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The difference between Class 2 and Class 3 in the PCB IPC standards

The abbreviation IPC stands for International Patent Classification. It was established in 1971 under the Strasbourg Agreement. The PCB IPC standard uses language-independent symbols to provide a hierarchical system. Today, the majority of the high-tech companies in the industry are using IPC electronics. For one to effectively understand and use the IPC standards, they have to learn the different classes. We will look at the meaning, categorization, and significance of complying with IPC standards.

Definition of IPC Class

One must adhere to PCB when manufacturing electronics. Further, there are three fundamental categories that PCB electronics fall to. These categories define and show the different circuit board quality levels. They are class 1, class 2, and class 3. Class 1 is the lowest quality level, while class 3 is the highest quality level. All these classifications fall under the IPS-6011 standards. So we can define an IPC class as the PCB categorization standard used in electronics.

Class definition and significance of classification

Various manufacturers apply these classifications to PCB products for different reasons. Some of the existing codes and the three classifications ensure adherence to the allowed number of defects and severity in a PCB product.  

The lowest PCB quality level, class 1, has a significant acceptance rate of defective aspects. However, Class 3 PCB products have a very low tolerance to manufacturing defects. Circuit boards with multiple defects will not make it to the class 3 level. The stringent restriction on class 3 PCB products drives manufacturers to go above and beyond to ensure that their products meet the class 3 quality level if they want to remain relevant.

Defining the IPC categories

IPC for pcb

Here, we will define the IPC classes concerning their significant elements to help buyers choose a suitable product.

Class 1 – General Electronic Products

We can categorize class 1 products under the electronic boards’ group. These products have simple functions and a short lifespan. They comprise the day-to-day electronic product that we have at home and are easy to find. They include products such as TV remote control, LED lights, and children’s toys. Most of the products’ lifespan is relative to their cost.

Class 2 – Dedicated Service Electronic products

This Class exhibits higher characteristics compared to class 1 boards. Class 2 boards have an extended lifespan and are more reliable. To achieve this long lifespan and reliability, the products go through stringent standards in their manufacturing. Class 2 boards are not highly critical, and they run continuously. We find class 2 boards on devices such as tablets, communication equipment, laptops, and smartphones.

Class 3 – High-reliability Electronic Products

These are highly critical products that must continuously provide the required performance at all times. Equipment with class 3 boards should not experience any downtime. During the manufacturing process, the class 3 products undergo a high level of inspection to ensure that they are reliable and dependable. Equipment that uses class 3 boards includes electronic manufacturing systems, support systems, and military devices.

A-Level or IPC 6012 class 3 – Advanced Electronic Products

The IPC 6012 class 3 is the topmost level and goes through highly stringent manufacturing processes. The PCB products in this class include aerospace applications, military airborne systems, missile systems, space equipment, and military avionics. Similar to their high standards and regulation in manufacturing, their design and production cost is very high.

Advantages of Class 2 PCB manufacturing

Most of the devices we used daily belong to Class 2 PCB. The popularity of class 2 boards are because of the following advantages:

  • Inspection

It is easier to perform an inspection on class 2 boars compared to class 3 ones. For example, the specific rules guiding class 3 components increase the inspection time. And the more time it takes, the high the cost rises. On the other hand, class 2 boards have an easy and fast inspection process which takes less time.

  • Manufacturing

It takes a lot of time when manufacturing class 3 boards since some processes need to slow down to achieve perfection. In manufacturing, the more time one takes on the product, the more the expenses grow, making the products very expensive. A close examination of the manufacturing process shows that one uses 75% of the solder to fill thru-hole leads when working with class 3 IPC standards. However, with class 2 boards, one uses only 50% solder.

  • Design

One must exercise low tolerance to defects and follow stringent specifications when manufacturing class 3 boards. But for class 2 PCBs, the rules are not as rigorous, and they have a simple design. With class 2 products, you can easily place and route all the components.

Advantages of Class 3 Production

IPC 6012 class 2

Class 3 products are fundamental in keeping planes noticeable all around, people alive, and organizations to remain set up. Class 3 boards have unquestionable requirements when dependability and broadened lifetime of an item are fundamental. Below is a portion of the benefits that accompany type 3 PCB production.

