Types of Finishes Applied to Aluminum Extrusion Profiles

Release time:2022-09-13

Aluminum is an ideal material for custom extrusion profiles because it is eco-friendly, non-corrosive, thermally conducive, versatile, and cost-effective. In addition, it has a high strength-to-weight ratio. This means that although the metal is light, it is very sturdy. 

When the alloy metal is exposed to air, it naturally forms a layer that acts as a corrosion barrier. To enhance aluminum’s non-corrosive properties and make it aesthetically pleasing, an extra layer of protection (finish) is necessary. The finish also prepares the aluminum surface for painting/coating. 

While an excellent finish has benefits, the wrong finish could damage the metal, leading to structural problems. To avoid this, ensure you only hire a reliable aluminum extrusion manufacturer. 

Types of Aluminum Extrusion 

Aluminum extrusion profiles are made by subjecting the metal to heat until it is malleable enough to go into a die. The die has patterns/shapes that are used to shape aluminum and other metals. 

Manufacturers use these main methods to design aluminum extrusions; direct, indirect, and hydrostatic. 

1. Direct Extrusion (Forward Extrusion)

Direct extrusion is the most popular way of extruding aluminum. Heated aluminum is placed in a hot walled container with a ram that pressures the movement of the billet through the die. 

Since it requires a lot of pressure, blocks of material are placed to prevent the die from coming to contact with the heated billet. 

2. Indirect Extrusion (Backward Extrusion)

The die stays in place in indirect extrusion as the billet uses pressure to push the heated container. The malleable aluminum flows against the direction of the ram. Extruders use a stem that holds the die in place. 

Backward extrusion regulates heat and friction compared to forward extrusion. Hence, extruders can achieve temperature control which enhances aluminum's mechanical properties. The process also improves the grain of the metal's structure.  

3. Hydrostatic Extrusion

This extrusion process can happen in hot, cold, or warm temperatures. Here, manufacturers place the die in a liquid under immense pressure. The pressurized fluid then controls temperature stability. 

Types of Finishes Applied to Aluminum Extrusions

There are seven main categories of aluminum extrusion finishes. 

1. Mechanical Finishes 

Mechanical finishes are applied through grinding, blasting, polishing, buffing, or sanding. After the process, the extruded metal can appear patterned, rough, or mirrored, depending on the method used. 

Mechanical finishes are the most popular because they make the material more valuable by increasing the quality of the surface. They also prepare aluminum extrusions for further cosmetic finishes. 

2. Chemical Finishes 

Extrusion manufacturers create chemical finishes by dipping the aluminum extrusion in chemical mixtures. The commonly used types of chemical finishes are bright-dipping and etching. 

Bright-dipping finishes leave the surface with a glossy appearance. The chemical solution used for this process combines nitric acid and phosphoric acid. Etching is a less popular method for chemical finishes. 

3. Powder Coating 

Powder-coated finishes are durable and have a decorative effect. This finish is gaining popularity in the industry because they do not need VOCs or solvents. Therefore, they are plant-friendly. 

The solid plastic powder leaves a matte, glossy, or textured layer. Unlike other finishes, powder coating has minimal waste and pollutants. 

4.  Anodizing 

Anodizing is a procedure where the aluminum extrusion profile is dipped into an acidic electrolyte. After the metal is immersed in the electrolyte, an anodic oxide layer is formed. Manufacturers can customize the coating to different colors without compromising the surface's strength. 

5. Liquid Coating

Liquid paints can be polyesters, acrylics, and fluoropolymers in different colors. They give the aluminum surface a uniform, finished film. 

However, liquid coats have VOCs or solvents that may harm the environment. the pollutants are eliminated through curing and baking. 

6. Pre-Treatment

The first type of pre-treatment finishing was chrome conversion. Now, there are more environmental-friendly, chrome-free coatings on the market.

In pre-treatment, powder and paint adhesives are used to add an extra layer for other cosmetic finishings. 

7. Wood Grain (Sublimation)

Sublimation gives the aluminum surface a wood grain effect. During this process, a particular pattern is transferred to the aluminum's surface. Wood grain finishing is mainly used for home decorations.

8. Electrophoresis 

Electrophoresis is also referred to as e-coating, electrocoating, or electrophoretic coating. Aluminum extrusion profiles are immersed in an electric tank filled with a paint solution with ions. When the aluminum is dipped in the solution, paint coats its surface.

Why You Need to Add a Finish

There are many benefits of adding a finish to aluminum extrusions. They include:

· Metal Preparation – Finishes help prepare aluminum extrusions for paint jobs or coats. In addition, the extra finish anodizes the metal and increases the thickness of the oxidized layer. Hence, the aluminum extrusion will be more resistant to corrosion and wear. 

· Environmental Protection – Extreme environmental conditions can affect the properties of aluminum. An added finish helps prevent ecological factors like temperatures, moisture, and humidity from damaging the metal. 

· Aesthetic Appeal – Many consumers are attracted to products with a striking appearance. Finishes make aluminum extrusions appear glassy, brightly colored, matte, textured, and so on. A perfect finish is a strong selling point for any aluminum extrusion. 

Looking for an Aluminum Extrusion Company? 

According to statistics, the aluminum extrusion industry is anticipated to see a growth rate of approximately 4% between 2019 to 2023. However, before selecting a manufacturing company, there are a few things to consider. 

First, does the company have a versatile list of high-quality products? Are they reliable? Do they offer a quote that is within your budget? Fourth, is their licensing and insurance valid? Finally, do they have positive reviews and recommendations? 

Performing research before purchase makes you confident about your investment. If you are looking for an aluminum profiles company, you are at the right place. 

At JMA Aluminum, we have a skilled team that offers professional services and conducive customer support. Our products include doors, windows, and curtain walls for residential and commercial use. Contact us today for the best aluminum manufacturing services. We guarantee you will get your money's worth!