5
May
2010
Theory of Constraints Golden Nugget
#8 – When you say “red”, what do you mean?
(Production)
When we are told that a production company has 20% red orders, what does that mean? Seemingly the answer is clear – it means that if we go to the floor, we will see that 20% of the orders are red. But then again, maybe it means something else – that out of all the completed orders, 20% were finished while being red?
Here we have a situation where one term is being used to describe two different things. This ambiguity wouldn’t be a real problem if the practical implications, stemming from the two different interpretations, where the same. But this is definitely not the case; one of the above meanings of “red” is very important in terms of assessing the state of the operation, while the other has no practical implications and using it leads only to confusion.
In order to clarify the above statement, we ought to better understand the meaning of each definition. The first definition of red percentage is a description of a snapshot – the situation on the floor at a certain moment: how many orders from each color do the production workers see? Figure 1.a schematically shows a distribution of orders’ color on the floor at a specific point of time, under the assumption of a constant stream of incoming orders. The X axis is not a time axis, but rather represents the “age” of an order at the point of time when the snapshot was taken… Click here to continue reading.
|
||||
12
Mar
2010
Theory of Constraints Golden Nugget
#6 – Fine tune of the priority system – an exception
(MTO; Production)
The effectiveness of the priority system stems from the fact that it is robust yet simple; only three priority colors, with a strict instruction not to try being super- accurate and pin point which among the same-colored orders should be processed first. That being said, there is one exception – a unique case where refinement of the priority system is very much needed.
The case we refer to relates to situations where there are product families with considerably different production buffers. In such a situation, a product with a relatively long production buffer might have, at some work-centers, touch time which is indeed negligible relative to its own production buffer (< 10%), but is significant in comparison to another, shorter production buffer (> 1/6). Figure 1 schematically demonstrates the described situation… Click here to continue reading.
|
||||