  • Inspection

With regards to examination matters, you will notice that Class 3 goes through a thorough assessment. While others may contend that this is costly, makers will keep away from costs related to bad reviews because of defective items over the long haul. A careful assessment guarantees the distinguishing proof of deficiencies right on time before full creation. With such, the organization will acquire the trust of its clients dependent on high-performing hardware.

  • Manufacturing

There is a world of difference between class 2 and class 3 manufacturing processes. Class 3 products go through a greater manufacturing detail compared to class 2 boards. While this manufacturing process might be moderate, eventually, it achieves excellent boards comprising of well-adjusted parts.

  • Design

For a product to meet class 3 standards, they go through their process under close determinations. Consequently, clients of this hardware appreciate the affirmation of superior grade and dependable items. Their plan is exact, cautious, and up to the necessary industry specification.

Difference between Class 2 and Class 3 Assembly

As referenced in the definition, Class 2 items are of a somewhat lower quality contrasted with Class 3 items. As such, the higher the quantity of the Class, the better its degree of value. So, what is the distinction between the assembly of Class 3 and Class 2 boards? The significant differences include:

  1. The distinction in the barrel fill levels

A significant separating factor between Class 2 and Class 3 boards respects the total barrel fill that manufacturers use in the thru-hole leads. Class 2 items devour less barrel fill (half) than the three quarters utilized by Class 3 items. It is a fragile procedure getting the necessary measure of glue to little plated through-hole.

  • Refined assembly

Class 3 boards are much dependable and have an extremely long life expectancy. They are additionally ideal for high-unwavering quality electronic gadgets. Therefore, it implies that their assembly cycle is reasonably refined contrasted with Class 2.

  • Installation and cleanliness

A critical distinction between the two classes is the quality and thoroughness they will go through. The installation and cleanliness of parts among them are extraordinary.

Since clinical and military applications predominantly use class 3 products, they need intensive cleaning. Additionally, the cautious installation of its parts is not optional when contrasted with Class 2.

These items need a detailed and cautious assembly measure. They are answerable for keeping planes flying and those in intensive care. The Assembly cycle must be thorough, not normal for IPC Class 2 items. For Class 3 items, there are no missteps or defects during the assembly cycle.

Difference between class 2 and class 3 PCB production

  • PCB through-hole plating prerequisites

Class 3 items will, in general, be marginally astringent, particularly for copper voids. They are circumstances where copper plating in the opening’s barrel is not present. It will, in general, leave the penetrated holes’ dielectric material uncovered. Then again, IPC Class 2 allows a stipend of five percent critical opportunity of a solitary void in the board’s holes. With regards to plating thickness prerequisites, Class 3 requires one mil while Class 2 is 0.8 mil.

  • PCB dielectric prerequisites

As indicated by industry principles, the base dielectric rule for Class 3 and Class 2 ought to be 3.5 mils. Anything less or more than that figure is simply unacceptable.

  • Annular ring and drill breakout

Another big difference between Class 3 and Class 2 is on drill breakouts. PCBs in the Class 2 classification permit breakouts to happen from the annular rings. Nonetheless, Class 3 doesn’t allow cracked annular rings.

Printed Circuit Boards that fall under Class 3 should be extremely tough. It implies that there will not be huge harm to the whole board if there is a breakout. When managing Class 2 items, having a 90° break isn’t an issue if you keep up insignificant dividing on the sidelong sides.

The above is, however, a couple of issues that make Class 2 and Class 3 contrast. However, we would consistently encourage you to look for correspondence with your manufacturer. They can more readily control you to determine every single impending issue, and they will do it right. Likewise, remember to demand some cross-segment of your PCB. With this, you will guarantee that your manufacturer met either your Class 3 or Class 2 prerequisites, as you had prior mentioned.

Summary

Guaranteeing that your board’s producer conforms to the entire IPC standards for PCBA is more critical. Suppose it does not matter whether your board fits in any of the classifications. The correct method to guarantee IPC principles is by following the keys to a decent PCBA plan. In addition to other things, such would incorporate building up an early relationship with qualified and accredited manufacturers.

Also, knowing the difference between the classes is essential for you to get the right product that serves your needs. The above guidelines will help you determine the proper IPC soldering certification and IPC standard applicable to your needs.