
Automation

19. • Layout: the configuration of departments,
work centers, and equipment, with
particular emphasis on movement of work
(customers or materials) through the
system
Facilities Layout

20. • Requires substantial investments of money
and effort
• Involves long-term commitments
• Has significant impact on cost and
efficiency of short-term operations
Importance of Layout Decisions

21. The Need for Layout Decisions
• Inefficient operations
• High (variable) cost
• Bottlenecks
• Changes in the design of products or services
• The introduction of new products or services
• Safety
• Changes in environmental or other legal
requirements
• Changes in volume of output or mix of products
• Changes in methods and equipment
• Morale problems

22. Objectives of facility layout
Main: smooth flow of work, material and information
Supporting objectives:

23. • Product layouts
• Process layouts
• Fixed-Position layout
• Combination layouts:
– Cellular layout (& group technology)
– Flexible manufacturing systems
Basic Layout Types

24. • Product layout
– Layout that uses standardized processing
operations to achieve smooth, rapid, high-volume
flow
• Process layout
– Layout that can handle varied processing
requirements
• Fixed Position layout
– Layout in which the product or project remains
stationary, and workers, materials, and
equipment are moved as needed
Basic Layout Types

25. Used for Repetitive or Continuous Processing
Product Layout

26. • High rate of output
• Low unit cost
• Labor specialization
• Low material handling cost
• High utilization of labor and equipment
• Established routing and scheduling
• Routing accounting and purchasing
Advantages of Product Layout

27. • Creates dull, repetitive jobs
• Poorly skilled workers may not maintain
equipment or quality of output
• Fairly inflexible to changes in volume
• Highly susceptible to shutdowns
• Needs preventive maintenance
• Individual incentive plans are impractical
Disadvantages of Product Layout

28. A U-Shaped Production Line

29. Advantages/disadvantages of
U-shaped lines
• Shorter distances for
workers & machines
• Permits communication
thus facilitates teamwork
• More flexible work
assignments
• Optimal if the facility has
the same entry and exit
point
• If lines are highly
automated, there is no
need for communication
and travel
• If entry points are on the
opposite side as exit points
• Noise and contamination
factors are increased in the
U-shape

30. Dept. A
Dept. B Dept. D
Dept. C
Dept. F
Dept. E
Used for Intermittent processing
Job Shop or Batch
Process Layout
(functional)
Process Layout

31. • Can handle a variety of processing
requirements
• Not particularly vulnerable to equipment
failures
• Equipment used is less costly
• Possible to use individual incentive plans
Advantages of Process Layouts

32. • In-process inventory costs can be high
• Challenging routing and scheduling
• Equipment utilization rates are low
• Material handling slow and inefficient
• Complexities often reduce span of supervision
• Special attention for each product or
customer
• Accounting and purchasing are more involved
Disadvantages of Process Layouts

33. Fixed-position layouts
• The product or project remains stationary and
workers, materials, and equipment are moved
as needed.
• If weight, size, bulk, or some other factor
makes it undesirable or extremely difficult to
move the product.
• E.g. firefighting, road-building, home-building,
drilling for oil etc.

34. • Cellular Production
– Layout in which machines are grouped into a
cell that can process items that have similar
processing requirements
• Group Technology
– The grouping into part families of items with
similar design or manufacturing characteristics
– Makes cellular production much more effective
Cellular Layouts

35. Traditional process layout
Cellular layout

36. Dimension Functional Cellular
Number of moves
between departments
many few
Travel distances longer shorter
Travel paths variable fixed
Job waiting times greater shorter
Throughput time higher lower
Amount of work in
process
higher lower
Supervision difficulty higher lower
Scheduling complexity higher lower
Equipment utilization lower higher
Functional vs. Cellular Layouts

37. Flexible manufacturing systems
• FMS: a group of machnies designed to handle
intermittent processing requirements and
produce a variety of similar products.
• CIM (Computer Integrated Manufacturing): a
system of linking a broad range of
manufacturing activities through an
integrating computer system

38. • Warehouse and storage layouts
– Minimizing movement & picking time and cost
• Retail layouts
– Presence & influence of customers
• Office layouts:
– Information is computerized, image of openness
Service Layouts

39. Design Product Layouts: Line Balancing
Line Balancing is the process of assigning
tasks to workstations in such a way that the
workstations have approximately equal time
requirements.
This way the idle time will be minimized,
utilization will be maximized.
Specialization: dividing work into elemental
tasks that can be performed quickly and
routinely.

40. Cycle Time
Cycle time is the maximum time allowed at
each workstation to complete its set of
tasks on a unit.
tmax < Cycle time < ∑t

41. Determine the Minimum Number
of Workstations Required
Theoretical Nmin is not necessarily will be the
Nactual. The latter is affected by other technical
and practical considerations, too. Nmin ≤ Nactual
(rounded up to the next integer)

42. A diagram that shows elemental tasks and their
precedence requirements.
A simplified precedence
diagram
a b
c d e
0.1 min.
0.7 min.
1.0 min.
0.5 min. 0.2 min.
Precedence Diagram

43. Assume that the desired output is 480 units per day.
The facility is working 8 hours a day. The elemental
tasks and their connections are shown on the
previous slide.
• Calculate the cycle time.
• Calculate the minimum number of workstations.
• Arrange the tasks to these workstations in the order
of the greatest number of following tasks.
Example 1: Assembly Line Balancing

44. Workstation
Time
Remaining Eligible
Assign
Task
Revised
Time
Remaining
Station
Idle Time
1 1.0
0.9
0.2
a, c *
c **
none***
a
c
-
0.9
0.2
0.2
2 1.0 b b 0.0 0.0
3 1.0
0.5
0.3
d
e
-
d
e
-
0.5
0.3 0.3
Total: 0.5
Example 1 Solution
* Tasks that have no predecessors.
** b is not eligible, because it needs more time than than the remaining.
*** Every available task needs more time than 0.2.

45. Efficiency %= 100 x (1 – Percentage of idle time)
Calculate Percent Idle Time and efficiency

46. Line balancing procedure

47. • Assign tasks in order of most following
tasks.
– Count the number of tasks that follow
• Assign tasks in order of task time.
• Assign tasks in order of greatest positional
weight.
– Positional weight is the sum of each task’s time
plus the times of all following tasks.
Line Balancing Heuristics

48. Example 2
Working day is 8 hours and the desired output rate is 400 units per day.
Draw the precedence diagram.
Compute the cycle time & the minimum theoretical number of
workstations required.
Assign tasks to workstations according to the greatest number of
following tasks. Tiebreaker: longest processing time goes first.
Calculate Percent idle time & efficiency.

49. Solution 2
CT = (8*60)/400= 1.2; Nmin = ∑ti / CT = 3.17 → 4
a b e
c f
d h
g
Work station Tasks assigned Idle time
WS1 a,c,b 0
WS2 d,e 0.3
WS3 f 0.2
WS4 g,h 0.5
Percentage idle time = 1.0 / (4*1.2) = 20.83%
Efficiency = 100 – 20.83 = 79.17%

50. Other approaches
• Paralell workstations
• Cross-train workers (dynamic line balancing)
• Mixed model line
(more product on the same line)

51. 1 min.
2 min.
1 min.
1 min.
30/hr. 30/hr. 30/hr. 30/hr.
1 min.
1 min.
on average
1 min.
1 min.
60/hr.
30/hr. 30/hr.
60/hr.
30/hr.
30/hr.
Bottleneck
Parallel Workstations
Parallel Workstations
2 min.
2 min.

52. Thank you for your attention