注塑速度(国外英文资料).docVIP

注塑速度(国外英文资料)The proportional control of injection speed has been widely adopted by injection molding machine manufacturers. Although computer controlled injection speed segmentation control systems have long existed, the advantages of such machine settings are seldom given due to limited data. In this paper, a systematic description is given of the advantages of multi segment velocity injection molding, and its use in eliminating defects such as short shot, trapped gas and shrinkage is outlined. / z* L (Z6, V2, E)3, O6, s ([W, I), K4, CThe close relation between injection speed and product quality makes it become the key parameter of injection molding. The filling speed of segments starting middle end, and to achieve a smooth transition to the set point of another set point, can guarantee the stable speed of melt surface to produce the desired minimum stress molecules asked. We recommend the following principle of this velocity Division: 1) the velocity of the fluid surface should be constant. 2) rapid injection shall be used to prevent melt freezing during injection. 3) the setting of the injection speed should take into account the slowing of the velocity at the point of entry in the critical area such as the runner. 4) the injection speed shall be stopped immediately after the cavity is filled so as to avoid excessive filling, edge breaking and residual stress.The setting of velocity segments must take into account the geometry of the die, other flow limitations and instability factors. The speed setting must have a clear understanding of the injection process and material knowledge, otherwise the quality of the product will be difficult to control. Because the flow velocity of the melt is difficult to be measured directly, it can be calculated indirectly by measuring the screw advance speed or the cavity pressure. ) X6, U#, B4, X9, P8, B%, ^7, DThe material properties is very important, because the polymer may be due to different stress and degradation, increase