and how many bins could be held in inventory. Kanban cards were printed to
match the number of bins that could be produced. No card—no production—
no more inventory. Toyota worked on equipment reliability, built-in quality, and
operator training. Through continuous improvement, they had so little inven-
tory that there was no real value to collecting real-time inventory data at each
stage in the process—this is just waste. In other words, they worked on devel-
oping the true process of production and connecting production processes
through simple communication vehicles and standard processes. They were
less interested in non-value adding “business processes” aimed at getting
data into computers. Interestingly, having worked out these manual systems
Toyota has evolved to electronic kanban. But these run in parallel to a manual
kanban system that provides for visual control yet with the benefits of modern
computer technology.
The traditional supply chain software that promised visibility is actually
based on a philosophy of top-down control. The belief is that if top management
has all the information they need at their fingertips, they can control the system.
The kanban system is based on a philosophy of local control. The workplace is
viewed as a series of customer-supplier relationships with customers specifying
just what they need when they need it through the kanban. Top management are
expected to audit the system by walking down to the floor and seeing for them-
selves (Figure 9-4).
Chapter 9. Make Technology Fit 211TIP
Always Verify the Actual Condition Yourself
We were working on a particular process to achieve stability and
address operational availability issues, and the production planner
on the team frequently commented that the process was “behind.”
Observations on the floor revealed that there was no work waiting
to be processed. From a traditional Toyota standpoint, an operation
can’t be considered behind if an upstream process is starving it or
if the customer process is full. This is all visual, and easy to deter-
mine by looking at the work area and observing the connections
between operations. Confused, we asked the production planner
to explain how the machine could be “behind.” The answer was,
“That’s what the system says!” meaning that the MRP planning
system showed work that was scheduled to be complete at that
operation and wasn’t. Simply using system information without
corresponding process information can lead to false assumptions
and misguided efforts to correct the “problem.”