A major part of Product Control is Material Control.
Most finished, sale-able goods are a combination of multiple raw materials that have been manipulated by your process.
As a result, the quality of in-coming raw material is critical to finished goods quality.
In addition to in-coming raw material, Material Control must also be applied to work in progress (WIP), non-conforming product and finished goods.
In the event that Finished Goods need to be recalled or reworked, proper material control provides tracking and traceability and reduces your companies exposure to risk.
For example, if Lot 123 was bad, but the rest of the product was good, you wouldn’t have to recall everything in the market, just Lot 123.
For non-conforming product in manufacturing, proper material segregation is essential to prevent inadvertent distribution. This is recognized as a strict requirement under ISO 9001. That ISO requirement also requires an appropriate identification of all materials and their status within the process.
At some point in the manufacturing process, you as a CQE will have to disposition material that has been deemed non-conforming. Generally, there are a few major classes of disposition:
- Reject – The material or product is deemed unacceptable. The rejected component can either be scrapped, or returned to the original vendor.
- Sort/Rework – Non-conforming material can be sorted and/or reworked.
- Accept – Material can be inspected, meet quality standards and dispositioned as acceptable.
- Downgrade – Certain materials can be downgraded or reclassified based on the non-conformance that is recorded.
A key concept in product control is Material Traceability which is the ability to trace the history, application or location of an item by means of of recorded identification. According the Juran, there are 4 major reasons for material traceability:
- To ensure that only conforming materials & components get utilized in building the final product.
- To prevent mixing of parts.
- To permit recall of product.
- To aid in the root cause investigation of failures and corrective action.
Material Traceability is also required by regulatory standards for certain industries including Medical Devices, Pharmaceuticals, Nuclear, Automotive and Aerospace.
In addition to the 4 major reasons above, having material traceability can also aid in production planning and inventory control, but these are not a primary focus of the CQE.
What is of concern to the CQE, especially in the realm of Product & Process Control, is the control of material as it is consumed in the manufacturing process.
Having Material Traceability ensures that the material used in the production process are not only assured for quality during production, but that they were received from the supplier at an acceptable quality level. Another additional benefit of material traceability is in how it aids root cause investigation for non-conformances.
Failure Traceability systems provide data to the CQE for process & product improvement. The Failure Traceability System can follow the product all the way from raw material receipt to customer use.
Configuration Management which is a system used to track/manage any material or assemblies throughout the production process including a Bill of Material used for each unit or lot.
With a failure traceability system in place, it becomes possible for the CQE to analyze the resulting data to make improvements. This process could be part of the root cause analysis for failures to eliminate a failure mode.
If your root cause analysis shows that the root cause stems from an inadequate design, then a design change is required to address and improve product safety and reliability.
Design changes should be made quickly to eliminate reliability issues that are identified as part of the failure traceability system.
This will have a positive impact on Customer Satisfaction, inventory and replacements cost, and any potential litigation costs.
Material Segregation is the practice of ensuring that suspect material or product is segregated from the normal work flow of product.
This is meant to ensure that only conforming product is shipped to the customer. Preventing the mixing of acceptable and unacceptable components is a basic requirement of a Quality Management System.
A common and effective practice for Material Segregation is the physical identification & physical separation of suspect product from the normal work flow. Some companies take a more pro-active approach to material segregation by only shipping materials that are marked as such, this is called a “positive release” system.
Classification of Nonconformities & Defects
In the Product & Process Design section we discussed the Classification of Quality Characteristics. Similarly to that exercise, you the CQE may want to classify nonconformities and defects.
Both of these activities are performed so that you can identify those areas that are the highest priority so that you can leverage your time working on those activities. As for the classification of nonconformities, you the quality engineer is attempting to quantify different nonconformities to determine which are the most severe that require your immediate attention and corrective action.
Before we move on, this would be a good opportunity to point out a difference between the definitions between nonconformity and defect.
- Nonconformity (NC) – The non-fulfillment of a requirement.
- Defect – The non-fulfillment of a requirement related to intended or specific use.
As all other tools, the Classification of nonconformities is a general process that is flexible for your particular industry.
- Determine the level of classes of nonconformity (Critical, Major, Minor, Incidental. . . . etc)
- Define each of these levels
- Classify each nonconformity into each class
Below are some of the general classes of nonconformities to provide some guidance regarding their typical definitions and how you can use them as a CQE.
- Critical – A Defect or NC that is likely to result in a hazardous or unsafe condition for users, consumers, etc.
- Major – A Defect or NC that is likely to result in failure or reduced usability of the product.
- Minor – A Defect or NC that is not likely to result in failure or reduced usability of the product. Includes visual nonconformances.
Material Review Board
As a quality engineer you will likely be asked to participate on a Material Review Board. The Material Review Board (MRB) is a method that was developed for companies to make decisions about the Disposition of Materials.
The basic role of MRB is the review & disposition of material that does not meet the current standard along with any necessary corrective actions required to eliminate the recurrence of that material NC.