PCB Manufacturers: does the choice matter?

With 50+ PCB manufacturers in my contacts, you may think I have a to-go one, but… not really.

In the last 7 years, I’ve been discussing PCB (Printed Circuit Boards) projects with plentiful PCB manufacturers and assemblers. For the uninitiated, they are the companies that build the electronics boards that make almost everything electrically powered you know of. 

Researching a manufacturer for a specific project can become a daunting experience, and building trust and communication with them can prove to be almost impossible. So how do you choose one? Does the choice matter? Here you will find the main factors to consider while working on cheap projects and other too-big-to-fail ones.

What is the purpose of your PCB?

The most important thing to consider in PCB design and manufacturing is arguably the class you are aiming at. To be more precise, you should answer the question: what will you make out of the PCB, and how reliable should it be?  

The rationale behind my statement lies in an important thing to remember: manufacturing starts with the PCB design. Boards are designed by keeping in mind how they will be manufactured and who will do so. Therefore, what I’m going to write in this article, the first of a series, is something a designer should think about before starting the design process, not at the end!

The answer will point you to one of the following classes:

• Class 1: General Electronics Products Everything with a limited lifecycle, every project where the price must be as low as possible and where quality is secondary will fall into this category. Examples include cheap toys, cheap gate/tv/radio remote controllers and many, many consumer boards found in microwave ovens and old TVs.
  
• Class 2: Dedicated Service Electronic Products All the products where continued performance and an extended life cycle are required. Uninterrupted service is desired but not critical. Examples include medium-high end TVs, connected equipment, smartphones, laptops and almost everything that feels complex enough to need a brain. 
  
• Class 3: High-Reliability Electronics Products Uninterrupted service here is a must. The product must work and provide 100% uptime on an extended lifecycle that can reach even 30-40 years. Components to be placed on the PCBs must be selected accordingly. Meanwhile, a good amount of communication needs to happen between the designers and the manufacturers. This is the class in which we usually work at INFN, CERN and where all the electronic boards of spacecraft are. Of course, there are additional classes to Class 3 serving the purpose of a stricter, more detailed list of requirements. This depends on the final context of the product. Let it be a component for a commercial aeroplane, nuclear reactor or particle detector at CERN. For these specific cases, one should always check what was followed in previous works and all the novel laws in their field (i.e. ROHS, REACH).

Once you have a class in mind for your product, you can verify the rules and guidelines to be followed during the design process and manufacturing to achieve it. Class 1 ? There is really not a lot to keep in mind if not that your product must, at least, work. For classes 2, 3 and others, you may want to check the various requirements on the IPC and related standards. With those in mind, it is time to select the manufacturer.

Manufacturer Selection

The most important thing a manufacturer can have is alignment with your needs. If you need a class-3 PCB, this will translate to the availability to talk with you, follow your project, and understand your needs. Communication is key. Class-3 boards and beyond require attention to detail. For a class-1, this will be a cheap and probably not so fast manufacturing process.

In detail, an estensive checklist a designer should go through (depending on the project) is:

• Does the PCB Manufacturer (PCBM) have a reliable and fast way to ask questions?
  check for an online chat, phone numbers and emails in this order. You will have to contact them at some point and it must be effortless.
  
• Where is the PCBM located? Are they close enough you can pay them a visit if needed?
  check where their HQ is, their manufacturing plant, ask if they are open to visits and give a look at how they handle it. If you are managing a class-2 or class-3 project with a high degree of complexity you may need to visit them at some point.
  
• Does the PCBM have a reputation online or a verifiable portfolio?
  check for online reviews, videos, outreach, etc...
  
• Does the PCBM specify what materials (core, prepreg, silkscreen, etc) are they using?
  check datasheets, ROHS, REACH and other certification bodies documents released to them on their website! This is especially important if you are planning to run simulations on signal integrity, power integrity, power deliveery network and EMC in general.
  
• Does the PCBM have a clear technical capability document where one can either extract or download a DRC file from?
  check their website for pdfs of pages with their capabilities in terms of trace spacing, width, thickness, plating, layers and, if possible, look for DRC files that you can directly import in your design software of choice.

Additionally, every class has its own details to sort out:

Class 1 – Everything works. Try the cheaper, most environmentally friendly business (hopefully), and you should be fine. Class 1 boards must be simple, only 1 or 2 layers of copper, easy to manufacture and pretty fast to reproduce. The design must not include small details, like narrow clearances, traces and vias (the manufacturer will remind you of this). The budget for these projects can be tight, even below 500 € (including design), and the single PCBs can be as cheap as 50 cents each. The production can even be as fast as 24h to shipment. Two good names in this category are PCBway.com and mdslr.com.

Class 2 – Usually, companies taking care of class 1 or 3 products also do class 2 to sell either an upper-class result or a fallback for production lines not following class 3. These companies include big names, as well as small ones like mdslr.com (Italian), Eurocircuits.com (Belgium) or even circuithub.com (US), again PCBway.com  and a wide global selection. It is difficult to draw a budget range as the variables are too many. As a rule of thumb, for boards designed to have from 2 to 4-8 layers, it ranges from 1000 to 10.000 or more EUR. 

Class 3 – The real work starts. The first thing you should look for is communication and reassurance from the manufacturer that they know how to make reliable PCBs. Look for proof that they indeed have built class-3 or higher PCBs. Look for previous projects, case studies, and reports and even try to visit their factory. If you are designing a class-3 product, you should have the budget for these insights, especially if the amount of circuits is not low. Budget wise, projects in this category fall above 10.000/20.000 EUR. Names in this category are Fineline www.fineline-global.com , Advanced Circuits www.4pcb.com, Cirexx www.cirexx.com, US) and Somacis (www.somacis.com, Italy)

Another important class is prototypes. These will be, de facto, at least a class lower than your final target. The focus will be on a fast order to delivery cycle and low expenses. Another relevant aspect you should consider is the ability of the manufacturer to scale. 

Investing in a manufacturer is expensive. Getting to know their practices, visiting them, discussing projects etc., will take time. Therefore, finding someone that can deliver (ideally) all three classes can prove to be the right investing move. This way shifting from class-1 tests to class-2 final PCBs will be as easy as clicking a button or sending an email.

In the following articles of this series, thanks to PCBway.com, which is a manufacturer cabable of checking all the points in our checklist, you will see a comparison of class-1 PCB production with a class-2 manufacturing process and some intriguing details about material choices.