Infrared pattern based method for inspecting multi-nozzle spraying tools

Multi-nozzle spraying tools are applied in numerous industrial applications, one of the most common being die-casting. To ensure the quality of a cast product and to avoid production downtimes proper functioning is required, e.g. in terms of spray targeting, mass flow, or reproducibility. To enable regular functional controls of a spraying tool, we have developed a specific measuring principle based on monitoring the spray impact on a heated plate using infrared thermography. In this paper, the performance of the developed measuring principle is examined. The study is performed with a typical spraying tool from foundries, it has nine external mixing air-water nozzles, which are freely adjustable in their orientation. During an injection, the spray impacts a heated plate positioned in front of the spraying tool and creates a wetting pattern that is individual to each spraying tool, like a fingerprint. The recorded cooling pattern can be used to determine the position of the individual spray impact areas, the size of the spray impact areas, and the intensity of the cooling. Based on these parameters, conclusions can be drawn about the functionality of the water-bearing lines and the air-bearing lines-as well as the correct alignment of the individual nozzles. The result shows that the presented measuring principle leads to very high precision and reproducibility of the evaluated parameters. Thus, the developed measuring system enables detailed functional tests of complex spraying tools.

Automated summary

This paper examines the performance of a specific measuring principle based on infrared thermography for monitoring the spray impact of a multi-nozzle spraying tool. By analyzing the wetting pattern on a heated plate, the position, size, and intensity of the spray impact areas can be determined, enabling conclusions to be drawn about the alignment of the individual nozzles and the functionality of the water-bearing and air-bearing lines.