Powder painting is often the final stage in the production of a variety of things: from metal structures to decorative elements. And although, in general, painting is an insignificant share in the total cost of a product, its high quality, as a result, affects the final appearance and the desire or unwillingness to buy certain products.
The concept of painting quality is conventionally divided into aesthetic and functional components. What does it mean? Powder coating is always about the beauty and protection of the product. Ideally, both should be flawless.
The aesthetic component is a subjective indicator. It depends on the tastes of clients and the imagination of designers. And with powder paints, you can get a coating of any color and texture, with varying degrees of gloss or dullness. The appearance of the paint depends on the quality of pigments, resins, fillers and additives that must be included in the powder.
The functional component is about the protective functions, durability, resistance to chemical and mechanical influences of the coating. These indicators depend on adhesion – the bond strength of the coating and the surface. In turn, adhesion will be good only under the condition of high-quality preparation of the product and the normal ability of the paint to melt evenly.
It is best when the painted product has both ideal characteristics. However, depending on the needs of the client, something can be sacrificed to make the production economically viable.
Why we need to monitor the quality indicators of powder coating
It is necessary to control the process of applying the powder and the quality of the final coating in order to be able to guarantee strict compliance with the technical requirements of the paint and ensure all the necessary properties. If deviations are identified in time and promptly corrected, production can minimize possible losses.
The quality of painting is one of the important factors in the competitiveness of production. The topcoat must meet the requirements of potential customers in order for the product to be in demand. And the first thing a manufacturer should do is to carefully study his client, understand his needs and his requirements for coverage.
Determining the quality of a powder coating is always quite subjective. What a client of one manufacturer can accept will never suit another’s client. From this, production should form its own criteria for the quality of powder coating.
In order for the coating of parts to be cost effective, you need to record specific indicators for gloss and color on a daily basis, describe defects that may be acceptable, hardness, etc. – all that affect the final appearance.
And in accordance with what the client requires from the product, it is worth optimizing production. For example, if a customer can easily accept a coating with small inaccuracies, it would be economically disadvantageous to try to make it perfect. After all, when the quality exceeds the customer’s requirements, the cost of the product increases, and the manufacturer’s profit decreases. However, you need to be careful, because if the quality is lower than the customer’s expectations, the product may not be needed by anyone. And then the production bears serious losses.
That is why it is necessary to conduct daily analytics, record all indicators and accurately understand the needs of the client. Then the buyer will be satisfied and the manufacturer will have good profits
What properties of the powder need to be controlled
Manufacturing that uses powder paint must control the material, the application process and the finished coating
Having received a batch of powder, you need to check:
- particle size distribution
The particle size distribution of the powder particles determines the efficiency of material application, the smoothness of the final coating and the efficiency of distribution in the cyclone.
This indicator is especially important when a thin layer of coating is applied.
To control this indicator, laser diffraction or sieve analysis is used. The first one is more accurate and faster, it is done automatically. Works by analyzing the diffraction scattering of a laser beam. This option is suitable for large particles, over 70-80 microns.
The second is slower and depends on the person. Occurs by measuring whole powder. Suitable for particles over 80 and 125 microns.
Powder paint consumption depends on density. The real density of the powder material is determined by an automatic gas pycnometer or liquid pycnometer.
This indicator affects the property of the powder to combine with air and form a mobile mixture, and charge well to completely settle on the surface of the product.
This indicator is measured in special installations Sames.
The optimal fluidization value is 130-170 units.
The final result is also influenced by the quality of the polymerization. You can neither overexpose, nor remove the product earlier. Before applying the powder, it is imperative to check all indicators.
Can the quality of the coating be made even better
When the standard powder coating quality does not suit you, you should go for the perfect quality. What you can do:
- Make changes to the chemical surface preparation with the formation of a protective conversion layer. Substitute the newest and highest quality substances on the market. Check with paint manufacturers, innovations can be made in the pre-preparation of the product.
- Use quality raw materials. Carefully study the composition, demand quality certificates and clearly select the appropriate type of paint for each specific application.
- Follow the recommendations for the thickness of the powder layer. Try applying a primer before painting or clear varnish after.
- Equip your production with modern facilities. Make sure everything is in order.
The quality of preliminary preparation, adhesion, degree of approval, film thickness are indicators that are monitored and regulated. Therefore, experiment and track the results, seek help from specialists.
Thus, you will constantly improve the quality of your products and remain competitive in the market.