Factors of impacting plating crystal

Crystal nucleus generation speed is fast, while the crystal nucleus growth rate is slow, then resulting large number of crystal nucleus, and resulting the crystal nucleus small, conversely is bigger. If the generation rate of crystal nucleus is faster than growth rate, coating file crystallition will be more micromesh and tightening. Cathodic polarization of increasing electrocrystallization can accelerate the growth rate of growth speed of crystal nucleus, then easy to form smaller crystals.

1. The cathode polarization method improving metal electrical crystallization:

Enhancing the cathodic current density: generally, the cathode polarization will increase with cathode current density increasing, while the coating film become more delicate at the same time. Under the circumstance of polarization increase with cathode current density increasing, the appropriate way to improve the current density will increase cathodic polarization.

2. To lower electrolyte solution temperature properly :

Lowering the temperature can slow down the cathodic reaction speed or ion diffusion rate and improve the cathodic polarization. In actual operation, for the negative impact of increasing the temperature can get up by increasing current density. The specific production operation, in the according to the actual temperature to adjust the electrolyte solution.

3. Add complexing agent:

Complexing agent is a substance which can complex metal ions in electroplating process. Complex ion is relatively simple ion on the cathode which difficult to restore, thereby increasing cathodic polarization value.

4. Add additives:

Additives adsorped on the surface of the electrode preventing the precipitation of metal, increasing the cathodic polarization.Cathodic polarization effect is not alwarys the bigger the better, when polarization over a certain range, will lead to a large number of hydrogen precipitation, so that the plating film becomes porous and rough. In production process, the situation is more practical, to take specify measures to increase metal crystallization cathode polarization effect.

Factors of impacting plating crystal

Factors of impacting plating crystal

Factors of impacting platin crstal

Electroplating working principle

Plating is a technology which make the use of electrolytic to process the surface parts. When electroplating, the part in plating solution is negative, and metal ions under the action of DC power deposited the surface of parts to form a uniform, dense metal layer.

1,The necessary requirement for plating: external DC power supply, electroplating solution, electrolyzer constituted by plating workpiece and anode.

2, Electrolytic purpose: to change the parts’ surface appearance and physical and chemical properties, to acieve variety features of decorative, corrosion resistance, abrasion resistance, and other technical performance.

3, The crystallization of electrolytic process: the process of electrolyte metal ions or complex ions in the cathodic reduction to deposite metal coating called as electrolytic crystal.

Electroplating working principle

Electroplating working principle

Explain: Electrolytic crystal is an electrochemical reaction process, the metal ion is capable of reducing determined by cathode point . Only the cathode potential deviates from the equilibrium state, which produce certain overpotential will deposit metal crystal on cathode.

4. Metal electrodeposition is a complex process, which generally has several continuous stes or coincide interface reactions:
A. Metal ions in solution (such as Hydrated metal ions or complex of complexing ions) by mean of electromigration, convection, diffusion and other forms to arrive the near of of cathode surface .
B. Before reduction, the metal iron near by or on the cathode surface taking place of chemical conversion.
C. Metal ion gets electron from the cathode surface then reducts to metal atom.
D. Metal atom reach the growing point along the surface diffusion to reach growth point for crystal growth, or meet with other ions to form crystal nucleus and grow into crystals.
Explain: forming the metal crystals two steps: the formation and growth of crystal nucleus.

Electroplating machine important maintenance

The plating machine has two states, which are fully automatic production line and manual one. When the automatic state failure, will use the manual control, after the trouble removing, then resume automatic operation, that means will not because of a single failure to affect the whole production line, resulting in shut down. Production line in operation face with manual operation box, that enabling manual/automatic conversion, system start/stop, and the operation of translation, lifting; under the condition of crane running, there has a self-diagnostic function to prevent the failure occurrence of crane translation and lifting out of limit, and motor overheating. Automatic electroplating production line is based on the difference between size and capacity of the products to design different loading patterns and run beat, to formation corresponding run program, the crane will according to system requirements to move automatically, thus to realize the automation of the production process running. Complete electrical control system adopts PLC and IPC (optional) control, which has strong anti-jamming capability, to ensure long-term continuous and stable operation. The system has functions of good man-machine interface and database, interface with full English display, simple operation, achievable operation, tips and help functions etc.. Created real time and historical two databases in the computer. The historical database can achieved technical parameters history record and storage function, which will easy to trace product quality and production conditions for the management analysis. Real time database can realize to display entire production line running for dynamic process, to monitor the parameters. Through the database functions can complete variety statistical reports of records and generates.

