Archive: Nov 2019

PCB Stiffeners

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Multilayer Busbars Copper Bus Bars & PCB Circuit Board Stiffeners

Multilayer Busbars Copper Bus Bars & PCB Circuit Board Stiffeners

What is an E-FAB Busbar?

In electrical power distribution, a busbar (also spelled bus bar, or sometimes as buss bar or bussbar, with the term bus being a contraction of the Latin omnibus, “for all”) is a metallic strip or bar (typically copper or brass) that conducts electricity within a distribution board, circuit board, battery bank, power supply unit or other electrical apparatuses. Its main purpose is to conduct a substantial current of electricity, more than can be provided by standard circuit board traces.

The requirements for designing, engineering and manufacturing of lead-free PCBs, multilayers and backplanes for harsh use environments include: rigid circuit board stiffeners, high current carrying busbars, larger ground planes and other circuit components for specialized applications. E-FAB brass stiffeners and copper busbars are manufactured with the E-FAB PCM process and are the highest quality, direct replacements for the old CCI, Circuit Components, Inc. type.

What are the advantages of using E-FAB PCB stiffeners? Why use E-FAB PCB stiffeners and busbars on your electronics circuit boards?

One of the main reasons to use E-FAB circuit board stiffeners in PCBs and backplane manufacturing is to increase the rigidity of PCBs and strengthen the circuit boards themselves for use in severe and harsh environments such as used in military grade products, aerospace technology and other commercial sectors. Another application is in regards to the bus bar application; of higher power distribution for power and/or ground circuits on PCBs and power supply circuits. E-FAB Bus Bars are typically manufactured from copper, whereas E-FAB Stiffeners are typically manufactured from brass. Bus Bars can serve a dual purpose of being both a conducting bus or multi-busses and also provide structural integrity to a circuit board. Stiffeners are not recommended to be used as busses, since brass is said to have 28% IACS, it denotes an electrical conductivity 28% of that standard. [“IACS” is the International Annealed Copper Standard].1 (1. Copper Development Association Inc.)
Increasing the rigidity of modern circuit boards is more important than ever in both the manufacturing phase and the actual application usage phase. With the adaptation of lead-free solder for meeting the Restriction of Hazardous Substances Directive also known as RoHS, and the increased temperatures required in wave soldering of the circuit components to the PCBs because of having to deal with these various lead restrictions, and the manufacturing changes of having to use different metals and alloys for circuit board construction which are more brittle and require hotter temperatures in the assembly phases, this in turn places significant additional strains on the circuit boards, traces and circuit components used in all phases of a circuit board’s life.

PCB StiffnersE-FAB Circuit Board Stiffeners and Bus BarsKeeping circuit boards and backplanes flat through the manufacturing and assembly process is certainly critical for manufacturing quality and reliable boards, there is however an additional reason for using PCB stiffeners. Consider the natural environmental elements of thermal expansion and contraction through both hot and cold operating temperatures and the natural warming and cooling cycles when a circuit board is in use, and the normal vibration factors involved in various types of application usage (such as military, aerospace and other extreme environmental and rough use situations). These types of operating conditions can cause early board failures resulting from cracked traces and cold solder joints developing at the circuit components’ connections. These are typical applications where the PCB stiffeners solution should be applied.

“Lead-free solders, which were relative novelties a few years ago, are now widely understood, although not always in a positive sense. The most commonly used lead-free solders are known to be more brittle than lead-tin solders, and there have been suggestions recently that there may be large numbers of failures related to lead-free solders in the next several years, both in civilian and non-civilian applications.”

Another application for E-FAB Busbars is the ability to have two or more layers in one space saving device. The E-FAB 2-layer Busbars can be used on circuit boards, power supplies or other power distribution applications for both power(s) and/or ground at the same time.

The E-FAB 2-layer Busbar is designed essentially as a multilayer, with two conducting copper layers separated by an insulator layer. The copper layers are designed and manufactured with a staggered pin configuration (custom configurations are also available) so that every other pin is power and ground. The beauty of using the E-FAB 2-layer Busbars on your PCBs is having all the advanced features of an E-FAB PCB stiffener plus extra power(s) and ground busses rolled into one space saving design. E-FAB Busbars and Stiffeners can be manufactured in an uncoated design type or coated with an epoxy coating (see PDF engineering document for more information).