Printed circuit board assembly (PCBA) plays a critical role in electronics manufacturing. PCBs are the foundation of all modern electronic systems and devices. As electronic products are getting smaller and smarter, all electronic components like ICs, transistors, sensors, switches, and LEDs are assembled on the PCB to work.
How to ensure the quality of PCB assembly? Various PCBA tests come, which require custom-made test fixtures.
In this blog, you will learn about what PCBA test fixtures are and what tests they serve one by one.
In this article:
Part 1. What are PCBA Test Fixtures? Part 2. PCBA Functional Test Fixture Part 3. ICT Test Fixture Part 4. Burn-in fixture Part 5. Programming Fixture OEM PCBA Manufacturer Providing PCBA Test Fixtures and Value-addedWhat are PCBA Test Fixtures?
A PCBA test fixture, also known as a jig, is a custom-made device to operate electrical and functional testing on the PCBA after the electronic components have been surface-mounted and through-hole mounted on the board.
It uses a physical interface, such as spring pins and sockets, to connect to the PCBA for testing. It achieves automatic or half-automatic testing to increase PCBA testing accuracy and efficiency.
By using PCBA test fixtures, the PCBA manufacturer can prevent human test errors and ensure test consistency. It is suitable for mass production to use PCBA test fixtures to ensure the functions and performance of the products.
When you get a quote from a PCBA supplier for your PCB assembly project, you will find a cost item "Fixture fee". The fee for PCBA text fixtures is independent of the PCB assembly fee. This is because the PCBA manufacturer doesn’t fabricate the fixtures but only designs them and handles the custom fabrication to the mold/fixture factory it cooperates with.
How does the PCBA manufacturer PCBONLINE design the custom PCBA test fixtures? You may need to provide the PCB Gerber, BOM (bill of material), XY file containing PCBA test points, and test requirements to the PCBA manufacturer. Then, the PCBA manufacturer, PCBONLINE, will design the structure, circuit, and control logic of the PCBA test fixtures.
Now you understand what PCBA test fixtures are. Next, you will learn about the PCBA test fixtures one by one.
PCBA Functional Test Fixture
The functional test (FCT) is a necessary PCBA test for products with medium to high complexity, batch production, and high reliability requirements. PCBAs with a microcontroller (MCU), IoT devices, communication modules, medical PCBA, automotive PCBA, and industrial controls all require a functional test after PCB assembly and the in-circuit test.
The PCBA functional test fixture simulates the working environment of the product to perform button, signal, and voltage tests.
It ensures the PCBA performs well in applications.
A PCBA function test fixture includes:
Structural parts: aluminum profile frame, acrylic panel, positioning pins, and pressure plate
Electrical interface: Pogo Pin, connecting wire, socket, and relay
Control unit: MCU, switching power supply, USB interface, and PLC
Host software: automated test control, data recording, and report output
ICT Test Fixture
The in-circuit (ICT) test is conducted before the PCBA functional test after PCB assembly. It checks the electrical connections in the PCB and components to ensure no cold soldering and no shorts or open circuits in the PCBA.
Unlike the functional test fixture, an ICT test fixture doesn’t require powering. It connects to the test points of the PCB through the test needle bed.
The ICT test fixture checks these aspects:
- Open and short circuits
- Soldering quality inspection, such as cold soldering, open soldering, reverse soldering, and non-soldering
- Component polarity and value
- Power supply
- Basic electrical functions
An ICT test fixture includes:
Structural parts: aluminum profile frame, Acrylic or FR4 positioning panel, elastic gasket or cylinder, positioning pins, and guide columns
Electrical interface: Pogo Pin, needle bed substrate, connecting wires, connectors, electrical adapter board, and relay
Control unit: MCU or PLC, power module, USB, or serial communication interface
Host software (if applicable): automated test control, data recording, and report output
Burn-in Fixture
The burn-in test is an important PCBA test in the post-assembly stage. It ensures the PCBA can work stably under long-term high load or extreme conditions. The testing method is powering on for a long time (from hours to days), which is often in a high-temperature box.
