Performance of Printed Circuit Board Assemblers
A pcb assembler is a machine that prints circuit boards that have been soldered to other components. This is a critical step in the production of electronic devices, but it can be problematic if the device has been exposed to moisture. Moisture can lead to corrosion, electrochemical migration, delamination, and other problems that can affect the functionality of a finished product. Proper circuit design, manufacturing processes, and protection measures are necessary to prevent moisture from damaging a device during assembly or operation.
The most common cause of moisture in electronics is condensation. If a device is subjected to rapid temperature changes, the condensation that forms on its surface can leak into the interior of the device and cause damage. This is especially likely if the device is packaged in an enclosure that is not hermetically sealed.
Another way that moisture can cause damage to a pcb assembler is by direct contact with exposed conductors. Excessive amounts of moisture on the conductors can increase their resistance, which decreases the flow of electricity through them. Eventually, this will short the circuit and cause a device to malfunction. Moisture can also cause a device to fail due to oxidation. Oxidation occurs when metal ions bond with oxygen atoms to create oxides, which are electrically insulators.
How Does Moisture Affect the Performance of Printed Circuit Board Assemblers?
When it comes to printed circuit boards, moisture can be particularly dangerous because of the complexity of the components and their locations on the board. If an extremely small amount of moisture reaches a sensitive component, such as a ball grid array or chip scale package, it can cause irreparable damage that is difficult to detect during inspection. The damage may be limited to a small area of the component, but it can be incredibly costly for the manufacturer to repair.
A pcb has a complex structure with many layers. The first layer is a substrate, which provides the foundation for the rest of the board. The next layer is copper foil, which provides a place for circuits to connect with each other. The solder mask, which is a transparent layer that covers the copper and protects it from chemicals used in the assembly process, is added afterward. The silkscreen is a final layer that includes the labels that identify the function of each part on the board.
One method of combating PCB moisture is baking, which involves heating the board to high temperatures in order to drive out the moisture. While baking does effectively drive out most moisture, it can have some unexpected side effects. For instance, the copper planes in a PCB often swell momentarily as the baking process begins. This can cause moisture to diffuse in other parts of the board, and it can also degrade solderability and wettability.
The best solution for preventing moisture-related problems in a pcb is to use moisture-resistant connectors and conformal coating, and to implement proper sealing and encapsulation techniques. This will help prevent moisture from getting into a connector and shorting out the circuit, and it will also prevent a conformal coating from becoming damaged by the high-temperature baking process.