ONE PIECE FLOW
THE BASICS OF 2-SECOND LEAN
Warning
If you have not yet read the section on “The 8 Wastes”, please go back and familiarise yourself with them. Understanding the 8 wastes is key to understanding the benefits of using One Piece Flow.
One Piece Flow
In its simplest form, One Piece Flow involves working on one thing at a time. Rather than jumping between tasks, you perform one fully and then move onto the next. This contradicts most ways of working which would involve producing large batches at once, often called “Batch Work”.
This approach may seem slower, but it actually increases efficiency. By following the same steps, each item will be assembled carefully, with less chance of mistakes. It reduces potential errors, keeps the work organised and creates more efficiency. Especially on assembly lines, it will reduce the time that operators further down the line are waiting. Rather than waiting for a large batch to get passed along, they have a continuous flow of work.
Example
In the toy factory, the workbench where the action figures are assembled has become cluttered. There is a lack of standards in place and other departments are being slowed down. The flow of work on this bench has been affected by the tools being difficult to find amongst all the mess.
- Attach the 4 limbs using a press which pushes the limbs into the body.
- Attach the head by screwing it into the body.
- Insert the voice box into the back of the toy and screw on the cover.
In many factories, this may be done in batches. There would be a stack of 100 headless toys making their way to step 2 of the process. Then 100 voiceless figures making their way to step 3. In One Piece Flow however, the 3 processes will be done in sequence one after the other. The operator will fully assemble one action figure before moving onto the next.
The assembled action figures immediately move down to the next process where they get painted and packaged. Rather than the paint and packaging departments incurring massive amounts of Waiting, they have a steady flow throughout the day.
One Piece Flow can actually help reduce all of the 8 wastes:
Over Production
You only work on what is needed, there’s no surplus of extra items being produced in large batches.
Transport
By working on one job at a time, there’s less need to move partially completed items between processes or workstations.
Excess Inventory
It naturally limits the amount of work in progress or inventory at any step in time. With fewer unfinished items sat around, the materials and resources can be used where they are needed.
Defects
When an operator can focus on one task at a time, they can give it their full attention. By focusing on one task only, this will reduce the likelihood of errors or defects.
Excess Motion
Whilst focusing on one task, there will be less unnecessary movement or motion. You will not be constantly swapping between tasks, machinery or processes which all contribute to wasted movement.
Over-Processing
By focusing on one task at a time, tasks are less likely to be over-complicated. You do exactly and only what is needed at the time, rather than jumping between tasks.
Waiting
Waiting between tasks ins naturally minimised as each task is fully completed before moving on to the next. Workers further down the production line will not have to wait as long for parts as there will be a continuous flow.
Unused Employee Genius
If an operator is working on one task at a time, they can invest more thought into improving that exact task. They can focus on it and look at processes as a whole to improve flow, reduce steps or identify improvement opportunities.
Exercise
Go and watch a process being performed. Can you detect any elements of batch work? Look for any operators who are focusing on one task only. Look to see if they have any excess inventory or work-in-progress building up.
