Lean manufacturing

Gemba (現場) means actual place. As consultants, we ask clients to show us their gemba, and we exhort their managers to do it routinely. But we must have a clear idea of why we should go to the gemba and what to do once we are in it. In Manufacturing, the gemba is the production shop floor.

Consultants and Managers on Gemba Walks

For a consultant, the point of walking through a factory shop floor is to learn about its current state, complete through direct observation what could not be known through previously received written or oral input, and to validate or refute this input. For a manager, making daily rounds through the shop floor is different, and involves two-way communication.

The manager’s presence, body language, and attire are a message to the work force. Everybody watches the manager.He or she can listen and ask questions, but must be cautious not to give instructions to operators over the heads of supervisors.

Example: Scheduling

From documents received ahead of time or personal communication, the consultant might know that the plant is using dispatch lists from an ERP system. On the shop floor, he or she sees these dispatch lists and the way operators use them.

Manual annotations reveal where operators do not follow the recommended task sequence. A supervisor then explains how this is due to setups or missing parts. In other words, you don’t go to the shop floor to find out what the intended scheduling system. You go to find out how operators actually sequence the work, and what relationship it has with the scheduling system. A manager walking with the consultant would make a note of the situation, and follow up on it later with supervisors and Production Control.

What to See

Shop floor observations include the overall design of the plant for production and internal logistics, as well as operational details. You can tell whether it is a job-shop, a flow line, or a collection of flow lines. You can tell whether the flow of materials is visible, what kind of equipment is used for materials handling, and how much of the floor is used for warehousing versus production.

When you zoom in on individual stations, you can assess the level of automation and the attention that has been paid to the design of operator jobs. You can also check out the accuracy of the signage, the presence and use of andons, mistake-proofing devices, production monitors, and team performance  boards.

Tell-Tale Signs

It is quite possible to walk through the aisles and not notice that the plant is anything but a tight ship. The key to actually seeing is to not just watch but instead act. This activity yields information both directly and indirectly. Several tools are available to help you see better, some of which require more than a quick visit. They include the following:

1. Using a Seven Wastes Checklist. The list of seven wastes helps you identify occurrences of them, whether you keep in on a paper checklist or in your mind.
2. Following the flow. Pretending you are a work piece and following the process backwards from the end to the beginning,  noting where and how many times it waits for transportation or processing, how operators perceive upstream and downstream colleagues, the tools,  fixtures and storage devices  used at each operation.
3. Counting. You emulate Sesame Street’s “The Count”  and start counting people, machines, parts or fixtures. That’s how you may notice that 20% of the people are walking in the aisles. You ask questions and find out that half of those 20% are going to or returning from the tool crib. You have not only discovered that the plant uses a wasteful method for distributing tools. You also have a ballpark estimate of the productivity improvements at stake in setting up tool pickup and delivery milk runs. Thus the simple act of counting people has led you to discover a pattern of wasteful operation. You will then recognize elsewhere. In other words, you have learned to see it.
4. Hunting for bugs. Kei Abe came up with the “bug hunt” as a means of making managers aware of common small problems that are easily overlooked. 10 to 20 managers get each a stack of 10 red tags. They have 20 minutes to attach them to frayed cables, broken gauges or switches, puddles of oil, lubricant on the floor, devices held in place by duct tape,… Wherever I have seen this method used, all managers used up their stack of tags. They came away stunned by the sheer number of small maintenance problems they found.
5. Conducting video time studies. These directly generates process time data, and indirectly causes you to notice details of the work that you would otherwise miss. For example, you see that an operator is much busier than a neighbor, or lit from behind behind and working in his or her own shadow, etc.

Other Perspectives

Other perspectives on this topic include the following:

• Michael Bremer, in 2018,  has written a book on How to Do a Gemba Walk.
• Eugene R. Goodson, in the May 2002 issue of the Harvard Business Review, published a paper entitled Read a Plant — Fast proposing a method for a small team to rate a plant in 11 categories–including safety, scheduling, inventory, teamwork, and supply chain. The recommendations are useful but insufficient, particularly in layout and workstation design. I also don’t believe in assigning scores on subjective scales, with categories ranging from “poor” to “best-in-class.”
• Joseph Paris has a blog post called The Gemba Beyond the Window, with insights on the monetary value of the shop floor.
• The AME’s Accelerating the Journey blog contains the following list of  “10 Questions asked on a Gemba Walk”:

1. What are the business issues with this product?
2. Who is responsible for the value stream for this product?
3. How are orders from the customer received?
4. Where is the pacemaker process, triggered by customer orders?
5. How capable, available, adequate, and waste-free are assembly activities?
6. How capable, available, adequate, and waste-free are the fabrication activities feeding assembly?
7. How are orders transmitted up the value stream from the pacemaker process?
8. How are materials supplied to the assembly and fabrication processes?
9. How are materials obtained from upstream suppliers?
10. How are employees trained in Lean procedures motivated to apply them?

I find these questions puzzling, for the following reasons:

1. You don’t need to be on the shop floor to find the answers to questions 1, 2, 3, 4, 7 and 10.
2. Questions 5 and  6, that are really about the shop floor, are leading. Asked in this form, they suggest that assembly and fabrication are indeed waste-free. What you are really after is finding out where the waste is, and where the processes lack capability or capacity.
3. Question 4 implies that production is scheduled by heijunka on a pacemaker process and pull on other processes. The more general question is of how production is scheduled in the plant. As discussed above, only part of this answer is found on the shop floor.

1. Question 10 implies that there should be a Lean training program. I don’t understand why training should be the only aspect of the company’s Lean program to rate a question. Before coming to the floor, I would ask whether the plant has such a program. On the shop floor, you should see its effects.