【正文】 ailable after the constraint in the process in which to place production pleted by the constraint operation. Do231。lent Sezen 57 three reasons for a loss of throughput… 2. The constraint is starved. In this condition, there is no inventory from the preceding processes available for work by the constraint. The constraint is capable of production, but cannot produce without material to work on. The solution to this problem is using a buffer in front of the constraint. The buffer is inventory released early into the system. Do231。lent Sezen 56 1. The constraint is broken. This is the same basic issue we found with a lean production system. Without much inventory in the system, processes tend to be tightly linked, and the loss of any operation will quickly bring the entire system down. Maintenance bees important for TOC for roughly the same reason as for lean production systems the potential high cost of a drop in throughput for the entire system. Do231。lent Sezen 55 1. The constraint is broken. One major solution to this potential problem is a good program of preventive maintenance. Such a program needs to be scheduled and managed carefully, for even preventive maintenance represents a use of capacity for the constraint. In general, this situation is patible with a basic principle of maintenance – the higher the cost of an unscheduled breakdown of a process, the more critical the following of a welldesigned preventive maintenance program. Do231。lent Sezen 54 three reasons for a loss of throughput 1. The constraint is broken. Since no excess capacity exists on a constraint, the loss of capacity will directly result in a loss of throughput for the entire business. Do231。lent Sezen 53 Logistics and the Theory of Constraints… There are often three reasons given for a loss of throughput, and these reasons are focused on the constraint in the system. Do231。lent Sezen 52 Logistics and the Theory of Constraints… Most activities have statistical fluctuations inherent in their operation. This implies that activity times are not deterministic and deviations about the mean will exist. The TOC approach suggests that it is these statistical fluctuations that make traditional assembly line balancing approaches impractical. Do231。lent Sezen 51 Logistics and the Theory of Constraints… Most systems are made up of a series of dependent events, or a series of specific steps that must be followed in a correct order to plete a job. This implies that any lateness at an early station in the process will potentially impact negatively later stations in the process. Do231。lent Sezen 50 Logistics and the Theory of Constraints Logistics deals with the physical movement of material through the production process. The Theory of Constraints has specific issues dealing with logistics, as well as some methods to deal with making logistical movement effective. Do231。lent Sezen 49 Impact On Operation Strategy… If they were placed after the constraint, then the implication is that some product that has already been through the constraint will not be scrapped or need rework using the constraint. Since the idea behind TOC is to have all items going through the constraint be turned into sales, clearly it is not a good idea to have constraint time being wasted by being used for a product that will later be rejected. Do231。lent Sezen 48 Impact On Operation Strategy… If, on the other hand, there are processes early in the overall process that have poor quality yield, the constraint should be placed later in the overall process. Some processes, especially certain chemical processes, have poor yield by their very nature. The idea is to have those processes placed prior to the constraint. Do231。lent Sezen 47 Impact On Operation Strategy… If the pany has a choice as to where the constraint is located in the process, they may elect to have the constraint early in the process. In that way the size of the required buffer needed to guard the constraint against starvation of material will be minimized. Do231。lent Sezen 46 Impact On Operation Strategy… Engineering and other process improvement activities can and should be focused on making the constraint process more efficient and effective. The pany should consider if and how the nonconstraint processes may be used to supplement or be used to make the constraint resources more effective. Do231。lent Sezen 45 Impact On Operation Strategy For a given type and mix of products, management can elect to consciously decide where the constraint should be located and then proceed to develop the operational strategy around that selected constraint. Marketing and Sales can be tightly tied to the constraint. Specifically, an analysis can be made to determine the mix of products to sell to maximize profits, and also it is possible to sell more of products that do not use the constraint (implying that excess capacity is available to make more of those products). Do231。lent Sezen 44 Notes on the five steps: At one time the mix of process requirements may point to one constraint, while at another time the mix may create an entirely different constraint. If the constraint shifting occurs frequently, then there could be far too little opportunity to apply the TOC approaches on one constraint before it shifts to another point in the process. Do231。lent Sezen 43 Notes on the five steps: After understanding these five steps, it may be helpful to consider that not all facilities operating in all types of business environments may find the approach to TOC easy to implement. For example, if an operation has a highly volatile product mix due to constantly shifting customer orders for a la