The difference between Quality Assurance and Quality Control

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They focus on different areas of the value chain, but both are needed to keep customers happy.


C Sridhar, Director-Technical,
Advance Institute of Welding Technology,
Chennai, Tamilnadu

Quality assurance is involved in almost every phase of fabrication. Quality control ensures all final checks meet customer specifications. Both are needed to keep customers satisfied.


Figure 1
Quality Assurance team members stay on top of daily production efforts. Dashboards that bring together information such as rework rates for certain manufacturing processes are helpful tools in this task.

If you Google “QA vs. QC,” it returns thousands of results. While that’s only slightly more than half the number of search results as “Taylor Swift” produces, it illustrates how much confusion exists around the differences between Quality Assurance (QA)and Quality Control (QC).

While not every company defines QA and QC in the exact same way and the departments and areas might overlap in some manufacturing facilities, QA and QC do share some commonalities in the way they are treated in metal fabrication environments.

The role of QA is more about quality planning and ensuring potential quality issues are prevented, rather than just correcting problems that have already occurred. Of course, when quality issues do arise, quality personnel implement corrective action as well.

QA specialists also review customer returns and handle internal rejections, all with an eye toward continuous improvement and achieving the goals set up in the Quality Management System (QMS). The Quality Assurance team also works with vendors on quality-related issues, so they are able to make improvements.

On the other hand, the role of QC is skewed more toward the back end of the fabrication process, including in-process inspections, final inspections, receiving inspections, calibration, and first-article inspections.

In other words, QA is more about prevention, while QC focuses more on post-fabrication inspection and remediation when necessary. Both are important and are concerned with quality, but they have sharply different focuses and immediate objectives.

 How Do QA and QC Roles Differ?

The QA role requires juggling a lot of different details and objectives, depending on what projects are going through the QA process at any given time. This means that no two days are exactly alike. One day might involve reviewing sales orders for new parts before releasing them to the shop floor as per the new product checklist; handling reviews of customer returns or rejections; or analyzing internal rejections and disposition of rejections with the materials review board.

The next day might necessitate the initiation of corrective and preventive actions as required on a customer return or because of an internal rejection; coordinating quality-related issues with customers and vendors; or reviewing the performance of the QMS to make any changes that may be needed to achieve goals.

The QC team’s daily responsibilities are no less complex. They may spend an entire day performing first /lastpiece approval for each order during each stage of fabrication and finishing; a morning receiving inspections for purchased items; an afternoon calibrating measuring equipment; or most of a day handling final inspection of a product before it’s released for shipment.

QA is involved with a job from the very start. Modern manufacturing projects require QA standards be built directly into design plans from the beginning. QA team is involved with the fabrication process from the job’s kickoff, working alongside the engineering team to ensure design-for-manufacturability factors are considered upfront at the same time that customer specifications and other project requirements are being reviewed. QA assists in determining the many criteria necessary for efficient, cost-effective, and quality fabrication. This can include the design of manufacturing sequences, definition of critical dimensions at the component level, review of jig requirements during spot welding, and welding process and postmortem after first-build to address issues or make changes.

Quality Control plays a huge part in ensuring quality goals are achieved with each production order. A check of part dimensions on a coordinate measuring machine is one way they do just that.


Figure 2

In other words, QA is involved at just about every stage of fabrication, from product design to the setup of job processes to the management of production flow (see Figure 1). QC then takes over, ensuring all of the final measurements meet the specs set out at the beginning (see Figure 2).

QA + QC: The Dream Team

QA team have to tackle complex projects. By keeping a close eye on the manufacturing process stipulated by QA from the start of fabrication to final inspection, the QC team ensured the final product met the customer’s requirements. This will help to prevent any issues during the on-site integration and ultimately made for one happy customer.

Challenges, Continuous improvement, and the Future of Quality

With years of combined experience in the fabrication and machining job sectors, QA & QC has to work in tandem. For instance, customer requirements for cosmetic finishes generally are not well-documented when they are handed over to quality. In fact, most customers’ drawings are generated with software that assigns closed tolerances on all features.

So when they are not feasible for the price a customer is able to pay, QA team works to find creative ways to make that customer’s fabrication dreams come true. The company’s quality team takes into account bottom-line job requirements and expectations, so they are able to markup internal documents and make design changes that allow the customer to get its expected tolerances without the additional cost.

In terms of the industry overall, however, one of the biggest challenges the company’s quality team faces is change. It’s absolutely a constant and keeping up with the latest trends can be a job in and of itself. Whether playing a part in instituting new applications of Six Sigma and lean methodologies, tracking regulatory updates, or analyzing a QMS for additional potential efficiencies across business processes, continuous improvement simply never ends.

QA and QC may not be the same, but both play very important parts in the most central issue of maintaining overall product quality. From design to deployment, a quality team ensures that every job meets the requirements set out at each stage of the manufacturing process, so that the end result is the same every time – products that meet, if not exceed, customer expectations, each and every time.

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