This include copper plating thickness in the holes, annular ring requirements, multilayer spacing requirements, manufacturing process controls, facilities process controls just to mention a few. Also, see attached article I wrote for Circuitree covering this subject. Class 2 products are defined as products where continued performance and extended life is required, and for which uninterrupted service is desired but not critical. Or use these links to go directly to the order page for , and. This I define later in this memo. If you have any questions please give us a call and if you are in the area we would be happy to schedule a tour for you. For an assembly to be built to Class 3 it must be defined as such on the procurement document or contract to the board shop.Next
The implementation of the Classes is done mostly by sorting product to the Class that is specified. The new Revision D is available from Document Center Inc. And it also includes electrical, mechanical and environmental requirements as well. Tosun has published numerous technical articles. Whereas, Class 3 products demand continued high performance and equipment downtime cannot be tolerated such as life support systems and other critical systems e. In which standards is the difference most significant and notable? Operating the processes and as a manufacturing engineer for the last 14 years. So, if you have all Class 2 materials, and they do not meet even one Class 3 requirement, let alone all of them, you cannot build to Class 3.Next
This is a big answer and there are many parts to the answer. Let me start by stating there are two issues to address, the product and the process and both are necessary for building a class 3 product and recommended for a class 2 product. I think it is important to note the major difference in the four Classes is in the degree of inspection and what level of acceptance that one inspects too. 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. However submission of a sample product and the accompanying coupons to an outside laboratory to measure conformity will provide them with certified test results confirming their capabilities.Next
Materials have to be the same class for all the standards. Senior Applications Engineer Flexible Circuit Technologies Mark Finstad has over 30 years in the flex circuit industry in both design and manufacturing. Hughes has been in the electronics manufacturing field for 20 years. Tests results and reports should be made available as verification that the manufacturer has the capability to meet the 6012 requirements. Design of Experiments DoE techniques have been an area of independent study. The following identifies some of the elements which need to be specifically defined.Next
My understanding is that they are 2 different standards. 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. The Acceptance Quality Level determines the maximum number of defective units, beyond which a batch is rejected. Experts Comments Yes, they are different requirements. Class 2 allows 1 void in 5% of the holes.Next
However the board designer needs to be aware of how the design is affecting the final assembly. I look at it that you can't be any better than what you start with. My understanding is that they are 2 different standards. The goal of the fabricator is to produce product with no voids. Class 3 A class 3 printed board would include end use where continued high performance or performance on demand is critical, failure of circuit board assemblies cannot be tolerated and the product must function when required.
The third issue would be the definition for the three classes of product. If there are voids what the fabricator would do is inspect and then scrap the boards that have voids based on the Class that is specified. In this case if a class 3 product defined by the customer, contract or internally, all materials, equipment and process has to conform to this classification. Networking solutions need to be quoted separately. In addition, the specification requires production coupons on each panel that represent the boards. Remember a defect in Class 2 implies also a defect in Class 3. The board design needs to be able to achieve this result.
Meaning if you want to meet class 2 or 3 in either, the design has to be able to achieve the desired standard. Of course, the print edition remains the most flexible option in many cases, given the traditional portability of the paper format. One question we need to answer first is what is the end use of the assembly that you are building. Fritz's educational background is in mechanical engineering with an emphasis on materials science. Class 2 A class 2 printed board would be one where continued performance, extended life and uninterrupted service is desired but not critical. If it is Class 2 or Class 3 then inspect according to the end user. Thank you Janice for contributing to Ask the Expert.Next
The testing of the coupons confirms that the boards meet the specification requirements in place of using product for the destructive testing. What I find is that the Class most often is level of inspection rather than a planned goal of the fabricator. For example let's take the requirement for voids in copper. Additionally it has to be built in a facility that has the proper environment, quality management system, and continuous improvement plan in place along with the traceability of the materials throughout the process. His area of expertise includes how circuit board's copper interconnections and material fails in assembly, rework and in the field, as a result of thermal cycling.Next