Lean Management Exercises Guide PDF

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Lean Management Exercises Guide 1) Value Stream Mapping The first part consists in mapping the Material Flow The starting point is the customer: demand eventually mix eventually tray size shifts available available time The second point are the different production stages. For each stage: cycle time...

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Lean Management Exercises Guide 1) Value Stream Mapping The first part consists in mapping the Material Flow The starting point is the customer: -

daily/weekly/monthly demand [u/d] eventually mix [u/d] eventually tray size [u] shifts available [shifts]  available time [min]

The second point are the different production stages. For each stage: -

cycle time [s] setup time [min] (and when the setup is required) availability [%] shifts available [shifts]  available time [min] dedicated or not

Then we have to add the inventories between the different stages. For each inventory triangle: -

quantity [u] (if the professor doesn’t give us directly the amount of inventory, but tells us the days that can be covered we can compute the inventory as: I =Days covered∗Daily Demand

The last step in the material flow mapping is the representation of the trucks with the relative delivery frequency The second part consists in mapping the Information Flow -

production control orders from the customer frequency forecasts from the customer frequency orders to the supplier frequency forecast to the supplier frequency production plan frequency shipping plan frequency

The last point in the Value Stream Map is the timeline Here we have to quantify what the Lead time of the system is taking in consideration both the Processing times in the several stages and the time spent in the queues. If there are two possible paths in parallel, we have to report in the timeline the worst one. -

Processing time=Cycle time Inventory level Waiting time∈the queue= Daily demand

 Little’s Law

The ratio between the total processing time and the total lead time in the queue should be as close as possible to 1, meaning that the Inventory level should tend to 0.

EPE=

SetupTime∗¿ setups CT ∗ D Available time− A

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EPE of each stage:

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If we have a target EPE which is not satisfied by our actual EPE we should work on the Setup time. From the formula we can compute the maximum Setup time in order to satisfy the target EPE. We

can obtain these reductions in terms of setup time applying the SMED principles (in the exam is not necessary to describe them) - EPE of stages working in parallel and in series: LOOK LM-EX-6-valuestreammapexamsimulation 2) Future state map design 1. What is the takt time

Takt time=

Available time per day Daily demand

, the Takt time computation is fundamental in order to

understand what the production pace should be. Aligning everything to the takt time is often possible to use less workers reducing wastes. 2. Will you build to a finished goods supermarket (MTS), or directly to shipping (MTO)? To answer this question, we should consider different drivers: 1. Time the customer is willing to wait > lead time*: MTS 2. Demand variability in terms of volume: HIGH = MTS 3. Obsolescence risk: LOW = MTS 4. Variety: it depends on the turnover if the turnover is HIGH = MTS 5. Value of stock: LOW = MTS 6. Customisation level: LOW = MTS 7. Range: LOW = MTS *In this case the Lead time I refer to is the time between the order of the customer and the actual shipping of the goods. Under the hypothesis of raw material availability, it can be computed as

lead time=total lead time – waiting time∈the first queue

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Rossini consiglia 3 main drivers: Total number of variants (range) Fluctuation in demand Time the customer is willing to wait (if it is higher that 2 days we should always try to set the MTO e vedere se è feasible or not) 3. Where can you use continuous flow processing? First of all, identifying stages with similar Cycle time, Setup time, Availability and Shifts we create a single cell. The values of the different parameters for the cell will be:

CT=max CTi Setup time=Setuptime Availabiliy =Ai∗ Aj∗ Ax … Then, we should identify the number of required workers as:

Required workers=

Work Content Takt time

Then, we need to focus on the DeCAF conditions: De: the machines have to be dedicated to the process and not shared among different processes; if it is shared for example at 50% but has to operator we can change from a situation in which we have 2 operators working 50% to a situation with a fully dedicated operator. C: CT...