1. LFT introduction: LFT, long fiber reinforced thermoplastic material, English is Long Fiber reinforced Thermoplastics, which is compared with ordinary fiber reinforced thermoplastic materials. Normally, the fiber length in fiber reinforced thermoplastic materials is less than 1 mm. In LFT, the fiber length is generally greater than 2 mm. The current processing technology has been able to keep the fiber length in LFT above 5 mm.
2. LFT composition: LFT (Long Glass Fiber Reinforced Plastic) analysis is based on the micro-spectrum analysis technology, and analyzes the content of each component of the profile through the micro-spectrum, and restores the basic formula. Long fiber reinforced thermoplastic materials are compared with ordinary fiber reinforced thermoplastic materials. The most used matrix resin is PP, followed by PA, and some resins such as PBT, PPS, SAN, etc. are also used. There are many applications of LFT in automobiles, and the main advantage is the flexibility of materials that can be compounded in it.
3. The difference between LFT and SMC: The product manufacturing process of LFT sheet is very similar to the SMC (sheet molding material) in the thermosetting composite glass fiber reinforced plastic. The same is made by pressing a sheet in a mold. LFT is a hard sheet that is heated and softened and then cold-pressed in a mold, while SMC is a cold-pressed soft sheet that is placed in the mold and hot-pressed.
Compared with SMC sheet, the technical performance of LFT sheet has the following advantages:
1) . It is harmless and tasteless, which can improve the working environment.
2) . Lightweight, with a density of only 1~1.2g/cm3.
3) . Leftovers and waste products can be recycled to minimize waste.
4) . The strength is higher than that of SMC, and the impact toughness is particularly outstanding.
5) . Corrosion resistance and electrical performance are better.
6) . The product pressing speed is several times faster than that of SMC, and the production efficiency is greatly improved.
The compression molding mold usually uses a hydraulic press, and the upper and lower parts of the mold are fixed on the press. The mold includes a cavity core, which is the same as an injection mold. The trial material is placed on the opened mold, and then the press is closed. The set temperature and pressure generated by the press melt the raw material into the cavity of the mold.
The test materials for this type of mold are usually SMC, BMC, GMT. Therefore, we often call such molds as SMC molds, BMC molds, and GMT molds.
SMC is a sheet-like reinforced thermoplastic material, usually used for large products, and such products require greater strength.
The BMC material is in the form of lumps, rich in short fibers, has excellent mechanical properties, low shrinkage, and stable color.
The GMT material is a glass fiber reinforced thermoplastic, which can be widely used in various parts of the car body. It can replace traditional metal parts, reduce weight and reduce costs. Unlike injection molds, SMC molds need to be heated rather than cooled. The usual heating methods are steam, oil, electricity, and high-pressure water.
The temperature of the SMC mold is usually between 140 and 160. When designing the temperature system of the mold, special attention should be paid to keeping the temperature of the entire surface of the mold consistent. The uniformity of temperature can reduce deformation, improve dimensional stability, and uniformity of the product surface.
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Post time: Dec-07-2021