Release agent is essential in the production process of hand pasted fiberglass products. So, how can hand pasted fiberglass products be smoothly demolded?
1、 The die structure should be reasonable
The product has no demoulding taper and a large vertical surface. If there is a reverse taper that affects the demoulding of concave and convex parts, a segmented combination mold should be used. If the air pressure method is used for demolding, it can be made into a whole mold.
2、 Selection of release agent
Everyone knows that synthetic resins have good adhesion. Even if the surface of the mold is smooth, it will cause the product to stick to the mold. To achieve good demolding effect, efficient demoulding agents need to be used. If selected improperly, it will not only bring great difficulties to the construction, but also damage the molds and products, directly affecting production quality and efficiency, causing unpredictable losses!
3、 Usage of release agent
1. Manual demolding
The general practice is to strike the mold with a rubber hammer or wooden hammer to partially separate the product from the mold. The separation between the mold and the product can be determined by the sound of tapping. If the sound is empty or light, it has already been separated. After separation, gradually expand the tapping point to expand the separation range. The last section can be separated by prying the product with a tool. When prying, select at the edge of the product where it has been folded. If there are no folded edges, reserve a few folded edges at the edge of the product and separate them before removing them. If the tool is directly inserted into the gap between the product and the mold and pried, it will damage the product and the mold, affecting the service life of the mold and the quality of the product.
2. Mechanical demolding
The commonly used mechanical demolding methods include traction method, pneumatic method, and screw jacking method. Traction method generally uses winches, cranes, etc. to pull products or molds to achieve demolding effect; The air pressure method compresses the compressed air generated by the air compressor into the contact surface between the product and the mold, and uses the expansion force of the compressed air to separate the product from the mold. This is the simplest and most effective demolding method, which can be used regardless of the size of the product, whether it is a male mold or a female mold. It is particularly suitable for cylindrical bodies without demolding taper; Another method is the screw jacking method, which involves installing a screw jacking device on the mold.
The above are all common demolding methods, but during the production process, using the same demolding agent for different products may sometimes result in mold sticking. If conventional methods cannot demold, other methods can be used:
1. Utilizing temperature difference: move the product and mold outdoors and expose them to sunlight. Generally, fiberglass has a slower thermal conductivity, and the fiberglass products on the mold will first expand and then generate internal stress when heated. Then, using a prying method can easily separate them;
2. Use wedges: Insert wooden wedges into the gap between the product and the mold and strike them with a hammer to separate them. Multiple wedges can be used, but they cannot be pried open with objects harder than fiberglass (remember);
3. Cutting and peeling: cutting the product into several parts and peeling them off to ensure the integrity of the mold;
4. Watering: The product has partially detached and is still partially bonded. You can pour water into the gaps and then pry the wedge to separate it; When encountering products with deeper shapes, the buoyancy of water can be used to help separate the product from the mold
Based on the above explanation, it can be concluded that the correct selection of mold release agents and methods is crucial for producing qualified hand pasted fiberglass products!
