Chapter%205%20Value%20Stream%20Mapping

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Chapter 5Value Stream Mapping
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5 Principles of LEAN
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Mapping the value stream

• Following the product or product family from
  beginning to end (really from end to beginning).
  
• Each value-added and non-value added step is
  noted and timed
• What does value added mean?

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What is value added?

• Value added (VA) activities are those that
  customer is willing to pay for. (Also called
  customer value-added CVA). They transform the
  product service or transaction in a way that is
  meaningful to the customer.
• Examples?
• Non-value-added (NVA) are all those activities
  required by a business to execute work that adds
  no value from a customer point of view and that
  customers are not willing to pay for.
• Examples?

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Should all NVA steps be eliminated?

• What about
• Equipment maintenance?
• Janitor service?
• Payroll? Internal audit? Budget forecasting
• These dont add-value to the customer, but are
  necessary for the functioning of the business.
• So really there are 3 types of steps in a value
  stream
• Steps that create value
• Steps that create no value but are necessary
• Steps that create no value and therefore can be
  eliminated.

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Traditional vs. Waste elimination approach
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So what is Value Stream Mapping?

• Value stream mapping is a tool that helps you see
  and understand the flow of material and
  information as a product/service makes its way
  through the value stream.

• Usually a pencil and paper process at first.
• Carefully draw a visual representation of every
  process in the material and information flow.
• Then ask a set of key questions and draw a
  future state map of how value should flow.

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Why is VSM an essential tool?

• The real voyage of discovery consists
• not in making new landscapes but in
• having new eyes.
• Marcel Proust (1871-1922), Novelist
• Helps you visualize more than just the
  single-process level, you can see the whole flow.
• Helps you see more than waste, and identify the
  sources of waste.
• Makes decisions about the flow apparent
• It forms the basis of an implementation plan.
  Value stream maps become a blueprint for lean
  implementation.
• Show the link between the information flow and
  the material flow.
• Is a qualitative and quantitative tool by which
  you describe in detail how your facility should
  operate in order to create flow.

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Phases in VSM
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Mapping the Current State

• Draw by hand and pencil
• Try to collect current information
• Check for integrity of the data
• Start at the end and work upstream
• Bring your stopwatch to perform needed or missing
  time and motion studies
• Do the value stream yourself (walk the floor)
• Should be one person
• Map material information flows

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Production flow
Production System Definition Consequences
PUSH Builds to plan regardless of customer demand. Overproduction or shortages that dont meet the actual needs of the customer.
PULL Driven by actual consumption and controlled by synchronized replenishment. Removes inventory (waste) allows flexibility, WIP, handling, quality errors, defects, and lead time.
After Value Stream mapping the next step LEAN
step is flow. Flow produces a product without
unnecessary interruption or delay.
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Key conceptTakt Time

• Pace of customer demand

• Minus lunch breaks, briefings, other
• Can also apply to transactions, services, or
  parts
• Can be defined in terms of per day, month, or
  other metric.
• Creates a sense of urgency, without it everyone
  will produce at their own schedule.
• As soon as the customer demand is determined, the
  organization must make the commitment to meet it.

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Takt Time Example

• Customer demand is 100 widgets/ day
• Production time available/day 8 hours 480
  minutes
• Lunch 45 minutes/day
• Breaks 30 minutes
• TAKT TIME In order to meet customer demand
  within available work time, we must produce a
  widget every 4.05 minutes.
• If product is grouped, or batched then we can
  calculate Pitch Time
• PitchTime Takt Time batch size
• If demand cant be met with current resources and
  processes, Lean tools such as Buffer or Safety
  resources should be used.

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Creating a map
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Common VSM Symbols

• There is some variation between software and
  companies. But on a whole very similar.(Book
  lists them on page 97.)
• Typical Process data/ form

Process

Cycle Time Production time Changeover time Uptime
C/T
P/T
CO
U/T-SHFs
Chart from http//www.edrawsoft.com/Value-Added-F
low-Chart.php
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Example Scorpion PBJ Factory

• Daily demand of 700 pieces
• With the following factory arrangement.
• Hours per shift 8
• Break minutes per shift 30
• Shifts per day 1
• Days per week 5
• CALCULATE TAKT TIME
• Get out your pencil and a (big) piece of paper

Example from http//lssacademy.com/2008/02/24/le
ts-create-a-current-state-value-stream-map/
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Start the map with the customer
Draw in the customer box / details. In the top
right hand side of the paper we draw the little
saw topped box representing our customer. We also
note their monthly and/or daily demand along with
the takt time as calculated in step 1.
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Material Flow

• PROCESS What would be the general steps needed?
  define the start and stop point of the process.
• Peanut butter Application 1 operator - 25
  second cycle time
• Jelly Application 1 operator 30 second cycle
  time
• Packaging- 1 operator 42 second cycle time
• Shipping

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Focus on the material flow first
Start at the END of the process and begin drawing
the map back to front. Focus on the material
flow first. Focus on the material flow side of
things first (bottom portion of the map). This
includes the process boxes and data boxes.
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Inventory

• Before PB Application 700 pieces
• Before Jelly Application 359 pieces
• Before Packaging 486 pieces
• Before Shipping 128 pieces
• (In our example, we chose to simply count two
  pieces of bread as one subassembly since they
  move together down the production line. Also, we
  are not accounting for the peanut butter and
  jelly raw material at this point. )
• During the walk through of the process we noticed
  that each process step seemed to be working in
  isolation. In other words, the lady working at
  the peanut butter application seemed to produce
  as many units as she could and then pushed them
  along to the jelly application process.

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Add the Inventory/Wait Times. Once you have all
the process and data boxes in, its time to add
in inventory and/or waiting times. For
inventory, we simply count the number of pieces
in between the processes and note them under the
triangle.
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Information flow..

• We learned that production schedules each process
  step in isolation. In other words, each work
  station gets its unique production schedule.
• Scorpions customer sends 30 days electronic
  forecasts as well as electronic daily orders.
  Conversely, Scorpion sends its bread supplier an
  electronic weekly forecast.

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Draw in the information flow. If it is moves
about electronically use a lighting bolt . If it
is communicated manually use a straight arrowed
line. During this step we also draw in our
production control box.
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Add in the timeline to the bottom of the value
stream map. This saw tooth looking line helps us
separate the value added cycle time (taken from
data boxes) from the non value added time. The
last step in the process is to sum up all the
value-add cycle times and note them at the end
of the timeline. Likewise, we also sum up the
inventory times and note that on the timeline.
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Calculating Total Lead Time

• Queuing time - time that a work unit waits for
  a downstream process to begin work on it.
• Cycle Time the elapsed time for an individual
  activity from start to completion.
• Total Cycle Time Sum of all the cycle times for
  individual activities in the process in the value
  stream. Referred to as Value Added time (VAT)
  because it is the time during which value is
  added as the work unit flows through the process.
• Total Lead Time Total Cycle time Total
  Queuing time

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Questions to think about

• How many days of inventory do you have waiting
  between processes?
• What is the total non-value added (or queuing)
  time?
• What is the total cycle time?
• Can the Scorpion PBJ factory meet the customer
  demand? How does the capacity relate to the takt
  time we calculated?
• What is the pacemaker process? (the process
  that should set the pace for all the rest?)
• What is wrong in this process flow? Use the 5
  whys to identify opportunities for improvement.