mapping your value stream

MAPPING YOUR VALUE STREAM

Maps Show how work is currently being done Help to make work visible Increased visibility

Improves communication Improves understanding Provides common frame of reference to all

those who involved with the work processShows the pathways for improvement

Think of constructing a house without a blue print – an architect communicates with the client using a draft/map

Process Mapping

Level ofPerformance

(Work) Map Type View of Work

Organization

Relationship Map

Relationship between departments, the supplier customer relationships that exist between parts of an organization

ProcessCross functional process maps (Swim lane diagrams)

Workflow; the path of work as it flows across several functions

Job Flow Chartthe value added or non-value added effort performed by individuals

Relationship map

Organization and its major partsSuppliers

Product or Srivice

Order

Customer

Materials

Cross functional map

Flow Charts

Post-it notes As a map will have to be drawn and

redrawn several times A detail map is drawn with Post-it-notes

Get all team members to write their own activities Only put one activity on each Post-it note The note can be coloured for different functions Get the owner of the note to place it Add Post-it notes and rearrange

What is a Value Stream

A value stream is defined as all the value added and non value added actions required to bring a specific product, service or a combination of products and services , to a customer, including those who in the overall supply chain as well as those in internal operations.

Think of a value stream of making a cup of tea

A method to look at the production process to produce your product

Maps/represents production flow and information flow All levels,

not just individual processes include your suppliers, and customers too

Total Value Stream

Suppliers In-house activities Customer /end user

Total Value Stream

Suppliers In-house activities Customer /end user

What is Value Stream Mapping

A Value Stream Map

Product family•Mapping a value stream is done for one product/ product family, not for every product that moves through the production floor

•A product family is a group of products that pass through similar process and through similar machines and equipments

•Not possible to have dedicated line for each product

•If a single line is used for more products, change over may be high, WIP high, transportation high etc.

ASSEMBLY STEPS & EQUIPMENT

PR

OD

UC

TS

1 2 3 4 5 6 7

A X X X X X

B X X X X X

C X X X X

D X X X X X

E X X X X X

F X X X X X

G X X X X

Drawing the current state map

Draw the current state map by hand.

Map the flow of both material and information by walking.

Start by identifying the customer requirements and then work the process

backwards.IMPORTANT

Always start at the customer end of the

stream.-What do they see as value?

Customer Requirements

•When •Where•How many•How often•Customer forecast •Packing details (size of pack)

Process information to be collected

1. Cycle Time - The length of time which the product spends in a specific part of a process

2. Changeover time - The time taken to change between one product stream/variety to the next

3. Batch sizes - The number of parts in a batch

4. Number of operators - total (+ shift breakdown)

5. Shift time - standard working hours

6. Scrap rate - an indication of the level of quality (e.g. cost of quality, part per million, %success rate, operator gut feeling)

7. Inventory - Number of parts not being worked on

8. Lead-time - The time taken from the receipt of raw material to the delivery to the customer.

9. Make Span - The time between removing the raw material from stores and putting the finished good into stores.

Icons used in value stream mapping

How to Draw the Current State MapMaterial Flow

Mix in Bowl Pour into Mould Cook in Microwave Present

Keep it simple as top level not interested in what happens at each of the stages.

ie don’t need to know what the ingredients are.



Batch Size = 1Cycle Time = 10 minsNo. Operators = 1 per shiftShift = Days/Nights



Require basic information at each of the stages.

Push vs. Pull Supply

Pull - demand driven supply, the upstream process pulls the part from the supplier only when required. The supplier makes the next part only when the previous one has been taken.

Push - The supplier makes the part to a given schedule whether the customer requires it or not. The customer takes the part when they are ready for it (if it is ready to take!)






0 15 mins 20 mins

PUSH PULLPUSH

Look at what’s happening in between the stages of the process.Are things waiting are they being pushed or pulled.

Mix in Bowl


CargilsKeelsArpico

Who supplies the ingredients at each stage.List of ingredients.

SUPPLIERS

180 mins

How to Draw the Current State MapInformation Flow

30 day forecast

Daily order

Monthly Visit

Daily Phone

Same for material flow, just find the main constituent parts of the process.Find out how that information is passed on Electronically or manually.

How to Draw the Current State Map

30 day forecast

Daily order

Monthly Visit

Daily Phone





0

0

1

15 mins

2

20 mins

PUSH PULLPUSHCargilsKeelsArpico

Daily Input

2

180 mins

180 mins10 mins

0 mins2 mins

15 mins60 mins

20 minsLeadtime = 287 mins

VA =72 mins

Daily/ Monthly

Daily

Why value stream mapping is an essential tool

•It helps to visualise more than just a single process (e.g. cutting , packing etc.)- you can see flow

•It helps to see more than waste, it helps to identify the sources of waste

•It brings discussion points

•It forms the basis of the implementation plan - The blue print for achieving door-to-door flow

•It shows the linkage between the information and material flow

•Value stream mapping is good for describing what you actually going to do

Information Flow

•In value stream mapping information flow is as important as the material flow

•In lean we should flow information so that one process may make only what is need by the next process and when it is needed

What Makes a Value Stream Lean

All we are trying to do is to make only what the next process needs, when it needs it. We are trying to link

all processes in a smooth flow, that generates the shortest lead time, with minimum waste.

Definition of Lean Manufacturing – The researches of the International Motor Vehicle Programme (IMVP) of Massachusetts Institute of Technology (MIT) defines Lean Manufacturing as “A philosophy that when implemented reduces the time from customer order to delivery by eliminating sources of waste in the production floor”.

