Как делают парусные лодки из полиэтилена. Технология ротационного формования

This video uses the following materials: Rotational molding company for plastic products in Ireland STURDI PRODUCTS LTD https://www.sturdyproducts.com/ Distributor of bakery and confectionery equipment in Spain SERMONT https://sermont.es/ Rotational molding company for plastic products in the UK Matrix Polymers https://www.matrixpolymers.com/ The method of forming hollow objects in a rotary mold was invented back in 1855. In progressive Britain at that time, wax and chocolate products were created this way. Incidentally, the very first chocolate eggs were made using this method. With the advent of new polymers and PVC plastisols, rotational molding technology for hollow objects has experienced renewed vigorous development and is now widely used. This method allows for the rapid and high-quality production of polyethylene tanks, automotive parts, and even sailing yachts, with minimal manufacturing costs. Most modern boats are made of plastic using rotational molding. To provide strength without adding excess weight, the boat hull is formed from three layers of polyethylene, each with different properties. The outer layer is made of linear polyethylene, with the highest physical and chemical properties, characterized by high tensile strength. The middle layer consists of voluminous and lightweight polyethylene foam, which increases the thickness of the boat hull without significantly increasing its weight. Finally, to create a smooth interior finish, the final layer is formed from standard general-purpose polyethylene. Before production begins, a specially designed graphic decal with the logo is applied to the mold wall using an adhesive spray. The special graphic is made of plastic and will transfer to the boat wall during the molding process, giving it an attractive design. It will be impossible to peel off or wash off such a logo. Metal reinforcement inserts are attached to the inside of the mold for installing the mast and securing the ropes. During the molding process, the molten polymer will fill the entire space around the metal parts and securely hold them in place, creating a single, strong structure. Next, the first layer of polymer is poured into the mold. This is a powder of super-strong linear polyethylene, which will form the outer layer of the boat. The mold is closed and tightly secured with clamps that are part of its structure. The entire setup, loaded with polymer powder, is moved into a heating chamber, similar to an oven, and begins to rotate. Under the influence of high temperatures, the polyethylene melts and coats the entire inside, forming the boat's hull. Once the first layer is complete, the mold is cooled slightly and removed from the oven to add a portion of foaming polyethylene powder to form the second layer. This time, the mold is not opened, but a special funnel-shaped tool is used to pour in the powder, after which the mold is returned to the oven for a second cycle. The third and final layer is formed similarly to the second, using the same funnel. The mold is then returned to the heating chamber to complete the process. Once all three layers are formed, the mold containing the completed boat hull is gradually cooled, after which the polyethylene crystallizes, giving the product strength. The mold is carefully opened, and the completed boat is removed. The shrinkage of the cooled polymer material allows for easy removal.