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Process Design and Facility Layout
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
DMA Kulasooriya
ISL- Certified Six Sigma Black Belt
Process Selection and System Design
Forecasting
Product and
service design
Capacity
planning
Facilities and
Equipment
Layout
Work
design
Process
selection
Technological
change
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Introduction
• Make or Buy?
– Available capacity
– Expertise
– Quality Consideration
– The nature of demand
– Cost
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Variety
◦ How much
Flexibility
◦ What degree
Volume ◦ Expected output
Process Selection
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Process Types
• Job Shops
– Small runs
• Batch Processing
• Repetitive/Assembly
– Semicontinuous
• Continuous Processing
• Projects
– Nonroutine jobs
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
ProductVariety
High Moderate Low Very Low
Equipmentflexibility
High Moderate Low Very Low
LowVolume
ModerateVolume
HighVolume
Very highVolume
Job
Shop
Batch
Repetitive
assembly
Continuous
Flow
Variety, Flexibility, & Volume
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Product-Process Matrix
Flexibility-Quality Dependability-Cost
Continuous
Flow
Assembly
Line
Batch
Job
Shop
Low
Volume
One of a
Kind
Multiple
Products,
Low
Volume
Few
Major
Products,
Higher
Volume
High
Volume,
High
Standard-
ization
Commercial
Printer
Heavy
Equipment
Automobile
Assembly
Sugar
Refinery
Flexibility-
Quality
Dependability
Cost
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Automation: Machinery that has sensing and control devices that enables it to operate
Automation
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Automation
• Computer-aided design and
manufacturing systems (CAD/CAM)
• Numerically controlled (NC) machines
• Robot
• Manufacturing cell
• Flexible manufacturing systems
• Computer-integrated manufacturing
(CIM)
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Layout:
the arrangement of departments, work station, and equipment, with particular emphasis on movement of work (people, information or materials) through the system
Layout
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Basic Layout Types
Product Layouts
Process Layouts
Fixed-Position
Combination Layouts
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Basic Layout Types
Product Layout ((Assembly line) ◦ Arrange activities in a line according to the sequence of operations for a particular product or service. Layout that uses standardized processing operations to achieve smooth, rapid, high-volume flow
Process Layout (functional layout) ◦ Group similar activities together according to the process they perform. Eg. Drilling, lathe
Fixed Position Layout ◦ Layout in which the product or project remains stationary, and workers, materials, and equipment are moved as needed ( ships, Air craft)
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
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
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
The Need for Layout Decisions
Inefficient operations
For Example:
High Cost
Bottlenecks
Changes in the design
of products or services
The introduction of new
products or services
Accidents
Safety hazards
The Need for Layout Designs (Cont’d) Changes in
environmental
or other legal
requirements
Changes in volume of
output or mix of
products
Changes in methods
and equipment
Morale problems
Basic Layout Formats
Group Technology Layout
Just-in-Time Layouts
◦ May be assembly-line or
◦ Group Technology formats
Fixed Position Layout ◦ e.g. Shipbuilding
Part Family W Part Family X
Part Family Y Part Family Z
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Cellular Layouts
Cellular Manufacturing
Group Technology
Flexible Manufacturing Systems
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Cellular Layouts
Cellular Manufacturing ◦ 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
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
A Flow Line for Production or Service
Flow Shop or Assembly Line Work Flow
Raw
materials
or customer
Finished
item Station
2
Station
3
Station
4
Material
and/or
labor
Statio
n
1
Material
and/or
labor
Material
and/or
labor
Material
and/or
labor
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
A U-Shaped Production Line
1 2 3 4
5
6
7 8 9 10
In
Out
Workers
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Process Layout
Process Layout - work travels
to dedicated process centers
Milling
Assembly
& Test Grinding
Drilling Plating
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Functional Layout
Gear
cutting
Mill Drill
Lathes
Grind
Heat
treat
Assembly
111
333
222
444
222
111
444
111 333 1111 2222
222
3333
111
444
111
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Cellular Manufacturing Layout
-1111 -1111
222222222 - 2222
As
se
mb
ly
3333333333 - 3333
44444444444444 - 4444
Lathe
Lathe
Mill
Mill
Mill
Mill
Drill
Drill
Drill
Heat
treat
Heat
treat
Heat
treat
Gear
cut
Gear
cut
Grind
Grind
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
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.
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Cycle Time
Cycle time is the maximum time
allowed at each workstation to
complete its set of tasks on a unit.
