Printed Circuit Design & Fab Online Magazine - Current Issue

Current Issue

Buyers beware: An ounce of copper is not 1 mil.

Long before I became part of the PCB industry some 30 years ago, a large study determined that for the typical two-layer printed circuit board, the amount of copper required for a reliable connection in a plated through-hole (PTH) was 0.0007 inches, or 0.7 mils.

Anything less than that could compromise PTH reliability, the study found, and anything more would not make much difference.

Simply put, the 0.001″, or 1 mil, as stated on most PCB fabrication drawings is a safety factor. Some corporate fab specs will even state a plating average of 1 mil, with 0.8 mils as the minimum, higher than the originally determined 0.7 mils.

However, even today, some PCB buyers confuse ounces with mils when it comes to the copper plating of a printed circuit board. It is important to know the difference.

Read more: When It Comes to Board Buying, Mind Your Units

Observations from Malaysia and Thailand.

There has been a push of late by many OEM and EMS companies in the PCB industry – intensified by Covid and simmering trade and political tensions – to reduce the West's reliance on China for printed circuit board manufacturing.

In the past year, several of our customers, primarily from OEMs in the automotive, RF and testing industries, have asked for an "Out of China" or "China+1" strategy.

These customers have been buying boards from China for years for products or technology that does not fall under any export control.

So why the change now?

Concerns about IP protection and supply chain issues certainly factor in. But also, the optics of buying PCBs from China are not as favorable as they once were.

In that vein, we recently traveled to Thailand and Malaysia to search for PCB manufacturing facilities in those countries.

Read more: There is No Drop-in Replacement for China PCB Manufacturing – Yet

Proper fab specs can prevent a deluge of engineering questions.

I have been selling bare printed circuit boards for over 30 years to a variety of customers who order a wide selection of PCBs. The most common complaint I hear from board buyers is about the number of engineering questions (EQs) asked whenever a new order is placed, or when a part number is moved from one supplier to another.

"Why can't you build the boards without all these questions?" they ask. "We sent you the working files!"

To many buyers, the inevitable EQs that come along with moving a PCB order to a more cost-effective supplier seem daunting. Sure, the new pricing may be great, but many PCB buyers will delay switching to a new supplier because they don't want to deal with engineering questions from the new fabricator.

Read more: There is No Such Thing as a Bad EQ

Make sure export-controlled information is going where it's supposed to go.

In my December column, "One Errant Click and IP Protection is Gone," I wrote of the importance of corporate IP protection. But the safe handling of ITAR or MIL data is even more vital to your company's well-being.

PCB buyers must know what information they're sending and where it's going.

"An export applies to more than just physical product placed in a box being shipped overseas," says Tom Reynolds, an export compliance consultant. "Most companies don't realize the act of electronically sending information out of the country is considered an export."

Read more: What's Your Process for Protecting ITAR or Sensitive Data?