The injection molding of the plastic thermoforming machine uses the thermophysical properties of the plastic to add the material from the hopper into the barrel. The outside of the barrel is heated by a heating ring to melt the material. The barrel is equipped with a screw driven by an external power motor to rotate. The material is gradually plasticized, melted and homogenized under the double action of screw shearing. When the screw rotates, the material will push the melted material to the head of the screw under the action of the friction force and shearing force of the falling groove. At the same time, the screw retreats under the reaction of the material, so that the head of the screw forms a storage space and completes the plasticization process. Then, under the action of the injection cylinder piston, the screw injects the molten material in the storage chamber through the nozzle at high speed and high pressure. In the cavity of the mold, after the molten material in the cavity has been pressure-maintained, cooled, solidified and shaped, the mold opens the mold under the action of the clamping mechanism, and the shaped product is ejected from the mold through the ejector device.
A mold that uses plastic plates and sheets as raw materials to form some simpler plastic products. In the case of softening, it is deformed and attached to the cavity of the mold to obtain the desired molded product, which is mainly used in the production of some daily necessities, food and toy packaging products.
Due to the low pressure during molding, the mold material is mostly made of cast aluminum or non-metallic materials, and the structure is relatively simple.
Both thermosetting plastics and thermoplastics can be produced by injection molding machines. If thermosetting plastics are produced, the injection molding machine needs to be slightly modified. That is, the nozzle of the injection molding machine needs to be replaced, the nozzle is enlarged, and the backstop ring needs to be replaced. The backstop ring is used to prevent the plastic from flowing back.
Thermoset yellowstone is used very little these days, and I have hardly heard of it. A long time ago, more than ten years ago, I heard that the reflectors of our car lights use that thermosetting plastic, and some bread machines, ovens, etc., also use some thermosetting materials. But it is rarely used now, because many are replaced by thermoplastics.
Thermosetting plastics are cumbersome and expensive. I don't know the price of thermosetting material, but it is definitely more expensive than ordinary PP. Thermosetting plastics cannot be crushed and remolded. If there is a problem with a waste product, it is useless, you smash it, and it cannot be melted again. Thermoplastic, it can be crushed and reused, you can crush it and reuse it, and crush it and reuse it. There are also thermosetting materials, many of which require baking paint and electroplating on the surface. If there is waste, it may be scrapped.
Injection molding machines that produce thermoset materials are generally modified from very old injection molding machines. Because it is easy to produce and does not need debugging, it is heated by a heating rod mold and has no waterway, so it is usually an old machine to be modified to produce thermosetting plastic products.