Pulse power supplies include single positive pulse and double positive and negative pulse power supplies, using unique modulation technology and digital control. The positive pulse turn-on width (T+) and the negative pulse turn-on time width (T-) can be adjusted within the full cycle respectively. The forward current, voltage regulation, negative current and voltage can be adjusted independently. Can fully meet the different needs of customers. It is suitable for gold plating, silver plating, nickel plating, tin plating, etc., and can significantly improve the coating performance.
Basic working principle of pulse power supply technology
During the pulse electroplating process of pulse power supply, when the current is turned on, the pulse (peak) current is equivalent to several times or even dozens of times of the ordinary DC current. It is this instantaneous high current density that causes metal ions to reduce under extremely high overpotential. , thus making the grains of the deposited layer thinner; when the current is turned off, the discharged ions near the cathode area return to the initial concentration, and the concentration polarization is eliminated, which is conducive to the use of high pulse (peak) current density in the same period of the next pulse. At the same time, the shutdown period is also accompanied by recrystallization, adsorption and desorption and other phenomena that are beneficial to the deposited layer. This process runs synchronously throughout the entire electroplating process, and the mechanism contained in it constitutes the most basic principle of pulse electroplating. Practice has proven that pulse power supply has incomparable advantages over traditional DC plating in terms of refining crystallization, improving physical and chemical properties of coatings, and saving precious metals.
First, it goes through slow energy storage to make the primary energy source have enough energy; then it charges (or flows into) the intermediate energy storage and pulse forming system. After the energy goes through some complex processes such as storage, compression, pulse formation or conversion, it is finally rapidly discharged. Give the load.
Pulse power supply application
When the pulse power supply is used for electroplating gold, silver, nickel, tin, and alloys, it can significantly improve the functionality of the coating; when used for protective-decorative electroplating (such as decorative gold), it can make the coating uniform in color, bright, and corrosion-resistant. Sexually strong;
When pulse power supply is used to purify precious metals, the purity of the precious metals is higher. Pulse power supply is superior to traditional electroplating power supply and is the development direction of electroplating power supply.
The double-pulse power supply plating is more detailed and has a better finish than the single-pulse power supply. The anodizing dissolution of the reverse pulse of the double-pulse power supply causes the metal ion concentration on the cathode surface to rise rapidly, which is conducive to the use of high pulse current density in the subsequent cathode cycle, so the coating is dense, bright and has low porosity; the reverse pulse of the double-pulse power supply The pulsed anodic stripping greatly reduces the adhesion of organic impurities (including brighteners) in the coating, so the coating has high purity and strong resistance to discoloration.
Double pulse power supply is suitable for electroplating of gold, silver, rare metals, nickel, zinc, tin, chromium and alloys; electroforming of copper, nickel, etc.; energy depositing of electrolytic capacitors; anodizing of aluminum, titanium and other products; precision parts of electrolytic polishing.
Pulse power supply selection method
According to the different requirements of the electroplating process, select the pulse power supply:
For ordinary electroplating process, single-phase input power supply can be selected for rectifiers with a capacity less than 3kW; while when the capacity is greater than 3KW, in order to prevent imbalance of the grid voltage, a three-phase input power supply should be selected. For special electroplating processes that require relatively high ripple coefficients (hard chromium plating, etc.), the continuity of the waveform is particularly important. You can choose a silicon rectifier with a voltage regulator or a thyristor rectifier with a filter.
Special electroplating processes also have certain requirements for output waveforms, such as one-time commutation, periodic commutation, unidirectional pulse, bidirectional pulse, DC superimposed pulse, DC superimposed AC and multi-segment mixed waveforms, etc. The output waveforms of the products are different, and the corresponding uses are also different. Power supply manufacturers specify different models for different output waveforms and uses, so you can select the type of power supply based on the required output waveform.
Characteristics of pulse power supply form
common forms
Square wave pulse is the most basic current form of pulse plating, generally called single pulse. Other common forms evolved from single pulses include DC superimposed pulses, periodic commutation pulses, intermittent pulses, etc. Among them, unidirectional pulses include single pulse, DC superimposed pulse, intermittent pulse, etc. Unidirectional pulse refers to a pulse waveform in which the direction of the current does not change with time; while periodic commutation pulse is a bidirectional pulse form with a reverse anode pulse.
