Gases often occur in injection molds, which occurs from […]
Gases often occur in injection molds, which occurs from defects?
The air contained in the casting system and the mold cavity; some materials are rich in moisture that has not been removed by boring, and they are vaporized into water vapor at high temperatures; some plastics that are unstable in nature may occur due to too high temperature during injection molding. Differentiated gases occur; some of the additives in the plastic material transpire may be chemically generated by each other.
The reason for the poor exhaustion of the same is also needed to find out quickly. The poor exhaust of the injection mold will bring a series of damages to many aspects such as the quality of the plastic parts. The first embodiment is that the melt will replace the gas in the cavity during the injection molding process, and the melt will be formed if the gas is not discharged in time. Filling is difficult, resulting in a small amount of injection and can not fill the cavity; the poorly cleaned gas collar will form a high pressure in the cavity, and enter the plastic inside under a certain degree of tightening, forming an empty, vent, arrangement and silver, etc. Quality disadvantage
Due to the high degree of compaction of the gas, the temperature in the cavity rises sharply, which causes the surrounding melt to differentiate and bake, which makes the plastic part appear somewhat carbonized and burnt. It is mainly at the junction of the two melts, the flange of the gate; the sweeping of the gas is not smooth, so that the melt velocity entering each cavity is different, so it is easy to form the active and fusion marks, and make the plastic parts The mechanical function is reduced; due to the obstruction of gas in the cavity, the filling speed will be reduced, the molding cycle will be affected, and the tax power will be reduced.
The scattering of bubbles in the plastic part, the bubbles generated by the air accumulated in the cavity are often scattered on the opposite part of the gate; the bubbles which are differentiated or chemically reacted in the plastic material are scattered along the thickness of the plastic part; The bubbles that occur in the residual water vaporization are scattered irregularly on all the plastic parts.