ICT vs FPT: Which one is the best choice for your PCB designs? These two testing processes are indispensable. But how can you choose the right one?
You are not alone if you are in question of what to apply between In-Circuit Testing (ICT) and Flying Probe Testing for your specific needs. Don’t worry, though; that’s what this article is here for. We will break down the key differences between ICT and FPT to make it simpler to choose the ideal testing method for your next project.
Let’s go, then.
What is FPT (Flying Probe Testing)?
Flying Probe Testing (FPT) is a method used to test PCBs without needing custom fixtures. Unlike ICT, which uses a fixed bed of nails, FPT employs flying probes that pass over the board for contact with test points.
These probes are flexible ones that can be applied to test a different design in the garage board. FPT uses probes arranged in certain spots against the PCB under test to verify its electrical performance and to find defects.
If you are interested in flying probe testing, you can read this more detailed article:
What is Flying Probe Testing (FPT)
What is ICT (In-Circuit Testing)?
In-Circuit Testing (ICT) is a method used to test PCBs using a specialized fixture known as a “bed of nails.” The fixture is populated with many pins that will come into contact with, and probe, all the PCB test points.
An ICT software scheme is capable of checking infrastructure performance electrically, basically at every node within a circuit, to infer shorts or opens and possible defects within their potential irregular patterns.
Using the bed of nails, an ICT runs fast tests all over a PCB for its thorough probing.
Advantages of ICT:
- High Coverage with Automated Testing: ICT has extensive test coverage, with many points on the PCB being checked for defects automatically in helping to guarantee quality.
- High Testing Rate for High-Volume PCB Production:Because of its speed and minimal manual interference, ICT is high volume.
- Ability to Perform Functional Tests: ICT can perform detailed functional tests, verifying that each PCB functions correctly according to its design specifications.
Limitations of ICT:
- High costs for Fixtures: Custom fixtures like bed-of-nails fixtures designed for the purpose, which ICT needs, are costly, especially with low production volumes.
- Less Flexible for Complicated Designs of PCBs:It is less adjustable to high complexity or variety in the design of the tested PCBs without further modifications.
- Requires Custom Tooling:The need for custom fixtures means that setting up ICT can be time-consuming and time-consuming.
FPT vs ICT: Key Differences
Here’s a comparison table that will help you understand the key differences between FPT and ICT:
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FPT (Flying Probe Testing)
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ICT (In-Circuit Testing)
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|---|---|---|
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Flexibility
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Very flexible; adapts to different designs
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Less flexible; depends on fixed fixtures
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Speed
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Slower, especially for large volumes
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Faster for high-volume production
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Cost-effective for large volumes
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Test Coverage
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Good for complex or low-volume boards
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Better coverage for simple, high-volume boards
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Best For
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Prototypes, varied designs, small batches
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Large production runs, straightforward designs
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- Flexibility:Various designs of PCBs can very easily be tested by FPT, requiring no special fixtures for the testing. In ICT testing, however, specially designed fixtures are required for testing, allowing less flexibility towards cost and changes or complexities in designs.
- Speed: ICT in relation to large production runs—ICT measures many PCBs quickly. FPT is slow, as the probes are moved manually, which might be a disadvantage in large batches.
- Cost: FPT is much cheaper with small quantities and prototypes since they do not require costly fixtures or set-up. Unlike FPT, which is less costly on cheap fixtures, it costs prices upfront due to the fixture, but with high volumes in production, it proves its cost in speed and efficiency.
- Test Coverage:ICT checks more test points at a go, hence best recommended for simple and high-volume boards. On the other hand, FPT is particularly useful for complex or low-volume boards; very detailed in testing and without the need for custom fixtures.
When to Choose FPT vs ICT Based on Specific PCB Requirements
Here’s when to choose FPT vs ICT:
Choose FPT (Flying Probe Testing) If:
- You’re Testing Prototypes: FPT is great as a tool for testing prototypes due to its flexibility and adaptability. Without the need for special fixtures, one can easily test and tweak different designs in the process.
- You have Complex Designs:If your PCB designs are ill-shaped or diverse, then FPT is perfect. It is capable of smoothly handling complex layouts and does not require special fixtures.
- You get Small and Medium Runs of Production: FPT is good for small-batch production. The process costs less due to not requiring special, expensive fixtures.
- Change Designs Regularly: If your designs change on a regular basis, FPT is a suitable choice since it does not need new fixtures each time you change the design.
Choose ICT (In-Circuit Testing) If:
- You Are Producing Volumes: The working of ICT is better for high volumes of production. It is testing many PCBs in a short amount of time.
- Yields Great Coverage and is Fast Check with this Test:Making simple designs in PCB. Yields great coverage and is fast Check with this test: Making simple designs in PCB.
- You Can Invest in Fixtures: If you have the budget for custom fixtures and are focused on large-scale production, ICT is more cost-effective in the long run.
- You Want Automated Testing:ICT is perfect when you need automated testing to be done quickly and with lots of coverage. This would increase the pace of the process and reduce manual work.
Conclusion
In conclusion, FPT is great for prototypes and small batches, while ICT excels in high-volume production. Using both can give you the best results—FPT for early testing and ICT for large-scale runs. This combination helps ensure thorough and efficient testing of your PCBs.
