First of all, in order to meet the needs of external customers, production plans should be differentiated according to different industrial types, namely, A-order production and B-production and sales types (independent products, supply-oriented production).

Quantity formulation of production plan

Order-based production is based on customer orders and order forecasts.

B the types of production and sales are based on market sales and market forecast.

In ERP, the production plan quantity is calculated according to the external demand (including the above two).

Time formulation of production plan

Order-based production is based on internal material planning and capacity.

B. The production and marketing model is based on the sales plan, in which the internal material plan and production capacity are considered.

In ERP, the production planning time is arranged according to the master plan (sales plan or shipment plan), material plan and production capacity.

Then, in order to meet the internal production demand, material demand planning combines the production plan with the sales plan or shipment plan for a period of time to carry out a series of resource planning. In ERP, the quantity and time of suggestions are put forward by running MRP, and the purchase consumes or adjusts the production time.