Introduction
Coverage is a key performance index in coatings, inks, pigments and other industries, and the traditional evaluation methods mainly rely on the mass method per unit area and the reflectance comparison method. With the advancement of detection technology, the instrumentation upgrade of the two methods has become an important direction to improve measurement accuracy, efficiency and consistency. This paper will discuss the method principle, instrumentation upgrade path and technology comparison.
Overview of the principles of the method
The mass per unit area method is based on uniformly coating the sample onto the specified substrate to achieve the minimum amount required for complete coverage, usually expressed in grams per square meter. The reflectance comparison method evaluates the masking effect by measuring the reflectance ratio of the coating film on the black and white substrate and calculating the contrast ratio. Both methods have a long history of application, but there are many manual steps in traditional operations, which are easy to introduce errors.
Instrumentation upgrade of the mass per unit area method
In traditional operations, steps such as coating, drying, and weighing rely on manual labor, which is less efficient. Instrumentation upgrades integrate automatic coating devices, online thickness monitoring and quality sensing systems to achieve precise control of coating thickness and area. After the upgrade, the system can automatically record the mass per unit area and pass the formulaM = (m₂ - m₁) / ADirect calculation, whichMis the mass per unit area,m₁Withm₂The quality of the substrate before and after coating,Ais the coating area. This upgrade reduces human intervention and improves repetition.
Instrumental upgrade of reflectance contrast method
Traditional reflectance measurements rely on spectrophotometers and manual sample placement, and contrast ratio calculations require measuring reflections on black and white substrates separately. The instrumentation upgrade integrates an automatic sample stage, a multi-angle spectral probe and a real-time data processing module. The system can automatically complete the positioning and measurement of the black and white substrate area according to the formulaCR = R_b / R_w × 100%Calculate the contrast ratio, whichCRfor the contrast ratio,R_bWithR_wThe reflectivity on the blackboard and the whiteboard respectively. The upgrade improves measurement speed and accuracy.
Technical comparison of the two upgrade paths
The upgrade of the quality per unit area method focuses on process automation and quality sensing, which is suitable for scenarios with strict requirements for coating volume. The reflectance comparison method has been upgraded to focus on the automation of optical measurement, and is more suitable for the comprehensive evaluation of color and masking effect. The following table briefly compares the characteristics of the two upgrade paths:
| Upgrade focus | Quality per unit area: automatic coating and quality monitoring |
| Reflectance contrast method: automatic optical measurement and data processing | |
| Applicable standards | Regulations on coating volume in relevant industry standards |
| Regulations on ratios in relevant industry standards | |
| Output parameters | Mass per unit area (grams per square meter) |
| Contrast Ratio (Percentage) | |
| Key benefits: | Directly related to material consumption |
| Intuitively reflect the visual covering effect |
Common technical elements of instrumentation and upgrading
Both upgrade paths rely on precision mechanical control, sensor integration, and software algorithm development. Key elements include: motion control module to ensure positioning accuracy; high-resolution sensors ensure the quality of data collection; Data analysis software realizes real-time calculations and report generation. The integration of these elements enhances the applicability and reliability of the method.
Summary and outlook
The instrumental upgrade of the mass per unit area method and the reflectance comparison method has effectively improved the accuracy and efficiency of the coverage evaluation through automation and intelligent technology. In the future, with the continuous development of sensing technology and data analysis methods, the two methods are expected to be further integrated to form a multi-parameter comprehensive evaluation system to provide more comprehensive support for industry quality control.
References
Determination method of coating covering force, national standard.
Colored paints and varnishes Determination of covering power, international standard.
Application of instrumented testing technology in coating evaluation, industry technical report.