What Is Effective Lead Time?
Lead time is also called "lead time". The working time period of a job, that is, the time from the start of the job to the end of the job. For example, the purchase lead time is the total time for the purchase order to reach the warehouse under the purchase order. The processing lead time is the total time from the start of production and processing of each process to the batch delivery to the next process. [1]
Lead time
Right!
- Lead time is also called "lead time". The working time period of a job, that is, the time from the start of the job to the end of the job. For example, the purchase lead time is the total time for the purchase order to reach the warehouse under the purchase order. The processing lead time is the total time from the start of production and processing of each process to the batch delivery to the next process. [1]
- The lead time is the period or time period in which the time invested in a product or part in each process stage is earlier than the time of final completion and production.
- Lead time is an important factor in determining the planned release time calculated by the MRP. For a product
Fixed lead time
- Fixed lead time is a lead time that takes a certain time regardless of the batch size. It is suitable for lead time for purchasing parts and raw materials. The variable lead time is the length of the lead time which varies with the processing volume of each batch. It is suitable for the lead time of self-made parts.
Lead time change lead time
- Calculation method of change lead time
- LT = tool change time + transportation time + processing volume per batch × processing time per unit (transfer time and waiting time)
- Or estimate by empirical method: LT = 2N + 6 (number of processes)
- application
- Among the above times, the waiting time is the longest, which generally accounts for about 90% of the lead time.The length of the waiting time is determined by the priority, and the waiting time with the highest priority is the shortest.If it is an emergency, the waiting time is The shortest working time.
- The computer automatically generates various material parts production plans and purchased parts and raw materials order plans. That is to say, the quantity and time of all net requirements for all kinds of materials in the future can be planned in a planned manner. On the premise of determining the batch calculation method and lead time, the computer can release the production plan of parts and components and the purchase plan of purchased parts and raw materials.These plans correctly show the required quantities and requirements of parts and purchased parts and raw materials. Time lays the foundation for future forecasting, enabling managers to know the future inventory, order quantity and production capacity requirements.
Order lead time
- Order lead time decision between supplier and retailer in the supply chain. Considering the ordering process in which suppliers usually determine delivery time and retailers determine the order quantity, which is common in reality, and the retailer determines the order quantity, under the condition that the lead time management cost is shared by upstream and downstream, an order advancement based on the Stankenberg game is established This model compares and analyzes the lead time and order lot decision in the case of supplier first move and retailer first move. It shows that it is beneficial to reduce the cost of suppliers and shorten the lead time in the supply chain. Finally, the model and conclusions are verified by examples. In the study of service level, the customer's choice behavior when facing out of stock is considered, the customer tolerance value is introduced, and the loss related to customer waiting time is measured, so that the established service level model can more realistically reflect the reality than the traditional model purchase behaviour. Based on this model, the impact of changes in order lead time on service level decisions is analyzed, and conclusions different from the traditional model are drawn, which provides new ideas for companies to make appropriate service level decisions in time-based competition. . The analysis of examples further validates the effectiveness of the model. A common resource constraint form of the inventory system is a linear resource constraint, but it will bring higher operating costs when applied to a multi-variety inventory system. In order to solve this problem, the optimal operation strategy of the multi-variety inventory system under the constraint of probabilistic resources is studied. The goal is to minimize the average system cost under long-term operation. Starting from the convexity of the cost function and the probability distribution of inventory levels, the basic properties of a multi-variety inventory system with order lead time under the ordering strategy and probability resource constraints are studied. Based on this, a fast search multiple Polynomial Heuristic Algorithm for Ordering Strategy of Variety Inventory System. Finally, an example is given, which proves that probabilistic resource constraints can reduce system operating costs more effectively than linear resource constraints.
Lead time
- The production lead time refers to the length of time that the date of production of the blank, part or component in each process stage should be earlier than the date of production of the product. The production lead time is divided into the input lead time and the production lead time. The general formula for calculating the lead time is: the production lead time of a workshop = the follow-up workshop lead time + insurance period, the input lead time of a workshop = the production lead time of the workshop + the workshop The production cycle, when the batches in different process stages are different, the formula is: a workshop production lead time = follow-up workshop input lead time + insurance period + (the workshop production interval-the post-shop production interval).
- Easier to understand the meaning of production lead time
Lead time
- Delayed delivery and inventory strategies for delivery lead times and price discounts, where price discounts are based on lead time price discounts, i.e.
- When there is a shortage of goods and the delivery cannot be made within the given lead time, the company will provide a price discount. At this time, some customers are willing to wait until the order is fulfilled, that is, the delivery is delayed. Among them, the proportion of willingness to wait for delayed delivery is inversely proportional to the lead time, and each part of the lead time can be compressed by increasing costs. Delay scheduling is of great significance in JIT production. The scheduling problem with a delivery window is a more general problem, but there is still no effective solution. This paper proposes a genetic algorithm for solving single-machine advanced / delayed scheduling problems with a delivery window. It is a new type of genetic algorithm provided to overcome the premature convergence of a simple genetic algorithm. After simulation research, the results show that the algorithm proposed by the West is effective. The problem of determining and sequencing the delivery time under the delivery window is one aspect of the research in the field of scheduling. In this paper, the problem of stand-alone operation under the delivery window is studied. The objective function considers not only early / delay penalties, but also additional penalties. Assume that if the task is completed within the delivery window, it will not be subject to the lead / delay penalty. If it is completed outside the delivery window, it will lead to early / delayed penalties. In this paper, the optimal public delivery time is determined, the corresponding optimal ranking is given, and a polynomial time algorithm is proposed to determine that the objective function is minimized. Optimal scheduling, the final numerical example illustrates the effectiveness of the algorithm.
Lead time
- In order to ensure that an order is completed before the actual demand date, an additional lead time is added to the usual lead time as a safety lead time. If a security lead time is used, the MRP system will set the order release date and completion date earlier than the corresponding date using the security lead time.