Lean Manufacturing

21 Questions to Ask When Walking the Model Line, Part 2

By Jon Miller Updated on May 22nd, 2017

Continuing our walk on the model line, here are questions 11 through 21 to ask when performing a lean maturity audit:

11. What methods are used to smooth out the variation in workload due to changes in product mix or work volume?
What is the frozen time window for order release to the line? How is this visualized? Is there any experimentation with heijunka wheels or old-fashioned mailbox-like heijunka boxes? Do orders enter the line in mixed model flows, in small lot runs, or based on a set repeating pattern? What trade-offs are being made between finished goods inventory buffer levels and degrees of smoothing and stabilization of the line?

12. How repeatable are changeover times for the line or equipment on the line?
When the answer to the question, “How long are changeover times?” is “Between X and Y minutes” you know there is opportunity for stabilization, standardization and continuous improvement even if those X and Y minutes are single digit. The 5 why process will reveal that variation in changeover times can have causes related to the 4Ms: manpower, material, machines and methods. Products may have differing numbers of tools, materials and fixtures that need to be removed, attached, and adjusted. Test results or product yield may take stabilize at different rates for different products. Different people may do this slightly differently, or have hidden knacks that only they know. A world class model line will at least have studied these causes of variation in changeover times, posted a Pareto chart and begun planning countermeasures.

13. Who handles materials, parts replenishment, and transportation of goods to and from the model line?
The correct answer is basically “anybody but the operator” or the people working directly on the line. Of course a world class model line will have dedicated water spiders or at least a materials person assigned to the line and working in synchronization. How this question is answered can reveal the invisible thinking of management and how they view planning, production, logistics and other silos either as individually managed and measured functions or as part of a value stream.

14. How are special materials, product-specific materials or seldom-used materials managed?
In order for materials to be managed according to world class practices in a model line, a plan for ever part (PFEP) table or database should have been created. Based on this information and the take time (customer-driven pace) of the line, and pack out quantities it is possible to determine the pitch, or frequency of goods movement. Look for evidence of material segregation and arrangement as a result of ABC analysis, size, risk of damage, item price and other risk factors. Materials in pallets or cardboard packaging with foreign lettering should raise questions about the maturity of a model line. At a minimum there should be a long-term plan towards returnables and off-line material preparation, and ideally pilot examples of these already started.

15. Where are the “fixed positions” to allow handoff of work between stations, and if necessary signal line stop?
The fixed position stop system is an essential feature of a moving assembly line. This system involves marking the pitch of work in the space through which a product moves, defining where the supporting tools, equipment and materials belong, and “drawing a line” at the point where the moving product should be completed. Away from assembly lines we can look for hand-off points, relay points or otherwise defined spaces between people where work can be pulled ahead by the downstream process.

16. How clear is the procedure for responding to defects (problems) found or produced in the line?
One of the better examples I have seen of this was at a factory in Brazil where a series of colorful concentric circles showed how information flowed from point of problem origin to the appropriate manager or support person of the appropriate function. Using photos of the people who were responsible for problem response and the amount of time that could elapse before the call was triggered, it was a truly visual procedure.

17. How quickly does the responsible person respond to line stoppages or andon calls?
This question should be asked in three ways: first verbally to the managers and other responders, second to the team leaders and team members who call for help, and third by actually pulling the andon cord or equivalent and counting the seconds to check the stories against reality. Be sure to check with the head of site and gain approval for creating a bit of downtime, and that the “line stop” test is one that does not cause irreparable harm. Material shortages, wrong materials presented to the line during changeover or missing pieces found downstream are all relatively safe, but use good judgment in designing this experiment.

18. Who is in charge of each zone within the model line?
Unless the model line is very small and is operated by 7 or fewer people, the world class shop floor management approach is to divide it into zones in order to enhance team identify and engagement. A zone defines the working area of responsibility of the team and its team leader, but depending on the team size and span of control of the leaders there may be multiple zones. How well is this being managed?

19. Where and how are new people introduced into the model line?
One of the most common reasons for missed quality, cost and delivery targets on a production line are “new people”. This is a well-known root cause yet too few organizations address this systematically by investing in a system of training and induction. While walking the model line, look for evidence of “beginner processes”. Is it immediately obvious who is a new person on the line? Do you see evidence of training or follow-up taking place cycle-to-cycle for this new person? Is there a separate training center in which people spend hours or even days gaining basic skills and process familiarity? Is there a buddy system? Who are the trainers? How are new employees rotated into new processes? How do the answers to these questions differ between the HR person, the line leads and the team members?

20. How do teams on the model line end their shift?
It’s a shame when an otherwise excellent model line fails a lean maturity audit because everyone just walks away from the production line and goes home at shift end. At a minimum we should expect to see a brief tidying around each station, confirmation that standard in-process stock is in place for the next shift, and that performance metrics are reviewed at least informally. Stay around a little longer to observe the handover from shift to shift by team leaders to their group leaders.

21. Which of these questions do we not need to ask because the answer is visually obvious?
The world class model line answer to this question is “all twenty”.
“Why no questions abut 5S?” some of you have asked. By the same token that a world class model line should be visually manageable and immediately comprehensible, if there is any need to ask questions about the condition of 5S on the model line it is better to walk away and leave the audit for another day.
Jump to Part 1

  1. Joseph

    June 10, 2010 - 1:51 pm

    Your posts are BRILLIANT and a pleasure to read. As I am a bit slow I some times have to read them several times before the penny drops. With the wisdom that you have I think you must be over 100 years of age. It is meant as a complement. This is a great post. All levels of practitioner can use it as a guide.
    Sorry I failed the test on the first 10 items but you can’t keep a good man down.
    Do you think that people should be looking for a new lean area to be working towards “one pitch, one return” for getting the stock from the racks / pallets to the job. As a lot of waste is generated by walking it is best if people use in station carrying devices to achieve this end or did I miss some thing again.
    The comment by “ericmo” on the first ten items was correct for a young lean area to make allowances for “sudden part delays, broken tools” I had my seasoned TPM and SMF head on were we do not tolerate poor services to production.

  2. Jon

    June 11, 2010 - 11:16 am

    Joseph you’re too kind. According to scientists my basic components are more than 4.5 billion years old but in this current configuration I am less than half a hundred.
    “One pitch, one return” is a good goal just like “one touch logistics” from truck to point of use is a good goal. There are all sorts of trade offs, risks and practicalities that make us settle for something less in the short term.
    I’m in favor of walking around so long as it’s done safely and in a deliberately designed way that keeps value flowing rapidly to the customer.

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