Pre-compliance can have a huge effect on your product’s profit margins later down the line. Read more to understand how to use this.
What is EMC?
Whatever market your products are in, if they contain electronics or have electrical components, like motors. It is very likely that some form of Electromagnetic Compatibility (EMC) testing is required for CE marking.
EMC testing is intended to ensure that emissions from the equipment under test (EUT) don’t negatively impact on other electrical products in its vicinity. It also ensures that it is not affected, or is immune, to electrical disturbances caused by other electronics or machinery.
Generally, there are four areas of interest for EMC. Two of these check the electromagnetic emissions made by the product over the air (radiated emissions) and its attached cables (conducted emissions). The other two make a corresponding evaluation of the immunity of the product to sources of interference from other electronic devices or phenomena. Which, are also either over the air (radiated immunity) or via connected cables (conducted immunity).
Expensive equipment = high approval costs
EMC testing requires a relatively large and expensive specialist test chamber. The smallest of these are known as 3-metre chambers. Typically they have internal dimensions of around 9m x 6m x 6m and are designed to perform radiated measurements at a 3-meter distance. For larger EUTs, there are 5 and 10-meter chambers also.
The test chambers often feature a turntable in the centre to allow the EUT to be rotated for ease of measurement. In addition to the chamber there is a wide range of test and measurement equipment, cabling and antennas. Much of which needs to be kept calibrated. This all adds up to an initial significant capital spend and an ongoing cost overhead. This makes EMC test chamber hire an expensive proposition. The typical cost per day is between £1000-£1500 including a test engineer. Depending upon the required testing full compliance can take a number of weeks to complete. The cost can, therefore, add up to multiple thousand pounds with no guarantee of a pass being achieved.
Are the expenses of EMC worth it for product development?
It’s easy to focus on the aesthetics and functionality of a product during the development and ignore, or avoid compliance completely. Due to the expense of using an EMC chamber, it’s tempting to want to only undertake EMC testing at the completion of a project, this is a big risk.
Getting a product all the way through to completion and then having to undertake a major redesign right at the end of the development, due to an EMC failure, will likely result in a significant project overspend and time slippage.
Pre-compliance testing provides the ability to perform a quicker set of sets, at a correspondingly lower cost. This allows the products likely to be EMC compliant to be assessed much earlier on in the prototyping phase. Issues can then be addressed to reduce the likelihood of nasty surprises when product development is complete. It is possible, in an R&D lab, to use near field antennas to identify the cause of emissions peaks. You can then make changes to address them. Further visits for pre-compliance can then be made to confirm that the issue has been resolved. Additionally, this shows that the product is likely to get through formal testing without surprise issues occurring.
Early Testing saves money
It is worthwhile to note the economic impact that pre-compliance testing can make. The above-simplified graph shows the product profitability for three scenarios. All of the lines show the development costs increasing until the point of sale. This is where revenue comes in and the product then becomes profitable.
- The solid blue line shows product development has been performed and been submitted for compliance. There was a minor EMC failure, as is typical of many products, which is quickly addressed by the design team and the product passes on the second compliance attempt.
- The dotted blue line shows the same product but this time there has been a significant failure during compliance requiring some electronics changes. As well as major printed circuit board layout changes and then further full compliance testing that passes on the second round.
- The purple line shows a more aggressive spend rate. This is allowing for pre-compliance testing to be performed a couple of times during product development. Full compliance test can then be performed with much more confidence at the end. The overall spend is more than the solid blue line and is similar to the dotted blue line.
For ease of comparison, the rate of revenue generated for each of the three development approaches has been kept the same. In reality, product delays can allow competitors to steal a march and take market share. This will reduce total revenues even further.
Pre-compliance testing increases revenues
It is very interesting to note the area under the line at the dotted line point in time. Even though the pre-compliance approach has cost more money than the typical approach, this approach typically gets the product to market sooner. It can then generate more total revenue in its lifetime. The time lag, for a minor rework later on in the product, reduces the product revenue because it gets to market later. The line where a major compliance issue was discovered late on shows a marked reduction in revenue. If the product’s lifecycle ended at the dotted line this product would barely have broken even!
Why pre-compliance testing can save you money later
Product issues left undiscovered until late on in their development cycle can cost significantly more than the costs of pre-compliance. I cannot think of an occasion where some level of pre-compliance testing was unnecessary Of course, it is necessary to find the balance.
The upfront costs of compliance testing may appear to be avoidable. These, however, allow change to be made early on in the design, if required. The earlier the change is made, the lower the overall cost and the greater probability that the product is a success.
If you have any questions, don’t hesitate to get in touch. We’d be happy to have a chat.