Aluminum Profile Powder Coating Line

Aluminum profile requires proper coating treatment for surface protection and fruitful color preparation. When you use aluminum products for decoration purpose, high quality coating simply gives you confortable feeling. We will introduce how to setup a perfect line with your requirements and things you need pay attention to for high quality coating.

Aluminum profile coating process

Similar to other metal coating lines, proper pretreatment is crucial here. From the industry, there’re different coating techniques being used: Powder coating and liquid coating. There’s big difference for workflows. Let’s firstly see traditional liquid coating.

Loading -> Pretreatment(rinsing, degreasing, phosphating) -> Pre-heating -> base coat painting -> leveling -> drying -> Top coat painting -> leveling -> leveling -> drying -> varnish painting -> leveling -> drying -> unloading

As we see, there’re lots of sections for this coating line setup. However, it’s different for powder coating. Powder coating for aluminum profile is followed by this workflow:

Loading -> Pretreatment(rinsing, degreasing, phosphating) -> Pre-heating -> powder coating -> Curing -> unloading

The powder coating solution simplified the entire process and can bring us the same level quality. The powder coating solution is applied by most modern manufacturers for low cost investment and high efficiency.

Aluminum Profile Powder Coating Crucial Process

Pre-treatment

Aluminum profiles need to pass through degreasing /pickling then alkaline washing to remove surface grease and oxide layers. This step is crucial because any residual dirt can affect paint adhesion. Typically, an alkaline degreasing agent is used, with the temperature controlled at 50-60°C and a duration of about 5-10 minutes.

Washing
After degreasing and acid pickling, the aluminum profiles need to be thoroughly rinsed with clean water to ensure no chemical residues remain on the surface. The washing is usually done in multiple stages, including cold water wash and hot water wash, to ensure cleanliness.

Passivation Treatment
To enhance the corrosion resistance of aluminum profiles, a passivation treatment is usually applied. The passivation solution usually contains either chromate or non-chromate components, with a treatment time of about 1-3 minutes.

Drying
After passivation, the aluminum profiles need to be thoroughly dried. This is usually done by hot air drying or natural air drying, with the temperature controlled at 60-80°C and a duration of about 10-15 minutes.

Powder coating /painting
The dried aluminum profiles are then moved to the painting process. Painting can be done using manual or automatic spray equipment, the paint is usually polyester or fluorocarbon. During spraying, attention must be paid to the spray gun pressure (usually 0.3-0.5 MPa) and distance (20-30 cm) to ensure an even coating.

Curing
After painting, the aluminum profiles need to be placed in a baking oven for curing. The curing temperature is usually 180-200°C, with a duration of about 15-20 minutes. Temperature and time must be strictly controlled during curing to avoid blistering or discoloration of the coating.

Cooling
Once curing is complete, the aluminum profiles need to cool naturally to room temperature, followed by quality inspection.

Quality Inspection
The final step is to conduct a quality inspection of the painted aluminum profiles, including coating thickness (usually 60-80 μm), adhesion (cross-cut test), and appearance (free of bubbles, drips, etc.).

Aluminum profile coating line structures include: water tank, hanging conveyor, Spray booth, curing oven, electric control box.

Unlike any other products, aluminum profiless come with long shapes and sometimes with big size(like boards). Thus, the spray booth and curing oven is pretty big comparing to any other coating line setup. Especially for hanging conveyor, it can be as high as 12 meters for smooth operation.

Aluminum profile coating line faqs

How much space required for coating line installation?

200㎡ is minimum requirement for basic installation. It completely depends your output rate and techniques to use.

How to get high quality coating products?

You will need to hire experienced technicians for quality control. Both pretreatment and coating are important to ensure final products quality.

Is it 100% automatic?

No, at least you need to load/unload manually. Sometimes you also need to monitor each section carefully to make sure it’s working right.

What do you need for coating line design?

We need to know about your product size, output rate, the technique to use and your workshop structure design. Since it’s fully custom design, all questions must be cleared first.