Electrophoretic coating is a process that uses the action of an electric field to deposit charged coating particles onto the surface of a workpiece, which is divided into anodic electrophoresis (AED) and cathodic electrophoresis (CED, currently more widely used). For small batch sheet metal orders, their core characteristics, costs, and effects can be analyzed from the following dimensions:
1、 Core advantages of the process (highlights suitable for small batches)
- Excellent coating uniformity
The electric field drives the uniform deposition of coating particles, which can form a complete coating even on complex shaped workpieces such as grooves, welds, and edges, avoiding the problems of missed coating and sagging in traditional spraying. Small batch orders do not need to worry about the pain point of “uneven coating of irregular parts”.
- Outstanding anti-corrosion performance
The salt spray resistance of cathodic electrophoretic coating can reach 500~1000 hours or more, and it is widely used in scenarios with high anti-corrosion requirements such as automotive chassis and home appliance shells. If small batch sheet metal parts are used outdoors or in humid environments, their service life can be greatly extended.
- High environmental protection and material utilization rate
Using water as the dispersing medium, the VOC emissions are extremely low and comply with environmental regulations; The utilization rate of the coating is over 95% (ultrafiltration technology can recycle the tank solution), and although there is no economies of scale for small batch orders, the cost of individual materials is still lower than that of traditional spraying.
- High degree of automation and stable quality
It can be combined with pre-treatment (oil removal, phosphating), baking and other processes to form a continuous production line, reducing human operation errors. Even small batch orders can ensure “batch consistency” and avoid the “color difference and uneven thickness” problems of traditional spraying.
2、 The Cost and Limitations of Small Batch Orders
- Cost structure: High equipment investment, single piece cost decreases with batch production
Equipment investment: The total price of equipment such as electrophoresis tank, temperature control system, circulation system, ultrafiltration system, rectifier, etc. is about 500000 to 2 million yuan. Small batch orders need to share fixed costs, and the cost per piece is 30% to 50% higher than that of large batches.
- Single piece cost: The cost of electrophoresis for small batch sheet metal parts is about 80-300 yuan (depending on the area, coating thickness, and pre-treatment requirements). If the batch is less than 100 pieces, the single piece cost may exceed 300 yuan (due to the high proportion of production line switching and debugging costs).
- Labor and cycle: Professional operators are required, and the cycle time for small batch orders is about 5-10 days (including pre-treatment, electrophoresis, cleaning, baking), slightly longer than powder coating (37 days).
- Core limitations: Only applicable to conductive substrates
Electrophoresis needs to be carried out under electrified conditions and is only suitable for conductive metals such as steel and aluminum alloys. Non conductive materials such as wood, plastic, and rubber cannot be used. If multiple materials are mixed for small batch orders, the separation process is required.
- Process complexity: The threshold for small batch orders is relatively high
Strict pre-treatment (oil removal, phosphating, passivation) is required, otherwise problems such as poor adhesion and foaming may occur; The tank solution needs regular maintenance (temperature, pH value, solid content). If products are frequently switched for small batch orders, the risk of tank solution contamination is high, which may increase costs.