ALUMINUM POWDER COATING:
EVERYTHING YOU NEED TO KNOW
Aluminum powder coating is a very great choice when it comes to quality surface finishing. It helps to increase the durability, looks, lifespan and overall performance of your metal piece.
But not all the aluminum parts need this treatment. As this process adds cost to the product, you only need to have a surface finishing when necessary for your project.
For instance, if your part is a functional part, assembled on the inside of a machine or vehicle, you won’t need this kind of surface finishing. Chromating would be the best option for you as it makes the part corrosion-resistant and increases the part’s functionality.
On the contrary, if your part is a visual part, like medical devices, you’d want to have a powder coating finishing to make the piece look nice and sharp and better performance overall.
But that’s not the only option. You can choose the surface finishing from a wide variety of options. Especially painting and anodizing finishings are also very popular.
So why do you want to choose powder coating over other finishes on your aluminum parts ?
In this guide, we’ll discuss everything about this particular surface finishing, including:
What is Aluminum Powder Coating?
Unlike other surface finishings, powder coating is a dry finishing process, which is applied as a dry powder with the electrostatic process’s help. The finish provides a very high-quality result.
Since its introduction, it has been extremely popular among manufacturers for its long durability and better performance overall.
Types
The coating method is categorized into three main categories.
Thermosets
Thermosets are the most common type among the three categories. It has a wide range of features at a lower cost than its competition, making it a favorite among buyers and manufacturers.
The coating provides a thin but very hard and legit finish over the metal with a great appearance. Their high mechanical property and higher resistance to temperature make them a great choice.
Thermoplastics
Thermoplastics offer higher performance and plenty of additional features compared to thermosets. However, it’s a significantly less often used category. The reason is that the cost of thermoplastic is relatively higher and the coating process is more challenging.
But if you decide to go with this type, you’ll get some additional benefits along with it, such as increased adhesion, recyclability and chemical, chip and corrosion resistance.
Other than being more expensive, the only downside of this is that it’s not as great as thermosets in higher temperature resistance.
UV Curable Powder Coatings
This is a new set of technology, developed to meet the worldwide demand for UV resistant finishings. The technology was developed first in the early 2000s and gained an excellent response from buyers and manufacturers.
This coating type has some additional benefits and features over conventional thermosetting. Due to their higher performance, exceptional wear resistance, cost-effectiveness and more comfortable to handle capability makes them a great choice.
The Coating Process
Now it’s time for me to show the 4 step process of powder coating.
Pre-treatment of the Metal
Pretreating is when you make the aluminum ready for the surface finishing. This step includes cleaning the metal thoroughly and making sure there’s no dirt, grease oil, old paint or any other substance in the metal.
If not done correctly, the result won’t be satisfactory and there will be defects on the metal.
Apply Powder
For this step, an electrostatic gun is used to spray the powder on the body. The powder then bonds with the workpiece because of the positive charge.
There are different types of nozzle available to attach with the gun. Based on the workpiece size, you need to get the right nozzle for your project.
Heat the Extrusion
Now it’s time to heat the extrusions in a large and hot curing oven. Until the extrusion is uniformly melted, the oven continues to heat the piece.
Alternatively, we can first heat the metal and then apply the powder. Both techniques will work. Heating the workpiece beforehand will ensure the powder is more uniformly melted. However, it can cause some other problems that can harm the final product.
Cool off the Piece
The final step, where you take the extrusion off the oven and let it cool off. When it’s cold, it forms a hard and smooth finishing on the aluminum.
Why Pretreatment is Necessary And How to Do It
As we discussed above, this occurs at the beginning of the process before we apply the powder or heat to the body. Now, let’s see why it’s so important.
When you’re working with an old piece, often there will be old paints, dirt or other substances present on the surface. We clean it thoroughly to remove all of it and make the workpiece super clean.
If you fail to clean it properly and apply the coating over a dirty surface where there are remains, the layer will have flaws and defects. Sometimes you’ll see bubbles or even worse; the coating will chip and fall off the body.
And it’s not much different with new metals as well. Because aluminum gets oxidized fast, if you keep a new metal open to the air, there’ll be a layer of oxidation that will negatively impact the coating.
