Non-Conformance in Manufacturing and How to Correct It

Non-conformance in manufacturing processes can cause issues including increased costs. But what is nonconformance and how do you correct it?

Quality assurance in manufacturing is incredibly vital to the success and profitability of a product. Without ensuring quality, defective material can overwhelm the costs with expensive rework, repair, and even cause safety issues. In this article, we will learn what non-conformance in manufacturing is, how to identify it, and take corrective action against it.

What is non conformance?

Non conformance (or nonconformity/nonconformance) is any part or product that does not meet (or conform to) the specification. The specification is what the engineering team provide the production team, or contract manufacturer for mass production. If the materials produced from manufacturing are not within the tolerances defined on the specifications, then the part or product is “out of spec” or considered “nonconforming”.

Non-conformance may also be a violation of industry-defined regulations and standards. In this case, a third-party authority (such as the FDA) may regulate certain levels of acceptability in various food products. For example, the FDA may not allow the use of certain ingredients or materials in various food items, supplements, or medical devices. Or, they may allow only a certain amount in the products. Manufacturers must submit samples for testing and verification before they are allowed to sell them in the open market. Re-testing is required and if products are found to be non conforming, corrective action is required.

non conformance in manufacturing

How are non conformances identified?

Non-conformances are identified through a QC (quality control) process ideally during the mass production phase. Such a QC process must be robust enough to catch any and all non conforming materials before proceeding through the supply chain.

Internal and External Audits

Internal and outside audits are typically a part of a good QC process. These audits occur on a regular basis, and when a nonconforming product is identified, an NCMR (non conforming material report) is prepared to address the issue. When an NCMR is submitted to the proper team, adjustments in the manufacturing process, product design, or other procedures can take place to correct the non-conformance.

If the defective components are not caught until later in the supply chain cycle, the cost grows exponentially to correct it. This is because it takes time, sometimes a lot, to move product through the supply chain. Meanwhile, mass production has continued producing more potentially non conforming materials which inflate the cost for any corrective action.

4 Stages of Non Conformance Identification

The following are the 4 stages of the supply chain in which non conformities are identified. As products move through each phase, the corrective action for non conforming material becomes more and more costly.

  1. Raw Materials
  2. Manufacturing Process
  3. Finished Goods
  4. End-Customer Returns
a nail that is non-conforming to the material specification of the other nails

What are the types of non conformance?

When performing an audit, it’s helpful to have a way to classify different types of nonconforming product. The simplest and most common way to do this is “major” and “minor” non conformity. This way, corrective action can take place by priority on those classified as major non conforming over minor issues.

Minor Non Conformance

A minor non-conformance is usually a rare occurrence. Most often, these are easily identified and corrected, but do not directly impact the finished goods. Minor non conformances may include isolated issues such as the beginning and end runs of plastic injection or machine calibration related misfires.

This type of non conformity may not persist in the mass production of a product and is attributable to a one-time setup or other rarely occurring source. However, just because this type of non conformity is considered “minor” does not mean it can be ignored. Minor non conformances often become major ones.

Major Non Conformance

A major non conformance is a persistent mass production issue that causes a product to miss its specification. These are harder to detect than a minor non conformance and therefore require a more stringent quality assurance system.

Major non conformances are caused by skipping validation and testing steps before mass production, or an unauthorized adjustment to the product’s specifications.

How are non-conformances corrected?

Non-conformances are corrected by identifying the cause of the issue and fixing it. However, the way you go about this needs to be structured and well communicated. If changes occur without stakeholder involvement or even documentation, more problems can arise.

This is why an NCMR is an important part of any corrective processes when a non conforming material is identified. This document notifies all the stakeholders and adheres to a specific process for correcting the non conforming material.

Steps for Correcting Non Conforming Material

The proper steps for correcting non conforming material depends upon where the defect was identified. If it was later in the supply chain, additional steps are needed such as determining the extent of the non conforming materials. However, the following list helps distill the steps down into a reasonable process for making corrections.

Containment

Before any corrective steps can take place, first you must determine the extent of the nonconforming product issue. If the product is already in the hands of end-customers, you may have to trace the steps back to its origin. If you have multiple factories, ideally your products have serial numbers so you can accomplish this. Even better, if your factories produce parts in batches you can determine exactly which batch of products may be affected. This allows you to take containment steps such as recalling other potentially faulty parts and segmenting any materials still in the production phase.

Root Cause Analysis

The root cause analysis is perhaps the most critical step when in correcting a non conforming material issue. If you only fix the symptoms of the problem, it will persist and cause more non conforming materials in the future. Therefore, you should take the time to study what the original cause of the problem is. This can be difficult and time consuming, however it is almost always worth it to improve quality assurance and reduce or eliminate nonconforming product issues.

A graphic showing a tree root as an example of root cause analysis

Short Term Corrective Action

During this step, you should identify any “band aid” or rapid procedures to bring your non conforming material back into conformance. This step is not always necessary, but if you have a lot of exposure or risk in a specific defect, you can look for quicker short-term fixes while you simultaneously address the long-term correction. It is important to ensure that short term corrections are not the only fixes you put in place. These are not a replacement for long term fixes, rather they enable you to begin production again while the long term fix is still in play.

If you have an NCMR document, you should also document the suggested steps for remedy. Whoever has the authority to sign off on the plan should do so after all the stakeholders agree. Be sure to include a detailed description of what steps need to take place.

Long Term Corrective Action

Long term corrective actions are the opposite of the short term “band aid” fix. These fully address the root cause of the non conforming material problem and prevent them from happening again. This may include a more robust quality control system for detecting defective parts, other types of inspections including machinery and metrology procedures, and even more regular service intervals. Whatever the solution, the long term plan should permanently solve the non conforming material problem.