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Line Balancing
Assembly line balancing operates under two constraints,
precedence requirements and cycle time restrictions’
Precedence requirements are expressed in the form of a
precedence diagram- network
Cycle time is calculated by dividing the time available for
production by the number of units to be produced – time
taken to completed item rolling off the assembly line.
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Determine Maximum Output
Output capacity = OT
CT
OT operating time per day
D = Desired output rate
CT = cycle tim e = OT
D
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Determine the Minimum Number of Workstations Required: Efficiency
s task timeof sum = t
CT Desired
t)( = N
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Real fruit Snack are made from a mixture of dried fruits and packaged. To meet demand real fruit needs to produce 6000 fruit strips every 40-hour week. Design an assembly line with fewest number of workstations that will achieve the production quota without violating precedence constraints
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Work Element Precedence Time (Min)
A Press out sheet of fruits
----- 0.1
B Cut into strips A 0.2
C Outline Fun Shapes A 0.4
D Roll up and package B,C 0.3
Total 1.0
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Precedence Diagram
Precedence diagram: Tool used in line
balancing to display elemental tasks and
sequence requirements A Simple Precedence
Diagram
A B
C
D
0.1 min. 0.2 min.
0.4 min.
0.3 min.
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Calculate the desired CT (Takt Time) TT = 40 h * 60 m/ h = 2400 6000 units 6000 = 0.4 minute
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Calculate the theoretical minimum number of workstations
N = 0.1 + 0.2 + 0.3 + 0.4 = 1.0 = 2.5
0.4 0.4
N= 2.5 = 3 workstations
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Assembly Line Balancing
Arrange tasks shown in the previous slide into workstations.
◦ Use a cycle time of 0.4 minute
◦ Assign tasks in order of the most number of followers
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Work Station
Work Element
Remaining time
Remaining Elements
1 A 0.3 B C
B 0.1 C D
2 C 00 D
3 D 0.1 None
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
A B
C
D
0.1 min. 0.2 min.
0.4 min.
0.3 min.
Assembly line with three workstations
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
A B C D
Workstation -01 Workstation -02 Workstation -03
0.3 m 0.4 m 0.3 m
Assembly Line
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Calculate Percent Idle Time
Percent idle time = Idle time per cycle
(N)(CT)
PIT = 0.2/ 3 (0.4) = 16.6 %
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Determine the Efficiency
s task timeof sum = t
actual) (CTn
t)( = E
E = 0.1 +0.2+0.3+0.4 = 1.0/ 1.2 = 83.3%
3 (0.4)
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
The Basic Block Company needs to produce 4000 boxes of
blocks per 40-hour week to meet upcoming holiday demand. The
process of making blocks can be broken down into six work
elements. The precedence and time requirements for each
element are as follows. Draw and label a precedence diagram for
the production process. Set up a balanced assembly line and
calculate the efficiency of the line
WORK PERFORMANCE
ELEMENT PRECEDENCE TIME (MIN)
A — 0.10
B A 0.40
C A 0.50
D — 0.20
E C, D 0.60
F B, E 0.40
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Quick Start Technologies (QST) helps companies design
facility layouts. One of its clients is building five new assembly
plants across the continental United States. QST will design
the assembly-line layout and ship the layout instructions,
along with the appropriate machinery to each new locale. Use
the precedence and time requirements.
given below to design an assembly line that will produce a new
product every 12 minutes. Construct a precedence diagram,
group the tasks into workstations, determine the efficiency of
the line, and calculate the expected output for an eight-hour
day.
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Task Precedence Time (mins)
A None 6
B A 2
C B 2
D A 1
E A 7
F A 5
G C 6
H D, E, F 5
I H 3
J G 5
K I, J 4
Line Balancing Rules
Assign tasks in order of most following tasks.
Assign tasks in order of greatest positional weight.
Positional weight is the sum of each task’s time and the times of all following tasks.
Some Heuristic (intuitive) Rules:
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Parallel Workstations
1 min. 2 min. 1 min. 1 min. 30/hr. 30/hr. 30/hr. 30/hr.
1 min.
1 min.
1 min. 1 min. 60/hr.
30/hr. 30/hr.
60/hr.
1 min.
30/hr.
30/hr.
Bottleneck
Parallel Workstations
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)
Requirements:
◦ List of departments
◦ Projection of work flows
◦ Distance between locations
◦ Amount of money to be invested
◦ List of special considerations
Designing Process Layouts
6/28/2015 DMA Kulasooriya, NIBM (UCD -BSc-2011)