When a defect is detected, the priority is to protect the customer while finding and correcting the root cause. In the 8D methodology, this corresponds to discipline D3, temporary containment actions. A well-structured containment plan avoids two common mistakes: containing too little, and the defect continuing to come in; or containing no data and being unable to prove that it worked.
1. Define the Scope
Identify which part numbers, lots, and production dates may be affected, and where suspect material is located: line, supplier warehouse, transit, customer warehouse, and customer line. It is better to start with a broad scope and narrow it with data.
2. Block and Segregate
Block the suspect material in the system and physically, with visible identification, so it does not move until it has been inspected.
3. Establish Criteria and Method
Define in a work instruction what is inspected, with what method or instrument, and how OK/NOK is decided, with photos for each failure mode. The method must be capable of detecting the defect; if it is not, sorting gives a false sense of security.
4. Inspect the Suspect Material
Suspect material is normally inspected 100% for the affected characteristics. Conforming material is identified with the agreed mark, and nonconforming material is separated as the customer defines.
5. Record and Report
Record the OK and NOK quantities by failure mode, along with hours used, by date, shift, part number, and lot. This data shows the defect trend and supports reporting to the customer.
6. Verify Effectiveness
Confirm there are no new escapes after the containment point. If any appear, review the scope, criterion, or method before continuing.
7. Define the Exit Criterion
Agree with the customer when the containment ends; for example, after implementing and verifying the corrective action and a period or amount of time without defects. Document it to prevent the containment from becoming permanent or being removed prematurely.
When to Escalate to CS1 or CS2
When self-containment is not sufficient, or the problem is serious or recurring, the customer can impose a Controlled Shipping:
- CS1 (Controlled Shipping Level 1): the supplier implements an additional inspection, redundant to its normal controls, with its own resources and reports the data to the customer.
- CS2 (Controlled Shipping Level 2): In addition to the CS1 process, an inspection performed by a third party is added, usually approved by the customer and carried out by the supplier. It is usually applied when CS1 was ineffective or when the severity of the problem justifies it.
The exact requirements, including entry and exit criteria, are defined by each customer in their specific requirements for suppliers. More details in CS1 and CS2: Differences.
Common mistakes
- Containing only the material at the customer’s plant and forgetting the material in transit or in storage.
- Starting without written criteria or OK/NOK photos.
- Recording only totals, with no breakdown by lot or failure mode.
- Not agreeing on the exit criterion from the start.
RIDYS Group supports containment plans with sorting, inspection, and Controlled Shipping CS1/CS2 in San Luis Potosí and the Bajío region. Learn about our CS1 and CS2 o request a quote.
