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Fresh PCB Concepts: Everything Your PCB Supplier Needs Upfront for Quoting

After more than 40 years in PCB manufacturing, I've come to appreciate that every PCB begins long before the first sheet of laminate enters a press or the first hole is drilled. A PCB’s journey begins with a request for quotation (RFQ). 

I’ve been involved with documentation practices since the days of 4:1-scaled and Blue & Red-taped mylars. They all underwent photo-reduction and resizing to 1:1-scale film for manufacturing, and this became our tooling package. With new media and technology involved, this process has undergone many changes, but the focus on tooling can never waver. I have learned that the accuracy of the quotation is directly tied to the quality of the information received. 

Two Types of Quotations
As a field application engineer, I review quotation packages from customers across many industries and applications. Some arrive with a complete and well-organized set of manufacturing data, allowing our engineering team to quickly evaluate the design, identify manufacturing considerations, and prepare an accurate quotation. Others have critical pieces of information missing, requiring additional engineering review, multiple rounds of communication, and, in some unfortunate cases that we work hard to prevent, assumptions that could easily lead to misunderstandings.

A common misconception is that every RFQ is created equally. Not so. There is a significant difference between a budgetary RFQ and one that is accurate and ready for manufacturing. 

A budgetary quotation normally serves an important purpose during the early planning stages of a project. It provides a reasonable estimate that can assist with preliminary budgeting or review. Because it is often based on limited information, assumptions are made about details such as laminate selection, copper weights, finished thickness, surface finish, testing requirements, or other manufacturing characteristics. Those assumptions may differ from the final product requirements, causing pricing to change once the complete design package is available.

A manufacturing quotation, on the other hand, is built upon engineering confidence rather than engineering assumptions. It reflects careful consideration of the complete design package, allowing us to evaluate every aspect of the board before establishing pricing. The more complete the information we receive at the outset, the greater the confidence that the quoted price accurately reflects the product to be manufactured.

Obstacles and Optimizations
Incomplete or missing information is the greatest obstacle to producing accurate quotes. Each unanswered question has the potential to introduce uncertainty into the quotation process. An email or phone call is needed for clarification, which introduces another waiting period. While each exchange may seem insignificant on its own, together they can add days to the quotation process before manufacturing has even been considered. While this part of the process can be frustrating for everyone involved, taking the time to assemble a complete RFQ package and partnering closely with your PCB supplier can eliminate unnecessary questions, reduce back-and-forth communication, and speed up the quotation process.

One lesson that years in this industry have reinforced is that engineering should never have to guess. If I assume, the possibility of misinterpretation increases dramatically. A seemingly minor assumption regarding copper weight, laminate type, board thickness, etc., can significantly affect manufacturing cost, lead time, and even the finished product itself. If my interpretation differs from the customer's intent, the quotation may no longer represent the board they need manufactured.

Receiving a complete manufacturing package allows your PCB supplier’s engineering team to focus on data optimization rather than detective work. Instead of attempting to reconstruct the design intent, I can evaluate the board exactly as the customer intended. When I have complete information available, I can often recognize areas where manufacturing can be simplified without compromising performance, reliability, or compliance with customer requirements. 

A few examples of optimization areas we can look for:

• Laminate alternatives that are more readily available: Opportunity to reduce lead-time without affecting electrical performance
• Areas to optimize the stackup for improved efficiency and to better align with manufacturing processes
• A change in surface finish to reduce errors during the assembly process

These conversations are possible when engineering has sufficient information to evaluate the complete design rather than spending valuable time requesting missing documentation.

What Is Included in a Robust Data Package?
The most efficient quotation process occurs when the customer submits a complete manufacturing-ready data package. At this stage, engineering possesses not only the electronic manufacturing files but also supports documentation necessary to define the finished product without interpretation. The Gerber is accompanied by NC drill data, fabrication specifications, mechanical blueprints, approved stackup information, controlled impedance requirements, detailed material specifications, and any supplemental engineering specifications unique to the product.

Fab notes are needed to identify (at least) the board attributes: layer count, finished thickness, base and/or finished copper thickness/weight for each copper layer, material type, board finish after copper plating (HASL, ENIG, etc.), solder mask color, and silkscreen color. This minimum amount of information will allow an accurate quote to be generated. Additional information is also common but not required, such as the IPC spec and required Class, the customer manufacturing specification, requirements that are tighter or looser than IPC standards, and special manufacturing requirements such as countersinks, gold fingers, edge-plating, via fill, etc. A sample of recommended fab notes can be provided upon request.

 Three different drawing files should be included in a robust data package. A drill drawing shows the list of finished hole sizes, plated or not, finished tolerances, and a symbol found on the corresponding symbol map. A dimensional drawing shows the overall size, any perimeter cuts or notches, and any hole-to-edge dimension required on the finished board.

An array drawing is crucial for assembly. If we do not receive one, our team can generate it. If a customer has an existing part that you might move PCB suppliers, or you are having another supplier quote, be sure to provide the existing array information (drawing, tooled files, etc.). Even a description is more helpful than nothing. For example: 3 up with 4 rails of .400, no space between for scoring, can save time and increase pricing accuracy.

Gerber files need to be included for all inner and outer copper layers, solder mask layers, silkscreen layers, solder paste layers, special layers (selective gold, peelable mask, via plug or fill, etc.). Our team recommends that the file format should be R274X Gerber Extended (apertures are embedded within the Gerber data for each layer), but we can also accept ODB++ format if R274X Gerber Extended is not possible. Rout outline files are not required but at least one Gerber layer should have an outline on it that matches the dimensional drawing supplied.

Last but certainly not least, drill file(s) are needed. These are usually supplied in N/C drill format, but our team can work with them in Gerber format if the apertures represent the different finished hole sizes required.

Conclusion
The benefits of submitting a complete manufacturing package extend well beyond obtaining a faster quotation. Pricing becomes more accurate because every manufacturing process has been identified before costs are calculated. Material procurement can begin immediately following receipt of the purchase order. Production planning proceeds without engineering holds. Factory questions are minimized because the documentation clearly communicates the customer's expectations. Most importantly, the risk of manufacturing nonconformances caused by incomplete or conflicting information is significantly reduced.

If you can take one lesson away from reading this column, I hope it is that providing complete manufacturing data upfront benefits everyone involved. It shortens the path from design to manufacturing, improves quotation accuracy, reduces engineering effort, uncovers opportunities for cost savings, minimizes soft costs, and allows manufacturing to begin with confidence.

PCB companies focus attention on the quoted price. A thorough and complete manufacturing package represents one of the simplest opportunities to reduce both cost and risk throughout the product lifecycle.

Michael Marshall is a field application engineer for NCAB Group.