Rubber products sometimes have edge bursting during the production process, which not only affects the appearance quality of the product but also may affect its performance and safety.
This article will analyze the causes of edge bursting of rubber products in detail and propose corresponding improvement methods to provide references for related industries.
Analysis of reasons for edge bursting
1. The molding temperature is too high or the upper and lower template temperatures are inconsistent:
Excessive molding temperature or large temperature difference between templates will cause the rubber material to be too fluid during the vulcanization process, and the edge part will burst due to being unable to withstand excessive pressure.
2. Poor exhaust:
Improper exhaust distance setting or too late exhaust time makes it impossible for the gas in the mold to be discharged in time, forming bubbles and bursting during the vulcanization process, resulting in edge bursting.
3. Rapid maturation of rubber:
Improper rubber formula or mixing process makes the rubber partially mature before vulcanization, and the fluidity is enhanced, which is easy to form edge bursting during molding.
4. Irrational mold structure:
The mold design lacks a material runner or has an unreasonable structure, which causes the rubber material to flow poorly in the mold, resulting in stress concentration, which in turn causes edge bursting.
5. Heavy material weight:
The weight of each material discharge exceeds the mold design tolerance range, causing the rubber material to burst due to excessive pressure during the vulcanization process.
6. Material hardness and mold edge problems:
Low-hardness silicone products often cause edge fragmentation due to low material hardness, overly sharp mold edges, or burrs.
Improvement methods
1. Adjust the molding vulcanization temperature:
According to the characteristics of the rubber material and the mold design, reasonably adjust the molding vulcanization temperature to ensure that the upper and lower mold temperatures are consistent to avoid edge bursting caused by excessive temperature.
2. Optimize the exhaust system:
Adjust the exhaust distance and exhaust time to ensure that the gas in the mold can be discharged in time to reduce bubble formation and edge bursting.
3. Improve the rubber formula and mixing process:
Strictly follow the mixing process standards to avoid using rubber that has been stored for too long and ensure that the rubber is in the best condition before vulcanization. For the problem of fast maturation, a special silicone rubber burning delay aid can be added to delay the fluidity of the rubber.
4. Optimize mold design:
Add a material runner to the mold design to improve the flow performance of the rubber material in the mold and reduce stress concentration. At the same time, check whether the mold blade is sharp or has burrs, and round it if necessary.
5. Control the weight of the blanking:
Strictly control the weight of the blanking according to the mold design requirements to avoid overweight and edge bursting.
6. Adjust the material hardness and mold temperature:
For low-hardness silicone products, the molding mold temperature can be appropriately reduced and the vulcanization time can be extended to reduce bubbles and white spots. At the same time, pay attention to the selection and use of silicone glue to ensure that the silicone material can be well attached to the surface of the metal or nylon substrate.
7. Choose high-quality vulcanizers and silicone glue:
Choose vulcanizers and silicone glues with reliable quality to avoid defective products. Appropriately reduce the amount of vulcanizer added to reduce the risk of low-hardness silicone rubber edge bursting.
Conclusion
There are many reasons for the edge bursting of rubber products, but through reasonable process adjustment, mold design, and material selection, this phenomenon can be effectively reduced and avoided. It is hoped that the analysis and suggestions in this article can provide useful references and references for related industries.
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