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Specifications About Hole Plating: What You Need to Know About the Plated Through Hole Process

Do you need PCB hole plating, or can your printed circuit boards survive without it? You have probably heard arguments for both. Here’s what you need to know about the benefits and risks of hole plating vs. no hole plating so you can decide what’s best for your PCBs.

Benefits of Hole Plating

The point of plated through holes is so you can use both sides of your printed circuit board and connect to other layers of the board. The plating on the through holes is copper, a conductor, so it allows electrical conductivity to travel through the board.

Non-plated through holes do not have conductivity, so if you use them, you can only have useful copper tracks on one side of the board. You cannot connect to the other side or other boards because there is no way for electricity to travel through. You can use non-plated through holes either to affix a PCB to its operational location or to mount components, but not to connect to other boards or the other side of the board.

Risks of Hole Plating

For this reason, if you wish to have efficient electronic products, you will almost certainly need to have printed circuit boards with plated through holes. However, plated through holes do carry some risk.

All products that contain printed circuit boards are subject to the thermal cycling effect. When we power them up, they heat up until powered down, which is when they cool. As the product is heating up, so is the printed circuit board inside it. Over time, with the board continually heating up and cooling down, the copper of the plated through hole can become fatigued and crack.

The thicker the copper plating the through hole, the longer it can go through this thermal cycling without cracking. Since this cracking will ultimately lead to failure, the life of the printed circuit board in the product is linked to the thickness of the copper plating of the through hole.

There are three types of thicknesses when it comes to plated through holes:

  • IPC Class 1: The least thick and the shortest-lasting, usually reserved for consumer electronics that are likely to become obsolete in a couple of years.
  • IPC Class 2: Longer-lasting, continuous-use holes for products like computers or copy machines that will be in frequent operation for five years or more.
  • IPC Class 3: The thickest and longest-lasting of plated through holes, for products that are expected to last ten years or more.

IPC Class I and II plated through holes require an average thickness of 20 microns, with spots no thinner than 18 microns, while IPC Class III holes require an average of 25 microns, with spots no thinner than 20 microns.

For more information on printed circuit boards and plated and non-plated through holes, or to order PCBs or PCB accessories for your business, contact Millennium Circuits Limitednow.

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