36 ISE Magazine | www.iise.org/ISEmagazine

In Chapter 2 of their 2003 groundbreaking book, Lean

Thinking, James P. Womack and Daniel T. Jones, the pio-

neers of Lean, wrote: “Our initial objective in creating

a value stream map identifying every action required to

design, order and make a speciﬁc product is to sort these

actions into three categories: 1. Those which actually cre-

ate value as perceived by the customer; 2. those which create no

value but are currently required by the product development,

order ﬁlling or production systems (Type One muda) and so

cannot be eliminated just yet; and 3. those actions which do

not create value as perceived by the customer (Type Two muda)

and so can be eliminated immediately. Once this third set has

been removed, the way is clear to go to work on the remaining

nonvalue-creating steps through use of (the principles of Lean).”

Value is what the customer gets, like a product or a service of

high quality, in a fair period of time at a fair price that he or she

is willing to pay.

A value stream is all the steps, both value-added and non-

value-added, which must be performed in a manufacturing or

service process or system to deliver that product or service to a

customer.

Value stream mapping (VSM) is the (manual) method that

produces a map that helps to see and understand the material

and information ﬂows involved in a product’s value stream as it

makes its way from beginning (raw material) to end (ﬁnished

product).

A value stream map permits the identiﬁcation of every pro-

cess in the ﬂow of a product family, pulls them out from the

background clutter of the organization and builds an entire

value stream based on the principles of Lean. The map helps

to plan and prioritize the changes within a value stream instead

of a whack-a-mole “blitzkrieg” of kaizens to eliminate waste

randomly throughout the organization, which is what typically

happens with other continuous improvement programs like

Theory of Constraints and Six Sigma.

The attached list on Page 37 includes the reasons why the

developers of VSM, Mike Rother and John Shook (“Learning

to See: Value Stream Mapping to Create Value and Eliminate Muda,”

2009), consider the method to be an essential tool to plan the

implementation of Lean in any manufacturing or service sys-

tem. However, the literature suggests that within Toyota, a val-

ue stream map is called a material and information ﬂow diagram

and value stream mapping is called material and information

ﬂow analysis.

How a value stream map helps

to implement Lean

The standard approach to prepare a current state map for a

product’s value stream is to follow the product’s production path

from customer to supplier and carefully draw a visual represen-

tation of every process (step) in the material and information

ﬂow(s) for that product. The VSM that results, such as the cur-

rent state map shown in Figure 1 (page 38) and the future state

map shown in Figure 2 (page 39), consists of three sections: The

Enhancing

value stream

mapping for

manufacturing

High-mix, low-volume shops

need software toolkit

to analyze production

By Shahrukh A. Irani

April 2021 | ISE Magazine 37

material ﬂow which is the section marked as 1 in both ﬁgures;

the information ﬂow, which is the section marked as 2 in both

ﬁgures; and a timeline, the section marked as 3.

Next is a standard set of key questions asked about the current

state map to develop a future state map, such as the one shown

in Figure 2:

• What is the takt time?

• Will you build to a ﬁnished goods supermarket or directly to

shipping?

• Where can you use continuous ﬂow processing?

• Where do you need to use supermarket pull systems to con-

trol production of upstream processes?

• At what single point in the production chain (the pacemaker

process) will you schedule production?

• How will you level the production mix at the pacemaker

process?

• What increment of work will you consistently release and

take away at the pacemaker process?

• What process improvement will be necessary for the value

stream to ﬂow as your future state design speciﬁes?

The future state map describes how value should ﬂow in the

value stream and displays a portfolio of projects that must be

done to improve the value-adding steps in the value stream and

eliminate or reduce the nonvalue-adding steps (waste) in the

value stream (Rother and Shook, 2009).

The primary goal of this article is to suggest that high-mix

low-volume (HMLV) manufacturers should quit using value

stream mapping. Instead, they should switch to using maps like

the ones shown in Figures 3-7 that help to visualize and analyze

multiproduct production systems.

