Agile production with kanban
The roots of the kanban method go back to techniques employed by large US companies – more specifically, American supermarket chains like A&P. In this context, the sale of a product at the till was always a signal for an upstream process to refill the shop shelves from a warehouse once a corresponding amount had been sold. As stocks were drawn down in the supermarket, goods were automatically refilled from the central warehouse, etc. This meant that a customer sale initiated a sequence of work steps that upstream processes used to keep downstream processes continuously replenished with products. In the 1950s, the Japanese Toyota Group then developed this basic idea further into the modern kanban model.
Supermarket pull system
Illustration of the supermarket pull system. Process D takes material from the supermarket after process C. Process C must then replenish the quantity removed. Upstream processes A and B also proceed in the same way.
Kanban types and approaches
Kanban is a truly powerful tool for organising the flow of materials along your production lines. While there are various types of kanban, they all have a number of things in common:
- On the one hand, there is always a customer in your production line who specifies the order quantity. This ‘customer’ can be a downstream process, process step or similar kind of entity.
- On the other hand, the order quantity must be provided by the upstream process in your line, termed the supplier.
- All of your information about the quantity, article identifier, customer, supplier, etc. is recorded on a card – the ‘kanban’.
- The number of kanbans results from lot sizes, bin numbers, number of parts per bin, etc.
Kanban implementation is handled in three phases:
- Analysis phase
This can involve a number of methods. First of all, we need to determine the current state of the supply system in use, supplemented with details of turnaround times and wastes. Value stream mapping can be used for this step, for example.
- Implementation phase
Alongside the design process for the new target system, the implementation phase also covers the implementation of this planned target state. It is important to ensure that the necessary resources are provided from the outset. The target state can then be planned using value stream design, for example. During implementation, the plans for kanban, closed loops, the ‘supermarket’ principle and more are introduced step-by-step. And always accompanied by training and other supporting activities.
- Stabilisation phase
During this phase, you create standards and set up monitoring, which has the task of tracking implementation progress. Methods are also taught in training sessions that help to ensure long-term knowledge transfer as well as discovering the root causes of any problems.
A successful kanban implementation provides a wide range of benefits:
- Continuous flow
Kanban creates a uniform and regulated flow of materials within your production line. This flow is also dependent on all machines working without malfunctions and unplanned downtime, as well as a constant focus on customer needs and meeting customer deadlines.
You deploy kanban to ensure that your processes always receive the materials they need in exactly the right quantity at the right time. This approach ensures that local stocks are reduced to only the level needed.
- Reduction in turnaround times
Turnaround times can also be reduced as a result of the regulated flow of material and the continuous, timely provisioning of processes with the materials they require.
- Agile production
Having a stable and well-organisation production unit makes it easier to adapt and to respond to change. You can then plan your production to be more flexible and more agile, and orient it towards the needs of your market.