E-coating or electro-coating was initially created for the automobile industry, where car manufacturers applied anti-corrosive coating on steel car bodies. Today they serve many industries and steel or metal manufacturing companies that need to add a blend of beauty and protection to their finished products.
Asides from offering a different look, there are several benefits to using e-coating and a few careful processes to follow. In this article, we highlight all of this and more; but first, what is e-coating and why do you need it?
What Is E-coating?
The e-coating process involves immersing a metal product or steel part inside paint emulsion or epoxy and water-based solution. The goal of this delicate process is to stick your paint of choice onto the surface of the metal product for a better look and protection.
With the help of a measure of electric current of voltage from 25 to even 400 during the immersion, the epoxy or paint condensed and shapes over the the metal part. The stronger the voltage, the thicker the coating you get.
E-coating is great for industrial parts that require an even but thin coating to cover a considerably larger surface area like with vehicle body panels. It can be applied to fabrics and plastics and other manufacturing processes where small parts are made in large amount.
Benefits of E-coating
E-coating is popular amongst manufacturers for its environmental and solar benefits, and its superior finishes. But its benefits aren’t limited to these alone, below are some of them:
Protection against Corrosion and Wear-resistantProtection against Corrosion and Wear-resistant
Extra coatings on metals and steel help protect the surfaces from corrosive harm. A rich coating like e-coating is designed to offer more than that. The coated material gets a strong barrier that protects it from moist or extreme environmental factors or substances that can ruin its exterior.
This is the reason why industries, where corrosion protection is non-negotiable, will use e-coating or other options like powder coating. The e-coated product will not be susceptible to heavy impact, abrasion, or even a scratch.
Uniform Coating Thickness
The dissatisfaction with old regular coating methods was the problem of unequal thickness levels. But thanks to e-coating, higher standards are delivering a more controlled and consistent protection layer.
The process of using electrical current during immersion helps the uniformity of the coating material. A consistent uniformity is very important for use cases where accurate e-coating thickness is needed for both appeal and performance.
Aesthetic Appearance
Aside from boosting the performance and durability of a coated product or component, e-coating serves great aesthetic appeal for use cases in several industries where appearance is a factor. There are several color choices to pick from to enhance the visual appeal of the product.
You can add a luxurious look with a silver finish or a mature but simple feel with a black finish depending on what looks best.
Environment Efficiency
E-coating is one of the best environmentally efficient coatings around. The process lowers the reliance on harmful solvents that affect our environment. It is also an efficient way of conserving resources and reducing waste thanks to the inhibitors and deionized water used.
Cost-effective for High Volumes
Buying e-coated goods or parts is a lot more affordable than other alternatives such as electroplated. This is crucial because buying in high volumes for large-scale production is cost-effective.
Diverse Applications
Versatility is another benefit of e-coating and this is thanks to its wide range of industrial and architectural use cases or applications. The paint bath component makes it easier to coat irregular shapes, difficult geometries, and delicate components or parts where different coating requirements are needed.
E-coating is a big part of the electrical appliance industry, automotive manufacturing, heavy machinery industry, aerospace, medical appliance, and marine industries. It also serves the agricultural and architectural landscapes.
Components of E-coating System
The e-coating process is quite simple and involves a few steps followed carefully to make sure the interior and exterior are properly insulated and the colors reflected. Within the processes are important components that play important roles in adding a reliable, attractive, and smooth coating to materials. Below are the main components:
Paint Bath
The paint bath is considered an important and central part of the E-coating process because of the mixtures it holds when immersion is done. It is a large hollow tank that holds the water, chemicals, and paint for the coating process.
It should be large enough to contain varying quantities of liquids and paint particles, depending on the size and volume of materials that are e-coated.
Electrodes
The electrode acts as a conductor to facilitate ample electrical contact between non-metallic components of the E-coating process. They are placed inside the paint bath and will create enough electric fields to attract paint particles towards the substrates, giving the materials uniformity in surface appearance.
Power Supply
Every e-coating process requires a strong and uninterrupted power source and this makes it one of the most crucial components. The power supply available determines how much current is generated towards the coating procedure. Keep in mind that you still need to apply the right voltage level if you want to modify the adhesion and thickness levels of the paint.
Rinsing Station
The rinsing or filtration station does exactly what the name says. It is a simple designated area away from the other components, created to eliminate contaminants and impure parts of the paint bath. A pure and contamination–free paint bath will prevent defects in the coated material and maintain a high and consistent quality in the finished work.
Curing Oven
The curing oven is the final component and step of the e-coating process and it is very important for the long-lasting properties of the finished material. It comes after the material must have been coated and placed in the curing oven.
The heat from the curing oven “cures” the paint or epoxy, boosting its bonding power and durability. This is why e-coated materials do not easily suffer from wear and tear.
Chemicals Used in E-coating
A few chemicals go into the electro-coating process that makes the finished material capable of withstanding harsh conditions. Here are these chemicals below:
Curing Agent
The job of the curing agent is to make sure the resins are hard and solid enough after the e-coating process. The presence of the curing agent makes the material durable and the paint film strong when the e-coat is applied.
Corrosion Inhibitors
The best quality of e-coated material is found in its ability to resist corrosion. The corrosion inhibitor is credited with elongating the life of the finished material no matter the toughness of the environment.
Deionized Water
Deionized water is a variation of clean water wherein most of the ions or dissolved minerals have been reduced or completely. In the e-coating process, deionized water is the primary carrier of the paint particles and it helps maintain the consistency and stability of the solution throughout.
