Tag Archives: Precision PCBs

Rethinking the Supply Line

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The PCB fabrication industry is older than most of us still working. It is overdue for modernization. We have not seen transformational manufacturing changes in the PCB bare board industry during the past 15 years.

What we have seen is the installed capacity moved to China. It has been reported that 60% of global board fabrication now comes from mainland China or Taiwan. This move created a forced shift in how boards are purchased, and consequently created new demands in communication and logistics. Specifically, language, time zone, and cultural considerations. Bigger companies with China-based feet on the ground could adapt easily; the rest of us had to learn new skills.

I am suggesting that the rest of us modernize and rethink our supply line strategy.

Some may remember the evolution of the electronics component industry. First, component manufacturers sold directly to OEMs. Gradually, customers and component manufacturers found that a better path was through a local distributor. Arrow, Avnet, Future, DigiKey, and many others were born out of this efficiency. Today, it is an exception to buy directly from a component manufacturer.

PCB fabrication is difficult for distributors because every board is custom. Repeat: every board is custom. Custom equals high potential for error, which equals close technical review required.

So, buyers must go to China directly and slog through the variety of China sources. With this come the multiple challenges of accountability, communication, logistics and culture. The most dangerous of the challenges is having picked a supplier that occasionally (or often) sends subpar boards and provides no recourse or no response to your complaint. Do you really want to commit such a critical part of your BoM to the lowest China bidder?

The modernization of the PCB industry is not in processing, but in supply chain. A new category of value-added distributor is evolving in the same way the component distributor evolved … to make things easier. We call it “Managed Manufacturing Services.”

Think of it as a value-added distributor of printed circuit boards. This concept can greatly improve the supply chain for both customer and China manufacturer, but only if they really add value.

What are the important values, and how does this approach add value?

Technical support. The value-added distributor must be your expert design reviewer, capable of counseling you and quickly fixing the errors.

Only technically trained PCB teams really understand the manufacturability challenges of bare boards. With the technology of new IC packages pushing toward smaller geometries, new thinking is required about designing for manufacturability. So, your value added distributor has to be technically trained to provide this service.

Communication. The value-added distributor must be capable of clearly and cleanly communicating with a factory in a different country.

We have been working with offshore factories for a long time. We learned through hard knocks that developing a strong relationship with your counterpart in Asia is critical. I call it “Pitcher-Catcher.” Whether a fastball or a curveball, the two communicate in one cohesive motion. This takes time to develop and not every factory gets it.

Time zones can work to your advantage. We pitch everything to China by 5 pm Pacific and have answers at 6 am the next day. Your distributor must know the factory requirements well enough that only a few questions (EQs) come back, lessening the need for middle of the night conference calls.

Accountability. Your value-added distributor must have carefully vetted and audited the factories they use. They must be US corporations with financial accountability to their customers.

Slogging through a variety of factory options is not a good idea. Jumping from one to the next based on price and email pressure is also not a good idea. It wastes time and invites disastrous quality issues. Customers with little or no knowledge of what makes a solid factory are at particular risk. Yet most customers fall into this category.

If you have someone on staff with experience in this area, you can send them to China to visit multiple factories, but unless this person has in-depth knowledge of what makes the difference between okay and fantastic at the granular level, it is waste of $10,000. It takes deeply experienced people to see the difference. It takes board manufacturing experience.

From the China manufacturer’s side, it is just like the component manufacturers of old. It is much more efficient to deal with a small handful of companies who service the US market than it is to staff and service everyone. The culturally smart ones are beginning to see this and actually do view us as distributors for them. It is a proven supply-chain solution.

Following the model of the component distributors, we can modernize this PCB industry. We can improve efficiency, quickly adopt new technologies, and capture lower costs all by modernizing the supply chain. Welcome the value-added PCB distributor, or as we call it Managed Manufacturing Services.

Thomas Smiley is president, Precision PCBs; [email protected].

Calculating PCB Fabrication Costs (Watch Out!)

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We get this question a lot: How much per square inch for a 4-layer board? (or double sided, or 6 layers … same question).  I won’t hold you to it, I promise. Right….

We understand that it is difficult to provide the boss with a project cost roll up if you do not have the board cost estimate. If you do a lot of designs you may have a feel for it or you may refer to a similar board cost from a past project. This actually can be very effective.

I have even seen online cost calculators that presume to give an accurate number.  Knowing what I know about PCB pricing, however, I can say that it just ain’t so.

Here is why calculating PCB cost is tricky and dangerous ground.

The biggest cost drivers for a bare board are:

  1. Who are you? Are you a stranger or newcomer, or do you have established relationships with board vendors? Most of us manufacturers figure the total dollar volume somewhere into the pricing equation.
  1. Board size. Square area of the board, plus the square inches of material remaining on the panel after routing your unique board shape. (You are charged by the processed panel).
  1. Production volumes in the 10 boards to 1000 boards range will have a very steep cost curve. The curve flattens out as the order rises above 1000 and gets very unpredictable at 100,000. Who you are begins to make a big difference at this level, along with your negotiating skills.

All manufacturers have a floor or minimum and it is best to ask how many boards you can get for the minimum charge. Some of the internet guys will sell one or five at a very low seemingly low cost, but your boards will have to fit perfectly into their narrow technical profile.

  1. Delivery days requirement. This can be very steep cost curve in the one to 10 day requirement range. After 10 days, little influence unless the volumes are large. We turn boards from our China factory in 10 working days and small expedite fees for five days. (Yes, we turn boards from China in five days.)
  1. Manufactured location. USA, China, Europe, Taiwan. This is usually a preferential decision, but clearly, China has the edge, followed by Taiwan. Differences can be great.
  1. Number of layers. No surprise here. From double-sided to four layers, costs will go up about 60%. From four layer to six layer add another 50%. For six to eight layers add 30%. Keep in mind that each added layer is the equivalent of a double-sided board added to the stack.  Also, remember that high-layer-count boards are often accompanied by tough technical requirements and buried vias.
  1. Technology stretching requirements, like exotic materials, super small geometries, buried vias, etc. This can be steep or moderate depending upon the manufacturer and the difficulty. Tg requirements will have a moderate impact.
  1. Surface finish, like HASL, ENIG, tin, OSP. If you can handle OSP, it is the lowest cost, followed by HASL, then ENIG. ENIG is so common these days that for low volumes, it can be as low cost as HASL.

Not the following:

  1. Number of drill hits; however, the total number drill tools used can drive costs up. Ten tools is the preferred maximum and usually can do the job.
  2. Presence or absence of a silk screen legend. (Minor influence.)
  3. Always insist on testing at no charge.

So, now think about putting all of this into an algorithm and coming up with a defensible, unchangeable answer. That is a dangerous guessing game.

My best advice is this: Get preliminary Gerbers to your preferred vendors and tell them they are preliminary. If the effort is conceptual, provide a simple description answering the cost drivers above and email your proposed or preferred vendors for a quote. (To make it easy for you, we offer a template. Go to precisionpcbs.com/pcb-manufacturing and click on the “Fab Drawing Template.”)