The material flow is essentially mapping the journey that materials (as opposed to information) embark on, right from the time that any material is received within the manufacturing site, right through to the point that customers actually receive the finished product/item.
The material flow has to be recorded at various stages throughout its journey. The creation of the Value stream map (VSM) is a process that is involved in terms of identifying waste and looking at where flow is subject to bottlenecks etc.
So the data provided for each part of the journey. For example, when the raw materials are first received within the manufacturing site, how are they stored? Are they stored in a warehouse or are they only received on an ‘as required’ basis, as part of a pull system?
It is also very important to look at the amount of stocks, materials and components that are stored at any particular time. After all, excess storage of components and raw materials will require at least lighting, possibly security, maybe even lighting, all of which use additional resources and will not add value to the process.
Another key aspect of material flow is even looking at how it is secured by operators who are on the manufacturing side. Do they have the materials they need to hand? Do they have to walk a considerable distance to get the new materials they need?
What systems are in place to ensure that stock, materials and inventory are replaced once they have been used? Is there a robust system to ensure that the supervisors can easily identify where stocks need to be replenished?
What happens to materials that have ended up as part of defective goods? Are they recycled or simply ditched? Although there should not be any or at least many defective goods, it is still important to look at what happens when these ‘blips’ occur.
Are products and finished items quickly dispatched or do they sit around waiting for transportation for a long time? If they do stand around, then this will require storage space, which does not add value. Goods waiting for transportation also are vulnerable to being stolen, being broken or damaged by unforeseen circumstances, so there are always substantial risks associated with having goods sitting around waiting on transportation.
Even the transportation should be looked at, both in terms of how the raw materials are brought in and how the finished goods are sent out. Transport needs to be as cost effective as possible and use as few resources as possible.
Identification Of Waste
Charting all these different aspects of ‘material flow’ within the Value Stream Map will enable all sorts of waste to be identified within the creation of the products that are the subject of the map itself.
This is done through looking at the flow and journey of the materials at all stages and if a specific aspect of that journey adds value to the process then it is not wasteful. If it adds no value, but needs to be done because of lawful requirements etc, then it can be identified as not adding value, but it is not, in fact wasteful.
However, those aspects of the journey or process where no value is added and there is no requirement for this to happen, then it is easy to clarify which areas are wasteful and which need to be radically altered to become more Lean and therefore more efficient.