PCB FCT test: A Comprehensive Guide

What is the FCT test? This is a question that you may have if you are new to PCBs. In this comprehensive guide, we will introduce you to the FCT test and explain what you can use it. FCT test is a key component of quality control in the PCB manufacturing process.  And it is essential that your PCB manufacturer performs this test on every batch of boards they produce. We will discuss the benefits of FCT testing and explain how it can help improve the quality of your PCBs.

What is FCT in PCB?/What is the ICT electronics test?

Multimeter probes examining a computer circuit board

Multimeter probes examining a computer circuit board

FCT test, or functional circuit test, is a type of testing performed on PCBs during the manufacturing process. And this test checks for shorts and open circuits in the PCB and verifies that the board is functioning correctly. In addition, FCT is an important step in quality control for PCBs, and it typically gets performed after the soldering process.

Why is FCT important?

Oscilloscope Probe on Electronic circuit

Oscilloscope Probe on Electronic circuit

FCT is important because it helps ensure that the PCBs function correctly and there are no manufacturing defects. Besides, this test can identify problems with the PCB before shipping to the customer, which can save time and money.

 What is required for functional testing??

For functional testing, you will need a test fixture, probe cards, and test software.

The test fixture is for holding the PCB in place during testing. And we use the probe cards to connect the test equipment to the PCB. Besides, you can use the test software to control the testing process and collect data.

Benefits of Performing FCT for Your PCB Assembly

Female digital electronic engineer testing computer PC motherboard in laboratory

Female digital electronic engineer testing computer PC motherboard in laboratory

There are some benefits of the FCT test for your PCB assembly.

First and foremost, FCT can improve product quality by detecting functional defects early in the manufacturing process.

Secondly, It allows you to make changes to the design quickly and easily without incurring high costs.

Lastly, FCT can save time by identifying potential problems with the PCB before shipping it to the customer.

Classification of Functional Test 

Pcb layout repairing technician soldering laptop

Pcb layout repairing technician soldering laptop

There are some different FCT tests for pcb functions. FCT is a process of testing, identifying, and isolating defects in an assembled printed circuit board. Besides, It helps to improve the reliability of the board and to verify compliance with the electrical specifications.

Firstly, different controllers.

Then we can classify it into in-circuit test(ICT), functional boundary scan test(BST), and off-board functional tests.

Secondly, different controllers.

We will classify it into PC controller analog FCT, MCU controller, PLC Controller, and Embedded CPU controller.

Thirdly,  by control modes’ difference.

There is a fully automatic control function test, manually control functional tests, and a semi-automatic control function test.

Other Different PCB Testings

Technician in the lab testing a circuit board with a multimeter

Technician in the lab testing a circuit board with a multimeter

Besides the FCT test,  there are other important tests for PCB like:

  • X-ray inspection
  • PCB contamination test
  • Micro-sectioning analysis
  • Peel test
  • PCB solderability test
  • Four-terminal sensing
  • Solder float test
  • Time-domain reflectometer test, or TDR

Take a look at the following sections to learn more about particular options:

Micro-sectioning analysis

It’s physically cutting the PCB to observe the internal structure and potential problems.

Although it may damage the board, it can provide information about the quality of the manufacturing process that other methods cannot. The technician can see any voids in the solder or if the copper traces are too thin.

FCT Test–X-ray inspection

This is a non-destructive technique that uses high-energy X-rays to penetrate the PCB and create a shadow image on film or a digital detector.

We use it to detect internal features, such as voids in solder joints, and external features, such as missing or misaligned components.

FCT Test–PCB Contamination Test

A contamination test is to determine if there are any foreign particles on the surface of the PCB.

This is important because these particles can cause electrical shorts or signal integrity problems.

And the most common way to do this is with a dust wand.   

PCB solderability test  

A solderability test is to determine if the PCB can be soldered.

While this is important because if you cannot solder the PCB, it will not be able to function.

And the most common way to do this is with a hot-air rework station.   

How to Make Functional Circuit Test (FCT Test)

Electronics workshop

Electronics workshop

Now that we know what the FCT test is, it’s time to learn how to make one.

First, you will need:

– A breadboard

DIY electronics on the breadboard

DIY electronics on the breadboard

– Jumper wires

Jumper cables

Jumper cables

– A power supply

– An oscilloscope

Digital oscilloscope and measuring devices with cables

Digital oscilloscope and measuring devices with cables

Connect the power supply to the positive and negative rails of the breadboard.

Then, connect the oscilloscope to the power supply.

Next, take a jumper wire and connect one end to the positive rail of the breadboard and the other end to the negative rail.

Now, take another jumper wire and connect one end to the positive rail of the breadboard and  the other end to one of the holes in the row above it.

Do this for each row until you have eight rows connected.

Finally, connect the last jumper wire from the top left hole to the ground.

Your FCT test is now complete!

FCT test fixture

Soldering iron and repairing electronic circuits

Soldering iron and repairing electronic circuits

In this section, we will be discussing the fct test fixture. Firstly, the fct test fixture is a device used to test Printed Circuit Boards (PCBs). In addition,  it consists of a power supply, an oscilloscope, and a breadboard. And the power supply provides power to the PCB while it uses the oscilloscope to measure the voltage levels on the PCB.  Also, we use the breadboard to connect the different components of the FCT test.

FCT Test–test points

Now that we have discussed the FCT test fixture let’s talk about the test points. The test points are the places on the PCB where we can measure the voltage levels. In addition, people also use them to connect different parts of the FCT test. And they are usually marked with a red or black dot.

FCT Test–ICT test

In this section, we will discuss the ICT test. The ICT test is a test that checks for shorts between the different tracks on the PCB. And it gets done by applying a high voltage to one way and then measuring the voltage on another track. If there is a short, then the voltage will be lower than expected.

The ICT test is a very important test because it can find shorts that are not visible to the naked eye. And these shorts can cause all sorts of problems. So, it’s important to make sure that your PCB passes this test.

What is an FCT machine?

Manual electronics soldering and oscilloscope testing

Manual electronics soldering and oscilloscope testing

The FCT test machine is a specialized tester to test Printed Circuit Boards (PCBs). In addition, the test machine also tests the functionality of the PCB. And it consists of a power supply, an oscilloscope, and a breadboard. The power supply provides power to the PCB while we use the oscilloscope to measure the voltage levels on the PCB.  Also, we use the breadboard to connect different components of the FCT test.

Summary

Technician inserting electronic components into a PDB for assembly

Technician inserting electronic components into a PDB for assembly

A PCB FCT test is essential during the PCB manufacturing process. This will help ensure that your boards are functioning as they should and that there are no errors or defects. If you’re looking for a quality PCB manufacturer, be sure to ask about their testing procedures and whether or not they include a functional test of the boards.  We take our quality seriously and have a full PCB FCT test in all manufacturing processes. Contact us today to get started on your next project!

Hey, I am John, General manager of Cloom and OurPCB.

I am a responsible, intelligent and experienced business professional with an extensive background in the electronics industry.

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