Guide lines to draw future state map1. Produce to your takt time

2. Develop continuous flow wherever possible (+line balancing)

3. Use supermarkets to control production where continuous flow does not extend upstream

4. Try to send the customer schedule to only one production process (pacemaker process)

5. Distribute the mix of products evenly over time at the pacemaker process (Level the production mix)

6. Release and take away only a small, consistent increment of work at the pacemaker process.

1. Produce to your Takt time

Your available work time per shift

Customer demand rate per shift

takt time=

•Take time indicates how often you should produce one part or product based on rate of sales

•Takt time is used to synchronize the pace of production with the pace of sales.

• it gives you the idea the rate at which you should be producing

•Producing to Takt time needs

- fast response to problems

- eliminate cause of unplanned downtime

-Eliminate or make the changeover time near zero

2. Develop a continuous flow This refers to producing one piece at a time

Immediately passed from one process step to next without stagnation

Continuous flow is the most efficient way to produce

In the future state map the continuous flow will replace few process boxes in the current state map

FIFO lane is a good way to start with

3. Use supermarkets where continuous flow does not extend upstream There are often instances where continuous flow is not

possible Some process are designed to operate at very high

rate or low rate and need to change over to multiple products

Suppliers or customers are far away Some process have a very high cycle time Unreliable to couple directly to other process in a

continuous flow Out sourcing some process steps

Supermarket means inventory and needs extra material handling requirements

Try to avoid

ShippingFinal Assembly

= Product

Production Card Withdrawal Card

Controlled Inventory

Customer

Supermarket pull system

For custom products, finished goods are not produced toa supermarket

4. Try to sent the customer schedule to only one process

The pull system typically needs to schedule only one point of the door-to-door value stream

This point is called the pacemaker process No supermarkets down stream to the pacemaker

process i.e. pacemaker process is the most

downstream continuous flow process

5. Level the production mix

Batching in the assembly mean the fabricated components are consumed in batches

This swells the inventory throughout the value stream

Leveling the product mix means distributing the production of different products evenly over the time

Instead of assembling all Type A product in the morning and Type B product in the afternoon, reputedly do both in smaller quantities.

Better you do leveling you will respond to your customer positively

6. Create an initial pull by releasing and withdrawing a small amount of work

Many companies release large batches of work

Then there is no sense of the takt The amount of work done by operators vary with

peaks and valleys Difficult to monitor ‘are we behind or ahead’ Respond for changes is difficult

Load leveling can be helped with a ‘load leveling box’ -heijunka

Current state map of ACME stamping

Q1 -What is ACME’s takt time

takt time=Your available work time per shift

Customer demand rate per shift

Available working time per shift=27,000 seconds

Customer demand = 460 units per shift

takt time= 60 seconds

Customer requirement-18,400 per month

Factory works 2 shifts and 20 days a month

Q2 –Should Acme produce finished goods to supermarket or directly to shipping

Always try to develop continuous flow, if not supermarkets could be used)

Continuous flow means producing one piece at a time..

Acme steering brackets are small (easy to store)

Have only two varieties

Customer demand rises and falls some what unpredictable

Decide to produce to a finished goods supermarket

Q3 –Where can Acme introduce continuous flow

Cycle time of ‘Stamping‘ is very low and therefore it has to operate as a batch process producing to a supermarket

Check the other times with the takt timeEvery operation should be slightly below the takt time

The operations weld (39s), weld 2 (46s), assemble (62s), and assemble (62s) can set in a cellular system, distributing the work among operators so that each operator has work just bellow takt

Total time is 187 s and operators are four, therefore they are slightly underutilised, a process improvement may help removing one operator.

Use a Kaizen burst to indicate this on the future state

Q4 –Where can Acme use supermarket pull systems-Stamping – comparatively short cycle timeideally a tiny stamping machine dedicated to this line not in immediate future

-Finished good supermarket – shipping in batches decide the batch size and introduce a withdrawal kanban for the supermarket

withdrawal kanban triggers the movement of parts

Production kanban triggers the production of parts

-Raw material- deliveries in batches

The amount in the supermarket is decided by the change over timesmachine down times etc.

Reduction in changeover times is essential.

Q5 –What single point in the production is scheduled? (pacemaker process)

-All process steps downstream the pacemaker should occur in a flow

- As there is a supermarket between weld/assembly and the stamping process,

-The weld/assembly process can be used as the pacemaker process

-This single scheduling point will regulate the entire value stream in acme plant

Q6 –What is production mix at the pacemaker process?

The daily deliver = 420*2 ( left and right brackets)

Customer wants 600 (30 trays) of left drive brackets and 320 (16 trays) of right drive brackets.

This amount is loaded onto a truck at one time.

LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLRRRRRRRRRRRRRRRR

Producing this large batches are not acceptable in lean although change over time is a concern

-needs reduced changeover time for stamping machine-mix the products more frequently reducing WIP and

better response for the customer

RLLRLLRLLRLLRLL

Q7 –What amount of work is released by the pacemaker process

This amount can be considered as one try of products, i.e. 20 pieces

This can be converted to time =20* takt= 20 minutes

A load levelling box can be designed to accommodate the kanban cards at this frequency

Left

Right

Future State map

mapping your value stream

Documents

value streama value

value streammapsshow

product product family

specific product

length of time

cycle time

changeover time

product streamvariety