Tips of filling silicone into embossing molds:
Filling speed: Slow and steady.
Use a slow, steady filling method to allow the silicone to flow over the mold surface, gradually penetrating every detail of the pattern (such as the bottoms of grooves and sharp corners). Filling too quickly can cause the silicone to form "waves" on the mold surface, causing localized deformation of the pattern or trapping air due to turbulent flow, forming bubbles (especially in recessed areas of the pattern).
For deep pattern areas (such as the grooves of a 3D relief), inject a small amount of silicone first, wait 10-20 seconds for it to penetrate naturally, and then continue filling other areas. This will prevent silicone from being lost at the bottom of the deep pattern due to insufficient silicone flow. Air Venting: Overcoming Air Traps in Patterns
The patterns of embossing molds (such as cross lines and closed grooves) are "air traps" where air is most likely to be trapped. During filling, observe these areas for air bubbles:
If air bubbles (tiny bubbles or "air lines") are found within the grooves of the pattern, gently vibrate the mold (by hand or on a vibration table) to cause the bubbles to rise to the surface of the silicone and burst.
For molds with complex patterns, pause at 80% filling, let the mold sit for 30 seconds to allow air to escape, and then slowly fill until the cavity is completely covered.
If the mold does not have air vents, create a small gap (0.01-0.03mm) at the highest point or edge of the pattern to act as an air vent (to avoid excessive gaps that may cause flash). Filling volume: Slightly above the surface of the pattern to allow for compression.
Embossing molds typically require mold closing and pressurization (especially during high-temperature vulcanization). When filling, the amount of silicone should be slightly greater than the cavity volume (approximately 10%-15%) to ensure that the silicone completely fills every part of the pattern after mold closing to avoid localized gaps caused by pressure.
Avoid overfilling: Excessive silicone overflow may form flash on the mold parting surface. If this flash connects to the edge of the pattern, it can pull on the pattern during demolding, causing deformation.