Powder Coatings

The multiple stage chemical pre-treatment normally involves the use of chromates and phosphates by spraying or in submersion. From the environmental point of view, the best option is the one the offers phosphate preparations. The reason is that chromates are toxic to the environment.

The other preparation method is shot-blasting and sandblasting. In this case, you use blasting abrasives to give surface preparation and texture for glass, plastic, and wood. Silicon carbide is ideal for metal grinding and plastic media blasting that utilizes plastic abrasives which are sensitive to the substrates like aluminum.

• Powder Preparation

The widely applied technique is electrostatic spraying through the spray gun. The object is grounded and then the gun imparts a positive electric charge to the powder that is thereafter sprayed and accelerated towards your component by a powerful electrostatic charge.

You heat the component to make the powder melt into a uniform film before it is cooled to make a hard coating. In some cases, you can heat the metal first and then spray your powder on the hot substrate. When you preheat, you will attain a more uniform finishing. However, it can also create other challenges like the runs that the excess powder courses.  You can also use specifically adaptive electrostatic discs to apply the powder.

The other method is what we refer to as the Fluidised Bed method. It entails heating the substrate before you dip it in an aerated and powder-filled bed. The powder will melt and stick on the hot object. However, you will require further heating to finalize the curing of the coat. The method is widely used when your coating exceeds 300 micros.

The other technique is the electrostatic fluidized bed coating. In this approach, you use the same fluidizing techniques like the ones above but with a less amount of powder depth on the bed. Electrostatic charging takes place in the bed so that the powder gets charged as the fluidizing air continues to lift up. Charged powder articles make a cloud of charged powder over the fluid bed. When you pass a grounded part through the charged cloud, it will attract the particles to its surface. The parts are not usually preheated. Electrostatic Magnetic Brush or EMB coating is a coating technique for flat materials that applies powder coating using the roller technique.

• Curing

When you expose thermoset powders to high-temperature increases (usually through an infrared cure oven or a convention), they begin melting, flowing out, and then reacting to form a high molecular weight polymer. The pure process is called cross-linking needs a particular degree of temperature for a specific time period to reach the full cure and also establish complete film properties for which you created the material to perform.

Benefits of Powder Coating

• Environmentally friendly as there are no solvents required
• Coating the metals reduces the emission of volatile organic compounds
• You can apply it on a broad range of thickness
• Rust free
• Exemptional retention of color
• Produces a thicker coating in comparison to the traditional liquid coating
• Produces thick coating without sagging or running
• Is recyclable hence facilitating 100% substance reusability
• A broad range of finishes and colors
• Less operation costs than the liquid lines
• Almost no wastes produced
• Produces less hazardous wastes in comparison to the traditional utilization of the liquid
• Protection against the external UV fading
• Generally, gives 100% solid coating
• Fast turnaround times
• Flexible and tough finishes that make it hard to crack or chip
• Easy to accomplish special effects
• Incredible electric insulation capabilities
• Cost-effective
• Resistance to most solvents and chemicals

Drawbacks of Powder Coating

• Very thin coatings show pinholes
• Can be challenging on sharp corners
• Color uniformity and matching tends to be harder than with the liquid paints
• Need the expertise to maintain thickness uniformity
• Inside corners may have a low film thickness
• Very frequent color changes consume a lot of time

The Powder Coating Equipment

The powder coating equipment is a tool that is used to apply the powder. The equipment does not involve solvents in its processes. It carries out the coating electrooptically before passing it under heat to allow the powder to flow and then form a ‘skin.’ It can either be a thermoplastic or a thermostat polymer. It is generally used to produce a hard finish than the conventional points that were formerly used. The equipment is mainly used in coating metals like aluminum extrusions, household appliances, and bicycle parts among others.

Before you apply powder coatings, it is essential to remove any oils, mud, metal oxides, and lubrication grease among others. There are several chemical methods as well as chemicals that you can use to remove these substances from the metal surface. The method depends on how you will be using the finished product. In the spray application process, the chemical pre-treatments entail using phosphates and chromates. Chromating and phosphating of the substrate take place at multiple stages.

Bonding the powder to the metal entails cleaning in the pre-treating process. The other method to prepare the surface before the coating is sandblasting. It is used for preparation, surface texturing, etching, finishing, and decreasing for products that are made of plastic, glass, and wood. Various powder coatings require alternative preparation methods like abrasive blasting before applying the coat. The online consumption market basically provides blasting services and coupled with their coating solutions increases the costs.

Corona gun or commonly electrostatic gun is used to apply the powder coating on metallic objects. It is good to understand how the electrostatic gun works. It imparts negative electric charges to the powder. Thereafter, the negatively charges powder is sprayed to the grounded object using the compressed or mechanical air spraying equipment. You then accelerate it towards the workpiece using the powerful electrostatic charge. The next step is to heat the object and the powder is melted into a uniform film. The powder is then cooled to produce a hard coating. To achieve a more uniform preheating finish us helpful by challenges can also emerge like runs that are caused by excess powder.

The second type of gun that is used in spraying powder in metallic surfaces is the Tribo gun. First, the triboelectric friction charges the powder, and then charged particles adhere to the grounded substrate. It needs a different powder formulation with regard to the corona gas.

Powder coating is an economical system that completes the desired appearance qualities of the product. It also offers excellent resistance and durability to chemical corrosion and scratches even in the harshest environments. The best company to work on your powder costings is Contract Manufacturing Specialists of Indiana.