Safety Stock series-safety stock, safety stock sharing, safety stock and availability check

I. Overview

Safety Stock is to adjust the demand and supply uncertainty (such as urgent orders, plugging orders, delivery delays, etc.), combined with the expected service level of the enterprise to get a number.

The security inventory function in SAP can be divided into the following parts.

1) Safety Stock-manual input

Enterprises can manually enter security inventory in the material master data based on their historical experience.

2) safety stock sharing (Safety Stock partially available)

Use the security stock sharing function to reduce scattered suggestions (Procurement applications, etc ).

3) safety time)

4) security inventory-automatically calculated by the System

In the consumption-based plan, the safety stock can be calculated automatically by the system according to a certain formula.

5) Dynamic Safety Stock)

Dynamic mainly refers to the situation of future needs, to get a security inventory.

 

Ii. Safety Stock (manual input)

When running MRP, the safety stock is equivalent to a requirement that needs to be met. In the following article, we compare the results of inventory and no safety stock.

Create finished product materials zfertss01, raw materials zss002, finished product materials zfertss01 plan policy for production by inventory, component zss002 for procurement, purchase batch set to ex (separately purchased) (transaction code mm01)

Create a BOM zfertss01 component zss002, A zfertss01 requires a zss002 (transaction code cs01)

Independent requirements for maintaining finished products: 52 in June 1 and 1 in June 5 (transaction code md62)

• Currently, zss002 has 100 inventories. If no security stock is set, no purchase suggestions are provided After MRP is run.

• If 50 safety stock items are manually maintained for zss002, two purchase suggestions will be generated After MRP is run, one for one and two for the other.

3. safety stock sharing (Safety Stock partially available)

In the above article, when there are 50 security stocks, the system generates two fragmented procurement suggestions, which may not be what we expected, this concept of security stock sharing is provided in SAP.

First, we define at the backend that the ratio of security stock sharing of the MRP group z002 under the factory h001 is 20% (transaction code omi1). In this example, the security stock is 50 and 20% are shared, this means that 10 instances can be shared.

NOTE: If no MRP group is defined, you should use the transaction code oppr to define the MRP group. The transaction code can also maintain the shared security inventory ratio.

Then, the MRP group z002 is assigned to the material zss002 (MRP1 view of the material master data)

Run MRP again. The last two scattered purchase applications will disappear.

If the independent demand of zfert1 changes and nine items are required in December June 5, a new purchase application will be generated After MRP is run. The number of items is 11, at this time, the shared security stock quantity does not play a role.

Therefore, when a purchase suggestion is generated, the system compares the quantity of the purchase suggestion and the quantity of the shared security stock. If the quantity of the purchase suggestion is smaller than the shared security stock

When the demand date is January 1, June 1, two procurement proposals should have been generated. However, because the number of procurement proposals is smaller than the number of shared security stocks, 10 procurement proposals will not be generated.

The demand date is June 9. At this time, 11 Purchase suggestions should be generated, which is greater than the number of shared security stocks. Therefore, 11 Purchase suggestions are generated.

Note: shared security stock does not mean that 10 security stocks are available (shared) each time MRP is run, but refers to the scattered net demand (less than 10 in this example ), you can use shared security inventory to cover this fragmented demand during MRP running, but if the demand is large (10 in this example ), when MRP is running, the shared security stock is no longer used to cover the demand.

Iv. Safety Stock and availability check

In SAP, the availability check rules (ATP) are defined to set whether the security stock is available.

In the availability check, we can define whether different operations allow the use of security inventory.

For example, we can define more important services, such as the availability check for production, safety stock as available stock.

For less important services, such as department-oriented (mobile type 201), the security stock in the availability check is not used as the available stock.

Shows the availability check interface of the production order. Safety Stock is included in the component availability check in the production order.

In this example, the related definitions are as follows:

Transaction code: opjj defines availability check control (as shown in the availability Inspection Group 02 and check rule pp combination)

Transaction code: opjk allocates the availability check rule PP to the production order type

Transaction code: mm02 allocates the availability inspection team 02 to the material

From the above settings, we can know whether the availability check includes safety stock in different factories for different materials and different production order types.