How to reduce internal stress accumulation and avoid warping in thick-plate design using liquid photopolymer?
Publish Time: 2026-05-29
In the corrugated board printing and flexographic plate making fields, liquid photopolymer is widely used in the manufacture of thick photosensitive resin plates due to its excellent formability and photosensitive curing properties. This type of thick plate structure provides higher pressure resistance and longer service life in practical applications, especially suitable for large-area image transfer and high-speed printing.
1. Optimize layered curing process to reduce volume shrinkage stress
During the UV curing process of thick photosensitive resin, there is often a phenomenon of "surface layer curing first, interior layer curing later." This curing gradient easily leads to uneven volume shrinkage, resulting in internal stress accumulation. By adopting layered exposure and gradient curing processes, the resin can react uniformly layer by layer, reducing instantaneous shrinkage differences. At the same time, rationally controlling the exposure energy of each layer makes the curing reaction more gradual, helping to reduce internal structural stress concentration and reducing the risk of warping from the source.
2. Optimize the formulation system to improve the material's internal stress release capability
The formulation design of liquid photopolymer has a significant impact on its stress state after curing. Introducing flexible segments or low-shrinkage monomers into the resin system can improve the material's stress buffering capacity, giving it a certain deformation absorption capacity during curing. Furthermore, adjusting the crosslinking density allows the material to maintain strength while possessing appropriate flexibility, facilitating the uniform release of internal stress and reducing the probability of structural deformation.
3. Improving Molds and Support Structures to Enhance Dimensional Stability
In thick-plate molding, the flatness and rigidity of the supporting substrate have a significant impact on the final product's shape. Even minor deformations in the substrate will be amplified into overall warping during curing. Therefore, using high-rigidity substrate materials and optimizing the mold support structure can effectively improve overall flatness. Simultaneously, adding a pressure-equalizing structure to the design ensures more uniform stress distribution during resin curing, contributing to dimensional stability.
4. Controlling Curing Temperature and Environmental Conditions to Reduce Thermal Stress
The UV curing process involves not only photochemical reactions but also certain thermal effects. Excessively high curing temperatures or uneven heat dissipation can lead to thermal gradients within the material, exacerbating stress accumulation. Therefore, during production, the ambient temperature should be strictly controlled, and heat dissipation conditions optimized to maintain a relatively stable thermal environment during curing, thereby reducing the impact of thermal stress on structural stability.
5. Optimize Post-Processing to Promote Stress Release and Balance
After curing, appropriate post-processing techniques, such as slow post-curing or phased static treatment, can gradually release residual stress within the material. This process helps the material structure transition from a non-equilibrium state to a stable state, further reducing the risk of warping. Simultaneously, by rationally controlling the post-processing time, the long-term dimensional stability and reliability of the printing plate can be improved.
The internal stress and deformation problems generated by liquid photopolymer in thick plate structure design essentially stem from the non-uniformity of the curing process and the shrinkage characteristics of the material structure. By optimizing the layered curing process, improving the formulation system, enhancing the substrate support performance, controlling the thermal environment, and perfecting the post-processing procedures, the accumulation of internal stress can be effectively reduced, and deformation and warping can be avoided.
