More often than not, a quote will be requested without enough information to price, never mind to manufacture. In 1957, IPC was founded as the Institute for Printed Circuits by Richard Zens (Printed Electronics Corp/Epec), Al Hughes (Electralab), Robert Swiggett (Photocircuits), William McGinley (Methode), and Carl Clayton (Tingstol).
According to IPC, as more electronics assembly companies became involved with the association, the name was changed to the Institute for Interconnecting and Packaging Electronic Circuits. By the 1990s, most people in the industry could not remember the full name and/or didn't agree on what the words in the name meant. and the standards were initially developed.
Although we have seen many revisions, the standards have maintained the core manufacturing guidelines for suppliers to follow since the beginning, with improved processing equipment and material considerations added as time has passed the standard have been an important part of manufacturing since.
Printed Circuit Board (PCB) Classifications
Let’s start by reviewing the types of PCBs as defined by IPC they are as follows.
- Type 1: All single-sided PCBs without plated through holes (PTH)
- Type 2: Double-sided PCBs with PTH
- Type 3: Multilayer PCBs without blind or buried vias
- Type 4: Multilayer PCBs with blind or buried vias (including microvias)
- Type 5: Multilayer metal core without blind or buried vias
- Type 6: Multilayer metal core with blind or buried vias may include microvias
The classification, I, II, or III coupled with the type of circuit board depends on the design and product. Class II, for example, the part is expected to operate and have a high reliability, but not necessarily operate in extreme elements of temperature, humidity, or when a life depends on the operation. Class II is in products such as cell phones, calculators, consumer products, and equipment. Class III PCBs are expected to operate in extreme temperatures and are of the highest quality in production.
Printed circuit board manufactured to Class III standards.
The PCBs pass extensive inspection and testing during production and assembly and are in products such as medical, automotive, and military equipment. The difference in cost between the two classes is 15% on average to cover additional quality controls, inspection, and processing.
Data Management
What does data management have to do with the classification of the PCB? Well, the short answer is everything. A good data set allows for standard processing in manufacturing to flow at Class II, a great data set allows for Class III to process through manufacturing as well.
There are parameters such as annular ring, pad-to-circuit interface, plating inspections, and imperfection allowances that make the larger differences when talking class. The inspection fallout can be costly when a data set is not prepped properly for class III to be met. In many cases data cannot be modified to meet all the requirements so knowing Class III standards during the design stage is advantageous to your suppliers.
Class III Is as Solid as Mil-Spec
Due to additional process controls and quality inspection needed as well as final QC paperwork, there is an upcharge to manufacture to Class III however this cost is minimal and comparable to Mil standards. Mil standards have additional costs and compliance that are required as well as qualification to carry the military certification.
These additional qualifications and recertification are costly and time-consuming to production as well as the demands of delivery and interruptions they can cause. The additional cost of military certification, documentation, and storage requirements with the small volume does not make this an appealing cert for us to carry.
In addition to standard military required paperwork and standards AS9102 certification is required for this additional paper trail upcharges of $750 to $1,000 may be required. We recommend class III and can build to class III the same quality product non-military certified as an alternative to Mil certification.
Summary
In the ever-changing PCB world, knowing the different circuit board types and classifications will guide you in your PCB design. The different types of PCB, how they are built, and where they can be produced are key to cost savings. We all want quality products and at Epec we hold to the standards developed initially nearly 70 years ago by the founders of IPC. We have deep roots within IPC, and we know our quality standards are the best and we stand behind our work. For free design for manufacturing report and direct engineering support, reach out through our 24/7 online link.
