From: Norman Bodek
Sent: April 18, 2005
This is the last of a series on Hiranos Eight Conditions for Flow Production. The
first seven conditions previously reviewed in early emails were:
Condition 1: To lay out facilities in
the sequence of processes
Condition 2: To make facilities small
and exclusive use
Condition 3: U-shape line·parallel
Condition 4: Working by standing
Condition 5: Multi-process
Condition 6: To bring up the degree of
processing one by one
The last is
Condition 8: To make the flow clean
Terms used by Mr. Hirano are:
"Turbulent flow" used for a job shop when each item produced
could be different.
Tidy flow used when products are produced in repetitive
manufacturing when the line is clean and items are produced without defects,
in takt time, in one-piece flow.
Muddy flow when parts are pushed forward from the preceding
process or defectives are produced.
Tidy, clean or smooth flow is when the succeeding process
pulls from the preceding process and a structure is created that prevents defectives from
being produced and surely never passed onto the succeeding process. Required are the first
seven conditions with machines fully synchronized, extensive TPM is being done to prevent
machine failures, poka-yoke devices are installed to absolutely prevent a defect from
occurring and people are highly skilled to run the equipment, with knowledge of the
requirements of production and have the ability to recognize and react quickly when
problems or potential problems might occur.
In the eight conditions mentioned above, the strongest condition for the flow production
by one-piece is to bring up the degree of processing one by one, Condition 6. This is
one piece flow, not two-piece flow, three-piece flow or lot flow either but
"one-piece flow" persistently. Of course, it will take you time to go from large
batch to one-piece flow, but you should be persistent, continually lowering
the batch size and attacking all of the problems that come up. It took Toyota many years
to perfect the system and they are still improving it.
If you find one-piece flow to be too difficult to do and use
larger lot sizes like a lot of ten pieces, there will be some waste within the ten pieces.
How thoroughly one-piece flow, can be maintained without a compromise is the
biggest key for a success of flow production.
I do hope you have found this series of interest.
Author of The Idea Generator - Quick and Easy Kaizen, Kaikaku The Power and Magic of Lean
(winner of the Shingo Prize) and All You Gotta Do Is Ask.