Page 251 - The Handbook for Quality Management a Complete Guide to Operational Excellence

238 P r o c e s s C o n t r o l S u p p l y C h a i n M a n a g e m e n t 239

can be obtained if the sources of variation are minimized and multiple
suppliers are an obvious source of variation.
Recently, floods caused by tsunamis in Japan have caused a devastat-
ing effect on the supplier chain, and the use of single long-term local sup-
pliers has hampered recovery of the nation as a whole. This would seem
to be a strong argument for maintaining multiple sources of key compo-
nents, especially from a geographical perspective.
The decision regarding single-source versus multiple-source must be
made on a case-by-case basis. In most cases, the many benefits of sole
sourcing are only outweighed when the risks are fairly substantial.
Traditional interactions between supplier and purchaser focused on
various forms of product inspection, which was often adversarial. Improved
levels of interaction might focus on prevention of quality-related issues,
based on the premise that quality must be built by the supplier with
the purchaser’s help. The relationship is not adversarial, but it is still
arm’s-length.
When customer-supplier partnerships are developed, purchasers and
suppliers work closely on such issues as joint training, planning, and shar-
ing confidential information (e.g., sales forecasts). Communications chan-
nels are wide open and include such new forms as designer to designer or
quality engineer to quality engineer. This approach results in parallel com-
munication, a dramatic change from the purchasing agent to sales represen-
tative approach used in the past (serial communication). A research study
showed that, for serial commu nications channels, quality levels stayed flat
or declined while, for paral lel communication, quality levels improved
dramatically.
Process improvement teams may also be formed and char tered as
described in Part IV, where the process to be improved is the supplier-
purchaser communication process. These teams meet at the suppli er’s and
purchaser’s facilities to set goals for the relationship and to devel op plans
for achieving their goals. Contact personnel and methods of contact are
established, including a schedule of meetings. These meetings are used to
update each other on progress and new plans, not merely for discussion of
problems. Purchasers show suppliers how the product is designed, where
the supplier’s materials are used, and the manufacturing processes involved.
In some cases, joint technological plans ( JTP) are developed coopera-
tively by suppliers and purchasers. The plans include specific perform ance
requirements, including quality, reliability, and maintainability require-
ments, and the supplier’s role in meeting those requirements is defined.
JTP also encompasses the processes to be used by suppliers and pur-
chasers. Process control plans are prepared, including the identification of
key process variables and how they are to be controlled and monitored.
Special tasks to be done by the supplier (e.g., in-process inspections, SPC)
are described. Classification of characteristics and defects is performed.

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