Epec's Blog | Electronics Manufacturing Solutions

When a blow hole defect occurs during the assembly process as a result of the PCB card, the primary culprit tends to be entrapped moisture or air. With moisture, any non-plated and non-masked areas on a bare circuit board that expose internal laminate can be suspect to absorbing moisture. Absorption can occur either during the board fabrication process or from improper storage. Examples of highly suspect areas include non-plated drilled holes and routed features.

When it comes to printed circuit board manufacturing, there are a variety of PCB via process requirements to consider. Each has their own pros, cons, and cost adders so knowing these requirements can aid you when designing your circuit boards. In this post we will discuss the differences for why you would either fill or plug a circuit board via.

It is not recommended to bake boards with an organic solderability preserve (OSP) surface finish. Although baking a printed circuit board with an organic solderability preserve finish can have negative consequences, the process itself can have positive performance in specific applications. OSP is a very thin protective layer of material placed over exposed copper, typically using a conveyorized process to protect the copper from tarnish.

Within the printed circuit board industry the term "tenting" originally indicated that the mask would fully enclose the via at one end by forming a skin or tent over the opening. While dry film solder mask is more expensive, it is capable of forming a reliable tent, while liquid photoimageable solder mask (LPI) generally will not.

Selecting the optimal heavy copper thickness to apply to the plated through hole (PTH) plays a critical factor towards the overall reliability of the printed circuit board. There are two key elements to consider when determining optimal PCB copper thickness. The first is the current capacity of the barrel for acceptable heat rise. The second is the mechanical strength determined by the copper thickness, hole-size and whether or not there are any support vias.

Generally pads are small round or square areas of copper which are normally used to make a connection to a component pin. If these pads are not sitting correctly or are lifted, it can cause the connection between the printed circuit board (PCB) and the component to fail.

Plated through holes are the holes in a printed circuit board (PCB) with copper coated walls. These holes allow electricity to be carried from one side of the circuit board through the copper in the hole to the other side of the board. For any printed circuit board design of two or more circuitry layers, plated through holes form the electrical interconnection between the different layers.

Printed circuit boards (PCBs) with immersion finishes such as electroless nickel immersion gold (ENIG), immersion tin, silver, and OSP are appealing because they are lead-free. However, if handled improperly, these materials are susceptible to oxidation and corrosion from exposure to moisture and humidity. This oxidation causes dewetting after soldering, which can lead to poor joints at assembly and ultimately lead to failure of the board.