Parting surface design directly affects the difficulty of mold-making with liquid mold silicone, the smoothness of demolding, and reproduction precision. A reasonable parting surface can reduce the pulling caused by undercuts, lower the risk of mold tearing, and improve finished product dimensional stability. Improper parting surface selection may lead to demolding difficulties, mold misalignment during closing, increased flash, or loss of detail.

When designing the parting surface, priority should be given to observing the position of the workpiece's maximum cross-section. Typically, the parting surface should be set at the position where the workpiece contour changes most and demolding resistance is relatively low. For symmetrical workpieces, center parting can be selected; for asymmetrical workpieces, comprehensive judgment is needed based on undercut distribution, detail orientation, and demolding path. If the workpiece has multiple undercuts, the parting surface should avoid being set at the deepest undercut position to prevent excessive stress during demolding.

The parting surface should also consider mold closing positioning. For two-half molds or multi-piece molds, positioning points, positioning grooves, or positioning pins need to be provided to ensure accurate positioning during mold closing. If mold closing is misaligned, reproduced parts may develop steps, uneven wall thickness, or dimensional deviation. For molds requiring multiple reproductions, the positioning structure should have sufficient stability to avoid loosening after repeated use.

For complex workpieces, multi-piece parting or localized insert structures can be adopted. Multi-piece parting can disperse demolding resistance, suitable for workpieces with complex structures and numerous undercuts; localized inserts can be used to handle fine undercuts or areas difficult to release. However, the more parting pieces there are, the greater the difficulty of mold closing and the risk of flash, so a balance should be struck between demolding convenience and structural complexity.

The parting surface position should also avoid key detail areas. If the parting surface passes through important textures, logos, or precision dimension positions, seam marks may be left at the mold closing location. For reproduced parts with high appearance requirements, the parting surface should be arranged on non-critical surfaces or positions that can be treated subsequently as much as possible.

Liquid mold silicone has elasticity, but this does not mean parting surface design can be neglected. A good parting solution can reduce demolding damage, increase mold reuse count, and lower operational difficulty. Before mold-making, enterprises can first conduct workpiece analysis, and when necessary, make simple models to verify the demolding path before determining the formal parting solution.

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