Scheduling by Formula – Why Bother?

I was at a client the other day and heard an interesting discussion.
The production scheduler was discussing an issue with the production manager about how the scheduler was scheduling production. The production manager was making the case that the scheduler was killing the production efficiency by changing products as often as he was. Production would like to run long runs of the same formula to avoid costly changeovers. Instead he was contending that the scheduler was requesting partial batches and forcing more clean ups than needed.
The scheduler was arguing that he was changing products to keep inventories low. His position was that low inventories was in the best interest of the company and the only way to accomplish that was to run short runs and for only the quantity needed.
So who was right?
My two cents is that a company needs to balance the needs of the customer (on time product often achieved by holding FG inventory) and reduction of working capital (keeping inventories as low as possible). But how can you do that in a formula based manufacturing facility?
The easiest way to achieve this balance is to look for opportunities to produce finished goods that share the same formula. In some facilities producing bulk formula is a possibility and then fill to order. From this bulk multiple finished goods can be produced off of the same blending/mixing batch of a formula. The result is to reduce the number of mixes of the formula which reduces the number of times a change over occurs in blending.
In other facilities multiple finished goods can be filled directly from the mixing tank without much bottling like changes.
It is important for a formula manufacturer's scheduling tool to be able to combine finished good SKU's by formula and then by filling line. This allows a scheduler to better see the opportunities to run like products at the same time. Thank goodness for me the application they are implementing (Vicinity) has this capability out of the box. This is not characteristic of products designed for assembly or discrete manufacturing.
So how did this end?
The scheduler looked out into the future at sales orders and forecasts and allowed the production manager to make some product that would be needed in upcoming weeks. At the same time the production manager grouped the formulas in a specific sequence to reduce his change over time.
Both came to me and asked that we move up the implementation of Vicinity scheduling. Not a bad day for me that is certain.