Is Burn-In Testing Essential for PCB Prototyping? | Jaycon Systems

Failure rates are also rising due to the increasing complexity of electronics and electronic systems. With proper testing and inspection, printed circuit boards can avoid becoming a statistic and offer a better, more functional product for end-users, increasing your brand authority and bottom line. Which types of tests and inspections do you need, though? Do they vary based on the kind of PCB you created?

In this guide, we’ll take a closer look at burn-in testing and other PCB prototyping test and inspection methods used by engineers today. A well-inspected circuit board design is the base for several electronics and electrical products, which means that it’s essential to deliver a certain level of quality so that mobile phones, automobiles, and even aircraft, can operate at a high level of efficiency and rely on their electrical components, including the printed circuit boards.

Of course, in addition to the proper tests, partnering with the right teams for PCB prototyping will make all the difference. Read on to learn all about the process. Then, when you’re done, reach out to us to discuss how Jaycon Systems can help you deliver a better PCB with our commitment to testing, inspection, and providing only the highest quality in all our services and solutions.

How Does PCB Prototyping Work?

As the name suggests, PCB prototyping refers to creating a single working prototype of a fully developed printed circuit board. This allows engineers to test for bugs and physical defects, ensure that the PCB performs as it should, and so forth. A large part of the validation process is inspecting the board to ensure everything is up to standards and working as it should. PCB development is similar to rapid mechanical prototyping, requiring small but constant iterative change until you land on a good design.

PCB testing and inspection are among the last steps of the prototyping process. Testing and inspection can assist in identifying problems within the PCB, whether physical or technical. They can save time and money by identifying all issues before final production. Everything will be tested and inspected for things like:

• Electrical conductivity
• Solder quality
• Mechanical strength
• Lamination/peel strength
• Cleanliness
• Component alignment, placement, orientation, etc.
• Quality of hole walls
• Target environment tests

When problems are identified and need to be fixed after the PCBs have been printed and assembled, it will be far more time-consuming, complicated, and expensive. So here is a simple checklist for effective PCB design. Plus, you’re reducing waste and costs because testers are using a single prototype to test instead of a complete, functional product. That also means no full-scale assemblies are ending up in the trash, which is a waste of money and material that profitable companies can’t afford to make.

Burn-In Testing

This is one of the most talked-about types of PCB testing, and for a good reason. Otherwise known as the stress test, this is one of the most critical processes and is usually performed over several days. This allows testers to operate the PCB at high and low temperatures and various voltages. There isn’t a specific hour standard for testing, but it needs to be enough testing to detect any potential defects or atypical behaviors.

Burn-in testing has three main goals:

1. Potential failure detection

2. Determining Time to Failure

3. Measuring MTBF (Mean Time Between Failures)

As such, it is an integral part of the design and assembly process that should not be overlooked. Burn-in testing uses a special burn-in chamber capable of operating at high temperatures. Before tests are conducted, a plan is created to ensure the run time, the number of samples and other variables are all agreed upon and in order.

Burn-in testing is critical for product reliability. Using this testing method to detect problems means you’ll spend much less fixing them. You can also use burn-in testing to determine how long specific components will last under certain operating conditions. It’s not a perfect science, but boards with higher failure rates typically fail faster during the burn-in testing process. That helps you predict which boards will have the best lifespan.

This testing allows manufacturers to reduce warranty issues and returns, stabilize production, reduce the risk of defective products that could damage our reputation, and more. Calculating the cost of production, malfunction, and status is necessary when starting a business from your product. It’s also an essential part of validation testing in manufacturing to ensure that the process is carried out correctly or not. This can reduce the costs of production and post-production alike and even guarantee that customers’ performance expectations are met above all else.

