Definition
A micron-scale adjustable film applicator is a type of laboratory equipment used to prepare a thick, uniform wet or dry film coating on a flat substrate surface. Its core function is to achieve micron-level accurate setting of coating thickness through precise mechanical adjustment, providing a standardized sample preparation basis for subsequent coating performance evaluation.
How it works:
The device is mainly based on the principle of mechanical scraping. Applicators typically consist of a base, precision guides, and adjustable scrapers. The two sides of the scraper are equipped with high-precision adjustment bolts, which can change the gap between the bottom of the scraper and the plane of the substrate by rotating the bolt. When an appropriate amount of liquid sample is placed in front of the scraper and the scraper is pushed at a uniform speed, the sample is scraped into a wet film with a thickness consistent with the set gap value. The theoretical thickness setpoint H can be determined by the mechanical parameters of the adjustment mechanism, usually related to the bolt pitch and rotation angle.
Measurement method
Confirmation of coating thickness is a combination of direct measurement and indirect calculation. Wet film thickness can be read directly from the applicator setpoint, but the final evaluation is usually based on the dry film thickness after curing. Dry film thickness measurement requires the use of a special thickness gauge, such as a contact or non-contact thickness gauge, to measure the average value at multiple locations of the coating. For specific systems, the dry film thickness can also be determined by the known solids content, coating area and dosage, according to the formula:干膜厚度 = (涂料质量 × 固体含量百分比) / (涂层面积 × 涂料密度)Theoretical estimation is carried out and cross-verified with measured values.
Influencing factors
Coating uniformity and thickness accuracy are affected by multiple factors. The operational aspects include the stability of the push speed, the uniformity of the applied pressure, and the flatness of the substrate. In terms of material properties, the rheological properties, viscosity, volatilization rate and wettability of the sample to the substrate will affect the film formation quality. Environmental conditions such as temperature and humidity may alter sample fluidity or drying processes. In addition, the manufacturing accuracy of the applicator itself, the wear state of the knife edge, and the repeatability of the adjustment mechanism are also key factors.
Applications:
This equipment is widely used in industrial R&D and quality control links that require standardized coating preparation. In the coatings industry, it is used to prepare samples for testing the adhesion, hardness, wear resistance and weather resistance of paint films. In the field of electronic materials, it is used to prepare conductive coatings, optical films, or packaging material layers. In paper, textile and composite surface treatment studies, it is used to apply functional coatings to evaluate their performance. At the same time, it is also a common tool for preparing test samples in the research and development of adhesives, inks and some daily chemicals.
Key points of selection
Choosing the right applicator requires a combination of parameters. The thickness range should cover the experimental requirements, with common equipment adjustments ranging from a few microns to hundreds of microns. Adjustment accuracy and repeatability are the core indicators, and attention should be paid to the resolution and stability of the adjustment mechanism. The scraper material should consider its hardness, wear resistance, and chemical compatibility with the sample. The size of the equipment should match the size of the commonly used substrate. In addition, consider whether a multi-tank design is available to meet the needs of preparing multiple parallel samples at once, and whether the base has reliable holding or vacuum adsorption to ensure that the substrate does not displace during coating.