Reverse Engineering of Multilayer PCBs

Reverse Engineering of Multilayer PCBs

Reverse Engineering of Multilayer PCBs

Objectives of reverse engineering

The first step when attempting reverse engineering something like a circuit is to take a good look at all of the components in that circuit. Equally important is to look at all of the traces between individual components and then to make a clone of that whole setup. One serious problem emerges when a PCB is inspected and that is the fact that all the traces are covered by a solder mask. Also, many traces are hidden under components and therefore using a single example will not make effective cloning easy. There may be an alternative solution and it may actually be possible to deconstruct most PCB’s layer by layer. There are a variety of techniques which can be used to successfully remove solder mask. Making use of non-destructive imaging can also be used to examine the internal layers of PCB’s. A relatively simple project will be those which involve two-layer boards. The most difficult part will be to remove the solder mask. This can be accomplished in various ways such as with a Dremel Flap Wheel, a fiberglass scratch brush or a laser ablation.

Removal of solder mask by Dremel Flap Wheel

Removal of solder mask by Dremel Flap Wheel

Professionals have become very skilled when it comes to solder mask removal and they do it by making use of a chemical process. All it takes to strip solder of boards is to dip them in Ristoff C-8 or Magnastrip 500 although this process can result in some noxious chemicals. PCB manufacturers frequently make use of these methods when it becomes necessary to remove solder mask during the manufacturing process.

PCB Solder Mask Removal- Magnastrip 50

PCB Solder Mask Removal: Magnastrip 50

Multilayer PCB’s

When working with a two-layer board the process of removing the solder mask will help you to update the layout of the PCB. There are also other techniques for the reverse engineering of two-layer boards. However, when you are working with multilayer boards it will be necessary to delaminate the entire board stack before you will be able to get a proper look at the interior copper layers. There are some very sophisticated ways to accomplish this and one of them is by making use of a machine which provides imaging techniques such as CT scanners and x-rays. There are also some other advanced technologies which could be used. Other technologies were investigated such as acoustic micro imaging and also acoustic microscopy but unfortunately, they were not successful. The fact is that reverse engineering is something which could potentially be used by a variety of professionals such as product designers, electrical engineers or system integrators. You might be confronted by a scenario where you have products which are based on very old designs. This might lead to a situation where a variety of components on PCB is very difficult to find. Some of those components are simply no longer available. It is also quite possible that the documentation which has been provided by the manufacturer is no longer obtainable and therefore the only viable solution is the process of reverse engineering. The question of how to reverse engineer PCB boards is something which is frequently considered by professionals across a variety of industries.

Going to the professionals

There are many companies whose business is reverse engineering. They will quickly disassemble any sample regardless of whether it is a bare PCB or an assembled unit. They will proceed to scan and examine such a PCB going from layer to layer. During the process, highly advanced techniques and tools will be used and the result will be a highly accurate documentation package which will provide all of the needed information relating to that PCB. There are reverse engineering companies which are able to handle as many as 28 layers and are able to provide schematic reverse engineering as well as BOM list reverse engineering. PCB reverse engineering has become an exact science and just about anything is possible when using modern technologies. It is important to keep in mind that PCB manufacturing involves a very specific process. In the first place, design engineers will look at function details and this will eventually result in the proposed schematic. The next part of the process will be to create a layout drawing. These drawings will then be used for PCB assembly as well as PCB fabrication and the result will be a workable product. It is important to keep all of these facts in mind when reverse engineering circuit boards. Reverse engineering PCB boards requires professionals to actually have the final product in their possession. The whole process works in reverse and when successful the customer is provided with a schematic and then they can decide whether they would like to proceed with the manufacturing process.

Leave a Comment

Your email address will not be published.