Horizontal U-Type Manual Anodizing Line with 200T Monthly Output Dual-Row Loading and 6-Stage Process Configuration

A horizontal U-type manual anodizing line is a floor-space-efficient surface treatment system designed for medium-scale aluminum profile finishing. The U-shaped tank layout minimizes workshop footprint while allowing operators to manage loading, transfer, and unloading from a central control corridor.

This configuration handles 200 metric tons per month with dual-row loading per flight bar, effectively doubling single-batch capacity without extending tank dimensions. It is engineered for manufacturers transitioning from batch dip tanks to a structured, semi-continuous workflow.

The standard process sequence covers degreasing, alkali etching, neutralizing, sulfuric acid anodizing, electrolytic coloring, and medium-temperature sealing -- delivering decorative anodic coatings compliant with ISO 7599 and GB/T 8013 standards.

1. Degreasing -- Aluminum profiles are immersed in an alkaline degreasing bath to remove extrusion oils, lubricants, and surface contaminants. Bath temperature: 50-60°C. Duration: 3-5 minutes.
2. Alkali Etching -- Caustic soda solution chemically dissolves the native oxide layer and micro-roughens the surface. This creates a uniform matte finish essential for consistent color absorption. Bath temperature: 50-60°C. Duration: 3-10 minutes (adjustable per finish requirement).
3. Neutralizing (Desmutting) -- A nitric acid or sulfuric acid rinse neutralizes residual alkali and dissolves insoluble smut (intermetallic compounds) deposited during etching. This prevents contamination of the anodizing electrolyte.
4. Sulfuric Acid Anodizing -- Profiles are anodized in a sulfuric acid electrolyte (15-20% concentration) with DC current to build a porous aluminum oxide (Al₂O₃) layer. For decorative applications, target thickness: 8-15 μm. Bath temperature: 18-22°C with continuous cooling.
5. Electrolytic Coloring -- An AC current drives metallic salt deposition (typically tin-based) into the porous anodic film. This produces stable bronze, champagne, or black tones with UV resistance superior to organic dyeing. Voltage: 15-20V. Duration: 30-120 seconds depending on target shade.
6. Medium-Temperature Sealing -- The porous anodic layer is hydrated and sealed in a nickel acetate bath at 60-80°C. This locks in color, enhances corrosion resistance, and meets ASTM B136 seal quality standards. Duration: 10-15 minutes per μm of coating thickness.

• Architectural Aluminum -- Curtain wall frames, window and door profiles requiring uniform bronze or champagne anodized finishes.
• Interior Decoration -- Furniture frames, handrails, and fixture profiles with decorative matte or satin surfaces.
• Industrial Profiles -- Conveyor rails, machine frames, and structural extrusions where moderate corrosion resistance is required.
• Automotive Trim -- Roof rack rails and interior trim components (non-structural).

What is the difference between a U-type and a linear anodizing line?
A U-type line arranges process tanks in a U-shaped configuration with a central aisle. This reduces overall length by approximately 40% compared to a straight-line layout, making it suitable for workshops with limited longitudinal space. A linear line requires more floor length but allows for fully automated conveyor systems.

How many operators are required for this manual anodizing line?
For 200T monthly output running two shifts, the line typically requires 4-6 operators: 2 for loading/unloading, 1 for crane transfer control, and 1-2 for bath monitoring and chemical maintenance. Exact staffing depends on shift structure and profile complexity.

Can the line process both Type II decorative and Type III hardcoat anodizing?
This configuration is optimized for Type II decorative anodizing (8-25 μm) with electrolytic coloring. Type III hardcoat anodizing requires lower bath temperatures (0-5°C), higher voltage rectifiers, and refrigeration units -- these can be retrofitted if specified during design.

What utilities must be prepared before installation?
You will need: three-phase industrial power (capacity calculated by rectifier load + heating), municipal or well water supply (30 T/day peak), compressed air (0.6-0.8 MPa for pneumatic valves), and a wastewater neutralization pit to treat acidic and alkaline rinse water before discharge.

How long does installation and commissioning take?
Standard delivery is 60-75 days after deposit. On-site installation and wet commissioning require 25-35 days, including tank leak testing, rectifier calibration, and trial production runs. Operator training is included during the commissioning phase.

Is the dual-row loading compatible with all profile geometries?
Dual-row loading is suitable for standard hollow and solid profiles with widths up to 150 mm per row. Large, irregular, or high-aspect-ratio profiles may require single-row loading to prevent solution trapping or uneven coating. We evaluate profile drawings before confirming loading configuration.