HMLV manufacturers, especially job shops that wish to

implement Lean, should stop using value stream mapping to

guide their Lean implementation. Any effort to use VSM to

implement Lean in an HMLV production system, especially a

job shop, will fail because of the numerous limitations of the

method ( Job Shop Lean: An Industrial Engineering Approach to

Implementing Lean in High-Mix Low-Volume Production Systems,

Irani, 2020). Instead, they should invest in a software toolkit

that has both the data analysis and visualization capabilities to

(heuristically) solve three commonplace and hard problems that

all industrial and systems engineers) are familiar with:

• Doing a cluster analysis of their entire product mix to identify

potential product families in their entire product mix. Each

product family is a value stream.

• Generating a ﬂow diagram for each product family. Alterna-

tively, this ﬂow diagram could display any large meaningful

sample of products extracted from their product mix based

on operational or business criteria or their entire product

mix.

• Generating a Gantt chart (Figure 7, Page 41) that shows the

production schedule for each cell and the external work cen-

ters (possibly including the vendors) in the facility. Or the

Gantt chart could display the production schedule for all pro-

duction resources in the entire facility.

The following provide the details for some of the major limi-

tations of value stream mapping with a brief description on how

to overcome each limitation using well-established ISE science

and software.

Limitations of value stream mapping: General

Limitation: VSM is a manual method that is slow, cumber-

some and error-prone.

How to eliminate it: Software, such as eVSM, IFAKT and

Minitab Companion, is available.

Limitation: VSM does not utilize the science and tools that

Why value stream mapping

is an essential tool

• It helps you visualize more than just the single process level,

i.e., assembly welding, etc., in production. You can see the

ﬂow.

• It helps you see more than waste. Mapping helps you see the

sources of waste in your value stream.

• It provides a common language for talking about manufac-

turing processes.

• It makes decisions about the ﬂow apparent so you can

discuss them; otherwise, many details and decisions on your

shop ﬂoor just happen by default.

• It ties together lean concepts and techniques, which helps

you avoid cherry-picking.

• It forms the basis of an implementation plan. By helping you

design how the whole door-to-door ﬂow should operate – a

missing piece in so many Lean efforts – value stream maps

become a blueprint for Lean implementation. Imagine trying

to build a house without a blueprint.

• It shows the linkage between the information ﬂow and the

material ﬂow. No other tool does this.

• It is much more useful than quantitative tools and layout

diagrams that produce a tally of nonvalue-added steps, lead

time, distance traveled, the amount of inventory and so on.

Value stream mapping is a qualitative tool by which you

describe in detail how your facility should operate in order

to create ﬂow. Numbers are good for creating a sense of

urgency or as before/after measures. Value stream mapping

is good for describing what you were actually going to do to

affect those numbers.

38 ISE Magazine | www.iise.org/ISEmagazine

Enhancing value stream mapping for manufacturing

ISEs (industrial and systems engineers) routinely use in their

jobs.

How to eliminate it: A future state can be achieved us-

ing practices similar to or even beyond those listed earlier. For

example, there is ample opportunity to utilize ISE methods like

assembly line balancing, work study, facilities planning, material

handling, production planning and control, inventory control,

systems simulation, supply chain management, warehouse de-

sign, operations research and quality control.

Limitation: A current state map is a single snapshot of the

state of a dynamic production system on the day (or during the

week) that the map was created.

How to eliminate it: The technique of work sampling

could be used to obtain multiple snapshots of a dynamic value

stream, especially if it is a dedicated multi-product assembly

line, aka, mixed model value stream.

Software for ﬁnite capacity scheduling, such as PREAC-

TOR, TACTIC and SCHEDLYZER, is available.

Software for dynamic simulation of systems, such as ANY-

LOGIC, FLEXSIM and SIMIO, is available.

Limitation: VSM assumes that the underlying production

system is an assembly line operating in a make-to-stock mode

producing a very limited range of highly similar products.

How to eliminate it: There is ample opportunity to ex-

tend VSM to handle make-to-order production systems that are

not assembly lines. For example, instead of single-piece ﬂow, an

order batch could be split into two or more transfer batches, and

instead of heijunka, there could be many different orders and

each order could have a due date.

Limitation: A single current state map is just about able to

capture all the data associated with just one product. It is infea-

sible (and impractical) to ﬁt and visually display the data for an

entire product family on a pencil-and-paper map.

How to eliminate it: In an ideal scenario, a value stream

map should become an electronic dashboard that is produced by

the ERP (enterprise resource planning) system.

The ERP system would keep refreshing the dashboard with

new data pulled in real time from other systems, such as an

MMS (machine monitoring system), an MES (manufacturing

execution system) and a QMS (quality management system).

