Process dsign and facility layout

Process Design
and Facility Layout
6/28/2015 DMAKulasooriya, 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

Introduction
• Make or Buy?
– Available capacity
– Expertise
– Quality Consideration
– The nature of demand
– Cost

 Variety
◦ How much
 Flexibility
◦ What degree
 Volume
◦ Expected output
Process Selection

Process Types
• Job Shops
– Small runs
• Batch Processing
• Repetitive/Assembly
– Semicontinuous
• Continuous Processing
• Projects
– Nonroutine jobs

Product
Variety
High Moderate Low Very Low
Equipment
flexibility
High Moderate Low Very Low
Low
Volume
Moderate
Volume
High
Volume
Very high
Volume
Job
Shop
Batch
Repetitive
assembly
Continuous
Flow
Variety, Flexibility, & Volume

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

 Automation: Machinery that has
sensing and control devices that
enables it to operate
Automation

Automation
• Computer-aided design and
manufacturing systems (CAD/CAM)
• Numerically controlled (NC) machines
• Robot
• Manufacturing cell
• Flexible manufacturing systems
• Computer-integrated manufacturing
(CIM)

 Layout:
the arrangement of departments, work
station, and equipment, with particular
emphasis on movement of work
(people, information or materials)
through the system
Layout

Basic Layout Types
 Product Layouts
 Process Layouts
 Fixed-Position
 Combination Layouts

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)

 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

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

Cellular Layouts
 Cellular Manufacturing
 Group Technology
 Flexible Manufacturing Systems

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

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

A U-Shaped Production Line
1 2 3 4
5
6
78910
In
Out
Workers

Process Layout
Process Layout - work travels
to dedicated process centers
Milling
Assembly
& Test
Grinding
Drilling Plating

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

Cellular Manufacturing Layout
-1111 -1111
222222222 - 2222
Assembly
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

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.

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

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.

Determine Maximum Output
O utput capacity =
O T
CT
O T operating tim e per day
D = Desired output rate
CT = cycle tim e =
O T
D


Determine the Minimum Number
of Workstations Required:
Efficiency
stask timeofsum=t
CTDesired
t)(
=N



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

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

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.

Calculate the desired CT (Takt
Time)
TT = 40 h * 60 m/ h = 2400
6000 units 6000
= 0.4 minute

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

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

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

A
B
C
D
0.1 min.
0.2 min.
0.4 min.
0.3 min.
Assembly line with three workstations

A B C D
Workstation -01 Workstation -02 Workstation -03
0.3 m 0.4 m 0.3 m
Assembly Line

Calculate Percent Idle Time
Percent idle time =
Idle time per cycle
(N)(CT)
PIT = 0.2/ 3 (0.4) = 16.6 %

Determine the Efficiency
stask timeofsum=t
actual)(CTn
t)(
=E


E = 0.1 +0.2+0.3+0.4 = 1.0/ 1.2 = 83.3%
3 (0.4)

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

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.

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:

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

Requirements:
◦ List of departments
◦ Projection of work flows
◦ Distance between locations
◦ Amount of money to be invested
◦ List of special considerations
Designing Process Layouts

Process dsign and facility layout

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