During the mold reproduction process, mold silicone rubber frequently encounters issues such as low reproduction counts, surface-dry/interior-wet conditions, and poor tensile strength. The following analysis addresses several typical problems and provides corresponding solutions.

Issue 1: Low Reproduction Count

Cause Analysis: During mold-making, excessive silicone oil is often added, which degrades the molecular weight of the silicone rubber, resulting in low reproduction counts and poor durability. Additionally, improper hardness selection can also cause problems—when making small products with intricate patterns, using high-hardness silicone for mold-making results in a mold that is too brittle and prone to breaking; conversely, when making large products with low-hardness silicone, the mold is too soft, reducing tensile and tear strength, causing deformation and similarly reducing reproduction counts.

Solution: Select silicone with appropriate hardness based on the complexity and size of the product's patterns. Mold silicone rubber itself cannot be classified as simply good or bad—only as suitable or unsuitable. Using silicone with a hardness level matched to the product will effectively prevent such issues.

Issue 2: Surface Dry, Interior Wet

Cause Analysis: Mold silicone rubber is a condensation-cure type, which cures by absorbing moisture from the air. During the mold-making process, if the moisture is evaporated away and an adequate amount is not reintroduced, the surface-dry/interior-wet phenomenon occurs.

Solution: This phenomenon is not a product quality issue but rather a result of inadequate moisture control. When using the silicone, simply add approximately 0.05% water and stir evenly to resolve the problem.

Issue 3: Poor Tensile Strength

Cause Analysis: To reduce the viscosity of the silicone and make it easier to work with, large amounts of silicone oil are added, which softens the silicone considerably, resulting in poor tensile performance, reduced tear strength, and diminished tensile strength—ultimately leading to poor mold durability, short service life, and low reproduction counts.

Solution: It is recommended not to add any silicone oil. If addition is necessary to improve workability, it should not exceed 5%–10%. Controlling the amount of silicone oil added is key to ensuring the mechanical properties of mold silicone rubber.

Summary

The performance of mold silicone rubber is closely related to operational processes. Issues such as low reproduction counts, surface-dry/interior-wet conditions, and poor tensile strength are mostly related to factors including silicone oil addition levels, hardness selection, and moisture control. By standardizing operating procedures, reasonably selecting material hardness, and controlling additive dosages, mold service life and reproduction quality can be effectively improved.