mm zg538-l5
DESCRIPTION
MM ZG538-L5TRANSCRIPT
-
5/28/2018 MM ZG538-L5
1/56
MMZG 538 Toyota Production
System
Rajiv Gupta
BITS PilaniJanuary 2014
Session 4
-
5/28/2018 MM ZG538-L5
2/56
Module 1 Recap of Session 4
Module 2 Value Stream Mapping Example (contd)
Lean Principles
Module 3 Value Stream Mapping Example (contd)
Future State Map
Module 4 Types of layouts and material flow
Module 5 Design of machine cells
Module 6 Summary and wrap up
2
-
5/28/2018 MM ZG538-L5
3/56
Session 4
Begin Module 1
Recap of Session 3
3
-
5/28/2018 MM ZG538-L5
4/56
Recap
Material flow is integral to TPS as it affects the lead
times and inventories on the shop floor
The principal reasons for intermittent movement of
materials is batch manufacturing, long set-up timesand an attempt to reduce per unit costs
Product type layouts were used in mass
manufacturing for high volume parts. Process
layouts were meant for low volume job shops.
4
-
5/28/2018 MM ZG538-L5
5/56
Recap
Group layouts were developed as a hybrid between
product and process layouts. They were efficient in
terms of flow and could be used for low to medium
volumes of families of products Typically, value is added to parts for less than one
percent of the time it spends in the plant. However,
the majority of improvement efforts are focused on
improving this one percent. There is a largerpotential for benefits by looking at the remaining
time the part spends in the system.
5
-
5/28/2018 MM ZG538-L5
6/56
Recap
Value Stream Mapping is a macro level charting
technique that highlights the discontinuities in flow in a
system. It can be used as a tool to significantly improve
material flow and system throughput
Value Stream Mapping is applicable to both
manufacturing, as well as non-manufacturing processes.
By analyzing the current state maps and applying lean
principles, we can greatly reduce discontinuities in
material and information flow.
6
-
5/28/2018 MM ZG538-L5
7/56
Session 4
End of module 1
7
-
5/28/2018 MM ZG538-L5
8/56
Session 4
Begin Module 2
Value Stream Mapping Example (contd)
Lean Principles
8
-
5/28/2018 MM ZG538-L5
9/56
9
Lean Principles
Takt time = Available time per shift/Customer demand rate per shift
= 27600 sec/460 pcs
= 60 sec/pc
i.e., we need to produce at the rate of one part every 60 secs.
In practice we may set the production rate a little higher to allow
for changeover time and equipment down time and delays
1. Avoid over-productionproduce to takt time
-
5/28/2018 MM ZG538-L5
10/56
10
Lean Principles
2. Develop Continuous Flow
One piece at a time
Little or no inventory between operations
Operations linked to each other
-
5/28/2018 MM ZG538-L5
11/56
11
Lean Principles
3. Where continuous flow is not possible, use supermarket
pull
- Used when operations are far apart
- Used when an operation is done at a supplier- Used when operations are not balanced
- Used when process is unreliable
Customer
ProcessSupplying
Process
Supermarket
KanbanKanban
-
5/28/2018 MM ZG538-L5
12/56
Lean Principles
Customer Process goes to supermarketand withdraws what it needs
This withdrawal triggers a kanban, which
is a signal to the supplier process toreplenish that product
The supermarket links the customer
process to the supplier process preventingindependent scheduling of the 2processes
12
-
5/28/2018 MM ZG538-L5
13/56
13
Lean Principles
4. Schedule only one process- It is called the pace maker
- Linked to the customer order
- Downstream processes have to be continuous flow
Process 1 Process 2Process 3 Process 4
Pace maker
-
5/28/2018 MM ZG538-L5
14/56
14
Lean Principles
5. Level Production Mix
O X
O X O X O X O X O
-
5/28/2018 MM ZG538-L5
15/56
Lean Principles
6. Create Initial Pull
- At the pacemaker
- Small consistent amount of work
- Could be a container or a bin
15
-
5/28/2018 MM ZG538-L5
16/56
Initial Pull
16
Decide on a pitch which represents consistent incremental work.
Let us say that the takt time = 30 seconds and the pack size is 20
pieces, then the pitch will be 30 seconds x 20 pieces = 10 minutes
So your production schedule will give the pacemaker instruction to
produce one pack quantity every 10 minutes.
