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PCBs Manufacturing – The Most Detailed Introduction(Helpful)

PCBs Manufacturing standard stands for Institute for Printed Circuits, currently known as Association Connecting Electronics Industries. It was found in 1975 to set the standards for bare PCBs and finished PCB assemblies.

The IPC classes for PCBs manufacturing are known as IPC Class-I, Class-II, Class-III, and Class-III/A. Class-I is the basis of PCB manufacturing quality.

As well as the Class-III/A the strictest. All three classes belong to the IPC-6011 standard. The significant difference between classes is their level of qualification.

1.PCBs ManufacturingBrief Introduction

Below is a brief introduction to the different classes:

1.1 PCBs ManufacturingClass-I

Class-I PCBs are in the “Limited Life Expectancy” group. Or the electronics assemblies. Those are expected to be used in a low-reliability environment.

These PCBs are used in general electronic products, circuits, and gadgets. Such as where the function of the product is sufficient to accept it. An LED light, flashlight, TV remote, etc. They are examples of Class-I PCBs.

1.2 Class-II

Class-II PCBs are in the “reliability products category.” But reliability is not considered critical. These types of PCBs are used in dedicated products. Such as personal computers, laptops, tablets, smartphones, etc.

1.3 PCBs ManufacturingClass-III

Class-III PCBs are highly reliable products. It does not compromise over reliable operation of the product. Examples are electro-medical equipment, military equipment, electronic monitoring parts of automotive, etc.

1.4 Class-III/A

This is another type of PCBs for which the manufacturing and inspection criteria are strictest. Their main applications are aerospace, military airborne systems, and missile systems.

2.PCBs ManufacturingIPC PCBs Manufacturing standard

These classes define the level of inspection. As well as acceptance of the user. In general, the manufacturing requirements of all the PCBs are approximately the same. But require tighter tolerances for inspection. That eventually results in enhanced product reliability. The parameters are controlled throughout the manufacturing process and final review.


The faults if occur in any of the produced items. They ensured traceability and if noticed that PCB may be destroyed. This practice makes sure that all of the PCBs had are ‘fault-free. And comply with the tolerances specified by the respective class.

Generally, any manufacturer can claim that he makes PCBs of class-II or III. But the coupons and the certificates provided for each PCB are verified. Another third-party laboratory-confirmed them. So that certifies the reality about claimed class. 

Because to manufacture qualify and certify the manufacturing of each PCB is the sole responsibility of the manufacturer.


So it is upon the manufacturer. He does manage to qualify each PCB for the respective class; either he makes more than requested PCBs and destroys the unqualified PCBs. Or makes every product with controlling the features up to his maximum and class category.

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Fig. 1:- Class-II vs. Class-III PCBs

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Fig. 2:- PCB inspection stage for class-II,class-III

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Fig. 3:- A comparison and list of IPC Manufacturing standard manufactured PCBs.  Inspection parameters

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Hommer Zhao
Hi, I am Hommer, the founder of WellPCB. So far, we have more than 4,000 customers worldwide. If you have any questions, you can feel free to contact me. I really appreciate any help you can provide.