This is why pretreatment is essential for this process.
How is it different from anodizing aluminum and painting?
Available color options
Both these surface treatments can be great if you need attractive color options for your project. You need to choose the right treatments for your parts based on the process and metal you’re using.
If it’s a machined aluminum part, you can very well go with anodizing. Because then you can have a lot of color options, which looks great after we apply the anodizing treatment.
On the other hand, if it’s an aluminum die casting part, you should avoid anodizing treatment because the silicon will have a substantial impact on the surface and harm the part’s finishing.
However, you’re in for a treat when you choose powder coating. Because then, you have an unlimited range of color options to choose from. You can choose from a wide variety of shades and textures as well.
Advantages and Disadvantages
You can have many additional benefits with powder coating over other surface finishing options.
Advantages:
- You have endless color options. If you need your parts or product to look beautiful, this is the right process for you.
- The powder creates a strong bond with a thick and hard wall that doesn’t peel off easily and has a better finishing quality.
- More eco friendly.
- It’s more durable with a longer lifespan than the other options available on the market.
- Cost-effective and faster process.
Disadvantages:
- If you’re looking for thin layers, you want to avoid it.
- It doesn’t react well with UV rays.
- You have less control over the coating.
- The start-up cost might be high.
Environmental Considerations
Unlike many other surface finishing methods, powder coating doesn’t have harmful solvents in it. This means it doesn’t release VOCs to the atmosphere, which is threatening to the environment.
The process has no on-site impact as it takes place in a sealed booth. Which also eliminates the chance of wastages. In addition to that, no heavy metals are used in this coating process and the metals’ recyclability.
And the great thing about it is that the powder doesn’t get wasted in this process. The used powder in the sealed room gets collected afterward and used again without any problem. And the powders can be recycled as well.
Applications
We use powder-coated aluminum almost every day in our life. However, we might not notice yet. Let me remind you of some of the most used items that you and I use regularly.
Everyday Products
The list is endless. We use many electric components, which is an ideal example of aluminum powder coating products. Antennas, mechanical pens, shelves, display racks, cabinets, furniture thumbtacks, and a ton of other products we use every day are on this list.
If you look around your home kitchen or bathroom, you’ll find plenty more examples.
Medical Equipments
Most of the medical devices made with aluminum die casting are visual parts. Hence they need a quality surface finishing treatment. Most companies prefer having a powder coating as their surface finishing because of the stunning look and additional benefits it adds.
Medical equipment such as ultrasound devices, dental equipment, surgical devices and other therapy and diagnostic devices are great examples.
Construction
Construction projects and buildings are using this coating method now more than ever. You might see it in the glass doors and windows, stadium sittings, poles or fences. Because of the high amount of strength it adds to the metal, it is now used in building facades.
Automotive
The automotive industry is one of the oldest and most prominent users of aluminum powder coating. All of the companies in this niche are heavy users of this process. Car wheels, handles, bumpers, motorbike frames are great examples of it.
Benefits of This Process
There are a couple of reasons why you might want to choose this particular coating technology for your project.
Like any other metal, aluminum is very open to corrosion and oxidation. This is why having a finishing is necessary for your parts or items. And you need a quality surface finishing to improve the durability and make it more productive.
With this process, you get everything you can ask for at a low price and lower lead time. When you order aluminum parts, you want it to last long, be corrosion and rust resistant. Without a proper finishing, you’ll have the product at hand, but the quality won’t be up to the mark.
This is why aluminum powder coating is loved by almost all small or large brands worldwide.
Machines We Use
Sunrise Metal has started providing quality surface finishing service to our clients to offer them an all in one solution in our facilities. Our state of the art custom made machines and technologies allow us to deliver flawless finishing for any size of aluminum and other metals.
The machines are completely automatic with robotic arms and advanced technologies. Sunrise Metal’s proprietary and high-end machines are designed to provide you the best result possible for your project.
Now that you have a better understanding of this critical factor, you might be looking for a manufacturer who can meet your requirements and deliver the best result for your project
Sunrise Metal helps small or large OEM? ODM businesses worldwide with all in one aluminum die casting solution. If you have any questions about how to order, what to order, we’ll be more than happy to help you with all your queries.