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When Should I Use Bare Board Testing?

A bare board and the bare board testing process have critical roles to play in printed circuit board (PCB) creation. In PCB development, the bare board layout determines your placement of through holes and electronic components. This PCB substrate also defines a finished board’s connections through its printed circuits. By using bare board testing in your PCB development process, you can improve the reliability of your results.

What Is a Bare Board?

In PCB terminology, the term “bare board” refers to the state of a PCB before it receives electronic components or through holes. A bare board consists of the PCB’s substrate, metal coating, conductive pathways and patterns. Some industry experts call a bare board a PCB and an assembled board a PCBA.

What Is Bare Board Testing?

Bare board testing involves testing the continuity and isolation of a bare circuit board’s connections. The continuity testing steps ensure that the circuits have no open points that will impede the current. Meanwhile, isolation testing determines the resistance between two separate electrical connections.

PCB companies use one of two methods to perform bare board testing:

  • Pinned fixture test: During a pinned fixture test, spring-loaded pogo pins test all of the board’s connective surfaces at once. Top and bottom plates apply pressure to a custom pin fixture to ensure a connection across the PCB. This method can test thousands of points at the same time, making it a more efficient option than the flying probe test. After the person testing the board sets up the pogo pins, it takes about five seconds for the test to be finished.
  • Flying probe test: The flying probe test for bare boards uses two robotic arms equipped with poles to verify a PCB’s connections. These flying probes travel across the connections using instruction from a software program. In exchange for longer testing lengths, the flying probe method offers better affordability and flexibility than the pinned fixture test. It suits smaller production volumes where slower testing speed will not hinder the design process.

Benefits of Bare Board Testing

Implementing bare board testing in the PCB design process can lead to:

  • Cost savings: Extensive testing in early design stages can help you save on the costs associated with faulty assembled PCBs.
  • Streamlined production: By identifying issues in the prototyping stage, you can save time in later phases of production.
  • Issue resolution: Bare board testing will help you identify potential issues early in production while narrowing down each problem’s source.

When to Consider Bare Board Testing for Your PCB

With this type of assessment, you can improve the PCB design process in most situations. Bare board testing becomes especially useful in earlier phases of development when it can save the most money and time. By integrating bare board testing into your process from the start, you can streamline many aspects of production.

Consider Millennium Circuits Limited for PCB Services

When you need a PCB supplier to accommodate your testing procedures, you’ll find that MCL offers prototype and small-scale production services. Learn more about our capabilities by requesting a quote online.

PCB Glossary

  • CEM1 or CEM3

    PCB material, both CEM1 and CEM3 are epoxy/fiberglass over a paper core, differing only in the type of paper used. These materials are less expensive, more punchable substitutes for FR4. Not a military grade material.
    CEM stands for composite epoxy material.