How to control shrinkage and improve dimensional stability of liquid photopolymer during rapid photopolymerization?
Publish Time: 2026-06-02
Liquid photopolymer, as a core material in photopolymerization molding technology, is widely used in 3D printing, precision mold making, deep relief carving, craft production, and industrial prototyping. Especially in deep relief carving applications, the material not only needs excellent detail rendering capabilities but also needs to maintain good dimensional accuracy and structural stability. Some liquid photopolymers specifically designed for deep relief carving use medium red-toned formulations, which can effectively enhance the contrast of optical pre-mount systems and improve pattern recognition and exposure control accuracy.
1. Optimize Resin Formulation to Reduce Polymerization Shrinkage
The material formulation is a key factor affecting the shrinkage rate of photopolymerization. Under light, monomers and oligomers undergo rapid cross-linking reactions to form a dense three-dimensional network structure, a process often accompanied by volume shrinkage. Therefore, during material development, it is necessary to rationally adjust the resin system composition, increase the proportion of polymer prepolymers, and reduce changes in intermolecular distances during the reaction. Simultaneously, by optimizing the types and contents of functional monomers, the volume change during curing can be reduced, minimizing shrinkage at the source and improving the dimensional stability of the finished product.
2. Controlling Curing Speed for Uniform Reaction
While rapid curing improves production efficiency, excessively fast polymerization can lead to internal stress concentration. When the surface layer of the material cures quickly while the interior remains fluid, shrinkage differences occur between different areas, causing warping and deformation. Therefore, it is necessary to rationally control the exposure energy and curing speed to ensure a more uniform polymerization reaction. By optimizing the light source power, exposure time, and curing path, the material can gradually complete the cross-linking process, reducing local stress accumulation and improving overall dimensional accuracy.
3. Improving Material Flowability to Enhance Stress Release
The flowability of liquid photopolymer before curing also affects the final molding effect. Insufficient material flowability can lead to uneven resin distribution in complex structural areas, resulting in increased differences in local shrinkage rates. Therefore, it is necessary to optimize the resin rheological properties while ensuring molding accuracy, enabling the material to quickly fill detailed areas and distribute evenly. Good flowability helps to naturally release stress during curing, thereby reducing the risk of deformation and improving the contour reproduction of deep relief products.
4. Optimizing Layered Molding Process to Improve Dimensional Consistency
Layered manufacturing is the primary molding method in photopolymer 3D printing and deep relief processing. Inconsistent curing conditions between layers can easily lead to cumulative errors and localized deformation. Therefore, it is necessary to rationally set layer thickness parameters and exposure strategies to ensure stable curing effects for each layer. Simultaneously, optimizing the interlayer bonding process reduces stress concentration caused by differences in curing shrinkage. A uniform and stable layering process not only improves dimensional consistency but also enhances the overall structural strength of the finished product.
5. Reducing Residual Stress Through Post-Curing Processes
After initial molding, some unreacted active groups will continue to cross-link. Improper control of subsequent reaction processes may lead to further dimensional changes. Therefore, a scientific post-curing process is needed to uniformly supplement the curing of the molded part. By rationally controlling the post-curing time and energy input, the internal structure can be gradually stabilized, reducing residual stress levels and improving the long-term dimensional stability and mechanical properties of the product.
6. Strengthening the Coordinated Control of Equipment and Optical Systems
For photosensitive polymers used in deep embossing designs with a medium red tone, one advantage is the ability to enhance the contrast of the optical pre-mounting system and improve pattern recognition accuracy. Therefore, in practical applications, it is also necessary to fully utilize the control capabilities of the optical system. By improving exposure positioning accuracy, optimizing light spot uniformity, and strengthening process monitoring, consistent curing conditions can be ensured across all areas, reducing dimensional errors caused by exposure deviations and further improving product quality.
In summary, liquid photopolymer, through optimizing resin formulation, controlling curing speed, improving material flowability, refining layering processes, perfecting post-curing treatments, and strengthening the coordinated control of the optical system during rapid photopolymerization, can effectively reduce shrinkage and improve dimensional stability. This not only helps enhance the detail and dimensional accuracy of deep relief products but also provides crucial support for the development of high-quality photopolymerization manufacturing technology.
