The reasons for the introduction and implementation of a Kanban system can be divided into two classes,
- as part of an existing, approved or proposed Toyota Production System or
- isolated introduction based on different motives.
Its full effect is achieved as part of a Kanban Toyota production system, but it can also serve as a precursor to the introduction of a holistic production system or isolated completely to be effective.
The motives that induce firms to introduce isolated kanban, arise for the most part from the disadvantages of the traditional ERP.
Other motives are:
- Pressure of purchasers and customers
- Simplified control of material flow, internally as well as with external suppliers
- Improve product quality
- Improved staff communication
- Increase of productivity in the manufacturing process
- Increase of material availability and reduction of missing parts
- Reduction of stocks
- Visualization of disturbances in material flow
- Pressure to rationalize
The demand of the customer is a common reason that is difficult to prevent. The assumption that the control is more easier, especially in-house applications, is not to assume without hesitation.
With the consistent requirement only to use perfect parts, the product quality can actually be improved, because the partner, who takes the parts can identify his supplier quickly and can directly pass on his complaint. Thus a better communication between employees will be achieved, which sometimes is a reason for the introduction of kanban.
In a conventional production control too many parts are often produced, because raw material is still present, because everything goes well so far or because no other jobs are available. Whether these excess quantities are really needed, is not defined. I remember a scene from my apprenticeship, when a guy produced some kind of blanks. “This is real work, not what they do in the office!” was his motto. When he created the multiple annual requirement, the master intervened.
With strict application of kanban it is no longer produced, than actually needed (plus possibly the fixed stock of Kanban). But it is also important that with better communication and quality and productivity is increased.
The original goal of T. Ohno`s vision to avoid waste is indirectly achieved by using a fixed Kanban material inventory determination which can be adapted to your needs. Therfor you have a tool to identify problems by reducing the stock in the material flow. This goal is quite exotic regarding a production philosophy done by Taylor. If you then temporarily increased the stock again, eliminating the cause of the fault and the stock falls down again, it creates a continuous improvement of material flow. And a trend towards rationalization.
Because of the property of Kanban to be sensitive to disturbances in the flow of material, the pressure comes up to determine the cause of the disturbances quickly to reduce the interference and thus to increase the productivity results.
There are a lot of causes of faults such as:
- long set-up times,
- faulty preparation,
- Failure of machinery and tools,
- defective production output,
- uneven production speed,
- high processing costs,
- low capacity
- confusing sequence, shortly inserted operations (quick shots), etc.
Especially you have to consider how economical it is to fix the cause. It has been shown that the recognized causes can often be eliminated with surprisingly simple measures.
If there is no intervention, the manufacturing system will be controlled by the Kanban loop itself. Because of these properties, Kanban has proven and applied as a supplement or in many cases as the only system, even in times of more expensive Enterprise Resource Management (ERP) Systems. This method is applied for both, internally and externally between companies.
Introduction of Kanban
If there is no Kanban experience in the company present, it is advisable to start with a pilot project. This should be a closed, multi-stage production, which is suitable for the use of Kanban, for example, the assembly of A-parts with a constant sales forecast, or in other words, having a constant production capacity utilization. But you can also start with the control of an external supplier by creating a Kanban loop.
Before the introduction of Kanban various studies should be performed regarding the suitability (e.g. ABC – XYZ analysis) and the flow of material.
Basically, the following measures will lead to favorable conditions
(But without the requirement to be):
- Stabilization of demand
- Reducing variations
- Standardization of parts
- Reduced downtimes
- Flow-based material operations (e.g. U-Shape)
- Staff qualifications
- Zero-defect quality
Simultaneously with the decision for deployment of Kanban, the targets should be set, to be achieved with Kanban. This is required among other things to decide whether measures to improve operations are useful or not. Objectives must be quantified and measured to track them. An unjustifiable goal is worthless.
For example, the following objectives can be defined:
- Reduction of cycle times and lead times (e.g. x days)
- Stock reduction (e.g. x Euro stocks or by x %)
- Increase of the availability of materials or reduction of missing parts (e.g. by x %)
- Reduction of committee (e.g. by x %)
- Simplification of the organization (e.g. steps to reduce by x %)
- Increase of flexibility (e.g. production / delivery within x days after order)
- Reducing the machine downtime (e.g. x hours / month)
These requirements and objectives are inevitably necessary to change the organization and production of the corresponding processes. There is agreement that
- Flexible means of production,
- Faultless deliverys,
- Acceptance of idling for staff and equipment,
- Management by View (“visual workplace”),
support the successful use of Kanban.
In addition, agreements are important between the different production stages internally and especially with external suppliers (framework contracts), so they can concentrate on the statement that within a certain period of time the requested product must be submitted in the exact quantity ordered and perfect quality and must be delivered to a defined location.
You can proceed with the introduction of Kanban in the following steps:
- Selecting an area for the first application of Kanban depending on the production environment
- Determination of the average daily consumption and replenishment times
- Definition of Kanban loops including transport facilities and storage locations
- Determining the required number of containers in the Kanban control cycle
- Provision of containers and Kanban cards
- Training of employees and/or suppliers
The practical implementation of Kanban is the creation of Kanban loops. This involves the definition of transport routes, spaces and shelf space, the procurement of equipment such as containers, devices for applying the Kanban etc. If everything is prepared, the completion of the old system must be awaited and then the remaining stocks need to be repacked. After that, the control can start with Kanban. This includes the elimination of detected weaknesses, because of using Kanban in the material flow.
Finaly the interfaces must be set up to other areas and to existing information systems.
manufactus GmbH in cooperation with Mr. Helmuth Gienke
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