Finally again: News from the powder industry

As no attendance events were possible in spring 2021, the period in which the Dresden Powder Symposium normally takes place, due to the lockdown, the 2021 Symposium was held in the fall for the first time. Around 220 participants came to Dresden from September 16 to 17. Even though the event was thus significantly smaller than the previous year, both participants and exhibitors were pleased with how the event went in light of the pandemic circumstances.

The two-day event kicked off with a presentation by TITV Greiz on powder coating in the functionalization of textile surfaces. Current examples include partial powder coatings for textile heaters in the outdoor and hygiene sectors. Electrically conductive or electroluminescent properties are also possible. This is an exciting area of application for powder coatings, which could become significantly more important in the future.

The consideration of environmental protection, sustainability and quality assurance from the perspective of a quality community was the topic of the GSB presentation. High-quality and quality-assured coatings prevent reworking and enable a longer service life. Furthermore, the Filiprüf research project was presented, in which filiform corrosion is considered as an essential evaluation criterion of the quality of a pretreatment. The aim of the project is to develop a reliable test concept for evaluating the tendency to filiform corrosion which will provide reproducible and, above all, laboratory-independent test results. The subject of recycled aluminum was also discussed. In this context, an interlaboratory test showed that coating results and also corrosion protection become increasingly difficult to predict as the proportion of recycled aluminum increases. Coaters must therefore focus more on the substrate alloy.

Henkel dealt with the opportunities and risks of low-temperature cleaning. A classic continuous spraying system served as a calculation example in which, apart from the bath heating, the vapor extraction of around 5000 m³/h and a water requirement of 150 l/h account for the main resource consumption. Calculation models show that temperature reduction can reduce energy use by up to 46 percent. But how does such a temperature reduction affect the growth of microorganisms? Among other things, it became clear that the active baths - even at lower temperatures - are usually not the source of microorganisms at all, but rather the microorganisms are transported forward by cascading from the last sink. In order to reduce the microbial load, the hygiene and hygienic design of the equipment plays a role. However, the use of biostable cleaners is also very effective, as shown by the results of some of the trials presented.

With the E-Line, Wagner presented a new approach to making high-quality application technology more affordable by reducing engineering costs through preassembled systems. Here, the E-Cube, with its edge extraction and flow-optimized sloped transitions in the cover area, hardly influences the powder cloud in the center area of the booth. Also promising is the EEP system, in which turbulence in tube bends is avoided by a special shape of tube angles. This is said to enable energy savings of up to 40 percent. Schürer GmbH, a manufacturer of metal goods from the Erz Mountains, complemented the presentation with its own positive experience regarding the E-Line system concept. Klaus Gazawi from Ruwac appealed in forceful words and pictures not to take dust in powder coating lightly. Furthermore, he showed how poor maintenance can actually turn explosion-proof plant technology into a source of ignition.

Dynamic contour detection without programming effort is obviously becoming more and more interesting for users. Nordson presented its own system, which uses laser scanners to achieve positioning accuracies of +/-1 mm - at production speeds of up to 5 m/min. Offset detection is said to work from 5 mm. Correct measuring was the topic of the manufacturer of coating thickness gauges Dr. Nix. Apart from the presentation of the new generation of coating thickness gauges, the subject of measuring accuracy was dealt with in a pleasingly well-founded manner. Overall, the speaker clearly explained why a multi-digit digital display is no guarantee for the accuracy of the measurement results.

The blast machine manufacturer SciTeeX dealt with the sweeping of zinc with ceramic abrasives and provided economic considerations for the comparison of compressed air blasting with wheel blast machines. For example, the amount of abrasive that can be applied is six times that of compressed air blasting, which means that the achievable area output increases by almost seven times, while energy consumption drops to less than one-third. As a case study, Noppel presented the integration of a powder coating system including multi-metal pretreatment at Uemet GmbH. Since studies show that up to 45 percent of damage to surface coatings is caused by inadequate or incorrect pretreatment, Uemesa commissioned Dr. Herrmann GmbH in advance to determine the optimum pretreatment chemistry.

Low complexity and very good edge protection

This year in Dresden, the global surface technology business unit of BASF's Coatings division, which operates under the Chemetall brand, focused on the topic of sustainability by means of a live survey conducted on site by cell phone. The survey showed that the majority of the companies present consider the topic important, but the statements regarding the importance of the topic for their customers were much more undecided. The new corrosion protection coating developed by Chemetall, which is applied without external current in an immersion process, can make a contribution to this, as it saves up to 40 percent CO2 compared to a classic cathodic dip coating. Although the price of the chemicals per square meter is higher than for a cathodic dip coating, between ten and 15 percent of the costs can be saved in the overall process. This was underpinned by empirical data from Kamp Coating Groep, the first user.

Injector and control system in one

In addition to further developments in application technology, such as improved contour detection systems, Gema presented the OptiStar All-in-One, a new powder conveying unit. It is based on an injector, but offers significantly better control behavior and color change times on a par with a dense phase pump. Read more about this starting on page 18 in this issue.

Corrosion on sea transport - process revised

The reason for optimizing the coating process at fan manufacturer Nicotra Gebhardt was an erroneous sea transport of assemblies designed for indoor use with low corrosion exposure. The seawater atmosphere caused severe edge corrosion - something those responsible did not want to experience a second time. As a result, the goal was for all components coated in a single layer to withstand 720 hours of salt spray testing, and components coated in two layers to withstand 1440 hours. A coating system with particularly high viscosity and barrier effect was therefore required. This was followed by a market analysis of suitable powder coatings and an evaluation of the various barrier-acting systems. Metallic zinc proved to be unsuitable in the powder coatings. Mechanical barriers using Pulverit Endurance platelets - chemically inert, very thin and homogeneously shaped platelets - proved to be particularly advantageous. The new coating system met all expectations and even does not necessarily require mechanical breaking of the edges. Thus, the desired increased safety against corrosion could be achieved.

Invisible flash

With the new SpectralBlue technology, Coatmaster succeeded in reducing the light effect of the well-known and proven gauge by 99.9 percent. The SpectralBlue-IR version, which is also available, is particularly recommended for older flame detector modules. Also highly interesting for many applications is the transition from point-by-point measurement of coating thickness to imaging measurement, which enables a much more comprehensive assessment of the application process and identifies problem areas.

In addition to further case studies, for example from the conveyor technology manufacturer CTI at the trailer manufacturer Prantner in Austria, other presentations dealt with the topic of parts logistics and optimization of system utilization. SLCR Lasertechnik also brought application possibilities for partial cleaning by laser onto the agenda. Last but not least, the possibilities and economic aspects of wastewater treatment by vacuum distillation were presented from different perspectives by H20 and KMU Loft.

Among other things, something for the eye was a presentation by Schlenk on the development and application possibilities of a powder coating that looks confusingly like gold. All in all, the Powder Symposium delivered an interesting and diverse range of topics, even under difficult conditions. Due to this year's fall date, the next Powder Symposium will not take place again until spring 2023. CB