Page 137 - Six Sigma Demystified

118 Six SigMa DemystifieD

Yet standardization need not result in reduced choices for your customers.
In some cases, processes can be shared among one or more product families,
allowing all the benefits of simplification, with customer- specific modifications
added at later stages. When these modifications can be provided quickly, this
allows overall inventory levels to be reduced with no disruption to supply.
Decision points and subsequent parallel paths on flowcharts provide indica-
tion of process complexities that sometimes can be avoided. The Six Sigma
process- optimization tools discussed in Chapter 7 provide another method for
decreasing cycle times. Rather than simply reducing errors, these tools allow the
process to operate at an improved level with respect to customer requirements.
For example, the cycle time may be reduced to a point that goes beyond the
elimination of complaints to the level of customer delight. These optimization
tools include designed experiments, response surface analysis, process simula-
tions, and failure modes and effects analysis (FMEA).

Reducing Non- Value- Added Activities

Reducing or eliminating NVA cycle times often provides the clearest and easi-
est methods to reduce cycle time and achieve better velocity (see Part 3 for a
further discussion of velocity). It’s not uncommon for more than 50 percent of
a process’s cycle time to consist of NVA activities.
The first step for cycle time reduction should be to identify and eliminate
the type 2 waste— the process steps that simply are not necessary. These may
include such activities as routine authorizations or approvals or information
and data collection that is not necessary or even used. After eliminating these
activities, the process flow often must be redesigned.
Significant cycle time reduction is achieved through a reduction of errors

requiring rework. Practices for reducing rework include standardization of pro-
cedures, mistake- proofing (using FMEA), and improvement of process capabil-
ity. (These last two items are discussed in Chapter 7; standardization procedures
are discussed in Chapter 8.) As errors requiring rework are eliminated, the
NVA inspections and approvals currently necessary may be reduced or
eliminated.
Unnecessary movement of materials or personnel is also an NVA activity.
Reducing movement typically affects the physical space in which the process
takes place: Offices may be redesigned, departments may be moved or reas-
signed, and even entire facilities may be moved closer to customers. Movement
analysis is aided by the use of spaghetti diagrams. Improvements can be realized
through application of the 5S tools, which are discussed in Part 3.