The Floating Pontoon Dock manufacturer introduced that […]
The Floating Pontoon Dock manufacturer introduced that from the perspective of the heating method of the rotomolding machine, there are currently only two types commonly used, direct fire and hot box heating.
The large-scale products are produced by direct fire heating, that is, the direct-fire heating swing-type rotomolding machine; the production of small and medium-sized products are mostly heated by a hot box. Machine, 3-4 arm tower rotomolding machine, hot box heating'clam' rotomolding machine has developed rapidly in recent years.
Rotational molding is also called rotational molding and rotational casting molding. A thermoplastic hollow molding method. That is, the powder or paste material is first injected into the mold, and the material is uniformly filled and melted in the mold cavity and melted by its own gravity and centrifugal force through heating and vertical and horizontal rolling of the mold. Get hollow products.
In the whole molding process of rotomolding products, the pressure in the mold will be atmospheric pressure. Allow air to enter and exit the mold to achieve pressure balance. Avoid internal materials leaving the mold. Avoid water entering from outside the mold. Maintaining the same internal and external pressure on the mold helps to avoid blow holes in the mold clamping line. Eliminate flash caused by pressure on the mold clamping line. During the cooling stage, the possibility of warpage due to reduced pressure is reduced. Avoid damage to the mold. Polyethylene rotational molding uses silicone oil or silicone resin with excellent heat resistance. Use silicone internal mold release agent, uniformly apply it to the entire surface of the cavity; if using silicone resin mold release agent, then apply the mold release agent evenly, then slowly increase the temperature, The solvent will dissipate, forming a thin resin layer, and then heated and cured at a temperature of 250~280°C for 1~2h to obtain a release layer with a certain strength, after which it can be fed and rotomolded.
The silicone oil-based mold release agent can only be used once after being applied to the mold cavity, and it must be coated once for each subsequent molding, and the use of silicone resin type mold release agent has a prominent advantage, that is, the coated mold release The layer is "semi-*" and can be used multiple times. Since the mold for rotomolding is not affected by external forces, the mold is simple, inexpensive, and easy to manufacture. In addition, the rotomolding equipment also has greater mobility. A rotomolding machine can install a large mold or arrange multiple small chess sets; it can not only mold parts of different sizes, but also at the same time. Products with very different sizes and shapes can be rotomolded at the same time as long as the raw materials used in the rotomolded products are the same and the thickness of the products is the same. Therefore, the rotomolding process has greater flexibility than other molding methods.