Introduction to Materials Management Study Notes-master plan preparation

The original name of this chapter is master scheduling, and the direct translation should be the main schedule or something else, but it feels better to compile the main plan.
Overview
After the production plan, the next step of the MPC is MPs (Master Production Schedule). In this chapter, the analysis is to be considered in the preparation and management of MPs. MPS is a very important planning tool for communication between sales and manufacturing. MPS is an important connection point in the Production Planning System:
1. It connects the production plan and the actual stuff to be produced;
2. Basic computing capabilities and resources;
3. MPS driver MRP (Material Requirement Plan ).
4. It makes the priority valid.
The Production Plan processes the product group, while MPs processes the final product. The products and products in MPs should be the same as those in the production plan. It aims to balance market demands and plant material, labor and equipment capabilities.
The information required for preparing the master plan comes from:
1. Production Plan)
2. Prediction of each final product; (forecasts for individual end items)
3. Actual order and inventory replenishment from the customer; (actual orders received ed from MERs and for stock replenishment)
4. inventory level of each final product (inventory levels for individual end items)
5. capacity restraints)
Relationship with production plans
The main example shows that the production plan is the basis of MPs, and MPS is the expansion and refinement of the production plan.
Prepare Master Plan
Goals of the Master Plan:
1. Maintain the expected customer service level by maintaining the inventory level of finished products or meeting the customer's delivery requirements through planning;
2. It is best to use materials, labor and equipment;
3. Maintain inventory investment at the required level.
Three steps for preparing the Master Plan:
1. Prepare the preliminary MPs (develop a preliminary MPs );
2. Check the preliminary MPs against available capacity with the available capability );
3. Solve the initial difference between MPs and availability.
Prepare a preliminary master plan
For example, how to prepare a preliminary master plan and compare it with the production plan to see if the sum of a single product is the same as that of the production plan, it needs to be adjusted to make it the same as the product plan.
After preliminary preparation of the master plan, you must use the available capacity to check the plan. This process is called rough-cut capacity planning ).
Rough capacity plan
The capacity plan checks whether key resources meet the requirements of the preliminary master plan. Key resources include bottleneck processes, labor, and key materials (which may be scarce or have long lead time materials ). The textbook provides a simple example of the specific check method.
Difference Solution

For Work Centers, if the available capacity is less than the required capacity, you need to find ways to increase the capacity, such as through overtime, hiring more workers, using other work centers for or outsourcing. If you still cannot increase the capacity through the above measures, you need to consider modifying MPs.
Master Schedule decisions)
For MTS, MTO, ATO, and Eto, the plan for these materials is introduced, and Fas (Final Assembly schedule) is also introduced ).
Planning Scope (planning horizon)
It must at least cover the time required to complete the plan. For most production plans, the minimum plan scope is the longest lead time. For several reasons, the scope of the plan is generally longer. The larger the scope of the plan, the higher the visibility. The better the management capability to avoid future problems, and some special situations can be used.
Production Plan, main production plan and sales (Production Planning, master scheduling and sales)
This section describes the relationship between the production plan, the main production plan, and the sales forecast. A production plan provides a framework under which MPs can develop more detailed plans. MPS is concerned with what products are to be produced, how much is to be produced, and when to meet requirements. Production Plans and production plans isolate sales forecasts from production activities by establishing a manufacturing plan, which attempts to balance the available resources, equipment, labor, materials and forecast needs of the plant. However, they are neither sales forecasts nor expectations. MPS is a plan for what products can be produced.
Of course, the main plan is not static (not meant to be rigid ). Changes in demand, problems in the production process, and sometimes, parts out of stock and other events are necessary to modify MPs.
Main Plan and delivery commitment
As the order is received, it consumes available inventory or capacity. What is not consumed by the actual customer order in the Plan is the amount that can be committed to the customer. In this way, MPs makes a reliable delivery commitment to the customer.
The amount of ATP (available to promise) that can be promised is a part of a company's inventory or planned production capacity that has not yet been submitted available to the customer, in fact, there is no order in my warehouse or the Dongdong that has been arranged for production. You can give a new order.
What is ATP calculated? Expected receipt (scheduled receipts) + initial inventory-the actual order amount before the next expected receipt (that is, before the next MPs.
This method assumes that ATP will be sold out next time it is expected to receive (next scheduled receept. If it is not sold out, it will be used as the inventory amount for the next phase.
Projected available balance)
The calculation of the expected amount is divided into two stages based on different time periods, which are divided by the demand time limit (demand time fence. The demand time limit means that the change plan will incur additional costs during this period, so the change is not allowed. The formula is as follows:
Pab = PAB or current quantity in the previous period + MPs-customer order volume
The formula is as follows:
Pab = PAB + MPs in the previous period-the largest customer order and forecast.
Time Limit
The closer the delivery date, the higher the cost of the change plan. To help the decision-making process, the company establishes a time-based area. The following zones are available ):
1. Freeze zone (frozen zone)
Capabilities and materials have been associated with specific orders. Changes will lead to excessive costs, reducing manufacturing efficiency and poor customer service. The scope of the freeze zone is determined by the demand time limit (demand time fence. Within the demand period, the demand is based on customer orders rather than predictions.
2. slushy Zone)
Slushy is muddy. It actually refers to the fact that in this area, materials have been scheduled and capabilities have been established, which is not easy to modify, but the priority is not difficult to modify. That is to say, it is a little loose area than the freeze area, so it is called the semi-freeze area. The scope of the semi-frozen zone is defined by the planning time limit (planning time fence. Within this time limit, computers cannot reschedule MPs orders.
3. Liquid Zone)
I think it's okay to call it a free zone. Any changes to MPs can be made within this region, as long as they are within the scope of the production plan. This change is usually made by computers Program Complete.
Error Management
Errors often occur in customer orders and require continuous attention. There are usually three error types:
1. Incorrect product or specification;
2. Number of errors (too small or too many );
3. incorrect delivery date (too early or too late ).
They need different processing, re-design or change, negotiate partial delivery, and speed up delivery.