In-Circuit Testing

ICT, as it is also known, is the most dynamic PCB testing option today, which can be seen in its high price. Although the cost depends on the size of the board and fixture, as well as other factors, these tests can cost tens of thousands of dollars and therefore are only designed for mature products that aren’t expected to require significant revisions. This test actuates the circuitry on the PCB and delivers 85–90% coverage. Although the test is usually designed for 100% coverage, it rarely gets there, but the range you get is free from human errors.

In-circuit testing uses fixed probes laid out in the same design as the circuit board. Those probes will test the connections to ensure the solder is good. The board would also have pre-designed access points that will create a point for the PCB and the probes to connect. This is generally performed on ball grid arrays and more prominent connections, and it has to be chosen from the start because it’s integrated into the design.

Engineers use specialized tools and test benches to properly perform routine inspections.

Flying Probe Testing

For those on a budget, flying probe testing offers a less expensive option similar to ICT but without operational testing. The non-powered test will check for things like:

• Diode issues
• Shorts
• Opens
• Resistance
• Inductance
• Capacitance

There are needles and a probe that operates on an x-y grid, to which your ECM can program coordinates to match the PCB so that the program can run properly. This may be a bit more time-consuming, but it is cheaper initially and often more reasonable for those with smaller orders or limited manufacturing needs. As a reminder, though, this testing does not power the board, so you’ll want to make sure that you have the necessary powered tests performed in some capacity before sending your PCB prototype for final production.

Automated Optical Inspection

Using a 2D or 3D camera, photos are taken of the PCB, which are then compared to a detailed schematic of your board. If the image is mismatched with the schematic, the AOI will flag the board to be inspected by a human technician for a second set of eyes. This is an excellent testing method for early issue detection so that you’re not shutting down production over something simple.

Like flying probe testing, this does not power up the board and might not cover all the different components and parts on your PCB. This method should always be used in conjunction with other tests, as it’s not effective as a test on its own. AOI can be combined with a flying probe, in-circuit testing, and functional testing methods for the best results.

After computer systems detect possible abnormalities, a professional visually inspects the board for faults and errors.

X-Ray Inspection

This is also known as AXI and is an inspection tool that ECMs use to locate potential defects early in the design process. This inspection allows a technician to see:

• Solder connections
• Barrels
• Internal traces
• Bad alignment or asymmetrical connections
• Popcorning

With 2D and 3D versions of the tests available, you can choose to get a faster test from the 3D version or save a little money with the standard 2D test. This can check for items and issues usually hidden from the naked eye, such as solder joints under chips, ball grid arrays, etc. But, of course, this type of inspection must be performed by experienced technicians who know what to look for.

One problem emerges: an x-ray machine won’t necessarily inspect the entire board because you can’t actually “see-through” the parts. However, you can see through various elements and take a closer look at components not visible to the naked eye. This is a more time-consuming, expensive testing process, but it is one that people may consider for the early detection of defects on PCBs during the prototyping stage.

Functional Testing

Functional testing is designed to deliver an array of inspections and tests that check for all the functionality needs of the PCB. Essentially, these tests verify that the PCB will work as it should and that the tested product will power up and operate correctly. Usually, it will be up to the customer to determine the parameters and process for functional testing. Often, the best thing to do is to take a people-centered approach when developing something. Still, you can work with your engineers to get their input on the process and ensure it goes off without a hitch.

Functional testing may require external equipment and fixtures, reaching various requirements from MSHA, UL, and other standards. If you have a small run and need to get the PCBs out the door quickly, this might not be the way to go. However, from the viewpoint of longevity and quality, functional testing is ideal for saving money and your reputation.

Other PCB Assembly Tests

Also considered functional tests, the following are some more detailed tests that can be performed during PCB assembly to ensure that they have been put together correctly and that there are no issues with the board itself.

