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What’s one of the simplest and most effective ways to ensure that a product is safe for consumer use, functions as specified and won’t provoke the need for a damaging recall? ALWAYS VERIFY THE CDF.

Destroyed washing machineDon’t know what a “CDF” is? Let’s talk about it. But before we do, imagine for a moment that you’re a distributor of household electric products and you’ve been receiving reports from customers that a clothes dryer you sell has been sparking and, in some cases, catching fire. After investigation, you discover that, although the manufacturer of the product had it tested at an ISO-certified lab, they recently started replacing critical components with inferior parts bought from cheaper suppliers. Aside from sending a sample to the lab for costly and time-consuming function testing every order, how could you know that the factory had started substituting machine parts without your approval?

CDF verification during normal inspection, while somewhat more complicated than the normal aspects of a regular inspection, is still one of the easiest, on-site fixes to situations like this.

What is a CDF?

Based on the above true example of a major supply chain failure relating to clothes dryers, you know the importance of checking the CDF. Now let’s get down to defining a CDF. A Diagram of motorcycle partsComponent Data Form, a.k.a. Constructional Data Form (CDF), is a table of critical components and approved manufacturers of those components. Before submitting a complete product for certification, a manufacturer will submit samples of critical parts for testing to make sure that each individual part meets specifications. This allows labs to test the design and construction of the product itself later without worrying about false negatives raised by substandard components. For this reason, a CDF is often required on testing forms and applications for certification.

When a manufacturer sends samples of critical components offsite for testing, the lab will test the parts to industry standards and criteria, noting all parts which conform to the CDF. This list of acceptable parts will include not only the part name and manufacturer, but also the part model, technical specs, testing criteria used and the ID markings for that specific part.

The CDF in product inspections

What does all this mean in terms of QC inspections of your products? When it comes to random inspection of electrical products, CDFs are an invaluable tool for checking safety standards from one shipment to the next. Normally, function testing can be very time consuming during inspection. Aside from that, in many cases, the factories and inspectors don’t necessarily have the equipment and training to perform the more complex checks for safety and certification that Verifying product partsmay be required. Although inspectors can check overall appearance and item assembly to some extent, function and stress testing are vital processes for ensuring a product is safe for consumer use.

CDF verification offers an alternative for testing in some cases. If a product passed when the manufacturer submitted it for testing, then it may be reasonable to assume that a similar product with all the same components and construction will, likewise, pass the same testing. This point is key because inspectors can verify the product’s construction visually and then follow the CDF to confirm that all the components are the same as that earlier tested product.

When verifying a CDF, the inspector disassembles one or two units, and checks the marks of conformity listed in the CDF against actual marks on the unit’s components. If there are partsAuditors checking bicycle parts that are inconsistent with those listed in the CDF, there’s reason to believe that the factory may have replaced critical components with untested ones. At this point, any testing the factory had already performed on the product is no longer valid here. For our purposes, we can now consider the product to be untested.

It’s not uncommon for a manufacturer to switch suppliers, which changes the source of their products’ critical components. Reasons for the switch range from seeking lower costs, needing more product, or a supplier simply going out of business. Whatever the reason for the change, it doesn’t mean the buyer should accept unapproved part substitutions. Ideally, the manufacturer will submit many different items from many different suppliers for their initial part testing so that they have a large pool of approved suppliers from which to buy. The manufacturer can always resubmit new parts to a lab for a revised CDF if needed.


Let’s recap with some of the key points from this message:

You want a quality product that is safe for the consumer and functions as it should. An essential step in accomplishing this is by checking that product parts match those in the CDF.

  • A CDF is a Component Data Form, a document listing approved critical components, and the suppliers that manufacture them. CDFs are an invaluable tool for checking safety standards from one order to the next.
  • An inspector uses the marks of conformity on a product’s individual parts as a basis for comparison with those in the CDF. If product parts are inconsistent with those listed in the CDF, it may mean that the factory has replaced them with untested or unapproved parts. If this occurs, the manufacturer should submit the new parts to a lab for testing and a revised CDF so that they can be confident the product is safe and meets specs.

If you’re thinking of disregarding CDFs as just one more part of QC that will add time and cost to your inspections, remember this: a product is only as good as the sum of its parts.


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Topics: Product Inspection

John Niggl

John Niggl comes from Bolton, Massachusetts and has worked in various roles in client services, sales and marketing at InTouch since 2013. He has lived in Shanghai, Jilin City, Guangzhou and Shenzhen.

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