How to judge whether the casting silicone is completely degassed?

How to judge whether the casting silicone is completely degassed?
To judge whether the casting silicone is completely degassed, you can start from the following aspects:
Observe the bubbles
Surface observation: After pouring the mixed and degassed casting silicone into the container or mold, carefully observe the surface of the silicone. If the degassed is thorough, the surface of the silicone should be relatively smooth and flat, with basically no large bubbles visible to the naked eye. If you can see obvious large bubbles attached to the surface, it means that the degassed is not thorough.
Internal observation: Under the condition of sufficient light, observe the inside of the silicone through the transparent or translucent container wall. If the inside of the silicone is uniform and there are no obvious bubbles, or there are only a few very small and difficult to detect bubbles, it can be considered that the degassed is relatively thorough; if you can see that there are more scattered bubbles inside, regardless of size, it means that the degassed is not enough.
Touch feeling
Initial touch: When the silicone is initially cured (not yet completely cured), gently touch its surface. If the surface feels smooth and there are no obvious bubble protrusions or depressions, it means that the degassed situation is good. If you touch it and feel small particles or bulges, it is likely that there are bubbles inside.
Deep pressing: Press the silicone slightly without damaging it. If the silicone is uniform in texture and there is no local softness or gas overflow, it generally means that the degassing is relatively thorough; if you feel a difference in elasticity when pressing, or gas is squeezed out of a certain part, it means that there may be bubbles inside and the degassing is not thorough.
Post-demolding inspection
Mold surface inspection: After the silicone is completely cured and demolded, carefully check the inner surface of the mold. If the surface is smooth and delicate, and there are no traces of bubbles left (such as pits, holes, etc.), it means that the degassing effect is good. If there are many small pits or holes on the surface of the mold, this is because the degassing is not thorough, causing bubbles to remain in the silicone during the curing process.
Copy detail inspection: Take the cast object out of the mold and observe its surface details. If the surface of the object is smooth, the subtle features of the prototype can be clearly reproduced, and there are no defects caused by bubbles, it means that the degassing is thorough; if there are obvious rough areas, holes or missing details on the surface of the object, it is likely that the degassing is not thorough, and the bubbles affect the replication of the prototype by the silicone during the molding process.
With the help of tools
Microscope observation: For some precision casting silicone products with extremely high requirements for bubbles, a microscope can be used to observe the cross-section of the silicone. Under the microscope, it is possible to see more clearly whether there are tiny bubbles inside the silicone. If there are almost no bubbles in the field of view, or only a very small number of tiny bubbles, it can be considered that the degassing is complete; if more tiny bubbles can be seen, the degassing is not up to standard.
Ultrasonic testing: Use ultrasonic testing equipment to test silicone. Ultrasonic waves can penetrate silicone, and when encountering bubbles, they will generate reflection and scattering signals. By analyzing these signals, it can be determined whether there are bubbles inside the silicone and the size and distribution of the bubbles. If the test results show no abnormal signals, it means that the degassing is complete; if there are abnormal signals, it means that there are bubbles and the degassing is not complete.