A Deeper Dive into PCBA Testing

Comprehensive PCBA testing is becoming more critical to the performance and functionality of circuit boards, especially in sensitive and high-reliability industries such as medical, precision, and industrial controls. For this reason, it is important that companies partner with a knowledgeable company, like RiverSide Integrated Solutions (RIS), for PCB assembly, testing and system integration. Whether you are bringing a new product to market or trying to optimize an existing product, RIS has the experience to assist customers with developing and executing a robust PCBA testing program.

Common PCBA Testing Methods

Quality testing is an integral aspect of electronics manufacturing. There is always the potential for design issues, manufacturing defects, or human error during fabrication and assembly – and testing is the checkpoint to catch these problems. The use of testing to identify and resolve quality issues is critical to the performance, functionality, and reliability of the final product.

Some PCBs contain hundreds of components and thousands of solder connections – so testing must be thorough as well as strategic to ensure a functional board. Various inspection and testing methods are available to ensure the quality of PCBs. Below is a deeper dive into some key PCBA testing procedures.

  • In-Circuit Test (ICT): this PCBA testing procedure is popular and provides a comprehensive test. ICT is also referred to as the “bed of nails” test. This test requires a test fixture with test points, which adds incremental cost and time to create. Using the test fixture, electrical probes in a bed of nails send current through specified test points on the PCB. The test checks for various defects such as shorts and open circuits, misorientation of diodes and transistors, and issues with the solder connections. ICT is often designed for 100% defect coverage with the result being around 85-95%. Since a test fixture is required, this test method is a good fit for higher volumes with “mature” designs that do not expect significant revisions to the PCB and, thus, the test fixture.
  • Flying Probe: this PCB test is programmed into the test equipment and, as suggested by the name, the test probes “fly” over test points on the board as directed. Flying probe does not require a custom fixture and, therefore, does not require tooling costs like the in-circuit test. However, the test takes longer increasing the unit cost. Flying probe tests for opens, shorts, resistance, capacitance, inductance, and diode issues. This method can also perform voltage measurements and check for diode and transistor orientations. Flying probe is typically a good choice for prototypes and small to medium volumes of PCBs, but may take too long for high volumes, especially if the boards are complex.
  • X-ray Inspections: this PCBA testing procedure employs x-rays as the name implies. 2D or 3D images of the PCB solder joints can be generated using this technology. During the test, an x-ray technician is able to identify defects by viewing the PCB solder joints and connections, internal traces, and barrels. One of the main benefits of x-ray technology is that hidden parts of the PCB become “visible” – revealing issues, such as solder voids, that may impact PCB functionality or integrity in the field. This test method is often used for prototypes or smaller volumes as the process is often time consuming and requires a trained technician.

Looking for a manufacturing partner that offers a wide range of PCBA test methods?

Contact the experts at RIS to learn more about our PCBA expertise and how we can customize a solution for you.

  • Burn-in Testing: during the burn-in test, power is run continuously through the PCB at the maximum capacity for many hours – up to several days. This method simulates high-stress conditions, including temperatures, operating duration and frequency, and voltage load in order to detect issues with load capacity. When stresses or failures occur during burn-in testing, some or all of the PCB may be damaged. This PCBA test method is often used in industries that demand high reliability electronics and cannot sustain failures in the field. This method is accurate, but can be time consuming.
  • Automated Optical Inspection (AOI): this PCBA testing procedure employs a 2D or 3D camera to photograph the board and compare the photos to the PCB design schematic. When inconsistencies between the photos and the schematic are detected, the PCB will be flagged for further inspection. AOI is more reliable than manual/visual inspections. Since this method does not power up the PCB and can only detect surface defects, AOI is typically used in conjunction with other test methods such as flying probe or ICT.
  • Functional Tests: the purpose of these tests is to simulate operating conditions in order to ensure the PCB operates as intended. There are a variety of functional tests ranging in complexity. These tests are customizable, and are typically used in conjunction with other PCBA testing processes. Depending on the batch size, some companies perform functional testing on 100% of the PCBs to confirm every board is fully operational before entering the field. It should be noted that functional tests typically do not stress the PCB as much as burn-in testing.

RIS PCBA Testing Expertise

RIS provides full circuit board and electromechanical assembly testing capabilities – including testability recommendations, test development, and test execution. We perform circuit board assembly testing, system-level integration testing, and thermal and mechanical stress testing depending on product requirements. We use assembly testing to confirm product quality and functionality to provide a means of monitoring the critical stages of our manufacturing process. Specific to circuit boards, our assembly and testing services include the following test procedures. To learn more, watch our short video about PCBA product testing.

  • Flying probe: highly-effective test method for low-volume to mid-volume production, as well as prototypes and boards that can pose access difficulties.
  • In-circuit test: with an incorporated functional in-circuit test software and in-system component programming, we are able to probe printed circuit boards to examine shorts, opens, resistance, capacitance, and other detailed information about the assembly.
  • Manufacturing defect analyzer: as a secondary in-circuit test, the MDA operates as a diagnostics tool to reveal any defects in manufacturing and components.
  • Functional test: designed and built in-house, our functional test software assesses the functionality of an application, basing results and case information on the software component of an assembly. Our test system capabilities include C++ programming and Visual Basic.
  • Burn-in chambers: with temperature and humidity cycling, environmental stress screening, and product life assessment, our burn-in chambers place assemblies into service simulation that forces failures to occur. This test reveals weaknesses and load capacities and is especially effective in evaluating the reliability of electronics.
  • Automated optical inspection: our AOI machines test boards and panels to communicate errors quickly, consistently, and accurately to the operator.

Contact us today at (507) 523-3220 to see how we can help with your next project, or click here for a quote.

A Deeper Dive into PCBA Testing
Article Name
A Deeper Dive into PCBA Testing
A deeper dive into PCBA testing including flying probe, in-circuit test (ICT), automatic optical inspection (AOI), and functional testing.
Publisher Name
RiverSide Integrated Solutions
Publisher Logo