IPC-6012 Class 3
On occasion the fabricator will plan to produce the printed board to a given Class level but mostly it is the same processes that produce the four different classes and inspection is used to sort to the specified class. My understanding is that they are 2 different standards.
Please Note: Holes will be plated if no specifications provided. This I define later in this memo.
IPC-6012 Class 3 - Of course, the print edition remains the most flexible option in many cases, given the traditional portability of the paper format. If the foundation is class 2, then you can't expect the finished assembly to be any better than the weakest point.
It is an inspection standard that prescribes the range of the number of defective components that is considered acceptable when random sampling those components during an inspection. For a product to be built to any class level it has to be designed to that class level from the board fabrication material selection to the final assembly. Class 1 has the lower requirements and Class 3 with the toughest requirements. So, why does all this matter to you? Operating the processes and as a manufacturing engineer for the last 14 years. Regular samples should also be submitted to assure that conformance is maintained on a continuous basis depending on the class of production being certified. They are used for required testing or inspections throughout the manufacturing process and final inspection. It is a tool for the internal and external inspections for printed circuit boards. The following identifies some of the elements which need to be specifically defined. If the end product is intended to be a class 3 product, then every step of the way all standards used in the design, development, substrate, assembly, inspection, and testing need to be completed to the class 3 level.