What is the role of acceptance sampling in your manufacturing organization? For most companies, the answer is simply to keep poor-quality components and materials from being incorporated into their processes and products. That’s a vital check—and one you can’t ignore. But the data you gather from acceptance sampling offers a great deal more information. By analyzing your acceptance sampling data, you can build a more resilient organization while strengthening communication and relationships with your vendors.
Acceptance Sampling is Not Optional
Would you wear a blindfold to drive to the grocery store? Maybe it’s a journey you’ve taken hundreds of times, and it’s only a quarter of a mile down the road. You could probably drive it in your sleep and describe in detail the turns, crossings, and traffic lights on the way.
Of course, you wouldn’t drive blindfolded. But when manufacturers forego acceptance sampling, that’s essentially what they are doing with their supply chain’s goods. They’re crossing their fingers and hoping vendor products meet requirements.
The scary truth is that some manufacturers don’t inspect incoming vendor products at all. And others rely solely on Certificates of Analysis (COAs) that they receive from vendors. In either case, they are placing a great amount of trust in their vendors.
Trusting vendors is important, but you probably know the old saying “trust, but verify.” Not verifying the quality of vendor materials with acceptance sampling is like driving blindfolded and hoping everything will be okay. No matter how well-intentioned, hope is not a strategy.
Acceptance sampling helps manufacturers minimize inspection costs, manage risk, and prevent off-quality product from entering their production processes.
And if you work with a supply chain of any kind or size, using both statistical process control (SPC) and acceptance sampling can prove to be a game-changer, supporting a more flexible and resilient operation.
What is Acceptance Sampling?
Acceptance sampling was created to refine manufacturing and reduce unacceptable lots. A sample is picked at random from the lot and, based on information that was yielded by the sample, a decision is made regarding the disposition of the entire lot. In general, the decision is either to accept or reject the entire lot.
Acceptance sampling occupies the middle ground between no inspection and 100% inspection. Because of the simplicity of its results, acceptance sampling has been given a bad name. It has been criticized as “just another set of inspection tools.”
But that’s not true. Together with SPC, acceptance sampling can be used as part of a formidable quality improvement strategy.
More than Accept or Reject, Pass or Fail?
By itself, acceptance sampling is a gatekeeper, of sorts. In simplest terms, it is an accept/reject moment in manufacturing. But with modern quality management software and analytics, it becomes much more than that. Acceptance sampling is an ally in the war against bad quality products and less-than-optimal supply chain quality.
Problems with quality typically begin with vendor materials that make up the foundation of your products. Let’s suppose you’re in the business of making aircraft or some other large, complicated vehicle. Manufacturing large metal anythings requires a lot of rivets. Thousands upon thousands. Maybe millions, depending on the size and type of vehicle. Pity the person who must inspect received rivets.
Can you imagine measuring and checking every one of 500,000 rivets in a single shipment? No way. Instead, out of a half million received rivets, they might check 50 as defined by their acceptance sampling plan.
Basically, the inspector compares their chosen sample against their company’s stringent requirements. They might perform a half dozen or more different tests for each rivet. Acceptance sampling says that when a specific number of the sample fails, the collective lot fails. If the number of failures is less than the “reject” number defined by the acceptance sampling plan, then the lot is accepted.
Generally, this is where most companies stop. Pass-fail. Yes-no. Accept or reject. Most companies don’t even save the data that allowed them to make critically important accept/reject decisions. That’s a mistake.
It doesn’t make sense that someone would ignore data. Yet, with acceptance sampling, that is exactly what happens. Once the lot has either been accepted or rejected, the data that lead to that decision is ignored or eliminated—as if those data had no other purpose or use than simply concluding whether or not to accept a lot of goods. What a waste!
Nearly every data set in manufacturing includes valuable information. The same is true for the data gathered during acceptance sampling activities. So, don’t ignore those data. Instead, use it to further improve your quality and the quality of your vendor’s products.
Take Data a Step Further
Some of the manufacturers of larger vehicles (like aircraft) and their ilk use so many rivets, cut so many holes, and use so many parts that they couldn’t possibly source rivets from one vendor. They might use five different vendors for rivets alone.
Creating a reliable, diverse pool of trusted vendors is essential not just to ensure an adequate supply, but to enable flexibility in the case of a supply chain disruption. Having the ability to quickly adapt to changing circumstances is essential for a resilient operation.
When you look closely at acceptance sampling data, you can determine which vendors are serving you best—and how to ensure all the vendors you work with are reliable and supportive of your requirements.
Using acceptance sampling data, you can:
- Determine which vendors are providing the highest quality products
- Analyze how vendor quality changes over time
- Determine whether vendor quality is improving or degrading over time
- Help vendors improve their products
- Identify which vendors should be rewarded with longer-term contracts
Acceptance Sampling Reports: Leverage Software Capabilities
When data have already been gathered using acceptance sampling techniques, you can analyze those data again using the statistical tools that are already included with InfinityQS’ quality management software, ProFicient™. This solution is designed to help manufacturers achieve quality excellence by transforming their operations with SPC methods.
ProFicient also includes expansive acceptance sampling capabilities. No other real-time quality software on the market today supports both extensive SPC and acceptance sampling features in the same application.
Beyond the ability to analyze acceptance sampling data using real-time statistical tools, ProFicient also creates reports that are specific to acceptance sampling, incorporating color coding to indicate acceptance (green) or rejection (red), inconclusive results (yellow), and lots that require retesting.
ProFicient even goes the extra mile to send email notifications to the appropriate parties when lots fail. That’s the kind of communication that keeps your entire team on the same page—and vendors’ quality in mind.
Use the Power of the Cloud
ProFicient is available as a Software-as-a-Service product, ProFicient on Demand (PoD), which uses the power of the cloud to add even more analyzing capability to an already robust tool. PoD offers companies a way to analyze across all plants, all regions, and even all vendors—a single, unified data repository.
The unified data repository offers manufacturers a way to keep all their data in one place, a place from which they can compare and contrast any value, line, or sample they wish. Seeing which vendor supplies the materials that generate the least amount of rejections just got a whole lot easier. That’s supply chain management in action.
SaaS provides manufacturers with data collection capabilities and visibility across an entire enterprise. PoD enables quality improvement experts at the corporate level (from anywhere around the globe) to sort, slice, and dice data anyway they want from across plants, across departments, across regions, across the enterprise. It just doesn't matter anymore; there are no limitations.
Protect Your Organization’s Future by Building Resilience Into Operations
Acceptance sampling data should not be ignored or eliminated after the accept/reject decision has been made. Instead, those data should be used to continue to improve quality levels across the value chain.
So, don’t drive blindfolded. Be sure to use acceptance sampling to monitor the materials your supply chain sends you to make your products. And use acceptance sampling as more than just an accept/reject moment in manufacturing. Analyze those data to ensure that you’re always using the best materials (and vendors) possible to make your products.
We invite you to visit our website to learn more about InfinityQS ProFicient and ProFicient on Demand.