The master production plan, sometimes called the MPS (Master Production Schedule), enables you to generate forecasts for incoming and outgoing material. It's based on forecasts of inputs and outputs by the logistics manager.
MPS, Procurement and Production
OpenERP distinguishes between Production, Purchase and Procurement.
Production is manufacture, Purchase is the acquisition of goods from another party, and Procurement is either or both of those. So it would be better to call the MPS the Master Procurement Schedule. Which OpenERP does!
Also called the Production Plan, this tool is also very useful for traded products which aren't manufactured. You can then use it for stock management with purchased and manufactured products.
To be able to use the production plan, you must install the stock_planning module. This can be found amongst OpenERP's addons-extra rather in the main set of addons. (Beware! One reason it is not in the core of OpenERP at the time of writing could be because some screens have no navigation controls, so you can't always easily get back to the main OpenERP system).
The first thing to do to work with a production plan is to define the periods for stock management. Some companies plan daily, others weekly or monthly.
Stock Management interval
The interval chosen for managing stock in the production plan will depend on the length of your production cycle. You generally work daily, weekly or monthly.
If your products take several days to assemble it's preferable to have a weekly plan. If your manufacturing cycles are several months you can work with a monthly plan.
To do this use the menu Sales Management ‣ Configuration ‣ Create Sales Periods. A window appears enabling you to automatically define the next periods that will be provided for stock management.
Salespeople can then enter their sales forecasts by product and by period using the menu Sales Management ‣ Sales Forecasts ‣ My Sales Forecasts. The forecasts can be made by quantity or by value. For a forecast by amount OpenERP automatically calculates for you the quantity equivalent to the estimated amount. This can be modified manually as needed before completion.
The manager responsible for logistics then plans receipts (manufacturing or purchases) and outgoings (consumption or customer deliveries) by period. To do this use the menu Stock Management ‣ Procurement Forecast ‣ Master Procurement Schedule.
For each period and product OpenERP gives you the following information:
stock estimated at the end of the period, calculated as stock in the following period less total estimated outgoings plus total estimated inputs,
closed entries, coming from production or confirmed purchases,
forecast inputs for the period, calculated using the incoming entries less the closing amounts,
planned inputs entered manually by the logistics manager,
closed outgoings which are the consumption of manufacturing waiting and deliveries to be made to customers,
forecast outgoings, calculated from the planned outgoings, less the closing amounts,
planned outgoings, manually entered by the logistics manager,
sales forecasts, which represent the sum of forecasts made by the salespeople.
The production plan then enables the logistics manager to play with the forecast income and outgoings and test the impact on the future stock for the product under consideration. It enables you for example to check that the stock doesn't fall below a certain level for the product under consideration.
You can also open the production plan for past periods. In this case OpenERP shows you the real stock moves, by period for forecast reports.
If you don't have automated procurement rules for a product you can start procurement at any time based on the estimates of the production plan. To do this press the button Procure Incoming Left (i.e. remaining) on the Master Procurement Schedule. OpenERP plans procurement for an amount equal to the entries forecast.