Wet Painting Line with P F Conveyor for Structural Parts Customized and After-Sales Service Guide Equipment Installation

Automatic Liquid Dipping Painting Line for Carbon Steel Structural Parts

Heavy-Duty Immersion Coating System with Power and Free Conveyor

This liquid painting production line is specially engineered for carbon steel structural components and other medium-to-heavy fabricated metal products. The system adopts an angled immersion coating process to achieve comprehensive paint coverage while using a Power and Free overhead conveyor for flexible workpiece transportation.

The line is designed for workpieces weighing up to 2,000 kg per carrier. Forklifts are used to assist with manual loading and unloading, while the conveyor automatically transfers workpieces through dipping, paint dripping, drying, and cooling stages.

This combination provides an effective coating solution for large and heavy structural components that require reliable corrosion protection and consistent surface coverage.

Main System Configuration

The production line incorporates:

• Power and Free overhead conveyor

• Heavy-duty workpiece carriers

• Forklift-assisted loading and unloading

• 45° angled dipping system

• Liquid coating tank

• Paint dripping area

• Heated drying section

• Natural cooling section

• Variable conveyor speed control

The equipment layout and dipping tank dimensions can be customized according to the workpiece size, production capacity, and available factory space.

45° Angled Immersion Coating Process

One of the key features of this production line is the 45-degree angled dipping method.

During coating, structural components are lowered into the liquid paint at a controlled angle rather than being immersed horizontally.

This arrangement helps:

• Improve paint contact with complex structures

• Reduce trapped air during immersion

• Promote coating coverage of recessed areas

• Facilitate paint drainage after dipping

• Provide more consistent coating on irregular components

The dipping angle, immersion time, tank dimensions, and carrier design can be adapted according to the actual product geometry.

Heavy-Duty Power and Free Conveyor

The line uses a Power and Free overhead conveyor system designed for transporting large structural components between individual process stages.

Maximum carrier load: 2,000 kg

Adjustable conveyor speed: 0.5–3.0 m/min

The Power and Free configuration allows carriers to be accumulated or released according to process requirements, which is particularly useful because dipping, dripping, drying, and cooling require significantly different processing times.

Main advantages include:

• Heavy-duty workpiece handling

• Flexible carrier accumulation

• Independent control between process sections

• Adjustable production flow

• Efficient utilization of factory space

• Reduced manual transfer between coating stages

Forklift-Assisted Loading and Unloading

Due to the size and weight of the structural components, forklifts are used to assist operators during loading and unloading.

At the loading station, workpieces are positioned onto the designated carriers before entering the automatic production process.

After coating, drying, and cooling are completed, the finished components return to the unloading station, where they are removed with forklift assistance.

This arrangement avoids the need for a complex fully automatic loading system while providing practical handling capability for large and heavy products.

Production Process Flow

The typical process for this liquid dipping painting line is:

Forklift-Assisted Loading → Dipping & Painting → Paint Dripping → Heated Drying → Natural Cooling → Forklift-Assisted Unloading

1. Forklift-Assisted Manual Loading

Carbon steel structural components are transported to the loading area by forklift and securely positioned on the heavy-duty carriers.

The hanger and carrier arrangement is designed according to:

• Workpiece dimensions

• Center of gravity

• Individual product weight

• Dipping orientation

• Required coating coverage

Correct positioning helps maintain workpiece stability throughout transportation and immersion.

2. Liquid Dipping and Painting

Typical dipping time: 6 minutes

The loaded carrier moves to the immersion coating section, where the workpiece is dipped into the paint tank at the designed angle.

Complete immersion allows liquid coating material to reach external surfaces, recessed sections, and other accessible areas of the structural component.

Process time can be adjusted according to the paint system, workpiece geometry, and coating specification.

3. Paint Dripping

Typical dripping time: 90 minutes

After immersion, the coated workpiece is transferred to the dripping area.

Sufficient dripping time allows excess paint to return from the workpiece surface, helping control coating build-up and reduce unnecessary coating material consumption.

The required dripping period depends on factors such as:

• Paint viscosity

• Coating thickness requirement

• Workpiece geometry

• Ambient conditions

• Drainage characteristics

4. Paint Drying

Typical drying time: 48 minutes
Operating temperature: 60–80°C

After dripping, the structural components enter the heated drying section.

Controlled heating removes solvents or moisture as required by the selected coating material and allows the coating to develop the required surface properties.

Actual drying temperature and residence time should be determined according to the paint manufacturer's technical specifications and the thermal characteristics of the workpiece.

5. Natural Cooling

Typical cooling time: 6 minutes

After leaving the drying section, the coated components undergo natural cooling.

The cooling stage reduces workpiece temperature and prepares the finished products for safe handling and unloading.

6. Forklift-Assisted Manual Unloading

Once the coating process is complete, finished structural components are transported to the unloading station.

Operators use forklifts to safely remove the heavy products from the conveyor carriers before they proceed to inspection, storage, assembly, or subsequent manufacturing operations.

Typical Operating Parameters

The above parameters represent a specific project configuration and can be modified according to different product and production requirements.

Advantages of Liquid Dipping Coating

• Comprehensive Surface Coverage: Complete immersion allows paint to contact the exposed surfaces of complicated structural components, including areas that may be difficult to reach using conventional spray application.
• Suitable for Heavy Structural Components: With a carrier capacity of up to 2,000 kg, the system is designed to accommodate large and heavy fabricated steel products.
• Flexible Production Flow: The Power and Free conveyor allows carriers to accumulate between process sections, making it possible to coordinate operations with significantly different processing times.
• Controlled Paint Drainage: The dedicated dripping stage allows excess coating material to drain from the workpiece before drying, helping improve coating consistency and material utilization.
• Reduced Manual Material Transfer: After forklift-assisted loading, the conveyor handles transportation between the main coating stages, reducing repeated manual handling of heavy components.
• Customized Equipment Configuration: The dipping tank, carriers, conveyor routing, drying section, and overall production layout can all be engineered according to the actual products and factory conditions.

Customized Liquid Painting Production Lines

Each liquid coating line is designed according to the customer's specific workpieces and production requirements.

Important engineering information includes:

• Maximum workpiece dimensions

• Maximum individual and carrier weight

• Carbon steel structure and geometry

• Required production capacity

• Paint type and technical data

• Required coating thickness

• Dipping and drainage requirements

• Drying temperature and time

• Available factory dimensions

• Available heating energy

• Required automation level

Based on these parameters, we can develop a customized solution covering the Power and Free conveyor, heavy-duty carriers, dipping equipment, paint tank, dripping area, drying system, cooling section, control system, and overall production line layout.

Contact us with your workpiece drawings, coating specifications, and production requirements for a customized liquid dipping painting line proposal.