IPC Class 3

IPC class 3

Just what is IPC Class III and why should you care? IPC-A-610 covers workmanship for electronic assemblies – the boards you design and get built up. The higher the number, the more stringent the build and inspection requirements are. Class II is the general commercial standard: items produced and inspected to IPC-A-610 Class II are deemed quality for typical commercial applications. Class III are deemed to be appropriate for hi-reliability and mission critical applications.

For most prototype and small volume applications, IPC Class II workmanship and inspection will be just fine. However, for some with tighter reliability requirements, e.g. aerospace, military, medical, harsh environments, class III workmanship and inspection may be required.

Class 3 products demand continued high performance or performance-on-demand is critical and equipment downtime cannot be tolerated, the end use environment may be uncommonly harsh, and the equipment must function when required, such as life support or other critical systems.

By reviewing the requirements of Class 3, within the IPC documents the differences are found in component placement for surface mount components, hole fill requirements for plated through holes, cleanliness requirements based upon residual contaminants on the surface of the product, plating thicknesses as defined in plated through holes and on the surfaces of printed circuit boards.

Although there are many other differences, these are ones which come to mind quickly. These individual issues can impact the performance requirements of Class 3 product, hindering their ability to function on demand.

A couple of examples that come to mind are a pacemaker, which has to work immediately and down time cannot be tolerated or a rocket on the wing of an aircraft has to fire when activated and its downtime cannot be tolerated.