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    Home > Coatings News > Paints and Coatings Market > PPG's latest technology Why is it so difficult to sharpen the border of metal parts? How do I fix it?

    PPG's latest technology Why is it so difficult to sharpen the border of metal parts? How do I fix it?

    • Last Update: 2020-10-31
    • Source: Internet
    • Author: User
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    PPG Industrial Coatings
    Research, development, production, processing and sales of coatings for automotive, industrial and other fields, and engaged in technical and after-sales service, as well as the import, export and wholesale and retail of similar products.
    This innovative
    technology significantly simplifies the corrosion protection process for heavy equipment and general coating applications, providing excellent corrosion protection for metal parts that are pre-chemically treated only. With just one coating line and one drying, productivity is significantly improved

    .
    sharp edge coating is a huge challenge for the coating industry. Low coating of sharp edges can impair coating performance. Exposing rust or corrosion caused by sharp edges is one of the major defects of the coating. From a manufacturing process and coating or technical point of view, there are a number of solutions to these problems. As far as the manufacturing process is concerned, the sharp edges of the grinding round parts are well known before coating. However, such a scheme would significantly increase manufacturing costs. In the case of coatings, many customers use dual coating systems, but this requires two separate ovens, which increases process complexity. The base coating cannot always be coated to a suitable thickness and may not provide true protection. Although the dry coating method does not require a complex double oven, the effect is not satisfactory. In addition, dry coating is difficult to implement and therefore less popular. Clearly, there is also a need to study innovative ways to improve sharp edge coating.PPG's technical team has developed a new single-layer, high-performance sharp edge protection powder bottomless coating technology that is far more corrosion-resistant than existing single-coated technologies. This article provides an overview of the research and development process of the above-mentioned new technologies.
    the challenge of sharp border
    why is it so difficult for metal sharp border corruption? The reason is that coatings (liquids or powders) flow during curing or drying. The figure above shows the changes in sharp edge coatings after curing.when the coating on the sharp edge shrinks during curing, the coating flows further away from the sharp edge, causing the metal sharp edge to be completely exposed. This is the beginning of the anti-corrosion failure. The challenge, therefore, is to apply the coating to the sharp edge and keep it in place during the curing process. We will address both of these challenges.
    coating of powder coatings to sharp edges
    for powder coatings, the coating process is slightly more complex than common liquid spray products. Special patented additives have been added to the formulation of new powder coating products to improve coating efficiency. As long as the coating parameters are set properly, the powder can stay on the sharp edge without worrying about anti-corona.
    to keep the powder coating in sharp position
    by limiting the fluidity of the coating so that it remains in sharp edge position during curing. If the coating thickness is sufficient, the bottom coating may no longer be required for corrosion protection. We hope to achieve corrosion protection by coating the sharp edges with uniform thickness. Our goal is to apply a coating on the sharp edge that achieves corrosion resistance.
    PPG's early experimental work, focusing on optimizing spray parameters and powder coating formulations. Starting with standard powder coatings, we optimize the fluidity of coatings during curing until we achieve a double-acting balance of appearance and corrosion protection. The image above shows the results of experiments performed in-house by PPG, comparing our high-performance edge protection coating formulations with the corrosion resistance of iron phosphate pre-treated laser cutting plates under a 500-hour neutral salt spray test for conventional coatings.
    image above is another experiment in high-performance sharp edge protection powder coatings. In this experiment, the product was coated on a pre-treated hot-rolled steel plate of iron phosphate and 40 corrosion test cycles were carried out according to THEJ23334 standard. It is worth mentioning that laser cutting hot-rolled steel plate is a kind of substrate with greater anti-corrosion difficulty. This is because in the laser cutting process, sharp edges produce oxides that are not conducive to pre-treatment, which in turn becomes a weak link in corrosion protection. Figure 4 shows our formula products, coated on the sharp edges of laser cutting, passing 40 corrosion test cycles, which is proof of the performance of PPG products. By contrast, conventional coatings have excessive corrosion problems at the sharp edges.
    with the help of the business team, we applied these techniques to the field and achieved excellent field test results. Figure 5 is a photograph of the results of the actual test after 1000 hours of salt spray testing. For faraday cage areas, especially sharp edge positions, our formula significantly reduces corrosion.
    as shown above, the mechanism behind improving corrosion resistance lies in our new powder coating formulation, which significantly increases the coating thickness at the edge position compared to the standard formulation. It is clear from the SEM diagram of the above test piece that the coating thickness of the two formulations is different. As shown in Figure 5, the sharp edge coating thickness reaches 2.5 mils (50um). This thickness level, which avoids the use of the base coating, is attractive to customers who want to reduce process complexity and save costs. Productivity is significantly improved due to the need for only one coating line and one drying.
    above shows the excellent results of the product coating on perforated parts with large jagged burrs. These photos strongly demonstrate that PPG's products are far better than conventional coatings and can be applied to sharp edges while remaining in place during curing.
    addition, we also conducted PPG high-performance edge protection products, compared to the optical effects of conventional coatings. In this test, PPG high-performance sharp edge protection products and conventional coatings are coated on the same parts that have been coated with primers. Optical tests have shown that conventional coatings do not completely cover sharp edges, while our coating products form thicker coating films on sharp edges.our products demonstrate strong performance both internally and during customer field testing, providing excellent corrosion protection for chemically pre-treated metal parts only. This anti-corrosion effect is due to the increase in the thickness of the sharp edge dry coating film. This innovative technology significantly simplifies the corrosion protection process for heavy equipment and general coating applications.
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