Project Case: Automatic Plastic Dipping Coating Line for Industrial Pipelines in Malaysia

Project Background:
With the acceleration of infrastructure development in Malaysia—particularly in the water supply and drainage, municipal gas, and industrial ventilation sectors—there is increasing demand for enhanced corrosion resistance and surface durability of pipeline products. A major local steel pipe manufacturer commissioned us to custom-build a fully automatic plastic dipping coating line, designed specifically for hot plastic coating of small- to medium-diameter steel pipes (DN50–DN200). The project aims to extend anti-corrosion service life, improve coating consistency, reduce manual operation risks, and enable stable, year-round mass production.

Project Overview:
Completion Date: December 2023
Workpiece Type: Mainly straight pipes, 3–6 meters in length, requiring high-adhesion and impact-resistant coatings
Design Capacity: 15 seconds per piece; approx. 2,000–2,200 pipes per shift
Coating Requirements: Plastic dipping thickness controlled between 250–400μm, full coverage with no blind spots, salt spray resistance ≥1,200 hours

Process Flow and System Highlights:

Pre-treatment System Before Dipping Tank:
Includes four process stages: degreasing, surface conditioning, water rinsing, and preheating drying
Fully enclosed tanks + circulating spray system, with automatic liquid level replenishment and heating control
Pipes are rotated automatically to ensure uniform cleaning of both inner and outer surfaces
Surface conditioning stage uses adhesion-promoting passivator to enhance coating adhesion

Pipe Heating Section:
Uses a gas-powered hot air furnace to preheat the workpieces to 180–200°C, creating optimal conditions for powder adsorption during dipping
Features a uniform hot air circulation design to avoid local overheating or underheating

Automatic Dipping Tank:
Tank length: 8.5 meters; powder holding capacity: 800 kg of polymer powder
Equipped with automatic constant-temperature heating and powder circulation system
Workpieces are vertically dipped and slowly lifted to ensure even powder adhesion and defect-free coating
Supports powder change for multi-color operations, with cleaning and trial run completed within 1 hour

Tunnel-type Curing Oven:
Length: 18 meters, divided into three temperature zones—preheat, middle, and holding—for progressive heating and leveling of the powder
Built-in hot air circulation ducts, with oven temperature controlled at 240–260°C
Equipped with high-temperature air curtains and diversion hoods at both ends to minimize heat loss

Electric Chain Hoist Conveyor System:
Closed-rail conveying combined with intelligent electric chain hoists
Pipe fixtures support multiple diameters and come with anti-sway stabilizers for high-temperature transport of long pipes
Control system includes takt time control, segmented operation, and automatic positioning
The entire line includes 16 workstation points with automated rhythm control to prevent process interference

Project Results and Client Feedback:
Post-dipping coatings are full, firmly adhered, and uniformly colored; random inspection pass rate remains consistently above 99.3%
The system runs an average of 16 hours per day with excellent continuous load performance and maintenance frequency significantly below expectations
Client reports noticeable reduction in labor intensity; number of operators per line reduced from 6 to 3, achieving over 18% in annual cost savings
Effective powder recovery system saves an average of 480 kg of raw material per month

This project showcases our system integration capability in high-temperature thermoplastic surface treatment for transportation infrastructure, and proves the high efficiency and compatibility of electric hoist conveyors with hot plastic dipping processes. Looking ahead, we will assist the client in integrating a QR code traceability system and remote fault monitoring module to further enhance smart manufacturing. The project has been reported by Malaysian local media as an “industry benchmark,” playing a positive role in enhancing the client's brand image.