4 Map Current State
4 Map Current State
4 Map Current State
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After attaininga solidunderstandingof lean, the nextstep is to map the current state of
production, showing the flow of material and information. With this "tep_you place a
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There are numerous ways to determine the scope of a value stream map. Here are a few
common ones:
77
78
~ You can define activibes and measure the time it takes to go from conceiving a
product to launching it.
~ You can define the activities and measure the time it takes from receiving raw materials to shipping finished parts to a customer.
~ You can define the activities that take place from the time an order is placed until
cash is received for the finished order.
In this book, we focus on defining the activibes and measuring the time it takes from
receiving raw materials to shipping finished parts to your customer or customers.
Map Material and InformationFlow
Because a value stream map gives a visual representabon of material and informabon
tlow for a product family (value stream), it is indispensable as a tool for visually managing
process improvements. To improve a process you must first obser\"e and understand it.
:'vlappinga process gives you a clean picture of the wastes that inhibit tlow. Eliminating
waste makes it possible to reduce manufacturing lead bme, \\"hich will help you consistently meet customer demand (Figure 4-2).
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As we delve more deeply into use of the value stream mapping tool, keep in mind that a
key to establishing a lean material f/ow is understanding how n{onnaton flows-that is,
how production scheduling is achieved. As you gather data at each point on a specific
value stream, keep asking, "How do you know what to make next?" This will allow you to
trace information flow along with material flow on your map. Capturing this informabon
is the essence of value stream mapping (Figure 4-3).
When you place your current-state map on the VSM storyboard, ~,ouare helping to promote good visual management on the factory floor. The current-state map represents
your baseline. With just a bit of training on the meaning of the value stream mapping
icons shown in Figure 4-4, anyone should be able to discern information on actual
material and information flow.
Mapping material and information flow will allow you to:
-/
Visualize
flow, instead
of a
Production
Control
Week~
Production
Supervisor
~
1,000
1,000
880
u=J
Thisportionofa current-state
mapshowsthatproduction
controlcommunicates
customerrequirements
to the
production
supervisor
onceperweek.Thesupervisor
communicates
requirements
to eachpartof thevalue
streameveryday.
Customer
orsupplier
--Supermarket
parts
Dedicated
process
box
--Truck
shipment
Shared
process
box
--Supermarkel
Material
push
Max= XX
006
assisted(MRP)
Computer
Heijunka
leveling
LJ
Lrxxl
Electronic
informalion
flow
Physical
material
pul!
Operator
Manual
information
flow
Qd /
Produclion
kanban
Withdrawal
kanban
Kanban
post
Buffer
Safety
inventory
Kaizen
focus
Kaizanflow
(mustflowfrom
kaizenfocus)
.[9-- .-
l..
FIFOlane
Inventory
WIPstagnalion
Signal
kanban
y
U-shaped
cel!
U1J
79
80
-1 Visualize how operations currently communicate with production control and with
each other.
-1 See problem areas and sources of waste.
-1 Locate bottlenecks and WIP.
-1 Spot potential safetyand equipment concerns.
-1 Provide a common language for all manufacturing personnel.
-1 Gain insight into how the operation truly is running that day.
Totaltimepershift
Regularly
planneddowntimeoccurences
suchas
Totalavailabledailyproduction
time(subtract
regularlyplanneddowntimeoccurences
fromthe
totaltimepershift)
D
D
Numberot operators
Reliabilitymetrics-expressdin termsot meantimebetweenfailures,uptime.or overallequipment
effectiveness
(theproductot availability,
performance,
andqualityrates)
O
D
O
Shiftsonwhichthe processoperates
Disruptions
in manutacturing
tlow
Exceptions
thatmayoccurdueto rework
breaks
andlunchthatreduce
available
time
Deliveryschedules
Number
ofpartspershipping
container
auantityof partsshippedpermonthandperday
(bypart)
D
D
D
D
D
D
Cycletimes
Changeover
times
Work-in-process
(WIP)amounts
Actuallotsizes
Pitchincrements
(itavailable)
Economic
lotsizes(economic
order-quantity)
D
D
D
D
Unespeeds
Preventive
maintenance
schedules(important,
becausetheycanreducenetavailabletimetor a
particularprocess)
81
3. Regroup awayfrom the floor to discuss the results of the data gathering efforts and
make sure that all necessary data has been collected.
The Etiquette of Factory FloorResearch
Wheveryou go out on the factory floorto gather data, be sure to do
the following:
O Communicateto all areas you willbe studyingbefore going to
the floor.
O Make proper introductionswhen you arrive on the floor.Workers
like to knowwhat's going on-especially if outside consultants or
representatives from a supplier or customer are presento
O Explain your purpose for studying operations.
O Be open and honest in responding to questions or issues
that arise.
