Electrolysis and Voltage Regulation Electrophoretic Coating Equipment for Stable Coating Process

Equipment Description:

I. Working Principle
‌1. Electric field driven deposition‌
Anodic electrophoretic coating (such as modified epoxy resin) is dissolved in water and ionized into negatively charged resin particles (RCOO⁻) and positively charged neutralizer ions (such as NH₄⁺).
The workpiece is connected to a DC power supply as an anode, and the negatively charged coating particles move to the anode under the action of the electric field and deposit to form a dense paint film.
The deposition process is accompanied by an electrolytic reaction: water is electrolyzed to generate H⁺ and O₂, and H⁺ enters the anode liquid through the anode membrane to avoid contaminating the tank liquid.

‌2. Core reaction process‌
‌Electrophoresis‌: charged particles migrate in a directional manner in an electric field.
‌Electrodeposition‌: resin and pigment precipitate to form a film on the anode surface.
‌Electroosmosis‌: the deposited layer is dehydrated to enhance the density of the paint film.
‌Electrolysis‌: water electrolysis produces gas, which needs to be discharged through the circulation system.

‌3. Key points of process control‌
‌Voltage regulation‌: DC voltage is adjustable from 50-300V, and the film thickness increases with the increase of voltage (10-30μm).
‌Temperature control‌: The bath temperature is 20-30℃ to prevent thermal decomposition of resin and sagging of paint film.
‌Conductivity management‌: Bath conductivity is <1000μS/cm, and the conductivity of the anode liquid is regularly tested and diluted.
2. Technical advantages
‌High coverage‌: The electric field drives the coating to cover the complex workpiece cavity/gap, and the uniformity error is <5%.
‌Environmental protection and energy saving‌: VOC emissions are only 1/5 of traditional spraying, and the coating utilization rate is >90%.
‌Low cost‌: Equipment investment is 30% lower than that of cathode electrophoresis, and maintenance costs are reduced by 50%.
3. Key points of maintenance
‌Anode membrane inspection‌: The anode liquid is turbid and needs to be shut down for maintenance to prevent the membrane from rupturing and contaminating the bath liquid. ‌Bath parameter monitoring‌: Regularly test pH value, conductivity and Fe²⁺/Zn²⁺ concentration to avoid coating pinhole defects.
‌Ultrafiltration system maintenance‌: Regularly backwash the membrane assembly to prevent clogging and reduce water permeability.

Main structures and components:

I. Core structure
‌1. Pretreatment system‌
‌Degreasing tank‌: Use alkaline solution (such as NaOH) to remove grease from the surface of the workpiece, and the treatment temperature is 60℃.
‌Phosphating tank‌: Zinc salt phosphating treatment forms a 1-2μm phosphating film to enhance the adhesion of the coating.
‌Multi-stage water washing unit‌: Remove residual chemical reagents by pure water spraying/immersion, and the conductivity is controlled to be <10μS/cm.
‌2. Electrophoresis tank‌
‌Material‌: PP or PVC lined anti-corrosion tank body, the volume is designed according to the production capacity (10-50m³).
‌Temperature control‌: Maintain the tank liquid temperature at 20-30℃ (±1℃) to prevent thermal decomposition of the resin.
‌Circulating filtration system‌: Equipped with a circulating pump (flow rate 6-8 times/hour) and a 50μm filter bag to prevent impurity deposition.
‌3. Anode system‌
‌Anode tube/anode cover‌: Titanium metal electrode combined with semipermeable membrane (such as canvas material), allowing H⁺ to pass but blocking resin particles to prevent anode oxidation products from contaminating the tank liquid.
‌Anode liquid circulation‌: Independent liquid storage tank and circulation pump control the conductivity of the anode liquid <1000μS/cm, and regularly replace pure water and acid.
‌4. Power supply system‌
‌DC rectifier‌: The output voltage is adjustable from 50-300V, and supports constant voltage/constant current mode switching.
‌Plate layout‌: Multiple groups of anodes are arranged on both sides and the bottom of the tank to optimize the uniformity of the electric field distribution.
5.‌Ultrafiltration system (UF)‌
‌Ultrafiltration membrane assembly‌: Pore size 0.001-0.1μm, interception of large molecular impurities (molecular weight>10,000 Daltons), recovery rate>95%.
‌Backwash device‌: Periodic backwashing to restore membrane flux, chemical cleaning to remove pollutants.

2. Auxiliary equipment
Post-processing system: Ultrafiltration water washing tank to remove floating paint, drying room (80-120℃) to solidify the coating.
Suspension conveyor chain: Mechanized conveying system (air suspension + ground sled) to ensure smooth transfer of workpieces.
Electrical control system: Integrated PLC module to realize automatic control of voltage, temperature and flow.

3. Technical features
Efficient coverage: The electric field drives the directional deposition of coating, and the coverage rate of the inner cavity of complex workpieces is >95%.
Environmental protection and energy saving: The coating utilization rate is >90%, and VOC emissions are only 1/5 of traditional spraying.
Intelligent control: Real-time monitoring of tank liquid parameters (pH, conductivity) and automatic triggering of maintenance procedures.

4. Precautions
Anodic liquid maintenance: The anodic liquid needs to be stopped for inspection if it is turbid to prevent the diaphragm from rupturing and contaminating the tank liquid.
Impurity prevention and control: Regularly detect the concentration of Fe²⁺, Zn²⁺ and other plasmas to avoid pinhole defects in the coating.
Ultrafiltration maintenance: prevent membrane components from drying out and ensure water permeability and lifespan through continuous operation.

Features:

1.High cost performance: Based on the customer's product positioning and development strategy, and with economic affordability as the foundation, we achieve the best cost performance.
2.The advanced and meticulous design concept of the equipment, along with the highly automated industrial equipment, showcases the image of a modern and advanced enterprise.
3. It has high adaptability, meeting the current production requirements and reserving room for development, taking into account the needs of increased production and improved quality in the future.
4.Quality compliance strictly adheres to the ISO900 quality management system, with every minute detail of the entire equipment installation being strictly controlled.