Also every 10 minutes, you will take away one finished pitch quantity
-
5/28/2018 MM ZG538-L5
17/56
17
7:00 am 7:10 am 7:20 am 7:30 am 7:40 am
O O
X
OO
X
Load Leveling Box
-
5/28/2018 MM ZG538-L5
18/56
Session 4
End of module 2
18
-
5/28/2018 MM ZG538-L5
19/56
Session 4
Begin Module 3
Value Stream Mapping Example (contd)
Future State Map
19
-
5/28/2018 MM ZG538-L5
20/56
Key Questions For The Future
State1. What is the takt time?
2. Will you build to a finished goods supermarket from
which the customer pulls, or directly to shipping?
3. Where can you use continuous flow processing?4. Where will you need to use supermarket pull systems?
5. Which will be the pacemaker process?
6. How will you level the production mix at the pacemaker
process?7. What increment of work will you consistently release to
the pacemaker process?
8. What process improvements will be necessary?
20
-
5/28/2018 MM ZG538-L5
21/56
Question 1: What will be the takt time?
Available time per shift = 28,800 secs
1200 secs (for 2 10-minute breaks) =
27,600 secs
Customer demand per shift = 460 pieces
Takt time = 27,600/460 = 60 secs
21
-
5/28/2018 MM ZG538-L5
22/56
Question 2: Should the company build to a
finished goods supermarket or directly to
shipping?
22
-
5/28/2018 MM ZG538-L5
23/56
23
Future State Map
Dispatch
L
R
Customer
Demand
Weld+Assy
First Step- Build to supermarket
FutureDirect to shipping
-
5/28/2018 MM ZG538-L5
24/56
Question 3: Where can the company
introduce continuous flow?
24
-
5/28/2018 MM ZG538-L5
25/56
25
Future State Map
Blank Weld Weld Assy Assy
60
1 s
39 s
46 s
62 s
40 s
Operators reqd = 187/60
= 3.12
3 or 4
Apply Kaizen to reduce
Total work content to 168 sec
Operators reqd = 168/60
= 2.8
Use 3 operators
-
5/28/2018 MM ZG538-L5
26/56
26
Future State Map
WeldWeld
Assy
Assy
Improve welder setup time
Improve welder uptime
Weldchangeover
Welderuptime
Work content
< 168 secs
-
5/28/2018 MM ZG538-L5
27/56
27
Future State Map
C/T = 56 sec
C/O = 0
Up =100%
Blanking
Dispatch
L
R
Customer
Demand
Weld+Assy
-
5/28/2018 MM ZG538-L5
28/56
Question 4: Where will supermarket pull
be used?
28
-
5/28/2018 MM ZG538-L5
29/56
29
60
L
R
Stamping
Batch
LH = 600
RH = 320
1.5 days Weld + Assembly
C/T = 56 sec
C/O = 0
Up =100%
-
5/28/2018 MM ZG538-L5
30/56
Question 5: Which single point should
receive the production schedule
(pacemaker)?
Question 6: How should production be
leveled at the pacemaker?
Every part every day
Every part every pitch
30
-
5/28/2018 MM ZG538-L5
31/56
Question 7: What consistent amount of workshould be released to the pacemaker
process?
Question 8: What process improvements arenecessary?
Elimination of changeover time in welding
Improvement of uptime of the second weldingprocess
Reduction of waste in assembly cell to bring total
work content to 168 seconds
Reduction of setup time at the stamping press 31
-
5/28/2018 MM ZG538-L5
32/56
32
Stage Coils Blanks Weld/
Assy
WIP
FG Prod
LT
Inv
Turns
Before 5d 7.6 d 6.5 d 4.5 d 23.6 d 10
After 2 d 1.5 d 0 4.5 d 8 d 30
-
5/28/2018 MM ZG538-L5
33/56
Session 4
End of module 3
33
-
5/28/2018 MM ZG538-L5
34/56
Session 4
Begin Module 4
Layout types and material flow
34
-
5/28/2018 MM ZG538-L5
35/56
Lathe
Lathe
Lathe
Drill
Drill
Drill
Milling
Milling
Milling
Process Layout
Lathe Drill Lathe
Drill Milling Grind
Lathe Grind
Product Layout 35
-
5/28/2018 MM ZG538-L5
36/56
Product Layouts
Product layouts were designed to maximize flow,
but for high volume products
The machines were special purpose and
automation was hard automation, i.e, the systemwas designed for a specific part and volume
The system was inflexible
It was easy to supervise
Scheduling was relatively easy
Lead times were generally short
WIP was low36
-
5/28/2018 MM ZG538-L5
37/56
Process Layouts
Process layouts were used for low volume
products
Machines were general purpose and parts
requiring processing could be produced on anymachine of a particular type, e.g., lathe, etc.