Limitation: VSM cannot handle the (upstream) complexity

of visualizing and scheduling the synchronized production and

delivery of components and sub-assemblies needed to build the

ﬁnal product.

How to eliminate it: An alternative to VSM is the method

of value network mapping (Value Network Mapping: Enhanc-

ing Value Stream Mapping to Enable Lean Manufacturing in

Job Shop-type Custom Manufacturing Facilities, Irani, 2004).

FIGURE 1

Current state map

The current state map for a manufacturing value stream.

April 2021 | ISE Magazine 39

In a value network map (1) the material ﬂow section of the map

would be occupied by an operations process chart and ﬂow dia-

gram, and (2) the information ﬂow section of the map would

be occupied by a Gantt chart. (www.leanmanufacturing.japan.

com)

Limitations of value stream mapping:

Material ﬂow(s)

Limitation: A current state map always shows only one prod-

uct routing. In practice, the product mix of any HMLV pro-

duction system could consist of hundreds of different products

being produced in a factory that could have anywhere from 10

to 100 different work centers.

How to eliminate it: This limitation can be overcome by

selecting a representative sample of products using PQ Analysis,

PQ$ Analysis or other sampling approaches.

Software for cluster analysis can be used to ﬁnd several prod-

uct families in a large product mix. Each product family could

be represented by a separate value network map.

Limitation: A current state map does not show the full ex-

tent of the “seven forms of waste,” especially transportation, in-

ventory, operator motion and waiting.

How to eliminate it: This limitation can be overcome by

generating a ﬂow diagram, a ﬂow process chart and a from-to

chart to complement the current state map.

These traditional ISE tools are better than a value stream map

for visualizing and measuring the wastes in the ﬂow represented

by each and every arrow that appears in a value stream map, re-

gardless of whether that arrow represents a (hard) material ﬂow

or a (soft) information ﬂow.

Limitation: A value stream map focuses on one product

family. It fails to show if that family is sharing manufacturing

resources with one or more other product families in the prod-

uct mix.

How to eliminate it: This limitation can be overcome by

generating a ﬂow diagram, a ﬂow process chart and a from-to

chart to complete the current state map.

Software, such as PFAST and SGETTI, is available to over-

come this limitation. For example, Figure 3 on Page 40 shows

the work centers that are common to the different product fam-

ilies in the product mix.

Limitation: A product family is a group of products that

pass through (almost) the same processing steps performed on

common equipment. In the case of a typical HMLV manufac-

turer, their product mix could have hundreds if not thousands of

different products. For example, Figures 3 and 4 (page 40) were

generated using data obtained from a multiproduct, multima-

chine printed circuit board fabrication facility. In contrast, VSM

FIGURE 2

Future state map

The future state map for a manufacturing value stream.

40 ISE Magazine | www.iise.org/ISEmagazine

Enhancing value stream mapping for manufacturing

does not have any demonstrated capability to analyze a large

product mix to identify one or more product families.

How to eliminate it: Cluster analysis would help to ap-

proximate the number of clusters and determine the extent of

duplication of work centers needed to separate product families

with common work centers. Figures 3 and 4 present a visualiza-

tion of two potential product families, and the corresponding

group of work centers that will constitute the cell to produce

each product family.

Software like Matlab, Minitab and JMP offer a range of well-

established cluster analysis algorithms. Alternatively, software

like Python and R can be used to program cluster analysis algo-

rithms from scratch.

Limitation: A value stream map ignores the impact of facil-

ity layout, material handling, lot splitting (or lot streaming), and

related practices.

How to eliminate it: This limitation can be overcome by

generating a ﬂow diagram, a ﬂow process chart

and a from-to chart to complement the current

state map.

Software, such as PFAST and SGETTI, is

available to overcome this limitation. Figure 5

is the ﬂow diagram for the current material ﬂow

in a custom forge shop with a product mix of

530 different part numbers. A value stream map

developed for a single forging could not have

exposed the waste that can be discovered using

a ﬂow diagram developed for the entire product

mix.

Limitations of value stream

mapping: Information ﬂow(s)

Limitation: The process parameters shown in

the data box for each process step in any current

state map may not be accurate because they are

recorded on the day that the map is created.

