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Printed Circuit Boards (PCBs) are an essential component of most modern electronic devices. PCBs allow electronic components to be connected via copper tracks that are coated on the circuit board. Once a PCB is manufactured, it must undergo rigorous functional testing to confirm design accuracy, manufacturing quality, and ensure that all components, circuits, and functions work as intended before being assembled into final products. PCB-FCT (PCB Function Test) is one of the final critical steps in manufacturing before a product is introduced to the market. This article provides a general introduction to PCB functional testing, its importance, and the overall process of conducting an FCT.
WHAT IS PCB FUNCTIONAL TEST AND WHY IS PCB-FCT IMPORTANT?
PCB functional testing, also known as Functional Circuit Testing (FCT), is the process of testing assembled PCBs to confirm that the circuitry, components, inputs and outputs, programming, and all functions meet design specifications. During functional testing, the PCB is powered up to simulate operation, test, and validate the response and functionality of circuit components in a variety of specified environments.
Performing comprehensive functional circuit testing on each PCB is critical to identifying any manufacturing or design defects before the board moves on to final assembly. Defective boards that pass testing and are incorporated into the final product can cause operational failures, costly recalls, and a severe impact on the manufacturer’s reputation. Performing rigorous functional testing helps manufacturers avoid these negative impacts by eliminating defective boards before they are assembled into commercial products.
PROBLEMS/ERROR THAT CAN BE FOUND DURING PCB FUNCTIONAL TEST
Power supply problem: Functional tests can detect problems with power supply stability during PCB operation. Fluctuations, voltage drops or abnormal currents indicate defects in the power supply or regulation.
Signal distortion: FCT tests can detect problems with interference, background noise, or data distortion with the signal. This indicates a problem with high frequency stability.
Incorrect voltage: Incorrect outputs or voltages can result from missing components, damaged components, or incorrect installation. Thorough functional validation can identify these defects.
Conductivity and insulation: Conductivity and insulation testing confirms proper connections between connection points on the board, ensuring no short circuits or out-of-design short circuits occur.
Resistance mismatch: PCB functional testing confirms that the measured impedance of points on the board matches the design values. This is important to prevent signal degradation and maintain signal integrity throughout the circuit.
Stability and durability: Functional circuit testing involves putting the PCB through temperature cycles, vibration, and impact testing to test its stability and durability. This ensures that the board can withstand varying environmental conditions without affecting performance.
BENEFITS OF CONDUCTING PCB FUNCTIONAL TESTING
Performing thorough functional testing on printed circuit boards offers manufacturers several significant benefits:
PCB FUNCTIONAL TEST PROCEDURE
PCB functional testing involves several key steps to verify the design and performance of the board:
IMPORTANT TESTS WHEN PERFORMING PCB-FCT
Comprehensive PCB functional testing ensures the performance and reliability of the board. Here are important methods for performing functional testing:
Test Procedure Planning
A detailed test plan documents all verification contents and methods to ensure comprehensive testing. For example, verifying resistance values with an ammeter, testing sensor functionality by monitoring voltage output, measuring capacitor performance.
Voltage Test
Using a voltmeter, the technician carefully checks the voltage levels at all circuit nodes to confirm that the power distribution is as designed. Power up the board and test for proper startup.
Check Load
Apply realistic simulated loads to determine design limits and potential errors. Variable conditions such as temperature, current levels, clock speeds provide performance limits.
Quality Control Testing
Extensive quality control (QC) testing reduces risk and further ensures product quality before release. Final functional testing confirms compliance with all product specifications and industry standards prior to release. Common tests include automated optical inspection, design rule testing, and regulatory compliance testing.
SEMIKI MANUFACTURES AND DISTRIBUTES FECT MOBILE BOARD TESTING EQUIPMENT - FCT
Semiki Corp Proud to be one of the leading companies in Vietnam with an engineering design department of electronics and mechanics to make complex fixtures and an R&D team to program and apply software based on the platform. Labview certified to produce complete FCT kits for delivery to customers.
With experience in regularly deploying Fixture Test Functional applications, Semiki researches and provides equipment and systems: testing PCB component functions; Testing LED lights, customized Jigs according to circuit boards connected to measuring systems; Automatic Fixture - Reading bardcode, Marking products after testing to meet standards.
Semiki can design custom fixtures according to each requirement such as hand-pulled mechanical fixtures, pneumatic fixtures, automatic fixtures. Semiki can also design and manufacture multi-level test applications (PCB level, integrated level, RF test, automatic system, endurance - reliability ...).
Refer to Fixture products manufactured by Semiki: https://www.semiki.com/tin-tuc/semiki-san-xuat-phan-phoi-thiet-bi-kiem-tra-chuc-nang-bo-machfct-165.html
