1. LCP material processing technology
Focus: LCP material should be dried before use, the temperature is about 150 ℃, the time is about 4 ~ 6 hours, after dehumidification LCP material residual moisture content should be below 0.02%, dew point maintained at -35 ℃.
note: It is recommended to use a vacuum dehumidifier dryer dryer, do not use a general dryer.Dry vacuum dehumidifier can extract the LCP material in the water, and the general dryer can not be fully extracted from the material, it is more difficult to achieve product requirements the quality of.
2. LCP material injection molding process
Molding should pay attention to the following questions:
① using proportional back pressure to feed more accurate and stable;
② large products can use the back pressure, small products back pressure is small;
③ large products if the back pressure is small, the relative density will be smaller, and the surface gloss is poor;
④ high sensitivity injection system and automatic VP (V injection pressure, P holding pressure) conversion function, the product precision and stability, where necessary (for example, products are very sophisticated), it is recommended to install a pressure sensor in the cavity gate, VP switch closer to reality;
nBeer flat product dwell time generally can not be too long, otherwise easily lead to product warpage and stress;
⑥ LCP material in the tube retention time is too long or too much residue easily LCP overheating, the surface of the product bubbles, the general tube melt within 3 seconds to open the mold, the residual amount guaranteed within 5mm;
⑦ If you shut down the machine again when the need to waste injection;
⑧ molding cycle depends on the size of the product, shape, thickness, mold structure and molding conditions. LCP material has good fluidity, so the filling time is relatively short, and crystallization forming faster, so the molding cycle is shorter.
3. LCP material for injection molding machine selection overview
Must choose LCP material dedicated injection molding machine;
Screw need to use the material with better wear resistance;
Screw head use to prevent the structure of the countercurrent;
Need more sophisticated temperature control system;
Nozzle part needs special design;
Feeding and injection reaction system should be sensitive;
Injection tube capacity to pay attention to the weight of products, not too much or too little.
4. LCP material mold process focus
① LCP product mold design is the key, the mold into the plastic mouth should be used ordinary mouth, instead of using hot mouth, hot mouth products easy foaming, that is, the temperature is too high can easily lead to over-products.
② The mold temperature is about 140 ℃, the upper (front) mold temperature should be higher than the lower (rear) mold, the mold temperature is low due to the high liquidity of the upper (front) Products easy crystallization, on (before) (after) mold temperature does not exceed 15 ℃.
③ in the mold temperature options, in order to shorten the molding cycle, to prevent the flash front, should choose a lower mold temperature; if the requirements of the product dimensional stability, reduce the generation of seams and insufficient filling and other issues, you should choose a higher Mold temperature.
Pressure and speed
The most appropriate pressure must depend on the material, the shape of the product, the mold design (especially sprue, runner, gate), and other forming conditions, but the LCP has very low melt viscosities without any grade, so the pressure ratio The average thermoplastic resin is low.
It is a good idea to use a low pressure at the beginning of the molding process and then slowly increase the pressure, which is a good approximation of the molded product under a pressure of 15 MPa-45 MPa. In addition, the LCP has a faster curing time, It is easy to get good results.
6. Molding cycle
The molding cycle depends on the size, shape, thickness, mold structure, and forming conditions of the molded product.As stated above, LCP has good fluidity, so its filling time is relatively short and the curing speed is fast, so we can Resulting in a shorter molding cycle.The typical molding cycle is 10 seconds to 30 seconds.