Page 321 - How To Implement Lean Manufacturing

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Process Maturity
Frequently, I receive requests from manufacturing firms to assist them in a Lean initia-
tive. Typically, they have done some background research on Lean manufacturing and
want guidance in making their operations Lean. Unfortunately, the most common thing
I find is that they do not have the foundational work elements in place to begin a Lean
initiative. More importantly, they do not recognize this and think that, independent of
the current state of the process, a Lean initiative can be implemented and techniques
such as kanban can then be readily applied. Their common perception is that they only
need to complete some training and they will be on the road to a Lean enterprise. Noth-
ing could be further from the truth. First, a number of precursors must be taken care of.
For example, they must have a reasonably stable materials supply, and they must have
good machine availability, to name a few. Most importantly, they must have in place a
process that already produces at high-quality levels; processes that exhibit both process
stability as well as adequate capability. This item is of particular importance to the suc-
cess of many Lean techniques.
It is to those groups who wish to undertake a Lean initiative that this document is
written. In this format, a specific order is implied. In practice, I have found that those
firms that deviate greatly from this basic format spend much more time and much more
of their resources in reaching the goal of becoming Lean. Those processes that produce
to this Lean standard I refer to as “mature.”
Process maturity differs from process “goodness.” Process or product “goodness”
usually means the product meets the needs of the customer. In this regard, “goodness”
is usually measured by the process capability indices of Cp and Cpk for a few key prod-
uct and process characteristics. If these two indices meet minimum standards, for
example, they are greater than 1.33, then the customer is satisfied, declares the process
to be “good enough” and the supplier is allowed to proceed with greater independence.
If, however, the indices fall short of the standard, then the supplier is required to do
extra processing, which is usually some form or containment or extra inspection cou-
pled with a specific action plan to achieve the desired levels of Cp and Cpk.
Process maturity goes beyond the measure of “good enough” so that a product is
not only good, but is produced with a minimum amount of waste. These processes have
other characteristics, such as minimum inventories and short production lead times, to
name a few. These processes are now widely referred to as Lean, and in this document,
the process that produces a Lean product is a mature process.
This treatment addresses levels of process maturity for a typical manufacturing
process and does not address some topics, which are outside the scope of this treat-
ment. Other aspects of the process not addressed herein, might include ergonomics,
environmental issues, and safety, to name but a few.
A process that is mature has five characteristics, which are:

1. Documentation
2. Flow, that is, a specific process routing
3. Quality understanding and performance
4. Inventory understanding and control
5. Leanness by all 20 measures; exhibit advanced levels of continuous improve-
ments, with Lean goals driving the process