In this case, the troubles experienced with materials and parts on a regular basis signal that the underlying problem is hidden and should be detected and explored further.
Although number of the solutions to the symptom problems is available, ranging from the radical moving the S close to T and P to, for example, more frequent deliveries from S, the problem is not the physical flow of the parts but the informational flow between the divisions. There are "gaps" or "gray areas", as Steven Spear and H. Kent Bower name them, in the information flows and the relationship between the supplier (facility S and its three manufacturing divisions) and customer (facilities T and P) with regard to the product supplied (parts and assembly materials).
The above mentioned two authors in their article Decoding the DNA of the Toyota Production System (1999) formulate an important rule with regard to customer-supplier relationship within the company's supply chain and internal production system. They emphasize that every connection must be standardized and direct, unambiguously specifying the people involved, the form and quantity of the goods and services to be provided, the way requests are made by each customer, and the expected time in which the requests will be met (p. 100).
The rule creates a supplier-customer relationship between each person and the individual who is responsible for providing that person with each specific good or service. As a result, there are no "gray zones" in deciding who provides what to whom and when. In Oregano plants manufacturing system embracing facilities S, T, and P does have the "gray zones". It is the result of ambiguous and not streamlined flow of physical parts and information between the facilities.
It should be also noted that all the three facilities have different process design and their needs are slightly different. Nevertheless, the facilities T and P, having the single high-volume customer and limited product line range, face the certain demand situation. It is true for the S facility as well, with regard to the demand for the parts from two other divisions, which is derived in nature.
Quality control is another issue to be addressed. Possibility of having up to seven subsequent shifts of producing the defective parts in the molding department due to the machine malfunctioning and raw materials defects, indicates that the currently established raw materials, process and finished goods quality control system does not work out.
The adequate documentation flow system should be developed, implemented and monitored for possible improvements on a regular basis.
The produced, shipped, received, and consumed components should be entered into the system in a correct way and