Validation

Putting a plan in place is useless without verifying that the plan is actually working. This is where validation comes into play. After you create, approve, and begin implementing your short term and long term corrective action plans, you should also include various validation gates in the process. These steps should be interstitial throughout the plan to correct the nonconforming product. As you validate the various new processes and procedures, the validation data should return to your stakeholder team for analysis. If everything passes specifications, the implementation can continue.

Once your process is implemented and validated, congratulations your non conforming material problem should be a thing of the past. However, that does not mean that it is the only non conformance that will arise. There are thousands of ways this can happen. So what is the best way to eliminate a non conformance? By preventing the non conformance in the first place.

inspection of defective product with no quality control

How To Prevent Non Conforming Problems

There are several steps to take in order to help prevent nonconforming product issues in manufacturing. This proactive approach to quality assurance and minimizing defects or other nonconformity issues is critical in the manufacturing process. If you decide to run your production process entirely reactionary, your quality will suffer, and your costs will increase. The end result is an unsatisfied customer who may decide to move to a competitor.

Perform a DFM Analysis

The first thing that you can do to minimize or prevent nonconforming, defective materials is to perform a DFM (design for manufacturing) analysis. A robust DFM analysis can identify any design issues with your product that may cause manufacturing quality problems.

Usually, an engineer may utilize software to assist in this process. However, some engineers have enough experience and knowledge of the various manufacturing processes to make suggestions on the fly. For example, injection molding works best with a draft angle on parts parallel to the mold cavity direction. Otherwise, they are not easily ejected from the machine and may break or get stuck. A DFM process will identify this and recommend certain levels of draft on these parts. At AMS, we provide this free of charge as a report that goes back to our customer’s engineering team.

Don’t Go With the Lowest Bidder

In today’s supply chain, you can find a vendor for just about any part you can imagine. Even Apple uses third-party manufacturers to build their products. However, because there are such a wide array of available vendors, there is also a wide array of vendor quality.

lowest bidder for poor quality

When deciding on the right supplier for your product manufacturing, you need to determine how they manage their quality control, inspection, and other related procedures. Don’t just go with the lowest bidder. Instead, you must review each company independently based on these metrics. Most often, the lowest bidders are the ones with the biggest non conforming material issues.

Be Reasonable With Your Specifications

Often, an engineering team has a specification in mind for every component in their product. This is fine, however requirements that are too rigid can cause more non conformance issues than should really exist. This all depends on what kind of product your are making, however. If your product is a SpaceX rocket or a high precision medical device, then of course your tolerances are much tighter. If your product is a pair of sunglasses, then tolerances have greater flexibility.

Understanding which tolerances are critical and which are not is also an important distinction. Review each of the specifications with your engineering team and determine if any bends, angles, thicknesses, and other specifications must have such a high level of control. If not, you may end up with NCMR, over inspection, and rework projects that aren’t actually necessary.

Perform Regular Service on Machinery

Probably the simplest way for quality to slip and nonconforming products to find their way into your inventory is a lack of attention on the performance of your machinery. As part of your quality system, you must include a regular inspection on all the critical maintenance and calibration components of all production related machinery.

If this is ignored, the likelihood of producing a nonconforming product increases. It may also be a safety concern. To reduce scrap, nonconforming problems and other issues, review your quality procedure and make sure regular maintenance for your machinery is included.

A person reviewing documents with charts and numbers for auditing supplier network

Audit Your Supplier Network

Just as important to your quality is your manufacturer, so are all of their suppliers. The biggest failure in this step is usually the raw materials supplier. If you focus all of your efforts only in ensuring your specification is correct, you have only managed half of the potential failure points.

Remember, all the components in your product must come from a raw materials supplier before they are turned into your parts. If the raw material suppliers have a quality issue, this can lead to nonconforming parts in production. You should review your supplier network, ideally with an on-site inspection and report from your product management teams. This should include a quality report from the supplier, a description of their quality management process, and documentation of as many other details of their organization as possible.

Implement a Strong Quality Management Process

It goes without saying that you must have a strong quality process in place. If this doesn’t exist, you could find yourself with a lot of scrap material, and a number of unhappy customers. Your quality management does not have to only exist after the product is made, but can include a control system for raw material suppliers and even machinery.

Your quality system may even include ways to deal with nonconformance material. For example, using nonconformity for scrap, repair, rework, or a number of other material uses. Whatever your procedure includes, make sure it is written with a detailed description and enforced so no one can claim ignorance when a non conforming material issue arises.

NCMR FAQ

Non-conforming material reports (NCMR) are standard methods for identifying material which doesn’t meet the predetermined specifications identified during the inspection. It may happen during receipt, manufacturing process or final inspections.

Non-Conformance report (also known as Non-Conformity Report) is a way of recording non-compliance in organizations. Non-conformities are caused because products, services or processes do not conform to industry standards.

You write a non-conformance report by first identifying the part or component that did not meet the specification. Once this is established, you can include an analysis of the extent of the issue, and a root cause analysis. Any NCMR (nonconforming material report) should involve all the stakeholders for that product and be reviewed together. This may include engineers, quality managers, and product managers.

Nonconforming products are those that do not meet their specification. When a product design is completed, engineers assign appropriate measurements to each part of each component. This even includes the type of raw material the part is made from. When the final part deviates from this specification, it is said to be nonconforming. This is why a good quality control process including an inspection is important, to identify any nonconformance and ultimately provide a nonconforming material report.

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