The burn-in fixture is also custom-made and often looks like an oven tray, which can be put into a constant-temperature box to test dozens of PCBAs.
A burn-in test fixture includes:
Structural parts: metal frame or aluminum profile structure, high-temperature resistant material tray or slot, fixing fixture or card rail, and heat dissipation opening
Electrical interface: multi-channel power supply interface, power cord set/DC plug/terminal, Pogo Pin/socket/PIN pin, load connection port, and communication port
Control unit: temperature control probe/thermocouple/fan control, MCU or PLC, timer, multi-channel voltage/current monitoring module, and overload protection circuit
Programming Fixture
The IC programming is a process of transferring the program into the blank MCU, Flash, or EEPROM ICs from the computer or the Cloud.
The programming fixture is used for IC programming and verifying whether the process is successful. So here we also list the programming fixture as a PCBA test fixture.
A programming fixture includes:
Structural parts: aluminum profile or plastic frame, acrylic panel/FR4 positioning plate, location pin/guide column, pressing plate, and anti-static pad
Electrical interface: Pogo Pin, socket, programming cable, interface board, short circuit detection, and contact confirmation circuit
Control unit: programming main control module, MCU or PLC, USB/UART/Ethernet communication port, trigger button
Programming software: batch programming, command line control, log output, programming verification, automatic switch serial number, and MAC address
OEM PCBA Manufacturer Providing PCBA Test Fixtures and Value-added
Looking for a professional OEM PCB manufacturer that handles all the tests and electronics manufacturing for your project? You can work with the turnkey PCB manufacturer, PCBONLINE, from DFM (design for manufacturing) to one-stop PCBA manufacturing and value-added until you receive the finished products ready to sell on the market.
Founded in 1999, PCBONLINE has two large advanced PCB manufacturing bases for PCB fabrication, one turnkey PCB assembly factory for turnkey PCB assembly and box-build assembly, stable material supply chains and strategic cooperation with electronic component manufacturers, and long-term cooperation with the top 3 mold and enclosure manufacturers in China for PCBA test fixtures, molds, and enclosures.
Besides, PCBONLINE has an R&D team and professional CAM engineers for project development and DFM, including PCBA test designs.
Provides one-on-one free and professional DFM for PCB, PCBA, and box builds before and during prototyping/sampling, including checking the test files, to ensure the manufacturability and project success.
The professionals at PCBONLINE design the PCBA test fixtures and manufacturing molds that accurately fit the PCBA manufacturing and test processes.
Complete PCBA test equipment and capabilities for PCB manufacturing, PCB assembly, and post-assembly, such as the AOI, flying probe test, ICT, X-ray, thermal shock, impedance, cross-section analysis, button strike, four-terminal sensing, tension, bonding, high-voltage, heat transfer, functional, programming, burn-in, and application test.
PCBONLINE manufactures, assembles, and tests from PCBs and PCBAs to box builds as a source factory manufacturer under one roof, from prototypes to bulky production, saving costs and time for you.
High-quality PCBA manufacturing certified with ISO 9001:2015, ISO 14001:2015, IATF 16949:2016, RoHS, REACH, UL, and IPC-A-610 Class 2/3.
PCBONLINE can design the test points for your PCB and offer improvement suggestions for your PCB design if there's any problem.
PCBONLINE provides comprehensive PCBA value-added services such as PCBA functional testing, conformal coating, IC programming, burn-in, enclosures, box-build assembly, application test, labelling, packaging, and shipping.
By working with the one-stop PCBA manufacturer PCBONLINE, you don't need to find other providers for tests and inspections. No matter what application your PCB will be used for, such as automotive, industrial control, medical, military, aerospace, communication, agriculture, etc, you can work with PCBONLINE. To get a quote from the OEM PCBA manufacturer PCBONLINE, contact info@pcbonline.com.
Conclusion
This blog introduces what PCBA test fixtures are and what tests they serve one by one. PCBA test fixtures are used in the post-assembly stage during the value-added services. To ensure the success of your PCB/PCBA projects with fixtures, work with the OEM PCBA manufacturer PCBONLINE.
PCB fabrication at PCBONLINE.pdf
