What Is Rework In PCB And How Is It Done?

What is rework in PCB and how is it done?

Image of PCB rework: Source Freepik

Printed circuit boards (PCBs) are the lifeline of modern electronics. They define how an electronic device will work and how it should perform.  A flaw in PCB, no matter how minor it may be, will have a huge impact on the final product. Manufacturers put stringent measures to minimize these errors. However, just like most production processes, everything may not turn out perfectly as expected. This is where the importance of PCB rework comes in.

It focuses on correcting mistakes that were made during the PCB production process. Not only does rework focus on mistakes but it is also necessary when you want to introduce some modifications to the PCB.  Engineers will be able to make the necessary on the PCB without having to format the entire board or build a new PCB just to introduce the changes.

PCB rework vs repair: what is the difference?

Most people in the industry tend to confuse PCB rework with PCB repair.  While the two have some similarities, they are completely two different procedures.  PCB rework focuses on modifying specific aspects of a PCB while repair is aimed at restoring the state of a damaged PCB.

Why PCB rework?

There are several reasons why PCB rework is an important element in PCB production. The main reason is to avoid discarding an entire PCB because of a mistake that might have been made during the design or at any stage of production. Printed circuit boards come at a significant cost and the last thing that you would want is to discard them.

Here are some of the other circumstances that make it necessary for PCB rework:

  • PCB modification: Even though the PCB may be in perfect shape and condition, there might be a need to change some of its features. This may be due to the changes in the product requirements. The surest way of solving this issue without having to change an entire PCB is through rework.
  • Replacing damaged components: PCBs are made of several electronic components such as resistors, capacitors, and transistors among others. When a single component is damaged, you don’t have to replace an entire PCB. A rework process may focus on replacing the damaged component.
  • Changes to the PCB design: A change in the PCB layout and design will make it necessary to do a PCB rework. You will have to alter PCB traces, change the component placement, or even add new components. All these activities are part of a PCB rework process.
  • Updates and upgrades: Technology keeps evolving with time. Some of the evolutions may force you to update the features and performance of the PCB. Instead of buying a new printed circuit board, you may opt to upgrade the current PCB. The process of upgrading to more powerful PCB components is also considered a rework process.
  • PCB quality control and assurance: Before a PCB is cleared for market, it has to go through various quality control and assurance procedures. Those in charge of this process may recommend changes on the PCB and for the sake of time and resources, manufacturers will opt for PCB rework.

Who does PCB rework?

The PCB rework process is usually done by specialized engineers at a PCB manufacturing facility. These technicians have deep knowledge and experience about printed circuit boards and are also equipped with the necessary tools for the job.

Most PCB manufacturing facilities have specially dedicated rework stations in which all the activities that are related to PCB rework are done.

All the tools and instruments for the job such as soldering irons, magnifiers, and desoldering tools are found here. Additionally, a rework station is designed in a way that provides optimum environmental conditions for the rework job. Keep in mind that a mistake during a PB rework process may cause further damage to the PCB, hence rendering the process counterproductive.

PCB rework process

PCB rework encompasses a series of procedures and steps that are followed until the ultimate goal of the process is attained.

  1. PCB analysis: The first step of the PCB rework process entails a deep analysis of the printed circuit board. The analysis process will determine the direction of the rework. You will know whether you should work on the entire PCB or a single damaged component. During PCB analysis, all the aspects of the PCB are magnified.
  2. Fault identification: From the analysis, you should be able to identify the exact problem on the PCB. The issue could be a damaged PCB component or a faulty design and layout. If it is a damaged component, your next course of action should be to replace it. In case the issue is with the layout, you will have to revise the PCB design.
  3. Preparing a rework: Now that you know what the issue is, the next process is to start implementing the rework process. Basic preparation procedures include gathering necessary tools.
  4. Removing faulty electronic components: If the rework has been triggered by the damaged component, you will have to remove them. This is done using tools such as soldering irons and desoldering wands.
  5. Replacing the components: Once you have removed the damaged components, the next phase is replacement. You will insert the new components in their respective positions. While doing so, ensure that each new component has a perfect alignment with the solder pads. You should follow all the necessary PCB component placements.
  6. Correct the design and layout: The PCB rework may be triggered by a faulty design. Here, you will have to implement the necessary design and layout changes. Specialized designers must be involved in the implementation of the design and layout changes.
  7. Testing the reworked PCB: After you are fully satisfied that all the rework procedures have been done as required, the next phase is testing the PCB. Testing may entail connecting the PCB to a power source to verify that all the components are working. However, in most commercial applications, specialized PCB testers are involved in the testing of a reworked printed circuit board.

Summary

The world of electronics is quite dynamic. The faster you adapt to the changes the better. PCB rework makes it possible to adapt to the changes without using too many resources. While at it, ensure that you involve experts who are good at implementing all the required PCB rework procedures.

Last Updated on October 30, 2023 by Kevin Chen

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