【正文】 he Theory Of Constraints… As a numerical example, consider the operation producing product A in Figure. Do231。lent Sezen 9 Fundamental Principles of the Theory Of Constraints… A constraint, in its most general form, is anything that limits the firm from meeting its goal. For most firms, that goal is to make money, which manifests itself by increasing throughputas measured by sales, not just production. Do231。lent Sezen 8 Fundamental Principles of the Theory Of Constraints… Since operation C is the constraint on the entire process, it will limit the amount of output from the process, regardless of the capacity of the remaining processes. Improving any of the other operations (increasing the size of the pipe in that section) will not improve the total amount of liquid ing out of the system of pipes. Do231。lent Sezen 7 Fundamental Principles of the Theory Of Constraints… The analogy often used is that production flowing through operational processes is like liquid flowing through a pipeline. Each process has a certain defined capacity, illustrated in the analogy by the diameter of the associated pipe. In the diagram shown, process E has the largest capacity to process production, while operation C has the least amount of capacity. Do231。lent Sezen 6 The Linked Process Pipe Analogy Do231。lent Sezen 5 Fundamental Principles of the Theory Of Constraints The fundamental concept behind the TOC is that every operation producing a product or service is primarily a series of linked processes. Each process has a specific capacity to produce the given defined output for the operation, and that in virtually every case there is one process that limits or constrains the throughput from the entire operation. Do231。lent Sezen 4 Introduction… Still others believe it can be either just a process improvement approach or a plete system approach, depending on the extent of the implementation taken. It may not, in the opinion of this third group, be the most appropriate approach for certain business environments, while it may prove highly effective for other business environments. Do231。lent Sezen 3 Introduction Opinions about the Theory of Constraints differ. Some think that the Theory of Constraints (TOC) is a good way to improve process capability while using other control systems such as JlT or MRP, while others believe that TOC is a standalone approach pletely unique and separate from other techniques. In this context, it is suggested that TOC can provide approaches to design, manage, schedule, and improve virtually any production system. Do231。lent Sezen 2 Introduction In recent years a rather unique and interesting approach to visualizing and managing an operation has emerged. Originally developed by Eliyahu M. Goldratt in his book The Goal, this Theory of Constraints has allowed many people to successfully rethink their approaches to improving and managing their production processes. Do231。lent Sezen Do231。lent Sezen 1 Fundamentals of the Theory of Constraints Do231。Do231。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。s constraint. In order for the anization to take full advantage of this knowledge, it must be assumed that all nonconstraint functions understand this drumbeat schedule and provide total support. Do231。lent Sezen 62 Scheduling and the Theory of Constraints… Buffer Since it is so important that the constraint never be starved for needed inventory, a time buffer is often established in front of the constraint. The idea is to protect the system from normal variations and thereby protect the constraint from disruptions or material starvation. Do231。lent Sezen 63 Buffer… Even though the buffer manifests itself as inventory released into the system, the product mix of this material can be very different based on the schedule. Since it is not based on specific inventory of specific products or ponents, it is generally called a time buffer. This is a key difference in the conceptual use of a time buffer instead of an inventory bufferthe time buffers tend to be largely immune to (protected from) variations in product mix. Do231。lent Sezen 64 Buffer… As an example, suppose variations in processing and the probability of some disruptions in operations upstream from the constraint could mean that material could be held up“ for as much as 4 hours. The implication, then, would be that based on the processing schedule at the constraint the material for constraint processing would be released into the first operation 4 hours earlier than the normal. Do231。lent Sezen 65 Scheduling and the Theory of Constraints… Rope The analogy is that the rope pulls production to the constraint for necessary processing. While this may imply a Kanbantype pull system, it can be done by a wellcoordinated release of material into the system at the right time. As can be seen, even the scheduling system has its primary focus on effective management of the anization39。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252。. Dr. B252