The quality inspection method of direct plating is commonly used

The main characteristics that reflect the quality of direct plating are the conductivity of hole wall and the deposition rate of electroplated copper layer. The strength of the conductive ability is related to the microstructure of the conductive layer, and the thickness of the conductive layer and the thickness of the board. After pre-treatment, the resistance value between the two sides of the printed board before copper plating can reflect the quality of the conductive layer formed by the direct plating process. In addition, after a short time of electroplating, the coverage rate of through hole copper can be observed to directly reflect the quality of direct electroplating performance. The commonly used quality inspection methods for direct plating are as follows:
First, "test board" resistance measurement Cut the copper-clad plate into a small plate of a certain size, drill a certain number of through holes of different apertures on it according to certain rules, hang it on the production plate hanger, complete the direct plating process, wash it directly without electroplating copper, air dry, and measure the resistance value of both sides of the plate.
It is recommended that the size of the "test" board is 7.6x10cm2, the thickness of the board is 1.6mm, the drilling hole is φ3mm2 (for hanging board), the test board is 10 holes of φ1.0mm, 20 holes of φ0.8mm, and 20 holes of φ0.5mm. The test board is dried by direct electroplating process, washed with a hair dryer, and then the resistance of both sides is measured.
Resistance 1.5KΩ is good
Resistance Value 6.0KΩ should carefully check the control indicators, and adjust.
2, 5 minutes full plate plating From the plate that has completed the direct plating process, one or several plates are randomly selected after normal pre-plating treatment! The whole plate was electroplated in minutes, removed and washed, and the effect of through hole electroplating was observed. If all copper plated, it is qualified, there are holes, that is to check the control parameters, and adjust, can also be sliced for backlight test, 0 to 1 light transmission points (3 through holes) for qualified, more than 2 light transmission points for unqualified. Electroplating conditions: the current density is 2-3A/dm2, there is air stirring, there is cathode movement (frequency 20 times/min, amplitude 2.5cm), the chemical composition of the copper plating tank is within the process control range.
Third, take the copper clad plate of the same size as the Hall slot Pick up of the same size and hole groove plate copper clad, in the central plate corrosion respectively 0.8 mmx50mm, mmx50mm 1.6, 3.2 mmx50mm without copper area, the plate after dealing with the direct plating process, air drying, plating in the hole, slot (normal current 2 a), all observed with no copper plating copper on time, Generally, all copper is applied within 2-3 minutes.
The size, aperture and number of holes of each type of production board are not necessarily, under normal process conditions, the resistance of both sides of the printed board after direct plating process treatment fluctuates within a certain range. After a period of experience accumulation, you can understand the range of qualified product resistance values of various production boards. At the beginning of the use of this method, it should be combined with several other quality inspection methods, and the effect of copper plating should be actually observed.
There are many quality inspection methods for direct plating, and the above several can be used for routine quality inspection in the production process. They are simple, effective and easy to operate.