• Solder Float Test: This test determines how much thermal stress the holes in a PCB can withstand.
• Solderability Test: This ensures the surface of the PCB is sturdy, and the solder joints will create high-quality reliable connections.
• Micro-Sectioning Analysis: This is an inspection to look for defects, shorts, opens, and other failures by taking a section-by-section look at the PCB.
• PCB Contamination Testing: Contamination testing will detect ionic residues that could cause contamination and corrosion, among other issues.
• Peel Test: This measures the strength required to peel the laminate from the PCB and is sometimes also called the laminate test.
• Time-Domain Reflectometer (TDR): This test can find failures in specific high-frequency circuit boards.

You can talk with your team to determine which testing and inspection methods you want to include in your PCB prototyping to ensure that you’re producing a high-quality product ready for market release with as few hiccups as possible.

Circuit boards go through temperature treatments to test their reliability and durability.

The Importance of Functional PCB Testing

You can inspect and test a PCB in a static environment, but virtual and laboratory settings won’t get the same results as if you examined it in a real-world backdrop. Functional testing simulates the actual operating environment that the PCB will see, which minimizes the customer cost and risk of failure. Functional testing requirements, including procedures and development, will vary depending on the PCB and the developed end product.

Testing ensures that your product functionality is at its peak. For example, did you know you’ll need to check and debug as much as 50–100% of the product you are shipping? Functional tests also pair well with other testing options discussed here and are ideal for detecting parametric failures and incorrect component values.

PCB contamination testing is one functional area that doesn’t get enough credit. For example, various elements can contaminate a circuit board, leading to degradation or corrosion, which happens more often than people might like to admit. In addition, the modern global economy makes products pass through more hands now than ever. That’s why it is critical to include contamination testing to remove anything that made its way into or onto the board during handling, production, testing, and more.

Although it will be up to you to determine the exact tests you choose to run here, you’ll need to consider the areas they test and the solutions they can offer for your PCB prototyping and creation needs.

How To Choose the Right PCB Testing and Inspection Methods

There will be a different test (or set of tests) that is ideal for each PCB, depending on its type and performance expectations, as well as the application and tolerance. For example, a gaming company might not require stringent reliability testing for printed circuit boards' medical or military applications. Usually, traditional testing is enough to handle single or dual-layer PCBs, but as the level of complexity of these boards is growing, so are the advanced testing technologies available.

While in-circuit testing will work for simple boards, the increasing complexity of devices means an increase in the number of and complexity of testing methods like AOI and AXI, as well as X-ray testing for larger, more complex boards. A combination of testing methods will comprehensively analyze how well the PCB would perform. Still, companies may need to consider the most cost-effective solutions and choose what they can afford.

Always work with an experienced engineer who understands all the aspects of testing and how to make the most of testing and inspection to minimize defects or performance issues after a product goes to market. Addressing concerns during the prototyping stage can save time and money, offering a far more effective strategy than waiting until the returns start rolling in to address any potential problems. Hiring a service business to handle testing and inspection is a possible route, and it is essential to know what service enterprises look for in potential clients.

Your production goals and the functions of the product themselves dictate the type of PCB testing and inspections.

How To Turn Your Ideas Into Reality

It can be somewhat of a challenge for you to narrow down the ideal type of testing, especially if you’re not an engineer yourself. Fortunately, there are teams of engineers and professional technicians dedicated to the fine skill of PCB prototyping and testing. However, although the manufacturing processes have improved significantly over the years, there will always be room for error, and that’s where testing needs to come into play.

Production will run more smoothly, and companies will see fewer failures on the market, in the hands of customers, and in general. Our team has no shortage of expertise in PCB testing and prototyping, so feel free to reach out and find out what we can do to help you get more out of your PCB design and assembly. With proper testing and inspection, your PCBs can be more successful overall.

Are you interested in setting up the best PCB design and assembly, including appropriate testing and inspections? Contact us for a 24-hour quote! Is the intellectual property on your mind? Don’t sweat it — you can even sign a mutual NDA talking details. Then, let one of our engineers help you create the perfect PCB design and assembly, whether you need ten boards or 10,000.

Originally published at https://jayconsystems.com on June 28, 2022.