Stop the Defect, not the Line. Blocking Notifications in Catena-X

A batch of parts has left the plant. A few days later, quality testing finds a problem. By now, the parts are already at the customer: in the warehouse, next to the production line, or about to go into a vehicle. What happens next decides the cost. It can be a few hundred euros in scrap or millions in rework and recalls.

In most supply chains, what happens next is a phone call, an e-mail and a spreadsheet. This is followed by a task force, intensive ad-hoc measures and status updates. Catena-X replaces that with a standardized, machine-readable Blocking Notification that lands directly in the customer's systems. This article explains how the process works today, how Blocking Notifications change it, which standards apply, and how sovity helps suppliers and OEMs to adopt it quickly.

The problem: blocking parts still runs on phone calls and spreadsheets

Defects are not always found before shipment. Sometimes a test result, a field return or a sub-supplier's alert reveals a problem in a batch that is already on its way to the customer, or already in their warehouse. At that point, the goal is simple: make sure none of the affected parts are used in production.

Today, the process to get there typically looks like this:

1. The supplier finds the defect and works out which serial numbers, batches or delivery notes are affected.

2. The supplier informs each customer and plant manually, by phone, e-mail, an Excel list or a customer-specific supplier portal.

3. The customer re-enters the data by hand and blocks the parts in its own ERP, QMS or MES.

4. Both sides chase confirmations to find out which parts were actually caught and which had already been used.

5. Affected parts are sorted out and replaced to keep production running.

Each step depends on people being available and lists being copied correctly. The result is a process that can take hours or days, while the line keeps running, or in the worst case stops.

These things make it worse:

• Every customer works differently. A supplier serving several OEMs maintains several formats, portals and contact chains for the same type of event. The same part may have different numbers at customer and supplier. Processes can even differ within one customer, depending on product or plant, and only a few people in the company actually know the interfaces and how to use them.

• Manual handovers create errors. A mistyped serial number or a missed plant means defective parts slip through, or good parts are blocked unnecessarily.

• There is rarely one final list. The affected parts change as the investigation goes on: more parts are added, others turn out to be fine. The result is a back and forth of copy-pasted CSV files, which makes it hard to track and audit the current state and to get both parties to agree on it.

• Delays multiply the cost. A part blocked at goods receipt costs little. The same part found in a finished vehicle means rework, warranty claims or a recall, and those costs land on everyone in the chain, not just the OEM.

• Information depends on individual communication and knowledge. Transparency on the status and necessary actions in some cases depends on single individuals, as only they know where parts are or received communication on the affected parts (the not-CC'd problem).

• Physical parts are hard to find. Someone has to locate the affected parts in storage or on the production line. This is slow and expensive, a result of poor data hygiene, and the costs almost always land on the company that caused the problem.

The data needed to block a part already exists on the supplier side. What is missing is a fast, reliable and standardized way to get it into the customer's systems.

The concept: identify, notify, block

A Blocking Notification is a standardized message from a supplier to its customer that says: these specific parts must be segregated or quarantined and must not be used in production. The principle fits into clear steps:

1. Identify the issue. The supplier detects a problem in parts that are already shipped or produced and determines which parts are affected.

2. Notify via Catena-X. The supplier sends a Blocking Notification to the affected customer. It lists each part with its unique Catena-X ID and, where available, additional details such as delivery note, package number, serial number, part number, production date or position in the container.

3. Block usage. The customer's systems receive the notification and are able to connect it to internal information, such as internal numbers, storage locations or production plans. They set the parts to blocked, at goods receipt, on the shop floor or in downstream operations.

4. Block down the chain. Beyond its own parts in production, the customer also identifies its affected products that were already shipped to its own customers. Affected parts are blocked precisely and in the shortest time, using the same principle along the chain.

The notification is not a one-off message. It follows the problem through its life cycle:

• Create opens the case with a problem description, a criticality level (low to urgent) and, optionally, a recommended handling such as scrapping, rework or return to supplier.

• Update adds more parts as the investigation continues, or changes details of parts already reported.

• Remove releases parts or closes the whole case, always with a documented reason.

• Feedback goes back from the customer to the supplier with the case ID, confirming the case and the number of blocked parts, or reporting a problem.

Because both sides reference the same case IDs throughout, every block and every release is traceable. Parts are blocked from the moment the notification arrives; releasing them is a deliberate, documented step. That gives quality teams an audit trail instead of a mailbox.

In practice, this turns a process measured in hours or days into one measured in minutes. In sovity's pilot projects, the time from upload to the block being visible in the customer's systems dropped to around two minutes.

