The presence of bubbles in the process of screen printing silicone may affect the printing effect and product quality, so a series of measures need to be taken to eliminate bubbles. The following are some effective ways to eliminate bubbles:
1. Adjust the viscosity of the ink
Dilution with diluent: You can try to dilute the ink to add diluent to reduce its viscosity, stir evenly and let it stand for half an hour, and wait for the bubbles inside to automatically eliminate before using it.
2. Optimize printing operation
Cleaning the surface of the product: Before screen printing, the surface of the product should be cleaned to remove dust and other impurities on the surface.
Adjust the operating environment temperature: Adjust the operating environment temperature to a suitable temperature.
Replace a suitable scraper: Regularly check and replace a suitable screen printing scraper.
Uniform speed printing: Maintain uniform speed printing during printing to reduce the generation of bubbles.
3. Use defoaming agent
Add defoaming agent: If the bubble problem is difficult to solve, you can consider using a screen printing silicone defoaming agent. Defoaming agent can solve the foaming problem in various printing processes. It is simple to operate, has a fast defoaming speed, takes a short time, and uses a small amount, which will not affect and interfere with the production operation process.
4. Adjust the silicone formula and curing process
Appropriately reduce the curing agent: By reducing the amount of curing agent, the curing time of silicone can be extended, which makes it easier for bubbles to float to the surface and then disappear, achieving a smooth finished product.
Adjust the vulcanization temperature: The vulcanization temperature is an important parameter for silicone rubber molding and needs to be set within a suitable range (such as 160~200℃) to avoid bubble problems caused by too low or too high temperature.
Adjust the vulcanization time: The length of the vulcanization time determines whether the thermal conductive silicone sheet can be completely vulcanized. Properly increasing the vulcanization time helps to reduce the generation of bubbles.
5. Use a vacuum machine
Vacuum treatment: Putting the silicone into a vacuum machine can effectively eliminate bubbles. However, this method is costly and is suitable for production scenarios that require high-quality products.
In summary, eliminating bubbles in silk-screen silicone requires multiple aspects, including adjusting ink viscosity, optimizing printing operations, using defoaming agents, adjusting silicone formulas and curing processes, and using vacuum machines. Choose the appropriate method or combine multiple methods according to the specific situation to achieve the best printing effect and product quality.