What are the basic conditions of injection molding
What are the basic conditions of injection molding
1. Close molding pressure: in principle, the total pressure should be greater than that of the plastic injection mould. 2. The pressure and speed have some of the same relationship in the mold. Objective to get the raw material into the mold evenly, thoroughly and evenly. Too low can be short shot, shrink, too high have hair head, overstuffed, sticky mold, burn, vulnerable die and internal stress higher bad phenomena. 3. Speed: the fast and slow decision of the material in the mold runner and the finished product, quick to have the edge, overfull, charred, slow the appearance of short shot, shrinkage, the combination of bad and easy to break, etc. 4. Temperature: the raw materials are different, the temperature is different, the color of the solution is not uniform and the internal stress of finished products increases. Because the temperature overpressurization is too high, may cause the screw to break, too high, the product has the edge, also because the cooling produces the temperature difference, causes shrinkage. Raw materials can be decomposed, yellowed, discolored and easily broken. The cooling time becomes longer, the gas is not easy to expel, there will be gas. 5. Back pressure: back pressure is called back pressure when the screw is rotating. It makes the material more tightly in the conveying compression. Can make the air of raw materials, water from the screw back. The composition of the gas that does not affect the surface of the finished product. Low can have bubbles, surface silver. High overheat, lumps, spillage, long cycle, screw not back. It is also important to pull back the same time: when the back is down, some of the raw materials are to be pulled back, while others are not needed (according to the raw materials of various properties). When the back pressure is high, be sure to check out and pay attention to the distance between the air and the non-spillway. 6. The length of the mold temperature and the cooling time will affect the mold of the finished product, shrinkage, dimensional tolerance, surface brightness, period, etc., and should be adjusted according to the actual situation. Press the pressure, the PC should have the mold temperature when the finished meat is thick, won't produce the bubble and the stress.
