April Newsletter From Aurora Circuits

Welcome to out first edition of our "LinkedIn Only" monthly newsletter. We hope you subscribe to get the latest Aurora Circuits updates and industry happenings.

The State of Our Industry

The new Congress has a lot of heavy lifting ahead of itself as we enter into and world continuously dogged by supply chain issues, inflationary pressures and global security uncertainty.?At a macro level, it is easy to see why microelectronics has previously not been top of mind. However, current and upcoming legislation (CHIPS Act and a soon-to-be released Supporting American Circuit Boards Act) display that we are no longer an unknown entity to the government and the voting public.?The momentum is definitely going in the right direction and we need to continue lobbying for more awareness regarding our industry.?

A pertinent fact remains that we (domestic PCB fabricators) are still losing ground to overseas competition.?Whether this is due to cost, capabilities or longstanding investment, all intervention measures will come up short if the single most important variable is not addressed: demand.?Without this, our slow descent to irrelevance will remain unchecked, slow walking towards an eventual demise.?We fully endorse the work that the PCBAA, USPAE and IPC are doing to bring awareness and any legislative actions must include incentives to all US domestic manufacturers to "buy American".?We are not looking for a "free lunch"; rather, we need a more even playing field to secure our industry's future and, subsequently, that of the United States.

PCB 101

PCB Finishes: The Who, What, When and Why:

Before we look at the good and bad points of each PCB final finish, it's important to understand the types of PCB surface finishes available, what they have to offer and their limitations. All printed circuit boards utilize copper as their main conductor. If the copper surface is left unprotected, the copper will oxidize quickly and be very difficult to solder.?

The overall best lead free solder surface finish would feature excellent solderability, produce a flat surface, have relatively low cost, and require a limited number of heat cycles to apply with no health or safety concerns.???

There are various protective finishes available and this month we will focus on:?

·??????Hot Air Solder Leveling (lead free HASL)?

HASL?

HASL is the predominant leaded and unleaded surface finish presently used in the industry, especially in low cost, high volume PCB applications. To understand the causes for uneven surfaces from HASL, it helps to expound on the process.?First of all, there are three types of HASL, vertical, vertical at 45 degrees and horizontal. The PCB board is first cleaned, then dipped into the hot solder, held there for a short time, and the excess solder is removed by withdrawing the PCB through air knives. The air knives blow hot air across the surface of the board, forcibly removing any excess solder. Some levelers use an angle based PCB panel set up to limit solder flow along the traces and produce a flatter surface. The pads aligned to the withdrawal will have thinner solder with less bumps than the pads aligned against the withdrawal.???

For the assembly process, lead free HASL has many advantages. It is one of the lowest cost PCB finishes available. The surface finish remains solderable through multiple reflow cycles, cleaning of flux and longer storage cycles. The coplanarity of the surface is poor when compared to other surface finishes. HASL has been used in the printed circuit industry for many years. However, with the introduction of more environmentally friendly processes, it is losing favor.?In addition to the lead free issues such as reduced solder pot life, the increased complexity of boards and the finer pitches have exposed many limitations with the lead free HASL finish.*

*Used with permission from Robert Tarzwell.??

Stay tuned for our May edition where we'll cover Electroplated Nickel Immersion Gold (ENIG).

Remember to contact us at [email protected] if you have any questions or designs needed for quote.

A lot has changed over the past 70 years, but what hasn't changed is Aurora Circuits dedication to remaining 100% American Made. With over 70 years of knowledge and experience to make your project a reality, we stand by our commitment to manufacture the highest quality products founded on expertise and innovation.?