Why ounce is used to describe copper thickness?
Ounce is the most common unit to describe copper thickness in PCB industry, and usually it is shorted as oz or Oz. Ounce is a unit to describe the weight. Then why ounce is used to describe the thickness, and what thickness does it equal to?
It is common to use Oz to describe copper thickness in PCB industry, like 1Oz copper, 2Oz copper, 3Oz copper, and so on. Why this weight unit becomes to a thickness unit gradually? There are some sayings of reasons for reference. Firstly, the ounce is a common weight unit. Secondly, the copper is weighed by ounce, like gold. The price of copper is related to weight measured by ounces. Copper is an important part of cost of the PCB materials as well as the PCB boards. And among the same kind of PCB materials or PCB boards, copper thickness is a key factor to distinguish their features and prices. So there is connection of prices and features between copper weight and copper thickness of PCB boards. Thirdly, it is more simple and short to write or speak copper thickness in ounces, like 1Oz, 2Oz, 3Oz, and so on. Comparatively, it is more complicated to mark the copper thickness in other units, like 35um, 0.035mm, 0.0014inch, 1.4mil, and so on. So the ounce is more and more widely used and becomes the most common unit now.
What thickness does one ounce equal to? According to the calculation, the average thickness is about 35um when one ounce copper is distributed evenly on the surface of boards. So 1Oz is used to describe 35um copper thickness. Similarly, 2Oz is about 70um copper thickness, and 3Oz is about 105um copper thickness.
Therefore, there are two different sayings to describe PCB boards with thick copper, heavy copper PCB and thick copper PCB, due to these two weight unit and thickness unit are used to describe the copper in PCB industry.
SDY is experienced in manufacture heavy copper PCBs. The heavy copper PCBs are widely used in industrial control and power supply industries. Warmly welcome to contact our engineer or Alex@sdy-pcb.com for any PCB questions or RFQs.