Solvents
Solvents are a great part of the coating process because of how much ease they bring to the process despite evaporating during curing. For the coating process, it helps manage the viscosity of paints so they can be applied easily.
Surfactants
Surfactants make working with paint less tedious. They help you improve how paint particles are distributed or spread across the coated material surface. Without surfactant, the paint may not cover the entire surface and may be uneven in some areas.
Resins
Resins are a vital structural part of the paint film that offer high levels of flexibility and toughness and they come in variations that you can use in the coating process. For instance, acrylic resins are great because of their color stability and how resistant they are to ultraviolet light (UV). Epoxy resins are the more popular choice for their corrosion-resistant qualities.
Pigments
The coated material needs a bit of color and aesthetic appeal and pigments offer this quality. Pigments help to block UV light that might ruin the finish prematurely, keeping the e-coated material lasting longer than regular metal or plastic.
Processes of E-coating
E-coating adds color and vibrancy to the look of a metal. The coating process is a delicate but comprehensive one. Here’s how we break it down:
Pre-treatment
The first stage of the e-coating process is preparing that metal or steel part ahead of coating. This is done by cleaning off any trace of contaminants to avoid improper adhesion. This stage might be the first but it is one of the most important stages because any contamination or pollution of the substrate might lead to defects.
Immersion
The next stage requires the material or components being prepped for coating, to be immersed or dipped into a special electro-coating bath. This bath will contain the necessary chemicals and liquids in the right amount. The liquid is able to form a uniform coat via electrophoretic measures.
Electrophoresis
This stage of the electro-coating process involves passing the material through an electric field. The goal of this stage is to cause the paint particles to spread evenly across the surface being worked on for total coverage.
Post-rinsing
The Post-rinsing stage is a test of the performance and durability of the coated material. It seeks to remove excess paint particles and check for inconsistent or uneven coating on the surfaces. By properly rinsing the material, there are no contaminants left and the material can go for the next and final stage.
Curing
The curing stage is designed to use defined temperatures to create a finish that is durable and strong enough to last long. Without the curing stage, the final coated material might stand the risk of poor adhesion and poor resistance to corrosion.
Types of E-coating
There are different variations of E-coating depending on corrosion resistance levels, color retention, and several other factors. Below are we of them:
Epoxy coating
The epoxy coating primarily uses epoxide based coating instead of paint emulsion. This is because epoxy E-coating is great for components that need plenty of protection from adverse environmental conditions. It also offers great adhesion.
Acrylic coating
Acrylic coating is another type of electro-coating that is great for both the shiny appeal it gives and the glossy retention that stays.
Polyester coating
Polyester E-Coatings are the best affordable choice for most users and they offer a consistent level of durability. There is no compromise on ease in application, corrosion resistance or aesthetic appeals either.
Applications of E-coating
Aerospace
The aerospace industry heavily relies on e-coating for making key structural components and parts. The solutions it offers aren’t just anti-corrosive, they do not disrupt aerodynamics as they are lightweight and can handle different moisture levels.
You can find the most applications of E-coating on the landing gear, hinges, doors, engine, and other parts of airplanes subject to increased stress. These e-coated parts are guaranteed to last several years with proper maintenance and responsible use.
Automotive
The vehicle manufacture industry is another industry where e-coating finds large scale application. e-coating for cars sees the bodies of cars and other small parts coated with electro-coating to safeguard all steel sheet metal components from rust. The fact that is affordable and easy to apply is why it continues to be widely used.
Medical Appliances
E-coated tools or parts are easy to clean and they maintain a high but consistent level of sterility to reduce the risk of spreading pollution or contamination. This is why they are perfect for the medical industry when making medical pieces of equipment, tools, devices, and wheelchairs. These tools are not susceptible to chemicals, corrosion, moisture, or even extreme temperature changes.
Industrial and Architectural Industry
The architectural industry relies on low e-coatings added to glass to lower or reflect the amount of solar heat that a building receives. Also, industrial pieces of equipment and machineries get e-coatings to protect them from wear and tear due to frequent use or pressure-heavy applications.
Marine
Sea and ocean vessels of all shapes and sizes are built with advanced electro-coating processes that are highly resistant to wear from constantly being in saltwater bodies. The aluminum and steel parts of boats and yachts are made from e-coated materials.
Electrical appliances
Manufacturers of electrical appliances leverage e-coating to give a beautiful and sophisticated look to their products. However, it is mostly used in the protection of circuit boards against oxidation and pollution to avoid dangerous cases of short circuits. Washing machines, dishwashers, and refrigerators are some electrical appliances that spot e-coated components.
How Long Does E-coating Last?
Electro-coating is a durable and attractive way to protect your metal, steel, and plastic products against harsh environments and wear. E-coated products can last for years but it also depends on the application and frequency of maintenance carried out.
Compared to other options for preserving and beautifying metal, it is one of few options where coating cuts across several industries that are subject to chemicals, moisture, and salt spray.
For example, jelwery coating ring can last owners several years especially if the wearer takes appropriate care of it. In a car body, thanks to its corrosion-resistant features, an e-coating guarantees more than 1500 hours of resistance against salt spray.
Conclusion
As amazing as e-coating can be, you will only make the most out of it when it’s done properly. HM is one of the leading manufacturers and suppliers of CNC machine parts globally. We have state-of-the-art equipment and facilities that ensure we offer the highest quality of e-coating services for our clients. You can check out our showroom to see some of our products or take a tour of our factory to see our latest workshops, assembly lines, and machines.