Motion & Transport Waste
Part 2 of Value Creation & Waste; A Lean Practitioner's Perspective
I like to deal with motion and transport wastes together as they are both related to excessive movement, often occur together and share similar causes and solutions. Transport Waste is the excessive movement of materials and WIP (Work In Progress) while Motion Waste is the excessive movement of people. Interestingly, the digital age has eliminated a great deal of motion and transport waste when it comes to the movement of information. Where once we waited for documents to move in various mail systems, they can now be made available anywhere virtually instantaneously. However, until a teleport is invented, motion and transport will continue to exist where physical products are involved.
Motion and Transport are usually not hidden wastes, but they do become normalised as they are always present. No-one tends to question the movement of material or people when they happen all day everywhere, especially in workplaces with physical products, such as factories and warehouses. A habit I frequently encourage is to “first watch the work, not the people”. When we learn to do this, we see that value is not being added to the work for much of the time. When we then look at those times when value is not being added, we see all sorts of movement and activity that can be targeted for reduction or elimination.
To minimise motion and transport, it is necessary to review our processes and the layout of our workplaces, looking for opportunities to reduce the number of material movements and distance of each move. Without wanting to dive too deeply into either factory layout planning or warehouse and inventory management principles, which we will discuss in other articles, the aim is to align material to the flow of the value stream. This should be considered from the point of arrival of products and raw materials at the premises, in and out of any storage points, delivery to and between the various work-cells, to staging at outwards goods and finally out to the next customer. Work-cells should be placed in the order of workflow and positioned to minimise the distance between them. U-Shaped factory layouts are often used to facilitate this as they occupy less space, make it easier for employees to communicate and allow goods to enter and leave on one side of the premises. Within the work cells, machines, tools and storage should be arranged to minimise movement of people, components and work. Often, a simple spaghetti diagram that traces personnel movement within a work cell will reveal opportunities for relocation of machines, tools, and storage. The diagram below is a real-life example of a study of one employee’s movement in a government office over a 4-hour period using a spaghetti diagram (the colours representing different reasons for the motion) .
Another useful tool is a Activity of the Person study. I recall a separate instance of working with a client in the printing industry, where we were observing a book binding process. There were quite a few manual activities involved and several machines were accessed to complete the process. On the surface, the team were working diligently and there didn’t appear to be excessive motion & transport waste, but we decided to do an Activity of the Person study to see if there was any opportunity left to squeeze out of the process. This is most easily done by making a video recording of the activity and using playback to note the timings different activities into an Activity of the Person Worksheet. Even in this supposedly efficient task, we identified that only 23% of the work was value adding with the remainder a combination of Motion & Transport (31%) and Setup Time (46%).
A subsequent revision of the locations of the collating and stapling machines was able to reduce motion and transport by more than 50%, reducing the labour cost per book by 15%, which is a significant reduction in this competitive industry!
