The molding temperature of LCP is high, and due to its different varieties, the melting temperature is within the range of 300-425 ℃. LCP melt has low viscosity and good flowability, similar to olefin plastics. LCP has a very small coefficient of linear expansion and good dimensional stability. The reference for molding processing conditions is: molding temperature of 300-390 ℃; Mold temperature ranges from 100 to 260 ℃; The molding pressure is 7~100MPa, the compression ratio is 2.5~4, and the molding shrinkage rate is 0.1~0.6.

Material barrel temperature

The usual barrel temperature, nozzle temperature, and material melting temperature are shown in the table.

If considering the service life of the screw, the temperature difference between the rear, middle, and front can be reduced. To prevent nozzle drooling, the nozzle temperature can be 10 ℃ lower than the temperature shown in the table. If fluidity is to be improved, the set temperature can be 20 ℃ higher than the temperature shown in the table, but the following situations must be noted.

When reducing the temperature of the material barrel: If the retention time is too long, it will not cause the particles to age in the barrel, nor will it produce corrosive gases. Therefore, a long retention time generally does not cause any major problems. However, if the molding process is interrupted for a long time, please lower the temperature of the material barrel and discard a few molds when molding again.

Mold temperature

The mold temperature for molding LCP plastic raw materials is between 30 ℃ and 150 ℃. But we usually set the mold temperature at around 70 ℃ -110 ℃. In order to shorten the molding cycle, prevent burrs and deformation, a low mold temperature should be selected; If it is required to have stable product dimensions (especially for products used under high temperature conditions), reduce the occurrence of fusion joints, and solve problems such as insufficient filling, a high mold temperature should be selected.

Plasticizing

The rotational speed of the screw is generally 100rpm. If it is a material containing fiberglass or carbon fiberglass (such as A130, A230, etc.), in order to prevent the fiberglass from breaking, we must choose a relatively low speed. In addition, the back pressure should be kept as low as possible. When the temperature of the barrel is set to 300 ℃, the retention time of the material in the barrel has an impact on the mechanical properties and color of the plastic.

Injection pressure and injection speed

The most suitable injection pressure must depend on the material, product shape, mold design (especially sprue, runner, sprue), and other molding conditions. However, LCP has no grade and its melt viscosity is very low, so the injection pressure is lower than that of general thermoplastic resins. Using low pressure at the beginning of molding and gradually increasing the pressure is a good method. Generally, molded products can be molded under injection pressures ranging from 15MPa to 45MPa. In addition, LCP has a relatively fast curing time, so a fast injection speed makes it easier to achieve good results.

Molding cycle

The molding cycle depends on the size, shape, thickness, mold structure, and molding conditions of the molded product. As mentioned above, LCP has good fluidity, so its filling time is relatively short and the curing speed is also relatively fast, so we can obtain a shorter molding cycle. The representative molding cycle is 10-30 seconds.