Definition
An experimental scraper coating machine is a specialized equipment used to prepare uniform coatings in a laboratory setting. It uses an adjustable scraper system to coat a liquid or paste sample at a preset thickness to the surface of the substrate to form a standardized film layer. This equipment plays a fundamental role in the R&D and quality control of coatings, inks, adhesives, electronic materials and functional films.
How it works:
The experimental scraper coating machine works based on the principle of mechanical scraping. It is mainly composed of precision guide rails, adjustable clearance scrapers, substrate platforms and drive systems. When working, the sample is placed on the substrate, and the squeegee is translated at a constant speed to control the wet film thickness through the gap between the knife edge and the substrate. The clearance height h can be calculated according to the formula h = (V)/(w· L) for theoretical estimation, where V is the sample volume, w is the coating width, and L is the scraping length. The actual film thickness is also affected by the rheological properties of the fluid.
Measurement method
The evaluation of coating performance is completed by system measurement. Wet film thickness can be measured at multiple points using a comb gauge immediately after application. The thickness of the dry film after drying needs to be measured with a micrometer or a non-contact optical profiler. Layer uniformity can be assessed by measuring the thickness at different locations and calculating the coefficient of variation. Adhesion, gloss, hardness and other properties need to be tested on the cured film layer using special instruments according to the corresponding industry standards.
Influencing factors
The quality of the coating is affected by multiple factors. In terms of equipment parameters, scraper clearance accuracy, translation speed stability and substrate platform flatness are the key factors. In terms of material properties, the viscosity, leveling, solids content and thixotropy of the sample directly affect the uniformity of the film layer. In terms of operating conditions, ambient temperature and humidity, substrate surface energy, scraping angle and curing procedure will also play a role in the final film structure. These factors need to be comprehensively controlled in the experimental design.
Applications:
Experimental scraper coating machine is widely used in several industrial research and development fields. In the coatings industry, it is used to prepare samples to test the properties of paint films. In printed electronics, functional coatings are used to prepare conductive inks. In adhesive research, it is used to make uniform adhesive films to test bond properties. In optical film development, it is used to prepare functional coatings with specific thickness requirements. It is also routinely used in laboratories in the fields of battery materials, textile coatings, and food packaging materials.
Key points of selection
Choosing an experimental squeegee coating machine requires considering technical and operational requirements. In terms of technical parameters, attention should be paid to the width range, gap adjustment accuracy, minimum adjustment increment and speed control stability. In terms of functional configuration, it is necessary to consider whether accessories such as heating platforms, vacuum adsorption substrates, or environmental isolation covers are required according to the characteristics of the sample. In terms of operational adaptability, attention should be paid to the compatibility of the equipment with commonly used substrate sizes and the convenience of cleaning and maintenance. Instruments that comply with relevant international standards such as ASTM D823 usually have good method applicability.