Look Up from Your Work and Ask: “Could We Flow This?”

At the center of the Toyota Production System, and therefore of Lean manufacturing, is the fundamental principle of creating flow. For example in a machine shop this means connecting processes so that an operator can be a multi-process handler and not just a multi-machine handler. In multi-process handling the work piece advances from process to process in sequence while in multi-machine work may be done in several batch operations.
Multi-machine handling is simply multi-tasking by making more full use of the operators’ time by having them run several machines. Individual processes may appear efficient, but the overall efficiency is not significantly better. Multi-process handling is working in a flow so that the work steadily converts raw materials into sellable finished product.
One benefit of creating flow and multi-process handling is reduced work in process inventory. Another benefit is that this requires cross-training of workers so that they can operate many types of machines and processes. This not only increases the skill level of the workers, it makes the process more flexible and scalable.
Working in a flow also improves teamwork. At some point (when takt time comes) a multi-process handler will need to “hand off” the part to the person in charge of the next process. This requires cooperation, rhythm, and in some cases actually helping out the person next to you to get their job done in time (e.g. when there is an abnormality).
This is possible because in a flow process the work is much more visible. In order to create flow, physical barriers must be removed. Naturally occurring barriers (work in process inventory) are also eliminated due to one-piece flow. The first step to solving problems is seeing them, and flow and visual management enable this.
Creating flow improves productivity, quality and response times. We have seen too many cases where improvement will focus first on equipment improvement, later on people’s work. This may be due to a lack of education in TPS, or simply because machines don’t complain when you change them. It is important to always design the work around the process factors of man, material and machine, in that order. This is a bigger problem for office work.
Recently we’ve been guilty of violating this rule in the Gemba office. We have been building desks and attempting to create an office that better supports flow. We built the desks based on a design concept, but did not think about the manual work flow and material flow first. Our office is already very visual, and we have succeeded in many areas in flowing transactional work but much of the work we do in the office is still in “batch” mode.
Let me give an example. One of our projects involves sending out direct mail to promote one of our products to potential customers. One member of our team is in charge of selecting 100 names of target prospects from a database, using a certain criteria. This person is doing his work in a batch.
When he has selected 100 names he will hand them off to the next person who will print the letters (perhaps 20 per day so it doesn’t interrupt her regular work flow). Then these letters will be signed by me. Once the letters are printed and signed, another person assembles the direct mail packages and ships them, 20 at a time.
Why not do this one name at a time? Select one name, print one cover letter, sign the letter, assemble the package, mail it. I have no doubt in my mind that this could be done with 30% fewer man hours and space, and with better quality than today.
We would need to move our desks closer so we could flow. We would need to cross-train each other so if one person was on the road we could still work in a flow. We would have to put our materials within arm’s reach so we wouldn’t have to walk to the supply area for each package. We may need to redesign our desks again. These would all be good things that people working in a Lean office should do.
Whatever type of work we do, periodically all of us should look up from our work and ask “Could we flow this?” You would need to understand something about cycle time measurement, takt time calculation and process design to make your work flow. Those of us who are Lean practitioners have no excuse.

2 Comments

  1. Kev McKay

    September 1, 2006 - 1:25 am

    This reminds me of a recent comment made by Womack in relation to his bicycle business. In his quest to be more Lean than Toyota, one piece flow was a strong driving goal and I believe they did a lot of work driving down changeover times amongst other improvements to meet this target. Womack recently lamented on the fact that they still only shipped once every day or two days (memory’s going!) hence (small) batches would have resulted in better efficiency and better profits.
    I would guess that your post leaves in a batch every day. Without including the tail end of your process maybe your incurring increased costs at the expense of chasing a theory.
    I guess my question would be how much should we flow this?

  2. Jon Miller

    September 1, 2006 - 8:50 am

    Hello Kev,
    I am not familiar with the Womack-bicycle situation or why that business failed in spite of one-piece flow. All I can say that one-piece flow by itself does not a Lean operation make.
    In my manufacturing example, the product would likely ship in a given order quantity or container quantity or trucking quantity once or more during the shift.
    The batching of shipments is a false economy of scale (avoidance of transportation waste if you trucked one piece) that prevents flow.
    Of course you will not flow when it is not sensible, but you should always try to flow. If you give up on flow, next you will also give up on making work visible and being able to solve problems.
    When you can’t flow you can kanban or pull it, and work on reducing the transaction costs / root causes of false economy of scale so that small lot / one-piece pull is enabled.
    Pursuit of one piece flow is not chasing a theory. It is an attempt to minimize waste by working in harmony with nature. Laminar flow is always more predictable than turbulent flow. This is a law of our universe.
    Jon