Kanban(10)

Kanban Made Simple

KanbanMade Simple

A Short History of KanbanThe Japanese word kanban, which translates as signboard, has become synonymous with demand scheduling. Kanban traces its roots to the early days of the Toyota production system. In the late 1940s and early 1950s, Taiichi Onho developed kanbans to control production between processes and to implement Just in Time (JIT) manufacturing at Toyota manufacturing plants in Japan. These ideas did not gain worldwide acceptance until the global recession in the1970s. By using kanbans, he minimized the work in process (or WIP) between processes and reduced the cost associated with holding inventory.

What Is KanbanWith kanban scheduling, the operators use visual signals to determine how much they run and when they stop or change over. We define kanban scheduling as demand scheduling. In processes controlled by kanbans, the operators produce products based on actual usage rather than forecasted usage. Therefore, for a scheduling process to be considered a true kanban, the production process it controls must: Only produce product to replace the product consumed by its customer(s) Only produce product based on signals sent by its customer(s)

Why Implement Kanban Scheduling1. Reduces inventory2. Improves flow3. Prevents overproduction4. Places control at the operations level (with the operator)5. Creates visual scheduling and management of the process6. Improves responsiveness to changes in demand7. Minimizes risk of inventory obsolescence8. Increases ability to manage the supply chain

Kanban Implementation Process1. Conduct data collection2. Calculate the kanban size3. Design the kanban4. Train everyone5. Start the kanban6. Audit and maintain the kanban7. Improve the kanban

Step 1: Conduct Data CollectionIn this phase you will collect the data necessary to characterize your production process. The act of gathering data will allow you to makea decision based on facts instead of on desires or gut hunches. Thisdata will allow you to calculate the kanban quantities (which is the next step). As you proceed through this step, be honest about the processs real capabilities so that you can calculate realistic kanban quantities that support customer demand. The first step also represents a golden opportunity for conducting value stream mapping (VSM) for your entire plant and allows you to determine which production processes would be good candidates for implementing pilot kanban scheduling systems. Additionally, the plans for kanban can be considered in the larger scheme of implementing lean manufacturing during the VSM process.

Step 2: Calculate the Kanban SizeOnce you know where you are, you can calculate the size of the kanban. Initially, you will calculate the kanban container size based on current conditions, not based on future plans or desires. However, step 7 will focus you on ways to reduce kanban quantities based on a realistic continuous improvement approach. The initial calculations will utilize the production requirements, the system scrap rate, the process productivity rate, planned downtime, and changeover times to calculate a replenishment interval. The replenishment interval (which will be explained in greater detail in Chapter 4) will establish your order quantities. The final kanban container quantities will also include a buffer for safety stock and to account for any process cure, drying, or normalization periods. These calculations will form the basis for the kanban design in the next step.

Step 3: Design the KanbanOnce you have calculated the kanban quantities required to support production requirements based on current conditions, youre ready to develop a design for the kanban. The completed kanban design will answer the question of how you will implement the kanban. The design will consider: How will the material be controlled? What are the visual signals? What will be the rules for conducting the kanban? Who will handle the kanban transactions? Who will make the scheduling decisions? Who will resolve problems? What visual management items will be needed? What training will be required? What is the implementation schedule?The end product of this step should be a plan for implementation of the kanban, including implementation actions, action assignments, and schedule milestones.As you finish the design step, dont be afraid to commit to a start date. Dont be guilty of analyzing yourself into inaction. Pick a start date, build a plan to support this date, and monitor the plan for progress toward hitting this date.

Step 4: Train EveryoneBefore starting to schedule with kanban, dont forget to train everyone on how the system will work and on their role in the process. Develop a simple presentation to explain the process and the visual signals. Also, review the rules during the training. Take the participants through what-if scenarios to help them understand their roles and the decision-making process. Conduct a dry run so that everyone knows how the kanban signals will be handled and what the signals mean. Keep the training focused on operating the kanban. Dont try to make everyone a kanban expertjust train them on their piece of the puzzle.

Step 5: Start the KanbanOnce you have a kanban design and training completed, you can start the kanban. Before you implement kanban scheduling, make sure you have all your visual management pieces in place. Having the signals set up, control points marked, and the rules completed and coordinated before you start will avoid confusion and make training much easier. As you deploy the kanban, anticipate problems that may impact success and take action to prevent or mitigate these problems. Finally, during the deployment stage, develop a scheduling transition plandetermine the exact point for the change and the amount of inventory required to make the change.

Step 6: Audit and Maintain the KanbanAfter the kanban starts, you must begin the next step of the process auditing the kanban. Auditing is the step that usually gets overlooked in most failed start-ups. So, when designing the kanban, identify who will audit the kanban. Typically, the auditor will be watching how the scheduling signals are handled and whether the customer stays supplied. When the auditor finds problems, then the problems need to be fixed immediately by the responsible party to maintain the integrity of the kanban design. Taking action prevents the kanban from being pronounced a failure by the operators. The auditor will also look at future requirements to make sure the kanban quantities meet expected demand. If you dont adjust the kanban quantities to forecasted demand, then expect to continually intervene manually in the scheduling process (a sure way to kill the kanban).

Step 7: Improve the KanbanFinally, after the kanban gets running, look at how to improve the kanban to reduce inventory quantities. Resist the urge to just start pulling containers. Look at how the system is running and identify any quantities that were oversized, and pull the necessary containers immediately. After this one-time adjustment, only reduce the quantities based on improvements made to the production process. Chapter 9 suggests potential improvement areas that create opportunities to reduce quantities. Dont be fooled into the fallacy of just reducing the kanban quantities on a whim. Determine the amount that can be reduced by using the same calculations you used in sizing the kanban to calculate the new quantities.

FORMING YOUR KANBAN TEAM

Other potential team members?

Role of the project leader.Conducts the team meetingsCoordinates team logisticsEnsures meeting minutes are taken and publishedManages deployment of the kanban designEnsures proper management of project budgetResolves any team conflicts

Set Up Team Rules and Develop Group Process Courtesy to each other when speaking Everyone gets a chance to be heard No personal attacks The decision-making process Meeting rules (e.g., no late arrivals, attend or send substitute,agenda twenty-four hours in advance) Regularly scheduled meeting dates and times Regular meeting location