Flow production - 3rd condition

From: Norman Bodek

Condition 3: U-shape lineĀ·parallel line

I remember on one of my first trips to Japan in the early 1980’s visiting Brother Industries and seeing 12 machines producing products in a manufacturing cell with hardly any operators. This was in comparison to factories in America with one person standing or sitting in front of each machine.

There are many advantages to having a U-shaped line:

1. With a straight line even with the operator walking from machine to machine you have the waste of returning to the beginning of the line for picking up the unprocessed work after completing the finished work. A “U-shaped line,” resembles the letter U in the alphabet. To eliminate this waste you want to make the inlet and outlet of work as close as possible. This is called "principle of the same I/O". If the location of unprocessed work and the location of finished work are made close than waste of returning to the starting point will not occur. In most cases, a, “U-shaped line” is for one product. For a line of more than two kinds of products often "parallel lines" are adopted.

2. There is a need for multi-skilled workers to run the various different machines; making jobs more interesting for people and giving more flexibility to the company.

3. To make sure the lines can produce in taht time requires eliminating machine problems: downtime, faulty processing, and surely no defects should be produced.

4. As machines are linked within the cell virtually all work in process is eliminated. I remember prior to my first study mission to Japan and seeing mountains of inventory at an Oldsmobile plant in Tarrytown, New York turning over inventory around four times a year while NipponDenso a Toyota prime subcontractor had a turn over ratio of 350 times a year, less than one day.

5. Transportation is kept at a minimum as, at first, each machine is just a few feet away from each other.

6. The person is more important then the machine. I have visited over 250 plants in Japan and to date have never seen a person standing and watching a machine. In the opposite, I have visited numerous plants in North America and always see people watching a machine. Somehow our accountants in the past confused us to think that the machine was more valuable than the person and that the machine must always be producing parts while people were not as valuable an asset and could just stand, wait and watch. In a “U-shaped line,” the machine can wait for the person, producing only what is needed when it is needed.

7. When orders increase you can add additional people to work within the cell to handle the flexible volume.

8. The machines are outfitted with simple grasping and unclasping features so that the worker can easily load and unload each machine as they walk around the cell.

9. Total Productivity Maintenance (TPM) is vital to keep the machines in the best of shape for when one machine goes down all of the machines must stop and wait until that one machine is brought back up. Greater pressure is placed on maintaining machines in top condition when you do have a “U-shaped Line.”

Norman Bodek
I wrote a new book with Chuck Yorke titled All You Gotta Do Is Ask which helps you discover the hidden creative power resting within every single worker. I am sure you will enjoy our stories, the examples and learn more about the fabulous results obtained by companies applying these very simple techniques.