Lead Time, LEAN indicator that allows you to see the time that elapses between the start and end of a process is either estimated or measured.
- Process : compared to the routing time
- Inventory : use of Little’s law
- Followed a piece from start to exit
⇒ In the first case, the database errors (false routing, stock errors) are that the calculation is not always accurate.
⇒ In the 2nd case, the difficulty of making measurements in the workshop, and the fact that they are made at a given time, also make the calculation is not very accurate.
The ideal is to have a set of measures on the value stream chain, and this at random times. To do this, follow parts from the arrival of the raw material to the delivery of the finished product. But unfortunately no one can be present continuously in the workshop for this monitoring.
In the case of based panels furniture manufacturers, there is a very simple method which can be reproduced regularly. To do this, simply place a tracking sticker at the reception of the main raw material : the panel. This sticker on which are written the date and time of arrival, will follow the parts to shipping service or even to the customer. At this point, you have only to note the effective date and time and calculate the time elapsed since the reception.
Sticking the label can be done randomly, for several weeks to get a measure on a large sample..
The advantages of this method are:
- Avoid calculation errors
- Avoid database errors
- Avoid workshop awaiting presence
- Allow regular measurements
However, this method does not replace a measure of Lead Time with a VSM. Indeed, the VSM, in addition to measuring the Lead Time, helps to identify waste and opportunities for progress.