Page 164 - How To Implement Lean Manufacturing

142 Cha pte r Ei g h t

effort (in about 1961), his production system was superior, at that time, to the manufac-
turing systems we are working with now, nearly 30 years later. This was not only sober-
ing to most, it was also depressing.
We understood the problem and began preaching that the failing of a JIT effort was
not due to the JIT effort itself, but the fact that the facility did not have the needed foun-
dational elements in place to start a JIT effort. These needed foundational elements we
named “The Five Precursors to Implementing a Lean Initiative.”
Today we find, without exception that all companies must work on one or more, or
often all five, of these precursors to have a fighting chance of implementing quantity
control measures. However, these issues need not be totally corrected before quantity
control can be initiated—often they can be done simultaneously. Let’s say, for example,
we have a process that has very high variation in hourly production. Although the stabil-
ity needs to be addressed and it needs to be one of the first things done, we have seen
instances where the solution to the rate variability problem was solved by a kanban sys-
tem. So voilà! We get better stability and quantity control at the same time. This is some-
thing that is frequently not seen by the novice, but your sensei can give guidance as to:
• Which precursors need to be addressed
• What order these precursors must be addressed
• What amount must be addressed

Each of the five precursors should be evaluated and the results of this evaluation
will often become a significant part of the implementation plan. A description of the
five precursors follows. Refer to the Matrix in Chap. 19 for clarifications.

Stability and Quality
High levels of stability and quality in both the product and the processes are the most
basic of standards. Ohno says that flow is the basic condition. It is the foundation of the
Toyota Production System (TPS). He says this only because he takes it for granted that
process stability is a given. (Return to Chap. 3, and reread the section “It Is Not a Com-
plete Manufacturing System.”) Absolutely nothing is more basic to quantity control
than process stability. So it is necessary to review all aspects of the product and process
stability and make a list of items to include in the goals of your Lean initiative. First,
evaluate and make sure the quality and the production rate of your product and pro-
cesses are statistically stable. This can easily be done on a simple control chart—most
often an Xbar-R or an XmR chart. Check the stability of the production rate: day by day,
shift by shift, and hour by hour. If there are instabilities, put them on the list of items to
address. For both the product and the process, check each quality characteristic for both
stability and levels; evaluate both. Each can be checked using control charts. List all
product and process quality characteristics that are not statistically stable. If they are
variables data, list all those that have Cpk below your threshold value, usually most
organizations start with a minimum of 1.33. If they are attribute data, work to improve
the process to eliminate the need to do the evaluation. If this is not practical in the short
term, work to correlate the attribute characteristic to variables data, and then strive to
reach the threshold Cpk for this as well. If there are processes that do not meet Level 2
criteria, this constitutes a crisis and should be addressed immediately. The minimum
goal for nine months is to have all product and process quality levels to Level 3 on the
matrix; Level 4 can be a goal for 18 months.