Firmware Burning-in and Functional Test

Weller is an ISO 9001:2015 certified company who delivers one-stop electronic manufacturing services with specialized support, reliable testing, and multi-functional features.

A perfect electronic product involves many factors, such as a creative circuit board design, high-quality PCB manufacturing and SMT assembly, comprehensive closed-loop functional testing, software and hardware compatibility adaptation, etc. In all of these, functional testing is a necessary step and means to verify the reliability of early diagram design and realistic Manufacturing.

What Is A Functional Testing?

Functional testing (also known as FCT testing) is a crucial quality assurance step performed at the end of electronic product manufacturing. Testing can ensure that electronic devices operate properly. 

It is a vital quality assurance procedure that differs from AOI, X-RAY and other quality inspecting methods. The testing purpose is to validate that hardware design and manufacturing is free of defects or flaws, and ensure that the product operate functionally in a system application.

This refer to test the electrical function of the populated printed circuit boards after SMT assembly, which differs the common flying probe testing that perforated in bare printed circuit boards fabrication process


How Is Functional Testing Performed?

FCT testing can range from simple type of testing like ‘red light/green light’, ‘power on/off’; and to more comprehensive sophisticated functional testing involving temperature testing, sensor testing, geospatial tracking and verification, multi-variant test output, test probe and edge connector measurements, and/or programming verification.

Typically, the power supply and the software test program will be loaded to the electronic device to make the testing work properly. Customer or electronic designer may be required to provide necessary testing specification and procedures. 

Difference Between Various Testing

Except functional testing, some other testing methods are also widely used to test electrical features of populated PCB boards, below are some common ways to functionally test assembled PCB or bare printed circuit boards.

In circuit tests (ICT): It is for inspection of populated printed circuit boards, contacting with specialised needle bed adapters, many test points simultaneously (including checking circuity of each component)

Flying probe test (PBT): This test mostly used to inspect bare printed circuit boards after PCB fabrication finishing, contacting with universal flying probe testers, few test points sequentially.

What Is Required For Functional Testing?

For functional testing performed in industrial environments, typically the following hardware and software is required:

A test fixture (or a test JIG): which is a type of fixture customized upon customer’s specific PCB board test points. It can be used to test bare printed circuit board or populated PCBs.

Software and firmware: Necessary software that executing the test sequences, and the firmware that programmed into MCU. The software could be a common one that compatible to same brand Chips such as ST, or it could be a customized one that uniquely designed by the PCB designer, or it could be a system software such as Linux. The firmware is to drive the MCU and drive the assembled board.

An experienced engineer: Apparently this looks simply but  very critical in all of the work, the time will be saved by skilled engineer once it comes to shot the bugs and problems in the test process.

Other particular condition required: Such as shielded test room.

Why Testing Is Crucial and How It Matters to You?

No matter how confident you are in your electronic design, and your contract manufacturer, functional testing is a confirmed assurance to both you and your supplier. Even a high capability and highly automatic manufacturing process factory, it is impossible to eliminate some hidden flaws such as damaged MCU by static hurts. Therefor the consistent tests can maintain manufacturer quality and guarantee your product is fit for sale.

Functional tests can identify the typical issues like:

Power issues: Being able to power on is a premise for a PCB to function properly. Functional PCBA tests can examine power strength and point out issues with checking output voltage on some critical test points.

Signal distortion: Tests can also explore problems with signal distortion or failure during use.

Inaccurate voltage: Multiple factors could cause incorrect voltage output, from incorrect component placement to a fake chip, or missing a part entirely. A functional test can thoroughly explore these issues and let your contract manufacturer shot the problem properly.

By performing functional test for your assembled printed circuit boards, you can maintain the confidence of the quality your products. It will increase customers satisfaction, achieve reputation and establish a long-term mutual-trusted business relationship. Electrical functional testing is an essential step for PCB fabrication and printed circuit board assembly.

What You Can Rely On From WELLER

With 10+ years experience in electronic manufacturing filed on serving a varied group of customers, we have accumulated a much wider arsenal of engineering knowledge, technology experience and filed expertise than common OEM customers.  Therefor, you can rely on WELLER as your trusted EMS provider including PCB fabrication, SMT assembly and final testing.

OEM customers or electronic designers can benefit greatly by working with us. The main reasons is that we are a knowledgeable, experienced, and savvy EMS provider draws from our past experience base and makes valuable suggestions relating to different reliability techniques and standards. We have experienced test engineers professional in programming and problem debugging for various of brand Chips, Atmel, ST, TI, Xilinx, Qualcomm, etc. Our experienced testing projects including multiple application fields, such as IOT, medical, defence, etc. Consequently, WELLER is perhaps in the best position to help you evaluate your test options and suggest the best test methods to improve product performance, manufacturability, quality, reliability, and most crucial, cost.

Contact WELLER Now with Your PCB Assembly Firmware Burn-in Needs