Agile Factory

Lean Manufacturing - APICS discussion

Eight Conditions for Flow Production

8th condition

From: Norman Bodek
Sent: April 18, 2005

Dear Group,
This is the last of a series on Hirano’s 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 line

Condition 4: Working by standing

Condition 5: Multi-process operation·multi-skill operator

Condition 6: To bring up the degree of processing one by one

Condition 7: Synchronization

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.

Norman Bodek
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.