What is the tolerance control for the secondary molding of liquid silicone encapsulation? Can we seal the glue?
Liquid Silicone Rubber (LSR) encapsulation secondary molding is a precision manufacturing process that involves injecting liquid silicone rubber onto a pre formed plastic part or other substrate. Tolerance control is crucial for ensuring product quality and performance. Here are some general guidelines on tolerances:
During the encapsulation process, liquid silicone gel is injected or poured onto the substrate that needs to be encapsulated, and after curing, it forms a protective layer or connecting layer. Secondary molding, on the other hand, refers to the injection or casting of liquid silicone gel on top of the existing layer of silicone gel on the substrate to achieve more complex structures or functions.
In this process, tolerance control has become a crucial factor. Excessive tolerance may result in liquid silicone not being able to fully cover the corners or gaps of the substrate, leaving a hidden risk of adhesive leakage; The tolerance is too small, and it may also be difficult to form or cause product deformation due to insufficient fluidity of silicone.
So, what is the tolerance control range for the secondary molding of liquid silicone encapsulation? This actually depends on multiple factors, including the viscosity of silicone, injection or casting pressure, shape and size of the substrate, ambient temperature, etc. But generally speaking, we can consider the following aspects:
1、 Viscosity of silicone gel
The viscosity of silicone directly affects its fluidity. Silicone with low viscosity has good fluidity and is easy to fill the corners and gaps of the substrate, but it is also prone to overflow due to excessive fluidity. Therefore, when choosing silicone, it is necessary to select the appropriate viscosity based on the specific application scenario and requirements.
2、 Pressure for injection or pouring
The pressure of injection or pouring is a key factor affecting the filling effect of silicone gel. If the pressure is too low, silicone may not be able to completely fill the gaps in the substrate; Excessive pressure may lead to silicone overflow or product deformation. Therefore, in practical operation, it is necessary to adjust the injection or pouring pressure reasonably according to factors such as the shape and size of the substrate, the viscosity of the silicone gel, etc.
3、 Shape and size of substrate
The shape and size of the substrate have a direct impact on tolerance control. For substrates with complex shapes and high dimensional accuracy requirements, tolerance control needs to be more stringent. In this case, it may be necessary to use higher precision molds and stricter process control to ensure the filling effect of silicone.
4、 Environmental temperature
The ambient temperature has a significant impact on the curing speed and flowability of silicone gel. In high temperature environments, the curing speed of silicone increases and its flowability decreases, so it is necessary to increase the tolerance appropriately to ensure that silicone can completely fill the substrate. On the contrary, in low-temperature environments, the curing speed of silicone gel slows down and its flowability increases, so it is necessary to reduce the tolerance appropriately to prevent silicone gel from overflowing.
Based on the comprehensive consideration of the above factors, we can derive a rough tolerance control range. However, it should be noted that this is only a reference range and not an absolute standard. In practical operation, flexible adjustments need to be made according to specific situations.
To ensure proper tolerance control of the secondary molding of liquid silicone encapsulation, we can take the following measures:
1. Strengthen raw material testing to ensure that the silicone used meets quality requirements;
2. Regularly maintain and upkeep the mold to ensure its accuracy and stability;
3. Strictly control the pressure and time of injection or pouring to ensure that the silicone can evenly and fully fill the substrate;
4. Strictly control the production environment to ensure that parameters such as temperature and humidity meet production requirements;
5. Strengthen product quality testing, promptly handle and provide feedback on non-conforming products.
Please note that these are only general guiding principles. In the actual production process, adjustments and optimizations should be made based on specific product design, material characteristics, and production processes to achieve the best results. If you need detailed recommendations for specific products, please provide more information for more accurate assistance.
