Therefore, you should first determine what’s the capacity of the PET bottles (500ML, 1000ML or 2L) you want to produce. The weight, stretch and transparency of the preform will affect the bottle quality. The PET preform is the foundation of the bottle.
PET preform-PET injection molding machine We can provide you with the entire PET preform and bottle production line solution - Custom Design Injection Molding Line Set Up.ġ. The first process is to manufacture the PET preform by an injection molding machine, and the second step is to blow molding into a bottle shape by a blow molding machine. PET bottles are made through two key steps and two different processes.
#Pet preform mold how to
However do you know how to make these PET bottles? The mold temperature is low and uniform.In our daily life, we can see mineral water bottles, drinks bottles and other bottles anywhere. If you need PET preforms very clear, make sure the preforms cooling fast, the mold temperature as low as possible and most uniform. Or it will cause the PET preform got whiten or looks like fog in it. ⑵Make sure the mold temperature and material drying and melting temperature is reasonable. ⑴DO NOT add too much recycled material(less than 20%), otherwise it is easy to cause “bridging” at the feeding place and materials will be struck below the hopper. If the downtime is less than 15 minutes, just empty the melted materials in the barrel will be okay But if it more than 15 minutes, please put some viscosity PE in the hopper and shot out all the PET material out and let the PE in the barrel, and reduce the barrel`s heating temperature to PE temperature until it is turned on again. Make sure the heating temperatures of PET raw material is below 300☌ all the time.
Just try your best to avoid long residence time to prevent the PET material molecular weight dropped down. Residence Time or Stop Time of PET Preform Making Production Line We normally not use backpressure during the PET preform injection molding process.ħ. PET Preform Injection Molding Backpressure Just make sure the injection time within 4 seconds should be good.Ħ. But it will cause too big molecular stress and the preform will be whitened and getting fragile if the injection speed is too fast. Normally, we prefer to have a high injection speed to prevent premature solidification during the injection process. Injection speed for PET Preform Injection Molding The temperature ranges is normally from 270-295℃, and the enhanced GF-PET can be set at 290-315℃.ĥ. It is set with injection molding machines nozzle temperature or by the main runner temperature of the PET preform mold. Here we talk about the PET injection molding temperature is about the melting temperature mostly. PET Preform Injection Molding Temperature The exhaust must be sufficient to avoid local overheating or chipping, but the depth of the exhaust port should generally not exceed 0.03mm, otherwise it is easy to produce flash.Ĥ. The thickness of which is about 12mm, and the heat shield must be able to withstand high pressure. It is better to have a heat shield between the PET preform mold and the PET injection molding machine platens. PET preforms are generally molded by hot runner molds. Please click the following link to learn more about how to pick the right PET Preform Making Machine. Since PET has a short stable time around the melting point and high melting point, it is necessary to choose an injection molding system with more temperature control sections and less self-friction heat generation during plasticization, and the actual weight of the product (including PET preforms` tails) cannot be less than the machine injection 2/3 of the amount. How to Selection a Right PET Preform Injection Molding Machine The proportion of recycled materials should generally not exceed 20%, and the recycled materials must be thoroughly dried.Ģ. The air shot method can be used to check whether the material is completely dry. The drying temperature is 150☌ for more than 4 hours, generally 170☌ for 3-4 hours. Because of this, the materials must be dried before processing. When the moisture content exceeds the limit, the molecular weight of PET decreases during processing, and the product becomes colored and brittle. Processing of PET Material before Injection Moldingīecause PET macromolecules contain fat bases and have certain hydrophilicity, pellets are more sensitive to water at high temperatures. Therefore, We mostly adjust the injection pressure to change the fluidity of the melted PET material.ġ. PET has better rheology in the molten state, and the pressure has a greater effect on viscosity than temperature. At present, GF-PET is the most used by customers, mainly for bottle preforms. The chemical name of PET is polyethylene terephthalate, also known as polyester. Key Technologies for PET Preform Injection Molding
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