Definition
The vacuum suction thermal coating testing machine is a type of laboratory equipment used to simulate the coating process. It creates a controlled negative pressure environment on the surface of the substrate to evenly adhere to the coated material, supplemented by a heating function to cure or dry the coating. This equipment is mainly used to evaluate the relationship between coating process parameters and coating performance, and provides an experimental basis for industrial production.
How it works:
The core working principle of the equipment is based on the synergy of vacuum adsorption and heat conduction. The vacuum system generates negative pressure under the substrate, allowing the flexible substrate to adsorb flat to the surface of the heating plate, eliminating wrinkles and bubbles. The coating material is applied to the substrate through a quantitative conveying system and is evenly distributed under negative pressure. Heating systems typically employ electric heating plates or infrared radiation to provide a stable thermal environment for the coating, promoting solvent volatilization or resin curing. The whole process can be accurately set and recorded by the program controller for parameters such as vacuum degree, temperature, and coating speed.
Evaluation methodology
When using this equipment for experiments, it is usually necessary to pay attention to the uniformity of coating thickness, adhesion strength, and surface topography. Coating thickness can be evaluated by measuring multi-point data with a micrometer or optical thickness gauge, calculating the thickness coefficient of variation (CV value) to evaluate uniformity, calculated as: CV = (σ / μ) × 100%, where σ is the standard deviation and μ is the average thickness. The adhesion strength can be quantified by the grid method or tensile test. Surface topography can be observed by optical microscope or profiler. For example, in the field of packaging materials, you can refer to the test specifications for the performance of coating layers in the ISO 283 series of standards.
Analysis of influencing factors
The coating quality is affected by the interaction of multiple parameters. Insufficient vacuum may lead to uneven adsorption of the substrate, resulting in uneven coating thickness. Too high may cause deformation of the substrate. The heating temperature directly affects the curing rate of the coating, and too high a temperature may cause thermal deformation of the substrate or cracking of the coating, while too low may lead to inadequate drying. The coating speed and material viscosity jointly determine the thickness of the wet film, which needs to be adjusted according to the rheological characteristics of the material. Ambient humidity has a significant impact on the drying process of water-based coatings. Substrate surface energy, roughness and other characteristics will also change the coating spreading behavior.
Applications:
The equipment has application value in material research and development and process optimization in many industrial fields. In the field of printed electronics, it is used to prepare functional coatings for conductive inks. In the packaging materials industry, it is used to simulate the production process of barrier coatings or decorative coatings. In the field of new energy, it can be used for the research of coating process of electrode materials. In textile coating treatment, help develop functional textile fabrics. In addition, the device provides a reliable process simulation platform in the development of special materials such as optical films, adhesive tapes, and release papers.
Equipment selection considerations
When selecting the sample, the characteristics and process objectives of the experimental materials should be clarified first. The heating system needs to consider whether the maximum operating temperature, heating rate and temperature control accuracy meet the requirements of material heat treatment. The effective adsorption area and vacuum degree range of the vacuum system should match the size and flatness requirements of the commonly used substrate. The coating head configuration needs to be compatible with the type of coating intended to be used, such as the squeegee type for high-viscosity slurries and the comma roller type for uniform thin coatings. The equipment should have reliable data logging functions to facilitate the traceability of process parameters. In terms of safety, it needs to have overheat protection and vacuum abnormal alarm functions. The size of the equipment needs to be appropriate to the space conditions of the laboratory.