Introduction
Detailed Explanation of the Curing Characteristics of Various Overmolding Materials
Basic Curing Time
The basic curing time required to achieve a moldable state varies depending on the material’s properties. Generally, hard, soft, or tough materials (such as ABS-like, TPU-like, and PP-like) cure in approximately 60–120 minutes. Transparent parts or special formulations (such as high-heat-resistant grades) require longer curing times of 90–180 minutes due to their slower chemical reactions.
Post-Cure Characteristics
Post-curing involves a long, low-temperature bake after the part is demolded to completely release internal stresses and stabilize material properties.
- Post-Curing Required: All transparent parts (such as PC and PMMA-like materials) and special performance materials (such as high-heat-resistant, flame-retardant, and fiber-reinforced grades) must be post-cured. This is crucial to ensure long-term dimensional stability and achieve the expected performance.
- Optional Post-Curing: Post-curing is optional for general rigid materials (such as ABS and PA-like materials). If the prototype is only used for appearance verification, this step can be omitted. However, if functional testing or dimensional stability is required, post-curing is recommended.
- Post-Curing Not Recommended: Post-curing is generally not recommended for soft or tough materials (such as TPU/TPE and PP/PE-like materials). This is because baking has limited performance benefits and may cause unnecessary shrinkage or warpage.
Basic Production Lead Time
Taking into account the silicone mold production, material curing, and possible post-curing and post-processing time, the lead time for first-part or small-batch production using vacuum casting (remolding) is generally estimated to be 7–12 days. For transparent parts or special materials that require post-curing, lead times may increase by an additional 1-2 days.
Key Concepts
- Curing: This refers to the process in which the two-component PU resin, after being mixed in the mold, undergoes a chemical reaction, transforming from a liquid to a solid state until it is strong enough to be removed from the mold.
- Post-curing: This involves placing the demolded part in an oven and heating it at a specific temperature (typically 60–70°C) for several hours. This process allows the material’s chemical reaction to complete, releasing internal stresses and improving mechanical properties and dimensional stability.
Conclusion
Understanding the material’s curing characteristics is crucial for managing the vacuum casting project schedule. Transparent parts and special performance parts, in particular, require more time in planning because they require post-curing. Confirming material and post-curing requirements with your manufacturing partner early in the project will help you achieve accurate timelines and consistent quality prototypes.

