How to maintain relation between Alternatives Materials in SAP.

How to maintain the relation between the alternatives in SAP? How the MRP considers the quantity of each alternative for the MRP calculation?

You can have 2 options:

1) Create only one generic material in your system and while placing orders for different equivalent materials, mention the equivalent product name in the vendor info record under vendor pr which will get copied to Purchase order. Thus in your system you will have only one material.

2) If this is not suitable for you, than you can configure Manufacturer Part Number functionality.

Option No 1 . Pl take this scenario of a Chemical co.

Step 1 - Creation of Material in SAP

Genaric Material Vendor
(Silicon Surfactant)

Alt.Material 1 Vendor X
Alt.Material 2 Vendor Y
Alt.Material 3 Vendor Z

In this case, you will create material in SAP as Silicon Surfactant. This material will be used in BOM.

You will not create 3 different alt.materials like Material 1,2 and 3 in system.

Step 2 - Vendor Info record will have Vendor Material No i.e Material 1 etc.

Thus whenever you will print PO, PO will be printed with reference to your internal SAP material no i.e of Silicon Surfactant and will also have vendor material no. If you want only Vendor material to be printed then you have change the print format.

Thus for MRP, only 1 material will be cionsidered. Hope this is clear.

Option No2 -Manufacturer's Part Number
Step 1 -
In customisng under Lo General - Material Master - You have to create a MPN profile.

Step 2 -
Create normal material under material type ROH or Traded as required. Under purchasing tab , maintain MPN Profile,Manufacturer's part number(Vendor material number) and Manufacturer's code.(Vendor Code)
This is a material in which you will maintain stock, use in BOM etc. This is your internal material number. This number will not be used in the PO.

Step 3
Create a new material each for your alternative materials under Material type HERS. Under this you will create material which is supplied by your vendor.In this material you will link the internal material number as created in step 2 above.

Step 4
Create a PO by using material number created under material type HERS.

Step 5 - Do a GRN

MPN process works like this :
Order is created for HERS material but whenever you will do GR against this PO, stock and other reports will get updated under material code created in step 2 i.e normal material created under material type ROH or traded. Thus HERS material is used only for ordering purpose.