Plating production line

Plating production line

Improving the automation control degree of plating equipment, not only can effectively improve production efficiency, reduce labor intensity, but also according to product characteristics to realize the pertinence structural design that is traditional manual production can not achieve, then to improve product electroplating quality. For example, barrel plating production line, automatic operation design of auto switch barrel doors and swing drum design. In the production process, when the barrel rotated to the door facing the anode, the barrel door will open, so that the liquor inside the barrel will be updated; further more, because there is no shield from barrel door, the power lines remain relatively smooth, under the constant pressure, the plating current density increases accordingly, which can speed up the coating deposition rate, and effectively avoid the workpiece appear problem of “bucket print”. Reduce energy consumption, reduce pollutant emissions and adapt to cleaner production requirements. The defination of cleaner production recognized from internationally recognized United Nations UNEP is: Cleaner production is a new kind of creative thinking, the thinking continue to apply overall preventive environmental strategy to production processes, products and services, in order to increase ecological efficiency and reduce human and environmental risks.

Regarding the production process, it is required to save raw materials and energy, to eliminate toxic raw materials, to reducte quatity and toxicity of all rubbish; refer to products, it is required to reduce adverse effect of full life circle which from raw material extraction to final products disposal; for service, it is required to bring environmental factors into design and provided services. The major contents of cleaner production including: cleaning energy; cleaning production processes; cleaning products. For the electroplating industry, water conservation technology and design, solution regeneration technology and so will be more and more popular. In the production line design process, using counter current rinsing, dripping delay, the receiving fluid design etc. all can reduce the waste of resource effectively in the production process. For renewable plating solution technology, due to solution effective recovery and regeneration, not only saves raw materials, but also reduce the amount of waste water treatment, and thus renewable plating solution technology also become one of the major trend for plating development. Improve the quality of electroplating workshop operating environment, strengthen the monitoring of harmful gases, is another important reflection of electroplating equipment user-friendly design. The acid mist, alkali mist, air containing cyanide and chrome anhydride generated in electroplating workshop will all bring serious harm to human body.

In addition to the exhaust system design, harmful gas real-time monitoring design will be an important measure to protect the operating worker’s health, when the operating environment contained harmful gas concentration exceeds the set value, the system will automatically alarm, causing the operator alert, thus protecting operator’s health. Electro plating waste water is an principle element causing environmental pollution. Ideally electroplating waste water treatment model is zero discharge of sewage systems, to achieve zero discharge of wastewater requires strict classification of harmful substances targeted for different treatment. But plating wastewater harmful substances contained species are very complex, in order to manage spilt-flow, the cost will be very high, which is electroplating enterprises unbearable. However, the zero-emission is the development direction of electroplating waste water treatment, along with increasingly stringent environmental requirements and water treatment technology, this technology must be developed and will eventually spread. Development of modern manufacturing needs, determine the electroplating industry must be present and will continue long-term development. However, compared with other professions, our electroplating manufacturing level and the international level there is still a significant gap. The electroplating industry, is inseparable from the improving of electroplating equipment manufacturing technology, so to meet the technical requirements of modern electroplating, more humane and intelligent technology development will become an inevitable trend in the development of electroplating equipment.

Plating equipment automation control system

chiller1, Plating equipment automation control system

With the electroplating machinery in plating production line, power device, heat exchange systems and other auxiliary facilities becoming better and approaching perfection day by day, the automation of automatic line will further towards to intelligent direction.

1.1 Temperature control features of Plating equipment automation control system

(1) When in the electroplating process, the process temperature control is very important, if the temperature fluctuation is too large, not only causing electrical energy waste, but also will have great impact to product quality. Using PID fuzzy control, will effectively reduce or even avoid these problems. In engineering practice, the most widely used regulator control law is a proportional, integral, differential calculus, referred to as PID control, also known as PID regulator. PID controller is based on the systematic errors,which make the use of proportional, integral and differential calculus to calculate the amount of control, its simple structure, good stability, reliable, easy to adjust and become one of the main technology of industrial control.

(2) Heating system matching liquid level control device, automatic water replenishment device, when the liquid level is below the set level, the system will conduct automatic level complement, then will protect the system reasonable, and to prevent heating pipe dry burning; meanwhile, each electric heating system equipped with a reliable ground protection measures to avoid accidents.

(3) Human machine interface set the pre-heating function, which set pre-heating time, if for the process which require higher temperature, will achieve the pre-heating system management, then greatly enhance the production efficiency of equipment.