How to eliminate it: Software for time and

motion study, such as OTRS10, TIMER PRO,

PROPLANNER and QUETECH, is available

to overcome this limitation.

Limitation: The process parameters shown

in the data box for each process step in any cur-

rent state map are assumed to remain constant.

How to eliminate it: Software for machine

monitoring, such as MACHINEMETRICS,

FACTORYWIZ and MERLIN, can collect

the data over a period of time to update standard

times and variability in that data.

Limitation: The future state map is de-

signed for a constant takt time and a very limited

product mix.

How to eliminate it: Software for dynamic

FIGURES 3 & 4

Identifying product families

The product-process matrix shows the work centers that are

common to the different product families in the product mix.

FIGURE 5

Flow diagram for large product mix

The current material ﬂow in a custom forge shop with a product mix of 530 different

part numbers.

A hierarchical cluster analysis dendrogram to identify product families.

April 2021 | ISE Magazine 41

simulation of systems, such as ANYLOGIC, FLEXSIM and SI-

MIO, is available to overcome this limitation.

Software, such as eVSM, IFAKT and Minitab Companion,

is available to model production systems like, 1. several variants

of the same standard product are produced on the same line; or

2. several products sharing the same platform are produced on

the same line.

Limitation: The template of icons for creating a future state

map is limited to a pull scheduling system for a make-to-stock

production system, speciﬁcally an assembly line.

How to eliminate it: There is ample opportunity for cre-

ative ISEs to expand the template of icons for creating a future

state map to capture other pull scheduling systems (CONWIP,

POLCA, DRUM-BUFFER-ROPE), different priority dis-

patching rules (earliest due date, critical ratio, common setup)

and other HMLV production systems (job shop, ﬂow shop,

ﬂexible job shop, engineer to order).

Limitations of value stream

mapping: Timeline for

production lead time

Limitation: At the bottom of every

current state map and future state

map, a timeline is drawn manually to

show the value-added times, nonval-

ue-added times and production lead

time (= VA times + NVA times) for

the product (family).

How to eliminate it: The same

timeline can be produced using the

Excel template for a Gantt chart as

shown in Figure 6.

Limitation: The only performance metric that is cal-

culated to assess the order fulﬁllment capabilities of the

production system is the value-added ratio) = (sum of all

VA times) ÷ production lead time.

How to eliminate it: The value-added ratio metric

should be complemented by the three Theory of Con-

straints metrics: throughput, inventory and operating

expenses.

A multiproduct Gantt chart produced by the ERP sys-

tem (or a third-party ﬁnite capacity scheduler integrated

with the ERP system) would help to see the nonvalue-

added times in the timeline for each product. The NVA

times on the timeline of each work center are due to the

competition for shared resources with other products,

material handling delays, etc. Figure 7 illustrates how a

multiproduct, multimachine Gantt chart can simultane-

ously display the timelines for many products on a single

value stream map.

HMLV manufacturers, especially job shops that wish

to implement Lean, should stop using value stream map-

ping to guide their Lean implementation. Instead, they

should use an ISE software toolkit that has the data analysis and

visualization capabilities to: 1. do a cluster analysis of their entire

product mix; 2. generate a ﬂow diagram for their entire product

mix; and 3. display one or more Gantt charts for the production

schedule for any planning horizon. 

Shahrukh A. Irani, Ph.D., is president of Lean & Flexible, a consult-

ing ﬁrm in Sugar Land, Texas. He is a former director of IE research at

Hoerbiger Corp. of America, a former associate and assistant professor in

the Department of Integrated Systems Engineering for The Ohio State

University, and an assistant professor in the IEOR Division, Depart-

ment of Mechanical Engineering, at the University of Minnesota. He

earned a Ph.D. in industrial engineering from Pennsylvania State Uni-

versity, a master’s degree in industrial engineering from the University of

South Florida and a bachelor’s degree in mechanical engineering from the

Indian Institute of Technology in Madras, India. He is an IISE member.

Contact him at shahrukhirani1023@yahoo.com.

FIGURE 6

Gantt chart template

The value-added ratio timeline generated using Excel template for a Gantt chart.

FIGURE 7

Gantt chart

The Gantt chart displays the timelines for many products displayed on one

value stream map. (Source: Prasad Velaga, optisol.biz/schedlyzer/)