Pictured users to scan books into the picture, I was CorelDRAW Miaocheng Vector, many sites have this figure, the specific source ominous figure before three fourth of the original machinery of the People's Republic of technical guidance documents "PCB Design "given in the same curve, the document did not last one there 1.5oz, because it is not commonly used have not been included. According to PCB suppliers, the general PCB no special instructions usually half an ounce that 0.5oz (approximately 18μm) copper foil thickness of about 6.8 to do the price / cm2. 1oz (approximately 35μm) thick copper price of about 7.5 / cm2 , 2oz (about 70μm) copper foil thickness of about 8.5 points more expensive / cm2, multi-use board walk when large currents 2oz board. If you have special needs 3oz (approximately 105μm) and more often require customized thick copper foil. The above prices for October 2006, Zhuhai City, Guangdong Province, 2.0mm thick FR-4 material wood panels finished double reference price. The actual double panel plated copper sink in the process of making, after plating copper thickness will increase 0.25 ~ 0.5oz thick. PCB substrates are typically used FR-4 material, the adhesion strength of the copper foil and the high temperature, the temperature is generally allowed to PCB 260 ℃, but the maximum temperature of the actual use of the PCB should not exceed 150 ℃, because above this temperature very close to the melting point of the solder (183 ℃) up. Board components should also take into account the allowable temperature, usually people can only withstand the highest grade IC 70 ℃, industrial grade IC is 85 ℃, the highest military level IC can only withstand 125 ℃. Thus equipped civilian IC on the PCB near the IC foil on the need to control the temperature in the lower level, only just installed a high temperature power devices (125 ℃ ~ 175 ℃) on the board to allow higher PCB temperature, but the impact on power device cooling temperatures higher PCB also needs to be considered.
Formulas, text excerpts of the following: "Due to the limited Bonded Copper foil thickness, requiring large current flows through the strip of copper foil, the foil should consider the issue of carrying capacity is still an example of a typical thickness of 0.03mm, if. As the copper foil width W (mm), length L (mm) of the strip conductor, a resistance of 0.0005 * L / W ohmic Further, the copper foil carrying capacity is also installed on the printed circuit board component types, Number and cooling conditions in the case under consideration to safety, according to the general empirical formula 0.15 * W (A) to calculate ampacity foil.
Usually provides the most experience in various forums are:
1mm wide, 1 ounce can walk 1A, compared with 50% derating table is more conservative., But not equal to 2mm wide, 1 ounce can walk 2A or 1mm wide, 2 oz can go 2A! There are not afraid of hot 1mm wide, 1 ounce can walk 3A this, more is not recommended.
Attached specification (1 mm2 copper) below for reference:
Open wire, no more than 7A.
Plastic power cord, is not greater than 5A.
Machine single line, no more than 5A.
Machine inside turns, is not greater than 3A.
Transformer internal discontinuous use, not more than 3A. Continuous use, not more than 2.5A.
