Industry News: Common cracks in the processing and production of resin white embryos
Cracking handicraft factory In the production of white blanks, after the product is demolded for a period of time, the phenomenon of cracking of the product is called cracking. In actual production, there are two types of cracking problems: one is the cracking of the product during demoulding. This problem is caused by slow post-curing of the resin or improper demoulding. The other is the cracks that appear after the product is demolded at the beginning. This situation is very rare, but it is more likely to occur when the product structure is complex. During resin curing, there will be volume shrinkage. At the same time, because resin curing is an exothermic process, there will be thermal expansion and contraction. In both cases, after curing the resin, a relatively large internal Stress, cracks will occur in parts with complex product structure, relatively large dimensional changes, and thin and small parts. To prevent this problem, you should start from the following aspects:
1. Select some resins with higher concentration. Generally speaking, under a certain resin production formula, the resin concentration is higher, the solid content is also higher, and the strength of the products produced will be correspondingly higher.
2. Improve the operation process. We can consider using a resin with a slower curing speed, which can reduce the internal stress of the product and avoid cracks. You can also refer to the partial treatment method to prevent deformation for operation.
(1) For hollow products, air holes are reserved to prevent the product from bursting due to high air pressure due to temperature increase. Products that require back cover can be sealed after the product has cured completely.
(2) Add silicone oil to the mold to increase the elasticity of the silicone mold, so as to prevent the product from being damaged during demoulding due to the rigidity of the mold.
(3) Place reinforcing ribs in the easy-cracking parts, such as: iron wire, bamboo sticks, off-duty fiber wire, etc., to improve its strength.
(4) When designing the product, try to avoid rapid curing of the size, and use smooth transitions in the corners and other places as much as possible to avoid the occurrence of stress concentration.
3. When grouting or brushing FRP, try to make the slurry even.
4. Adding 10% soft resin in the formula can increase the brittleness of the product and reduce the cracking of the product.
5. FRP products can reduce the internal stress of resin shrinkage by laminating warp and weft cross-laying.
6. With the permission of formula and quality, increase the amount of filler appropriately.
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