O Respect people's workspace, and thank them for their contributions. Use the opportunity to reinforce mutual trust and respecto
PREMIERE
MANUFACTURING
The t~am convenes and sketches the main production processes for the # 4 and
#6
hbses.
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Marking
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Shlpping
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The team reviews the attribute checklist and decides to be sure to collect data
on the following process attributes:
O Quantity of parts shipped per month and per day.
O Supplier delivery schedule.
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O Available production time.
O Cycle time.
O Changeover time.
O Uptime.
O Number of operators.
O Number of shifts.
O Inventory locations and quantities.
O Time between processes.
The team goes to the floor to collect the data, beginning with the shipping area
and working back to the machining process. They reconveneto review their notes
before beginningto map the current state. The data they collected is shown under
the heading "Premiere Process Attributes" in the form shown that follows.
Premiere
Current.State
Data Collection
.
..
.
CustomerRequirements
Averagedemand:10,080 unitsper month= 504perday:
336per day
./ 6,720#4 hoses
168per day
./ 3,360#6 hoses
Shipping month: 20 days
SupplierInformation
Premiere
receives
a weeklyshipment
of2,500unitsfromitssupplier,
ASC, In.
Premiere
,
Process
Attributes
Availability:Totalavailable
production
timeis8.5hours(510minutes)
pershift.Thereisa 30-minute
unpaidlunchbreakandtwo 10-minutebreaks-a totalof 50 regularlyscheduledminutesof planned
downtime.Therefore,the availableproductiontimeis 460minutes(27,600seconds)per shift.
Shipping:
Location= stagingarea
Frequency/method
= daily/UPS
Finished-goods
inventory= 2,000units
..
..
.
.
Marking:
Cycle time = 50 seconds
Changeover= 5 minutes
Availability= 27,600seconds
. Uptime= 99%
Marking-continued:
Operator = 1
WIP= 2000unitsbetweentestingandmarking
Timebetweenmarkingandshipping:4 days
Testing:
Cycletime= 30 seconds
Changeover= 5 minutes
Availability= 27,600seconds
Uptime= 99%
Operator= 1
WIP= 2000unitsbetweencrimpingandtesting
Timebetweentestingandmarking:4 days
Crimping:
Gycletime = 40 seconds
Changeover= 5 minutes
Availability= 27,600seconds
Uptime= 99%
Operator= 1
Shifts= 1
WIP= 3,500unitsbetweendeburringandcrimping
Timebetweencrimpingandtesting= 4 days
Deburring:
First-in,first-out(FIFO)lanebetweenmachininganddeburring
Cycletime= 5 seconds
Changeover= O
Availability= 27,600seconds
Uptime= 100%
Operator= O(Machiningoperatoralsorunsdeburringwhennecessary)
Shifts= 1
WIP= 3,360#4 and1,680#6 betweenMachiningandDeburring
Timebetweendeburringandcrimping:7 days
Machining:
Gycletime(Cn = 45 seconds
Changeover
time(C/O)= 60 minutes
Availability= 27,600seconds
Uptime= 87 percent
Operator= 1
Shifts= 1
WIP:2,500priorto machining
Timebetweenmachininganddeburring:10days
Flowof InformatlonandMaterial
83
84
Use the same icon to represent the customer and the supplier.
Draw the customer icon in the upper right comer of the sheet.
Draw the supplier icon in the upper left comer.
Draw the productioncontrol icon between the customer and supplier icons.
Ptovdorl
C.o..trol
ABC
l~
2. Draw a data box below the customer icon, and enter the customer requirements in
it. Include monthly and daily requirements of each product, and the number of
containers required per day.
PtoJve./;Orl
c.o..troI
ABC
85
Lo"tro I
ABC
4. Draw the I1wllufactllrillgoperatiolls along the bottom of thc map, with the mosl
upstream process on the left and the most downstream process on the right.
Represent each process with an icon, label it (for example, "machining," "deburring," "testing"), and dra\Vdata boxes below each process icono Add a notched line
below the process boxes on which you will record the production timeline.
O Determine the number of boxes (process icons) you will need ahead of time to be
sure you leave enough space for all of them.
O Alwaysplace the shipping icon at the far end of the process chain-directly below
the truck icon for the customer.
CI Leave enough space between each box for data. If material is stored or stands idle
between processes, for example, you will need to leave space between process icons
to note this and the WIP amounts (see step 7 below).
86
ProJ vdiorl
c.ontro I
ABC
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For each operation, availability S, in effect, the available production time. This is determined by taking the shift time or total available production time-8.5
hours (510 minutes) in the Premiere
Manufacturing case study-and subtracting regular planned downtime occurrences (a 30-minute unpaid lunch and two 10-minute
paid breaks). Therefore, the available production time is 460 minutes, or 27,600 seconds.
Changeover
times
planned
downtime
occur-
rences. Therefore, they diminish an operation's available production time to give you actual operating time.
87
Pto'vc.li.",
LOrltroI
ABC
'.
