You can define the delivery block in SM30 - V_TQ04A

In here, you define the keys to block supply relationships.

Depending on whether the block applies to all materials or only certain materials for a vendor, the blocking key is contained in the vendor master or in the quality information record for a material/vendor combination.

The key allows you to block the following business transactions:

• request for quotation 
• selection during source determination 
• purchase order 
• goods receipt 

• an information message 
• a warning message 
• an error message 

1. Together with the purchasing and inventory management departments, determine which blocking options are used in your company and how the system and the persons responsible will respond, in the event of a block.
2. Replace the blocking keys in the standard system with the keys that are needed in your company.
3. Set the system message type according to the arrangements made with the purchasing and materials management departments.

• blocking the vendor for general reasons (purchasing block)

This block suppresses all purchasing functions. In the vendor master, you specify whether such a block will apply to all or to certain purchasing organizations. 
 
• blocking the vendor for quality-related reasons

This block suppresses the procurement functions specified in the blocking key and is effective for materials for which the indicator QM in procurement is active. 
• If you set the blocking key in the vendor master, it applies to the vendor, regardless of the materials and plants involved. 
• If you set the blocking key in the quality info-record, it applies to a specific material and plant only. 

QM Material Setup
QM Workflow For Material Setup

SAP QM Books
SAP Quality Management Certification, Interview Questions and Configuration Reference Books

SAP QM Tips
SAP QM Tips and Quality Management

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