In the process of material research and development and quality control, the laboratory film coating machine is a basic and key sample preparation equipment. Its core function is to evenly apply the slurry to the surface of the substrate and form a film of specific thickness through a controlled drying process. This process simulates the core process parameters of large-scale coating production, providing R&D personnel with a closed-loop experimental platform from material formulation and rheological properties to final coating performance evaluation. Traditionally, the coating of different substrates such as aluminum foil and copper foil, or the preparation of other functional coatings, often requires multiple equipment to adapt to different substrate characteristics and process windows. Modern modular laboratory coating machines are designed to meet multiple coating needs with highly integrated function units and flexible parameter control.
Regulatory principle
The key to broad applicability lies in precise control of the core variables of the coating process. The coating thickness (Wet Thickness) is mainly determined by the coating gap and the rheological characteristics of the slurry, and for the scraper coating, the theoretical wet film thickness and gap relationship can be approximately expressed as:
h ≈ k · g
where h is the thickness of the wet film, g is the coating gap, and k is the correction coefficient related to the characteristics of the slurry and the coating speed. The device realizes the control of this parameter through a high-precision micron-level gap adjustment mechanism.
Coating speed directly affects the shear rate and drying kinetics, which is the key to affecting the uniformity and microstructure of the coating. The drying temperature and wind speed should be programmed according to the boiling point of the solvent, the heat resistance of the substrate, and the curing requirements of the coating to avoid surface defects (such as orange peel and cracks).
Adaptability to different substrates and slurries
As common current collector substrates, aluminum foil and copper foil have different surface energy, roughness and mechanical strength. Copper foil is softer and prone to scratches. To do this, the equipment must have:
1. Substrate tension adaptive control system: maintains constant and adjustable microtension during unwinding and winding to prevent wrinkling or tensile deformation of the soft foil.
2. Multifunctional Coating Head Module: Quickly change scrapers, wire rods, or slit coating heads to accommodate different rheological systems, from high-solids, high-viscosity electrode slurries to low-viscosity functional coatings.
3. Temperature-controlled platform: The substrate preheating platform can improve the spreadability of the slurry on low surface energy substrates; The post-coating drying section adopts multi-stage independent temperature zone control to meet the needs of gradient drying process.
Process development
This equipment is mainly used in process development to establish a "recipe-process-performance" database. By systematically changing the coating speed, clearance, drying temperature and other parameters, a series of samples were prepared, and the thickness uniformity, areal density, bond strength, conductivity and microscopic morphology of the coating could be correlated with the subsequent test coating. The following table lists some of the key adjustable parameters and their impacts:
| Adjustable parameters | Main Affected Objects |
| Coating gaps | Wet film thickness, areal density |
| Coating speed | Shear thinning effect, production efficiency |
| Drying temperature curve | Solvent volatilization rate, coating porosity |
| Substrate tension | Coating flatness, substrate deformation |
In terms of quality control, the equipment can be used to simulate production line processes, quickly verify the suitability of incoming slurries, or provide benchmark samples for product standard development.
Summary
Integrated, intelligent laboratory film coaters, through their wide process adjustment capabilities and modular design, truly provide an efficient and consistent solution for laboratory preparation from aluminum foil and copper foil electrode sheets to a variety of functional films. It shortens the path from laboratory R&D to pilot production, allowing researchers to focus more on the innovation and optimization of the material system itself. In the future, with the integration of auxiliary systems such as online thickness measurement and machine vision defect detection, its experimental accuracy and data output capabilities will be further improved.