Production planning is a plan in which an enterprise makes overall arrangements for production tasks and specifically formulates the variety, quantity, quality and progress of production products. It is an important part of the enterprise's business plan and an important basis for the enterprise's production management. It is not only an important means to achieve the business objectives of the enterprise, but also the basis for organizing and guiding the planned production activities of the enterprise. When companies prepare production plans, they must also consider the production organization and its form. But at the same time, the reasonable arrangement of production plans is also conducive to improving production organization.
Production planning refers to planning to meet the three elements of customer requirements "delivery, quality, and cost" on the one hand; on the other hand, it allows the enterprise to obtain appropriate benefits, and to plan for the three elements of production "materials, quality, and cost". The precise preparation, allocation and use of personnel, machinery and equipment.
Production scheduling is to arrange the production sequence of each production task, optimize the production sequence, and optimize the selection of production equipment when the quantity of materials is certain, so as to reduce waiting time and reduce waiting time. Balance production loads across machines and workers. Thereby optimizing production capacity, improving production efficiency, and shortening production LT. In short: it is the process of allocating production tasks to production resources.
What is more important is the basis and principles of production scheduling:
1) Scheduling requirements and principles when production orders are in short supply: Investigate product bottlenecks and limit production capacity processes as the basis, and use marginal Arrange production based on high profits.
2) Scheduling requirements and principles when production orders are in oversupply: Schedule production based on the cost priority principle and market and customer satisfaction orientation
3. Characteristics of production planning and workshop scheduling
First, delivery-oriented
Production planning is demand-oriented, with delivery as the ultimate goal. Its functions are developed to meet customer needs. The specific functions can be defined as:
Demand management, coarse production capacity balance, fine production capacity balance, material balance, related demand determination, delivery commitment and reply, etc.
Second, long-term demand management
In order to meet future customer needs, especially in MTS (standby database) scenarios, long-term demand management is required, and its time span can It is year, season, month, week, and day.
Third, emphasize completion
Because it is demand-oriented, it emphasizes completion. Because customers focus on the right start, and the right can be delivered. Therefore, production planning emphasizes completion.
First, output-oriented
Workshop scheduling is a task allocation process, so job-oriented is a process task-oriented and resource-oriented task matching process.
Workshop operations naturally involve the sequence, load, and assignment of independent resource process tasks. It also needs to consider alternative routes, etc. It is a very discrete NP problem.
Second, it is short-term.
Because the production process has dynamic characteristics (numerous exceptions), long-term can only be pre-arranged but not locked, so naturally only short-term can be considered. Generally speaking, it is more difficult to lock in a three-day schedule. Most people lock in a schedule of 1-3 days based on production characteristics
Third, emphasize the start of work
Since it is output-oriented , naturally we need to consider starting work, we need to have the production capacity and materials ready when starting work, and we need to consider output efficiency (switching optimization, etc.) when starting work.
Due to different goals, production planning and workshop scheduling are in conflict: the plan is delivery-oriented, and delivery is the priority, so batches should not be batched. Scheduling is delivery-oriented and needs to be batched based on output.
However, delivery and scheduling are strongly coupled, because although the plan emphasizes completion, construction needs to be started to ensure it.
Due to the dynamic nature of a factory's demand and the number of customer demands (forecasts/orders/stock preparations), it is a waiting queue. After decomposition of process-level MRP, it becomes a resource group. The process task queue of (work station, Opera) and the relationship between the previous and subsequent processes (SS, FF, SF, FF, etc.) combine complex processing paths, and then the completion of the order (multi-product combination) can be determined through pre-scheduling. Only personnel related to production planning can use the information system to dynamically monitor the deviation between the order's demand date and the order's planned completion date. Note: Due to the dynamic nature of demand, the planned completion date of an order is dynamic, and the deviation is naturally also dynamic.
APS Advanced Planning and Scheduling (Advanced Planning and Scheduling) solves production scheduling and production scheduling problems, which are often called sequencing problems or resource allocation problems. In the discrete industry, APS is used to solve the optimal scheduling problem of multiple processes and multiple resources; while in the process industry, APS is used to solve the sequence optimization problem. It simultaneously solves sequence and scheduling optimization problems for process and discrete hybrid models, thereby having great significance for project management and project manufacturing to solve critical chain and cost-time minimization.
APS Advanced Planning and Scheduling is a system that integrates production planning and workshop scheduling. It only needs to confirm the two links of demand and progress control, which greatly simplifies the difficulty and workload of production planning and workshop scheduling. It is a software system that enables production planning and workshop scheduling.
In the context of building digital factories (intelligent manufacturing), APS advanced planning and scheduling is being recognized by more and more factories and making useful attempts.
To realize a digital factory, it is necessary to realize the automatic flow of data and the overall optimization of factory operations. So far, only APS advanced planning software can achieve this. From the Ritter law WIP (work in progress) = TH (output rate) * CT (processing cycle), it can also be judged that APS advanced planning and scheduling optimize the material feeding Only through control can we achieve good delivery, high output and low inventory.
Using Excel for CTP and delivery replies, RCCP and CCP (MRP is generally used for related requirements) is a very tedious and complex process. If a planner is not a master of VBA and Excel, it will be difficult to reduce the workload and achieve relatively scientific results. Using Excel to schedule calculations will be even more difficult. Generally, the method of assigning work manually or even verbally is only a reflection of experience, not driven by data, and cannot be optimized.
Using APS advanced planning and scheduling, delivery, output and cost can be optimized due to the integration of planning and scheduling. In particular, it can balance the balance between "delivery" and "output" to ensure high output based on delivery optimization.
The performance of a factory is generally measured from two dimensions: the client side and the investment side, that is, good delivery and high output. The impact of output on costs is very high.
Under normal circumstances, it is a very simple assumption to use APS advanced planning and scheduling software to replace manual Excel planning and scheduling, reduce various buffer settings, and increase capacity utilization efficiency by 5-8. For a factory with sales of 500 million yuan, the effective output (when orders are abundant) can be increased by 25 million yuan. Calculated based on a gross profit margin of 20, the economic benefit is more than 5 million yuan/year.