A good example of a flow-through process is parts washing since all parts can be
processed similarly with only minor modifications to the operating parameters.
Identify the operation in your value stream where the specific part gets its
identity. Toward the beginning of the value stream a part may be a “base model”
for many finished goods parts. For example, an automobile body in the welding
department can become any color vehicle with any interior colors to match. As the
body is painted a specific color, it has a color identity. In assembly, each subsequent
operation may change the identity to the specific features, such as interior mate-
rial and option packages. Operations that create part identity will typically receive
information regarding what to produce. Depending on the situation, this opera-
tion may get an external schedule (from Production Control) or an internal signal,
such as a kanban returned from the following operation. Understanding these con-
ditions will be important for developing a future-state-connected value stream.
The future state map in Figure 3-1 shows the seven fundamental aspects
mentioned above. If we consider the basic flow, production control takes customer
data and the amount of finished goods inventory kept as a supermarket and
creates a leveled schedule for the final flow-through processes. This is the one
point in the value stream that is scheduled. That process then pulls material from
a supermarket, which then creates a production pull two steps back to a process
that flows through first in, first out, to the next process. That process pulls from the
supplier. This has the desirable properties of a leveled schedule sent to one point
and flows connected by pull from the supplier through to the customer.
Your future map will not look exactly like this one. Do not compare this
example to your situation and assume that you are unable to implement certain
aspects of the process. You should strive to achieve the best result possible for
your value stream and create a process that matches your operational needs.
Rest assured, however, that all seven elements are to some extent possible in
your value stream.
- Flexibility.In this value stream the finished goods supermarket at the
end of the process is applied to improve flexibility. It is used strategically
to shorten the time from order to delivery as well (by shipping high-volume
items from inventory). If you are a high-variety manufacturer, the use of
supermarkets may be possible in some situations (e.g., for the highest vol-
ume products). Note in this case that Production Control considers both
what is in finished goods inventory and the actual customer demand in
developing a leveled schedule (see Chapter 7). - Short lead-time.A key characteristic of lean value stream is a very short lead-
time. Note that in Figure 3-2 below the lead time is reduced by strategically
locating a supermarket of components after the first flow loop. While inven-
tory is considered waste, utilizing it in this manner both improves the flexi-
bility of the value stream and shortens the lead-time. The inventory level in