Supervision and scheduling were more difficult
Lead times were long
WIP was high
37
-
5/28/2018 MM ZG538-L5
38/56
Lathe Milling
Lathe Drill
Lathe Drill
Milling
Milling Milling Drill
Grind Grind
Group 1
Group 2
Group 3
Group Layouts
38
-
5/28/2018 MM ZG538-L5
39/56
Group Technology
Attributed to Mitofanov, a machinist, who was
looking for similarities in part shapes
Group technology was the forerunner to
machine cells Initial applications were in coding and
classification of parts for reducing redundant
effort in part design
John Burbidge devised Production Flow Analysis
to group parts that needed similar routings and
the machines into cells
39
-
5/28/2018 MM ZG538-L5
40/56
Machine Cells
Machine Cells A group of machines used to complete a sequence of
operations on a family of parts
The parts in a family does not have high volumes, but
the family has sufficient volume to justify thededication of the machine cell
By restricting the movement of each part to a smallarea, material handling and control is easier,inventories are low and therefore lead times short.This gives the machine cells the efficiency of productlayouts
40
-
5/28/2018 MM ZG538-L5
41/56
Machine Cells
Machine Cells Unlike product layouts, group layouts/machine cells
have the ability to accommodate a family of parts
Due to this, when product mix and volumes change,
the machine cell is able to absorb the fluctuation. Thismakes the group layout/machine cell flexible like theprocess layouts
Machine cells are easy to supervise and schedule
WIP and lead times tend to be low
41
-
5/28/2018 MM ZG538-L5
42/56
Session 3
End of module 4
42
-
5/28/2018 MM ZG538-L5
43/56
Session 3
Begin Module 5
Design of machine cells
43
-
5/28/2018 MM ZG538-L5
44/56
Machine Cells
Machine Cells
Machines are arranged typically in a U-shaped layout
Each operator is assigned multiple machines,not of the same type
Input and output stations tend to be near eachother next to a transportation aisle
Components are delivered either to the firststation and moved with the product, ordelivered by a water spider to each station
44
-
5/28/2018 MM ZG538-L5
45/56
Machine Cells
Machine Cells
Generally the machining capacity is morethan required.
As production volume changes, adjustment ismade to the staffing of the machine cell. Thismakes the machine cells flexible in terms ofproduct mix and volumes
By making a group of workers responsible forthe complete production of a part, there is agreater sense of satisfaction for the workers
45
-
5/28/2018 MM ZG538-L5
46/56
Machine Cells
Machine Cells
Due to better communication within the cell, ifthere is a quality problem, it is detected
quickly and adjustments made to preventfurther defectives from being produced
46
-
5/28/2018 MM ZG538-L5
47/56
Machine Cells
Input
Output
Mach 1Mach 2
Mach 3
Mach 4 Mach 5
Example of a machine cell with 2 operators
47
-
5/28/2018 MM ZG538-L5
48/56
Machine CellsMachine Cells
Input
Output
Mach 1Mach 2
Mach 3
Mach 4 Mach 5
Example of a machine cell with 1 operator
48
-
5/28/2018 MM ZG538-L5
49/56
49
-
5/28/2018 MM ZG538-L5
50/56
50
-
5/28/2018 MM ZG538-L5
51/56
Machine Cell Design
The number of operators and the assignment of
machines to the operators depends on the manual work
content, the walking times and the takt time
Takt time determines the pace at which the cell should
complete one piece
The sum of the manual times and the walking times
should be less than or equal to the takt time
When more than one operators are used, the largest
sum of the manual times plus the walk times should beless than or equal to the takt time
51
-
5/28/2018 MM ZG538-L5
52/56
Session 4
End of module 5
52
-
5/28/2018 MM ZG538-L5
53/56
Session 4
Begin Module 6
Summary and wrap up
53
-
5/28/2018 MM ZG538-L5
54/56
Summary
Lean principles are used to analyze Current State
VSMs
When creating Future State maps, the attempt is
reduce, or eliminate discontinuities in the flow
The VSM will indicate areas where Point Kaizen is
needed in order to achieve smoother flow
Machine cells are a hybrid between product and
process layouts Machine cells have the advantages of efficiency of
product layouts and flexibility of process layouts
54
-
5/28/2018 MM ZG538-L5
55/56
Summary
Machine cells require multi-skilling of operators
Due to the improved communication in of
machine cells, quality of products is improved
Due to the completion of all or most productionof a part within a cell, there is greater worker
satisfaction
In the design of machine cells, we need to
establish the number of workers based on takt
time and the manual time required
As the production volume changes, the number
of workers can be adjusted55
-
5/28/2018 MM ZG538-L5
56/56
End Module 6
Summary and wrap up
56