Blocking Notifications are most valuable when paired with digital twins, because twins make far more data available: measurement data, the bill of materials, logistical and handling information, and more.

To keep the entry barrier low, twins are not mandatory. The notification itself carries everything needed to take part, such as part numbers, serial numbers and logistical information, so a supplier can start with the first block today and add twins as the use case grows.

The multi-tier approach: from one link to the whole chain

Today, most Blocking Notifications run between a Tier-1 supplier and an OEM. CX-0164 itself governs exactly that: one supplier, one customer. The bigger opportunity starts when every link in the chain speaks the same language.

Picture a defect at a Tier-2 supplier, for example in a cell, a chip or a casting. Today, that news travels upward one phone call at a time: Tier-2 tells Tier-1, Tier-1 works out which of its own assemblies contain the affected parts, then tells the OEM. Each handover adds hours or days, and each one can lose information.

In a connected chain, the same event looks different:

1. The Tier-2 supplier sends a Blocking Notification to its Tier-1 customer.

2. The Tier-1 system blocks the incoming parts and, using traceability data (which serial numbers went into which assemblies), identifies the affected finished components.

3. The Tier-1 supplier sends its own Blocking Notification to the OEM, referencing the assemblies the OEM actually received.

4. Feedback flows back down the chain, so every tier knows what was caught where.

This is where Blocking Notifications and Traceability (CX-0125) meet. Blocking tells partners what to stop; traceability tells them where the problem went. Together, they let a block cascade through several tiers in the time it used to take to find the right contact person. This combination is not spelled out in CX-0164 itself. It belongs to the wider Catena-X quality concept (Quality KIT, "Quality in the Loop"), where blocking, traceability, root cause analysis and 8D reports work together.

The advantages grow with every tier that joins:

• Smaller containment scope. The earlier a block reaches the line, the fewer parts are built in, and the fewer vehicles need rework or recall.

• Shared savings. Recall and rework costs are spread across the chain. Every supplier that reacts faster reduces total costs and its own share.

• Less effort per incident. No re-keying of lists, no chasing confirmations, a complete audit trail for customers and auditors.

• One integration, many uses. The connector, identities and part IDs set up for Blocking Notifications are the same ones used for Quality Alerts, Traceability, Product Carbon Footprint or Certificate Management. Each new use case costs less than the first.

In short: one connection per partner, one standard for every partner, and a block that reaches every tier in minutes.

sovity's solution: Quintari Blocking Notifications

sovity has worked on Blocking Notifications since the early pilots with multiple OEMs and was among the first to run them productively with suppliers. Our experience from these projects is simple: the standard is the easy part. Adoption succeeds when the people on the shop floor can use it from day one.

Quintari Blocking Notifications is a module of Quintari, sovity's Catena-X certified managed service. Quintari bundles everything a company needs to take part in Catena-X (connector, digital twin registry, submodel repository, identity management, use case modules) and sovity operates it, so no in-house data space expertise is needed. The module lets you:

• Send Blocking Notifications to your customers, and update or release parts as your investigation progresses.

• Receive Blocking Notifications from your own suppliers.

• Track every case, part and status change in one place.

We recommend a staged adoption, so value comes before integration effort:

1. Web interface. Enter a Blocking Notification by hand to run a first exchange with your customer, confirm the technical setup and check data quality.

2. CSV upload. Upload long lists of affected parts from a template. This covers most real-world incidents without any IT project.

3. API integration. Connect Quintari to your MES, ERP or QMS, so blocks are sent and received automatically, with minimal human intervention.

Because Blocking Notifications run on the same Quintari setup as Traceability, Quality Alerts, PCF and Certificate Management, it is also a low-risk first step into Catena-X: fast to set up, with a measurable return, and a foundation for every use case that follows. Quintari Blocking Notifications is also available on the Cofinity-X marketplace.

Conclusion

Blocking defective parts is not a new process. Every supplier and every OEM already does it. Blocking Notifications in Catena-X make it faster, safer and the same for everyone: one standard (CX-0164), one connection per partner, and a block that reaches the customer's systems in minutes rather than days. The use case is about to get its own standard, and the first productive deployments show that adoption can take months, not years.

Ready to stop defects before they reach the line? Talk to our team about Quintari Blocking Notifications, or start with a first test exchange with your customer.

About the author

Max Mäffert is Data Space Consultant at sovity and a co-author of the Blocking Notifications standard. sovity actively engages in the creation of Catena-X standards to push the network and its application in the interest of its customers.