Many engineers look for theoretical formulas to predict dip coating thickness. While equations like the Landau-Levich model give a good estimate, real-world results often miss the mark. Let’s look at how thickness is calculated, why reality differs from theory, and how to get the exact thickness you want.
1. The Basics of Thickness Calculations
Three main factors decide your film thickness: liquid viscosity, withdrawal speed, and surface tension. A simple rule of thumb from the Landau-Levich equation:
簡単な法則
- Faster pull = Thicker film.
- Slower pull = Thinner film.
- Higher viscosity = Thicker film.
2. Why Don’t Calculations Work Perfectly?
In the real world, things get messy.
- Solvent Evaporation
As the part comes out, the solvent evaporates. This changes the liquid’s viscosity in real time. - Equipment Vibration
Tiny motor vibrations shake the liquid surface, causing uneven thickness. - Dripping
Gravity pulls the liquid down after it leaves the tank.
3. How to Get Precise Control
Formulas are just a starting point. To get things right, you have to adjust the actual machine. This is why precise speed control is everything. If your math says you need a specific speed, your machine has to maintain that speed flawlessly. SDI’s dip coaters control speed down to 1 nm/sec (one nanometer per second). By removing vibration and holding exact speeds, you can match your real-world results to your theoretical calculations.
Summary
Math is the first step, but machine quality decides the final result. If your calculations are right but your films are wrong, we can help. We sell and rent machines, and we also offer Contract Coating services to find the perfect settings for you.
▼ [Useful Tool] Simulate Instantly Online! Simple Film Thickness Calculator
https://www.sdicompany.com/en/dipcoating/thickness-calculator/embed.php