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lI'
ItO'
ltO\
6. Show infonnation flow, both electronic and manual. In most cases, information flows
between customers and suppliers electronically.
r:J Draw communications arrowsfrom the customer icon to the production control icon,
representing the customer's forecasts and orders, and label each arrow according to
frequency.
:J Draw communications arrows from the production control icon to the supplier icon,
representing production control's monthly forecast and weekly orders, and label
each according to frequency.
:J Draw a box representing the production supervisorin the middle of the map.
:J Draw a communication arrow between the production control icon and the production supervisorbox and label it according to the frequency with which orders are
released to the supervisor.
:: Draw communication arrows bel:ween the production supervisor box and the appropriate individual processboxes, and label each according to the frequency with
which orders are released to the individual operations.
88
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7. Draw invento~' icons in the places where inventory is stored between processes. Write
in the WIP quantities belo\Vthe icons. Calculate the days of inyentory on hand and
write the results on the timeline that runs below the process boxes.
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Calculating
89
You can determine days of WIP on hand by dividing the total number of hose s shipped per day (504) into the total amount of WIP
between processes. For example, there are a total of 3,500 partially manufactured hoses between Deburring and Crimping.
Here's how you calculate days of WIP on hand between the two
processes:
3,500 hoses -;- 504 hoses shipped per day = 6.94 or 7 days
8. Dra\V in push, pulI, and FIFO locations. If a process is producing to a schedule independent of the downstream process, then you are dealing with a push system. Other
scenarios would be some combinabon of pulI and FIFO.
Step 4 Wrap-Up
After everyone on the core team agrees on the map's details, create a clean copy, date it,
and post it on the VSM storyboard for everyone to see.
The Premiere case study that \Vehave referenced in this chapter is a simple one, with a
90
CommonProblemsto Avoid
The value stream mapping concept was developed by Toyota in the 1950s and attracted
more widespread attention among manufacturers in 1997with the publication of an arti-
X There
are a range of other wastes within a value stream, such as wasted energy (e.g.,
lighting, heating) and the waste of human potential when human resources are
under-used or their value and contribution is not recognized. Simply mapping the
value stream does not capture sllch wastes.
X The benefits of mapping are extremely limited if you do not indude the
information flow.
X Typically about
vVith these in mind, watch out for the following as YOllproceed \\"ith your current-state
mappmg.
X Tunnel
Vision. Do not become so focused on the task of mapping the value stream
that you are oblivious to other facts and observations. Caining a better understanding
of manufacturing processes is alwaysa good idea, even if you cannot use what you
learn in creating your value stream map. During the course of observing operations
and interviewing operators, for example, you might discover that when one worker is
performing a specific operation, he or she never creates defects. You would not want
to neglect this important observation. Although it will not help you to create your
map, it most certainly will prove to be a critical piece of information when it comes
time to implement process improvements. Focusing exdusively on the mechanics of
value stream mapping can also lead to the follow problems:
- inability to understand how to assign priorities to improvement opportunities.
- lack of management commitment for implementation.
- inability to tie the mapping process to a reporting mechanism for issue identifica-
tion to use value stream mapping strictly as a management too!. When you collect
data, listening to workers' opinions and concerns is as important as measuring cycle
times, changeover times, and other process attributes. Remember that becoming a
lean enterprise involves engaging everyone'sknowledge and creativity. If you demonstrate a sincere interest in what hourly workershave to say, you will establish trust
and learn everything you want to know-and then some.
1 Hines, Peter, and Nick Rich. 1997lntemational Joumal o[Operations and Prodllction Management, Voll7,
No. 1, pp. 46-64.
Step 4 Wrap-Up
X Incomplete
91
Current-State Mapping. Although many organizations have undertaken various steps of the Value Stream Management process, few, in our experience, tie themall together as \Venas Toyota. Failing to follo\vthe process from
beginning to end is a cornmon reason for this shortcoming. T;;picaIly, companies
also have difficulty rnodifying the technique to fit their culture: furthermore, they
get preoccupied with rnapping and start implernenting imprO\"ementsbefore gathering all the facts. \Vhen value strearn rnaps fail to represent accurately a current state,
they are of limited value when it comes to implementing significant, lasting
improvements. On the other hand, foIlowingthe Value Stream ~vlanagement process
from beginning to end will ensure your success. Don't forget: ,'alue stream mapping
is an important tool within a structured but flexible system known as Value Stream
:\Ianagement! Remember that the devil is in the details. You must understand where
you are currentl;.' if you hope to achieve success in implementing future state. Many
future-state implernentation attempts have failed precisely due to the tendency to
want to rush through creating the current state. In these attempts, the tendency is to
focus on the future state and not the current situation. As a result, core team members did not spend the necessary time to coIlect data on the current state. Do not
make this mistake.
POINTS TO REMEl\IBER FOR
CURRENT-STATEl\IAPPING
You must